Unusual Reactivity Mode of Coordinated Oximes: Platinum(IV)-Assisted Ring Closure by Reaction with Acetone

The platinum(II) complexes trans-[PtCl(2)(RR'C=NOH)(2)], where R = R' = Me, RR' = (CH(2))(4) and (CH(2))(5), react with m-chloroperoxybenzoic acid in Me(2)CO to give the platinum(IV) complexes [PtCl(2)(OCMe(2)ON=CRR')(2)] in 50-60% yields. The complexes [PtCl(2)(OCMe(2)ON=CRR')(2)] were characterized by elemental analysis, EI-MS, and IR and Raman spectroscopies; X-ray structure analyses were performed for both trans-[PtCl(2)(OCMe(2)ON=CC(4)H(8))(2)] and trans-[PtCl(2)(OCMe(2)ON=CC(5)H(10))(2)]. The former compound crystallizes in the triclinic space group P&onemacr; with a = 8.088(2) ?, b = 8.327(2) ?, c = 8.475(2) ?, alpha = 103.54(3) degrees, beta = 102.15(3) degrees, gamma = 108.37(3) degrees, V = 501.0(2) ?(3), Z = 1, and rho(calcd) = 1.917 g cm(-)(3). The latter complex crystallizes in the monoclinic space group C2/c with a = 12.5260(10) ?, b = 9.3360(10) ?, c = 18.699(2) ?, beta = 98.320(10) degrees, V = 2163.7(4) ?(3), Z = 4, and rho(calcd) = 1.862 g cm(-)(3). The structures of [PtCl(2)(OCMe(2)ON=CC(4)H(8))(2)] and [PtCl(2)(OCMe(2)ON=CC(5)H(10))(2)] show an octahedron of Pt where two Cl atoms and two chelate ligands are mutually trans, respectively.     

An Approach to Heterometallic Complexes with Selenolate and Tellurolate Ligands: Crystal Structures of cis-[Mn(CO)(4)(SePh)(2)](-), [(CO)(3)Mn(&mgr;-SeMe)(3)Mn(CO)(3)](-), (CO)(4)Mn(&mgr;-TePh)(2)Co(CO)(&mgr;-SePh)(3)Mn(CO)(3), and (CO)(3)Mn(&mgr;-SePh)(3)Fe(CO)(3)

Oxidative addition of diorganyl diselenides to the coordinatively unsaturated, low-valent transition-metal-carbonyl fragment [Mn(CO)(5)](-) produced cis-[Mn(CO)(4)(SeR)(2)](-). The complex cis-[PPN][Mn(CO)(4)(SePh)(2)] crystallized in triclinic space group P&onemacr; with a = 10.892(8) ?, b = 10.992(7) ?, c = 27.021(4) ?, alpha = 101.93(4) degrees, beta = 89.79(5) degrees, gamma = 116.94(5) degrees, V = 2807(3) ?(3), and Z = 2; final R = 0.085 and R(w) = 0.094. Thermolytic transformation of cis-[Mn(CO)(4)(SeMe)(2)](-) to [(CO)(3)Mn(&mgr;-SeMe)(3)Mn(CO)(3)](-) was accomplished in high yield in THF at room temperature. Crystal data for [Na-18-crown-6-ether][(CO)(3)Mn(&mgr;-SeMe)(3)Mn(CO)(3)]: trigonal space group R&thremacr;, a = 13.533(3) ?, c = 32.292(8) ?, V = 5122(2) ?(3), Z = 6, R = 0.042, R(w) = 0.041. Oxidation of Co(2+) to Co(3+) by diphenyl diselenide in the presence of chelating metallo ligands cis-[Mn(CO)(4)(SePh)(2)](-) and cis-[Mn(CO)(4)(TePh)(2)](-), followed by a bezenselenolate ligand rearranging to bridge two metals and a labile carbonyl shift from Mn to Co, led directly to [(CO)(4)Mn(&mgr;-TePh)(2)Co(CO)(&mgr;-SePh)(3)Mn(CO)(3)]. Crystal data: triclinic space group P&onemacr;, a = 11.712(3) ?, b = 12.197(3) ?, c = 15.754(3) ?, alpha = 83.56(2) degrees, beta = 76.13(2) degrees, gamma = 72.69(2) degrees, V = 2083.8(7) ?(3), Z = 2, R = 0.040, R(w) = 0.040. Addition of fac-[Fe(CO)(3)(SePh)(3)](-) to fac-[Mn(CO)(3)(CH(3)CN)(3)](+) resulted in formation of (CO)(3)Mn(&mgr;-SePh)(3)Fe(CO)(3). This neutral heterometallic complex crystallized in monoclinic space group P2(1)/n with a = 8.707(2) ?, b = 17.413(4) ?, c = 17.541(4) ?, beta = 99.72(2) degrees, V = 2621(1) ?(3), and Z = 4; final R = 0.033 and R(w) = 0.030.     

Coordinatively Unsaturated Derivatives of Group 6 Metal Carbonyls Containing the pi-Donating Ligand 3,5-Di-tert-butylcatecholate

The series of group 6 metal tricarbonyl derivatives of di-tert-butylcatecholate have been synthesized from the reactions of M(CO)(5)THF (M = Cr, Mo, W) with 2 equiv of [Et(4)N][3,5-(t)Bu(2)OC(6)H(2)OH]. Subsequent removal of the free catechol was achieved by the addition of NaOMe. The complexes were shown by X-ray crystallography to exhibit coordinatively unsaturated M degrees centers. These metal dianions which have formally 16e(-) configurations are stabilized by pi-donation from the oxygen atoms of the catecholate ligand. This is evident from the short M-O bond distances, e.g., for M = W, 2.059(6) ? vs 2.151(4) ? for a single bond. The structures of these five-coordinate dianions can be loosely defined as trigonal bipyramidal with the more electron-rich oxygen donor of the catecholate (ortho to the electron-releasing tert-butyl substituent) occupying an equatorial site as indicated by a shorter M-O bond length. The tungsten derivative was shown to reversibly react with CO or phosphines to afford the 18e(-), saturated complexes. Although the molybdenum tricarbonyl derivative reacts with CO to partially provide the tetracarbonyl complex, the analogous process involving chromium did not occur. That is, the formation of an O-->M pi bond vs an additional M-CO bond is favored for M = chromium. Complex 2, [Et(4)N](2)[W(CO)(4)DTBCat], crystallizes in the monoclinic space group P2(1)/c with a = 10.013(5) ?, b = 43.921(14) ?, c = 9.113(4) ?, beta = 115.76(3) degrees, V = 3609(3) ?(3), and d(calc) = 1.429 g/cm(3), for Z = 4. Complex 4, [Et(4)N](2)[Mo(CO)(3)DTBCat], crystallized in the monoclinic space group C2 with a = 18.255(7) ?, b = 8.596(3) ?, c = 22.369(7) ?, beta = 91.05(6) degrees, V = 3510(2) ?(3), and d(calc) = 1.251 g/cm(3), for Z = 4. Similarly, complex 5, [Et(4)N](2)[Cr(CO)(3)DTBCat], crystallized in the monoclinic space group C2 with a = 18.09(2) ?, b = 8.553(3) ?, c = 21.927(11) ?, beta = 91.09(8) degrees, V = 3393(4) ?(3), and d(calc) = 1.208 g/cm(3), for Z = 4.     

Formation and X-ray Structures of PCP Ligand Based Platinum(II) and Palladium(II) Macrocycles

The coordination behavior prior to C-M bond formation of the chelating aromatic PCP substrate DPPMH (3; DPPMH = 1,3-bis((diphenylphosphino)methylene)mesitylene) has been studied in order to determine the factors which control the complex formation of such ligands. Reacting 3 with (RCN)(2)MCl(2) (R = Me, Ph; M = Pd, Pt) and (COD)PtX(2) (X = Cl, Me; COD = 1,5-cyclooctadiene) resulted in the formation of several 8- and 16-membered mono- and binuclear palladium(II) and platinum(II) macrocycles: trans-[(DPPMH)PdCl(2)](2) (5), trans-[(DPPMH)PtCl(2)](2) (6), cis-(DPPMH)PtCl(2) (7), cis-(DPPMH)PtMe(2) (8), and cis-[(DPPMH)PtMe(2)](2) (9). Compounds 5-9 were fully characterized using NMR, FAB-MS, FD-MS, elemental analysis, and X-ray crystallography. Thermolysis of the bimetallic trans-[(DPPMH)PtCl(2)](2) (6) results in the formation of the monomeric cis-(DPPMH)PtCl(2) (7). The product formation depends on the neutral- (nitriles or COD) and anionic ligands (Cl and CH(3)) of the metal precursor. The molecular structures of trans-[(DPPMH)PdCl(2)](2) (5) and cis-[(DPPMH)PtMe(2)](2) (9) have been determined by complete single-crystal diffraction studies. Crystal data for 5: monoclinic, space group P2(1)/n with a = 14.547(3) ?, b = 17.431(4) ?, c = 27.839 (5) ?, beta = 99.56(2) degrees, V = 6961(3) ?(3), and Z = 4. The structure converged to R = 0.048 and R(w) = 0.049. Crystal data for 9: monoclinic, space group P2(1)/n with a = 19.187(4) ?, b = 19.189(4) ? c = 20.705(2) ?, beta = 103.41(3) degrees, V = 7415(3) ?(3), and Z = 4. The structure refinement converged to R = 0.0977 and R(w) = 0.2212.     

cis-Bis(bipyridine)ruthenium Imidazole Derivatives: A Spectroscopic, Kinetic, and Structural Study

The ruthenium bis(bipyridine) complexes cis-[Ru(bpy)(2)Im(OH(2))](2+), cis-[Ru(bpy)(2)(Im)(2)](2+), cis-[Ru(bpy)(2)(N-Im)(2)](2+), cis-[Ru(dmbpy)(2)Im(OH(2))](2+), cis-[Ru(dmbpy)(2)(N-Im)(OH(2))](2+)(bpy = 2,2'-bipyridine, dmbpy = 4,4'-dimethyl-2,2'-bipyridine, Im = imidazole, N-Im = N-methylimidazole), have been synthesized under ambient conditions in aqueous solution (pH 7). Their electrochemical and spectroscopic properties, absorption, emission, and lifetimes were determined and compared. The substitution kinetics of the cis-[Ru(bpy)(2)Im(OH(2))](2+) complexes show slower rates and have lower affinities for imidazole ligands than the corresponding cis-[Ru(NH(3))(4)Im(OH(2))](2+) complexes. The crystal structures of the monoclinic cis-[Ru(bpy)(2)(Im)(2)](BF(4))(2), space group = P2(1)/a, Z = 4, a = 11.344(1) ?, b = 17.499(3) ?, c = 15.114(3) ?, and beta = 100.17(1) degrees, and triclinic cis-[Ru(bpy)(2)(N-Im)(H(2)O)](CF(3)COO)(2).H(2)O, space group = P&onemacr;, Z = 2, a = 10.432(4) ?, b = 11.995(3) ?, c = 13.912(5) ?, alpha = 87.03(3) degrees, beta = 70.28(3) degrees, and gamma = 71.57(2) degrees, complexes show that these molecules crystallize as complexes of octahedral Ru(II) to two bidentate bipyridine ligands with two imidazole ligands or a water and an N-methylimidazole ligand cis to each other. The importance of these molecules is associated with their frequent use in the modification of proteins at histidine residues and in comparisons of the modified protein derivatives with these small molecule analogs.     

Heteroleptic Lanthanide Complexes with Aryloxide Ligands. Synthesis and Structural Characterization of Divalent and Trivalent Samarium Aryloxide/Halide and Aryloxide/Cyclopentadienide Complexes

Synthesis of a new class of heteroleptic samarium aryloxide complexes has been achieved by the use of homoleptic samarium(II) bis(aryloxide) Sm(OAr)(2)(THF)(3) (1, Ar = C(6)H(2)Bu(t)(2)-2,6-Me-4) as a starting material, which is easily obtained by reaction of Sm(N(SiMe(3))(2))(2)(THF)(2) with 2 equiv of ArOH in THF. 1 reacts with 1 equiv of SmI(2) in THF to give Sm(II) mixed aryloxide/iodide [(ArO)Sm(&mgr;-I)(THF)(3)](2) (2), which adopts a dimeric structure via very weak Sm.I (3.534(2) ?) interactions. Reaction of 2 with C(5)Me(5)K in THF/HMPA affords the corresponding Sm(II) aryloxide/cyclopentadienide (C(5)Me(5))Sm(OAr)(HMPA)(2) (3). Oxidation of 1 with 0.5 equiv of I(2) in THF gives monomeric samarium(III) aryloxide/iodide (ArO)(2)SmI(THF)(2) (4), while the similar reaction of 1 with ClCH(2)CH(2)Cl or (t)BuCl in THF affords dimeric samarium(III) aryloxide/chloride [(ArO)(2)Sm(&mgr;-Cl)(THF)](2) (5). Crystal data for 1: monoclinic, space group P2(1), a = 9.903(3) ?, b = 16.718(5) ?, c = 13.267(2) ?, beta = 95.17(2) degrees, V = 2187(2) ?(3), Z = 2, D(c) = 1.223 g cm(-)(3), R = 0.0634. Crystal data for 2.2THF: monoclinic, space group P2(1)/a, a = 18.330(6) ?, b = 14.320(4) ?, c = 13.949(3) ?, beta = 103.16(2) degrees, V = 3563(2) ?(3), Z = 2, D(c) = 1.46 g cm(-)(3), R = 0.0606. Crystal data for 3: triclinic, space group P&onemacr;, a = 10.528(1) ?, b = 12.335(2) ?, c = 19.260(2) ?, alpha = 101.33(1) degrees, beta = 95.230(9) degrees, gamma = 108.54(1) degrees, V = 2293.1(5) ?(3), Z = 2, D(c) = 1.25 g cm(-)(3), R = 0.0358. Crystal data for 4: monoclinic, space group C2/c, a = 17.191(7) ?, b = 10.737(6) ?, c = 21.773(7) ?, beta = 98.80(3) degrees, V = 3971(3) ?(3), Z = 4, D(c) = 1.44 g cm(-)(3), R = 0.0467. Crystal data for 5: monoclinic, space group P2(1)/n, a = 13.750(3) ?, b = 17.231(3) ?, c = 14.973(6) ?, beta = 95.81(2) degrees, V = 3529(2) ?(3), Z = 2, D(c) = 1.31 g cm(-)(3), R = 0.0557.     

Reactivity of rhenium(V) oxo Schiff base complexes with phosphine ligands: rearrangement and reduction reactions

The symmetric rhenium(V) oxo Schiff base complexes trans-[ReO(OH2)(acac2en)]Cl and trans-[ReOCl(acac2pn)], where acac2en and acac2pn are the tetradentate Schiff base ligands N,N'-ethylenebis(acetylacetone) diimine and N,N'-propylenebis(acetylacetone) diimine, respectively, were reacted with monodentate phosphine ligands to yield one of two unique cationic phosphine complexes depending on the ligand backbone length (en vs pn) and the identity of the phosphine ligand. Reduction of the Re(V) oxo core to Re(III) resulted on reaction of trans-[ReO(OH2)(acac2en)]Cl with triphenylphosphine or diethylphenylphosphine to yield a single reduced, disubstituted product of the general type trans-[Re(III)(PR3)2(acac2en)]+. Rather unexpectedly, a similar reaction with the stronger reducing agent triethylphosphine yielded the intramolecularly rearranged, asymmetric cis-[Re(V)O(PEt3)(acac2en)]+ complex. Reactions of trans-[Re(V)O(acac2pn)Cl] with the same phosphine ligands yielded only the rearranged asymmetric cis-[Re(V)O(PR3)(acac2pn)]+ complexes in quantitative yield. The compounds were characterized using standard spectroscopic methods, elemental analyses, cyclic voltammetry, and single-crystal X-ray diffraction. The crystallographic data for the structures reported are as follows: trans-[Re(III)(PPh3)2(acac2en)]PF6 (H48C48N2O2P2Re.PF6), 1, triclinic (P), a = 18.8261(12) A, b = 16.2517(10) A, c = 15.4556(10) A, alpha = 95.522(1) degrees , beta = 97.130(1) degrees , gamma = 91.350(1) degrees , V = 4667.4(5) A(3), Z = 4; trans-[Re(III)(PEt2Ph)2(acac2en)]PF6 (H48C32N2O2P2Re.PF6), 2, orthorhombic (Pccn), a = 10.4753(6) A, b =18.4315(10) A, c = 18.9245(11) A, V = 3653.9(4) A3, Z = 4; cis-[Re(V)O(PEt3)(acac2en)]PF6 (H33C18N2O3PRe.1.25PF6, 3, monoclinic (C2/c), a = 39.8194(15) A, b = 13.6187(5) A, c = 20.1777(8) A, beta = 107.7730(10) degrees , V = 10419.9(7) A3, Z = 16; cis-[Re(V)O(PPh3)(acac2pn)]PF6 (H35C31N2O3PRe.PF6), 4, triclinic (P), a = 10.3094(10) A, b =12.1196(12) A, c = 14.8146(15) A, alpha = 105.939(2) degrees , beta = 105.383(2) degrees , gamma = 93.525(2) degrees , V = 1698.0(3) A3, Z = 2; cis-[Re(V)O(PEt2Ph)(acac2pn)]PF6 (H35C23N2O3PRe.PF6), 5, monoclinic (P2(1)/n), a = 18.1183(18) A, b = 11.580(1) A, c = 28.519(3) A, beta = 101.861(2) degrees , V = 5855.9(10) A(3), Z = 4.     

Coordinatively and Electronically Unsaturated Tungsten(0) Carbonyl Complexes Stabilized by pi-Donating Amido Ligands

Novel, coordinatively and electronically unsaturated tungsten tricarbonyl dianions of 2-aminophenol and 1,2-diaminobenzene have been synthesized from the reaction of photogenerated W(CO)(5)THF and [Et(4)N][OC(6)H(4)NH(2)] with subsequent deprotonation by [Et(4)N][OH] accompanied by facile CO dissociation, and the reaction of W(CO)(5)THF and 2 equiv of [Et(4)N][NHC(6)H(4)NH(2)], respectively. These air-sensitive derivatives have been fully characterized both in solution (nu(CO) and (13)C NMR) and in the solid-state (X-ray crystallography). These metal dianions which have formally 16e(-) configurations are stabilized by pi-donation from the amido groups of the chelating ligands, as evident from short W-N bond distances. Both solution (nu(CO) and (13)C NMR) and solid-state (W-N vs W-O bond distances) data on these derivatives indicate the amido ligand to be a better pi-donor than the oxo ligand. Complex 2 crystallized in the monoclinic space group P2(1)/n with a = 14.499(5) ?, b = 14.708(5) ?, c = 15.137(4) ?, beta = 114.13(2) degrees, V = 2946(2) ?(3), and d(calc) = 1.433 g/cm(3), for Z = 4. Complex 3 crystallized in the triclinic space group P&onemacr; with a = 11.479(6) ?, b = 11.786(8) ?, c = 13.148(7) ?, alpha = 102.41(5) degrees, beta = 91.27(4) degrees, gamma = 99.96(5) degrees, V = 1708(2) ?(3), and d(calc) = 1.444 g/cm(3), for Z = 2.     

Comparison of the Properties of SnCl(3)(-) and SnBr(3)(-) Complexes of Platinum(II)

The complexes M(3)[Pt(SnX(3))(5)] (M = Bu(4)N(+), PhCH(2)PPh(3)(+); X = Cl, Br), cis-M(2)[PtX(2)(SnX(3))(2)] (M = Bu(4)N(+), PhCH(2)PPh(3)(+), CH(3)PPh(3)(+), Pr(4)N(+); X = Cl, Br), and [PhCH(2)PPh(3)](2)[PtBr(3)(SnBr(3))] have been prepared and characterized by (119)Sn and (195)Pt NMR, far-infrared, and electronic absorption and emission spectroscopies. In acetone solutions the [Pt(SnX(3))(5)](3)(-) ions retain their trigonal bipyramidal structures but are stereochemically nonrigid as evidenced by (119)Sn and (195)Pt NMR spectroscopy. For [Pt(SnCl(3))(5)](3)(-) spin correlation is preserved between 183 and 363 K establishing that the nonrigidity is due to intramolecular tin site exchange, probably via Berry pseudorotation. Whereas, [Pt(SnCl(3))(5)](3)(-) does not undergo loss of SnCl(3)(-) or SnCl(2) to form either [Pt(SnCl(3))(4)](2)(-) or [PtCl(2)(SnCl(3))(2)](2)(-), [Pt(SnBr(3))(5)](3)(-) is not stable in acetone solution in the absence of excess SnBr(2) and forms [PtBr(2)(SnBr(3))(2)](2)(-) and [PtBr(3)(SnBr(3))](2)(-) by loss of SnBr(2). Similarly, [PtCl(2)(SnCl(3))(2)](2)(-) is stable in acetone at ambient temperatures but disproportionates at elevated temperatures and [PtBr(2)(SnBr(3))(2)](2)(-) loses SnBr(2) in acetone to form [PtBr(3)(SnBr(3))](2)(-). The crystal structures of methyltriphenylphosphonium cis-dibromobis(tribromostannyl)platinate(II) and benzyltriphenylphosphonium tribromo(tribromostannyl)platinate(II) have been determined. Both compounds crystallize in the triclinic space group P&onemacr; in unit cells with a = 12.293(16) ?, b = 12.868(6) ?, c = 25.047(8) ?, alpha = 96.11(3) degrees, beta = 91.06(3) degrees, gamma = 116.53(3) degrees, rho(calc) = 2.30 g cm(-)(3), Z = 3 and with a = 11.046(7) ?, b = 14.164(9) ?, c = 22.549(10) ?, alpha = 89.44(4) degrees, beta = 83.32(5) degrees, gamma = 68.31(5) degrees, rho(calc) = 1.893 g cm(-)(3), Z = 2, respectively. Least-squares refinements converged at R = 0.057 and 0.099 for 4048 and 4666 independent observed reflections with I/sigma(I) > 3.0 and I/sigma(I) > 2.0, respectively. For the former, the asymmetric unit contains 1.5 cis-[PtBr(2)(SnBr(3))(2)](2)(-) ions, 0.5 of which is disordered in such a way as to be pseudocentrosymmetric. This disordering involves a half-occupied PtBr(2) unit appearing on either side of the center. Simultaneously, one bromine from each SnBr(3) ligand changes sides while the other two bromines appear in average positions with very small displacements between their positions. The Pt-Sn distance in [PtBr(3)(SnBr(3))](2)(-) (2.486(3) ?) is slightly shorter than that incis-[PtBr(2)(SnBr(3))(2)](2)(-) (2.4955(3) ?, average), and both are significantly longer than that previously found in cis-[PtCl(2)(SnCl(3))(2)](2)(-) (2.3556 ?, average), which is not consistent with the relative magnitudes of the (1)J((195)Pt-(119)Sn) coupling constants (28 487, 25 720, and 27 627 Hz, respectively). From our electronic absorption and emission studies of the Pt-SnX(3)(-) complexes, we conclude that (a) the low-energy transitions are d-d transitions analogous to those found in [PtX(4)](2)(-) systems, (b) the SnCl(3)(-) ligand is a stronger sigma donor than SnBr(3)(-), (c) the triplet state from which the emission occurs is split by spin-orbit coupling into different spin-orbit states, (d) a forbidden spin-orbit state must lie at or near the bottom of the spin-orbit manifold, (e) the solid state crystal environment perturbs the platinum-tin halide electronic states, and (f) dispersion of the samples in solvents changes this perturbation, which can be rationalized in terms of an in-plane distortion of the square planar platinum coordination sphere.     

Pd(II) complexes of N,S-heterocyclic carbenes with pendant and coordinated allyl function and their Suzuki coupling activities

3-(2-Propenyl)benzothiazolium bromide () provides a direct and simple entry to Pd(ii) complexes with N,S-heterocyclic carbene (NSHC) ligands functionalized with an allyl pendant with hemilabile potential. Addition of salt to Pd(OAc)(2) eliminates HOAc and affords the bis(carbene) complexes cis-[PdBr(2)(NHSC)(2)] (cis-, NSHC = 3-(2-propenyl)benzothiazolin-2-ylidene) and trans-[PdBr(2)(NHSC)(2)] (trans-) along with the monocarbene complexes [PdBr(2)(NSHC)] () and trans-[PdBr(2)(benzothiazole-kappaN)(NSHC)] () as minor side products. Salt-metathesis of cis- with AgO(2)CCF(3) yields the mixed dicarboxylato-bis(carbene) complex cis-[Pd(O(2)CCF(3))(2)(NSHC)(2)] (). Complexes cis-, trans- and were characterized by multinuclear NMR spectroscopies, ESI mass spectrometry and elemental analysis. The molecular structures of complexes cis-, and have been determined by X-ray single crystal diffraction. Complexes cis- and as well as an in situ mixture of Pd(OAc)(2) and salt are active toward Suzuki-Miyaura coupling of aryl bromides and activated aryl chlorides giving good conversions.     

Transition Metal Complexes of Cyanoisocyanoarenes as Building Blocks for One-, Two-, and Three-Dimensional Molecular Solids

The complexes trans-[MI(2)(CNC(6)H(4)-CN-4)(2)], (M = Pd and Pt), trans-[FeI(2)L(4)] (L = CNC(6)H(4)-CN-4 and CNC(6)H(2)-Me(2)-2,6-CN-4), and [Mn(CNC(6)H(4)-CN-4)(6)][SO(3)CF(3)] were prepared. The compounds are thermally stable up to 230 degrees C or higher. The molecular structure of trans-[FeI(2)(CNC(6)H(4)-CN-4)(4)] was determined by X-ray crystallography: monoclinic, space group P2(1)/n, a = 11.570(2) ?, b = 10.1052(8) ?, c = 28.138(7) ?, beta = 92.034(9) degrees, Z = 4, 3464 unique reflections, R = 0.074, R(w) = 0.089. The complexes contain the peripheral cyano groups in linear, planar, and octahedral dispositions, respectively. Solids were obtained by combining solutions of [PdI(2)(CNC(6)H(4)-CN-4)(2)] and [Cu(hfacac)(2)], [FeI(2)(CNC(6)H(4)-CN-4)(4)] and AgSO(3)CF(3), [FeI(2)(CNC(6)H(2)-Me(2)-2,6-CN-4)(4)] and [Rh(2)(O(2)CCF(3))(4)], and [Mn(CNC(6)H(4)-CN-4)(6)][SO(3)CF(3)] and [Rh(2)(O(2)CCF(3))(4)]. [PdI(2)(CNC(6)H(4)-CN-4)(2)] and [Cu(hfacac)(2)] in a ratio of 1:2 form a crystalline, one-dimensional solid: monoclinic, space group P2(1)/c, a = 8.317(2) ?, b = 13.541(1) ?, c = 22.568(5) ?, beta = 100.45(1) degrees, Z = 2, 3279 unique reflections, R = 0.037, R(w) = 0.047.     

Reactivity of trans-[PtX(2)(ketoxime)(2)] Complexes toward m-Chloroperoxybenzoic Acid: An Efficient Route to Coordinated Nitrosoalkanes and Solvent Dependence of the Reaction

The platinum(II) compounds trans-[PtX(2)(RR'C=NOH)(2)] [X = Cl, R = R' = Me, RR' = (CH(2))(4), (CH(2))(5); X = Br, R = R' = Me] react with m-chloroperoxybenzoic acid (MCPBA) in dimethylformamide to give the platinum(II) complexes [PtX(2){N(=O)CRR'ONCRR'}] containing coordinated nitrosoalkane ligands. The complexes [PtX(2){N(=O)CRR'ONCRR'}] were characterized by elemental analysis, EI-MS, IR, electronic absorption, and (1)H NMR spectroscopy; X-ray structure analysis was performed for [PtCl(2){N(=O)CC(5)H(10)ONCC(5)H(10)}]. The latter compound crystallizes in the triclinic P&onemacr; space group with a = 9.214(2) ?, b = 9.577(2) ?, c = 10.367(2) ?, alpha = 109.14(2) degrees, beta = 91.87(2) degrees, gamma = 115.62(2) degrees, V = 762.8(3) ?(3), Z = 2, and rho(calcd) = 2.135 g cm(-)(3). The reaction between trans-[PtX(2)(RR'C=NOH)(2)] and MCPBA displays a solvent dependence: interaction of these reagents in ketones, R(1)R(2)C=O, yields the platinum(IV) chelates [PtX(2)(OCR(1)R(2)ON=CRR')(2)], while the oxidation state of the oxime N atom remains unchanged. Heating [PtCl(2)(OCR(1)R(2)ON=CRR')(2)] in DMF or in DMF-d(7) at 100 degrees C leads to the extrusion of R(1)R(2)C=O and the formation of [PtCl(2){N(=O)CRR'ONCRR'}].     

Bis(1,2-bis(diphenylphosphino)ethane)tungsten(0) Complexes Containing Electron-Saturated Metal Centers and Singly-Coordinated Bridging Ligands

Reaction of 1,4-diisocyanobenzene or 4-isocyanobenzonitrile with trans-W(N(2))(2)(DPPE)(2) (DPPE = 1,2-bis(diphenylphosphino)ethane) produced cis-WL(2)(DPPE)(2), where L = 1,4-diisocyanobenzene or 4-isocyanobenzonitrile. cis-(CNC(6)H(4)NC)(2)W(DPPE)(2) crystallizes in the triclinic space group P&onemacr;, with a = 12.848(3) ?, b = 13.596(3) ?, c = 19.072(3) ?, alpha = 78.99(2) degrees, beta = 70.66(2) degrees, gamma = 65.26(2) degrees, V = 2849.8(11) ?(3), and Z = 2. cis-(NCC(6)H(4)NC)(2)W(DPPE)(2) crystallizes in the triclinic space group P&onemacr;, with a = 12.712(3) ?, b = 13.700(3) ?, c = 19.109(3) ?, alpha = 77.91(2) degrees, beta = 70.63(2) degrees, gamma = 64.76(2) degrees, V = 2830.7(13) ?(3), and Z = 2. Both compounds possess a distorted octahedral geometry about the metal center, with the two isocyanide ligands cis to one another. The isocyanide ligands are substantially bent along the CNC axis of the isocyanide group coordinated to tungsten. For the complex containing the symmetric ligand, CNC(6)H(4)NC, the mean CNC angle for the coordinated end of the isocyanide is 139.1(11) degrees, the average W-C bond length is 1.86(1) ?, and the C&tbd1;N bond lengths have a mean value of 1.30(2) ?. These data indicate substantial back-donation from an electron-saturated tungsten atom. This is supported spectroscopically, with substantial shifts to lower wavenumbers for the C-N stretching frequencies of the coordinated isocyanide groups. Similar trends are observed in cis-(NCC(6)H(4)NC)(2)W(DPPE)(2). Both compounds contain electron-rich metals surrounded by large ligands which apparently protect the metals from atmospheric oxidation. The isocyanide ligands in both complexes contain a second coordinating group pointing away from the metal into the environment surrounding the molecules, providing the potential for polymetallic complexes containing metals in a variety of oxidation states.     

Crystal Structures of a Family of New Copper(I) Cyanide Complexes of Thiourea and Substituted Thioureas

The syntheses and crystal structures of the first cyanide, sulfur mixed ligand copper(I) complexes are reported. The first complex of the family was discovered when (CuCN)(3)(C(6)H(12)N(4))(2) (1) (C(6)H(12)N(4) = hexamethylenetetramine) was treated with aqueous thiourea. The sulfur ligands include thiourea (tu), 1,3-dimethyl-2-thiourea (dmtu), 1,3-diethyl-2-thiourea (detu), 1,1,3,3-tetramethyl-2-thiourea (tmtu), and 2-imidazolidinethione (N,N'-ethylenethiourea, etu). Synthesis was effected by adding the ligand to a solution of CuCN in aqueous sodium thiosulfate. Complex 2, (CuCN)(2)(tu)(3)(H(2)O), crystallizes in the triclinic space group P&onemacr;with unit cell dimensions a = 7.696(5) ?, b = 9.346(2) ?, c = 10.772(2) ?, alpha = 106.53(2) degrees, beta = 91.11(4) degrees, gamma = 98.42(3) degrees, and Z = 2. Complex 3, (CuCN)(3)(dmtu)(2), crystallizes in the monoclinic space group Cc with unit cell dimensions a = 10.082(3) ?, b = 14.984(5) ?, c = 11.413(3) ?, beta = 104.50(2) degrees, and Z = 4. Complex 4, (CuCN)(2)(detu)(H(2)O), crystallizes in the monoclinic space group P2(1)/n with unit cell dimensions a = 7.969(5) ?, b = 11.559(4) ?, c = 13.736(5) ?, beta = 100.48(4) degrees, and Z = 4. Complex 5, (CuCN)(tmtu) (polymorph a), crystallizes in the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions a = 8.653(1) ?, b = 9.426(1) ?, c = 11.620(3) ?, and Z = 4. Complex 6, (CuCN)(tmtu) (polymorph b), which has the same connectivity as 5, crystallizes in the triclinic space group P&onemacr; with unit cell dimensions a = 9.660(4) ?, b = 14.202(4) ?, c = 16.03(1) ?, alpha = 101.68(5) degrees, beta = 107.08(6) degrees, gamma = 70.07(2) degrees, and Z = 8. The difference between the polymorphs is that 5 has a zig-zag chain with a repeat unit of two while 6 has a 4-fold helix. Complex 7, (CuCN)(2)(etu), crystallizes in the monoclinic space group P2(1)( )()with unit cell dimensions a = 3.994(2) ?, b = 13.886(3) ?, c = 7.556(1) ?, beta = 97.07(2) degrees, and Z = 2.     

Magnetostructural Correlations in Bis(&mgr;(2)-phenoxide)-Bridged Macrocyclic Dinuclear Copper(II) Complexes. Influence of Electron-Withdrawing Substituents on Exchange Coupling

Macrocyclic dicopper(II) complexes derived from 2,6-di(R)formylphenols and various linking diamines are surveyed and their magnetic and structural properties assessed. For those systems with "flat" dinuclear centers and no electronic perturbations associated with electron-withdrawing ligands or ligand groups, the complexes exhibit a "straight-line" relationship between exchange integral and phenoxide bridge angle. Within the angle range 98.8-104.7 degrees, 11 complexes are included with -2J in the range 689-902 cm(-)(1). When electron-withdrawing species are present, either as ligands or as groups bound to the macrocycle itself, considerable suppression of the antiferromagnetic exchange component is observed. Single-crystal X-ray diffraction studies are reported for three complexes. [Cu(2)(L1)(H(2)O)(2)]F(2)(CH(3)OH)(2) (1) crystallized in the triclinic system, space group P&onemacr;, with a = 8.1878(5) ?, b = 9.0346(7) ?, c = 10.4048(7) ?, alpha = 103.672(6) degrees, beta = 101.163(5) degrees, gamma = 104.017(5) degrees, and Z = 1. [Cu(2)(L2)Cl(2)] [Cu(2)(L2) (H(2)O)(2)]Cl(ClO(4)).5.5H(2)O (2) crystallized in the monoclinic system, space group P2(1)/n, with a = 14.4305(5) ?, b = 24.3149(8) ?, c = 18.6584(8) ?, beta = 111.282(3) degrees, and Z = 4. [Cu(2)(L3)(H(2)O)(2)](BF(4))(2) (3) crystallized in the triclinic system, space group P&onemacr;, with a = 8.6127(4) ?, b = 8.6321(7) ?, c = 10.8430(10) ?, a = 74.390(10) degrees, beta = 86.050(10) degrees, gamma = 76.350(10) degrees, and Z = 2. Square pyramidal copper ion stereochemistries are observed in all cases, with axially coordinated halogens or water molecules. Strong antiferromagnetic exchange is observed for all complexes (-2J = 784(8) cm(-)(1), Cu-O-Cu 103.65(10) degrees (1); -2J = 801(11) cm(-)(1), Cu-O-Cu 102.4(3), 107.5(3), 102.9(3), 106.1(3) degrees (2); -2J = 689(3) cm(-)(1), Cu-O-Cu 98.8(4) degrees (3)). The presence of electron-withdrawing CN groups on the periphery of the macrocyclic ligand leads to substantially reduced antiferromagnetic exchange.     

Preparation and Characterization of Halogen-Boron-Phosphorus Compounds. X-ray Crystal Structures of X(3)B.P(SiMe(3))(3) and [X(2)BP(SiMe(3))(2)](2) (X = Cl, Br)

The 1:1 mole ratio reactions of boron trihalides (BX(3)) with tris(trimethylsilyl)phosphine [P(SiMe(3))(3)] produced 1:1 Lewis acid/base adducts [X(3)B.P(SiMe(3))(3), X = Cl (1), Br (2), I (5)]. Analogous 1:1 mole ratio reactions of these boron trihalides with lithium bis(trimethylsilyl)phosphide [LiP(SiMe(3))(2)] produced dimeric boron-phosphorus ring compounds {[X(2)BP(SiMe(3))(2)](2), X = Br (3), Cl (4)}. X-ray crystallographic studies were successfully conducted on compounds 1-4. Compound 1 crystallized in the orthorhombic space group Pbca, with a = 13.420(3) ?, b = 17.044(5) ?, c = 21.731(7) ?, V = 4970.6(25) ?(3), and D(calc) = 1.229 g cm(-3) for Z = 8; the B-P bond length was 2.022(9) ?, Compound 2 crystallized in the orthorhombic space group Pbca, with a = 13.581(6) ?, b = 17.106(7) ?, c = 22.021(9) ?, V = 5116(4) ?(3), and D(calc) = 1.540 g cm(-3) for Z = 8; the B-P bond length was 2.00(2) ?. Compound 3 crystallized in the monoclinic space group P2(1)/n, with a = 9.063(5) ?, b = 16.391(8) ?, c = 9.331(4) ?, V = 1379.2(12) ?(3), and D(calc) = 1.676 g cm(-3) for Z = 2; the B-P bond length was 2.023(10) ?. Compound 4 crystallized in the monoclinic space group P2(1)/n, with a = 9.143(5) ?, b = 16.021(8) ?, c = 9.170(4) ?, V = 1342.2(11) ?(3), and D(calc) = 1.282 g cm(-3) for Z = 2; the B-P bond length was 2.025(3) ?. Thermal decomposition studies were performed on compounds 1-4, yielding colored powders with boron:phosphorus ratios greater than 1:1 and significant C and H contamination indicated by elemental analyses.     

Ion-Bearing Propellers: Alkali Metal Complexes of Tris(2-alkoxyphenyl)amine Ionophores

NMR spectroscopic studies reveal that binding of Na(+) by tris(2-methoxyphenyl)amine (3) brings two of these tripod ethers together about the metal ion; the related double-tripod-ether ionophore 1,2-bis[2-(bis(2-methoxyphenyl)amino)phenoxy]ethane (4), in which two triarylamines are covalently attached, binds LiI, LiBPh(4), NaI, NaBPh(4), and KB(4-ClPh)(4). Dynamic NMR puts lower limits on binding free energies of 4 for Na(+) (71.8 kJ mol(-)(1)) and K(+) (66.8 kJ mol(-)(1)) ions. X-ray studies of 3(2).NaBPh(4), 4.NaBPh(4), 4.NaB(4-ClPh)(4), and 4.KB(4-ClPh)(4).CH(3)NO(2) show eight-coordinate M(+) ions bound between crystallographically independent, homochiral triarylamine tripod ethers in structures reminiscent of alkali metal [2.2.2] cryptates. Complexes crystallize as follows: 3(2).NaBPh(4), monoclinic, P2(1)/c, Z = 4, a = 10.701(3) ?, b = 37.593(3) ?, c = 13.774(2) ?, and beta = 98.24(2) degrees; 4.NaBPh(4), triclinic, P&onemacr;, Z = 2, a = 12.157(1) ?, b = 14.811(1) ?, c = 15.860(2) ?, alpha = 105.400(8) degrees, beta = 91.594(9) degrees, and gamma = 95.354(8) degrees; 4.NaB(4-ClPh)(4), monoclinic, P2(1)/n, Z = 4, a = 13.652(5) ?, b = 18.75(1) ?, c = 22.805(5) ?, and beta = 92.21(5) degrees; 4.KB(4-ClPh)(4).CH(3)NO(2), monoclinic, Pn, Z = 2, a = 13.663(4) ?, b = 12.228(3) ?, c = 18.712(8) ?, and beta = 91.45(3) degrees. They show variable N-M-N angles; 3(2).NaBPh(4) is surprisingly bent ( angleN-Na-N = 154.5 degrees ), while the 4.M(+) complexes are normal: nearly linear for Na(+) ( angleN-Na-N = 178.6, 178.1 degrees ) and again bent with the larger K(+) ( angleN-K-N = 164.5 degrees ). Finally, free 4 is structurally similar to 3; it crystallizes in the triclinic space group P&onemacr;, with Z = 2, a = 8.068(1) ?, b = 14.599(2) ?, c = 16.475(3) ?, alpha = 115.43(1) degrees, beta = 92.51(1) degrees, and gamma = 90.40(1) degrees.     

Syntheses and Crystal Structures of Ruthenium Complexes of 1,4,8,11-Tetraazacyclotetradecane, Tris(2-aminoethyl)amine (tren), and Bis(2-aminoethyl)(iminomethyl)amine. A Microporous Layered Structure Consisting of {[K(tren)](2)[RuCl(6)]}(n)()(n)()(-) and {(H(5)O(2))(4)[RuCl(6)]}(n)()(n)()(+)

The second method for the synthesis of cis-[Ru(III)Cl(2)(cyclam)]Cl (1) (cyclam = 1,4,8,11-tetraazacyclotetradecane), with use of cis-Ru(II)Cl(2)(DMSO)(4) (DMSO = dimethyl sulfoxide) as a starting complex, is reported together with the synthesis of [Ru(II)(cyclam)(bpy)](BF(4))(2).H(2)O (2) (bpy = 2,2'-bipyridine) from 1. The syntheses of Ru complexes of tris(2-aminoethyl)amine (tren) are also reported. A reaction between K(3)[Ru(III)(ox)(3)] (ox = oxalate) and tren affords fac-[Ru(III)Cl(3)(trenH)]Cl.(1)/(2)H(2)O (3) (trenH = bis(2-aminoethyl)(2-ammonioethyl)amine = monoprotonated tren) and (H(5)O(2))(2)[K(tren)][Ru(III)Cl(6)] (4) as major products and gives fac-[Ru(III)Cl(ox)(trenH)]Cl.(3)/(2)H(2)O (5) in very low reproducibility. A reaction between 3 and bpy affords [Ru(II)(baia)(bpy)](BF(4))(2) (6) (baia = bis(2-aminoethyl)(iminomethyl)amine), in which tren undergoes a selective dehydrogenation into baia. The crystal structures of 2-6 have been determined by X-ray diffraction, and their structural features are discussed in detail. Crystallographic data are as follows: 2, RuF(8)ON(6)C(20)B(2)H(34), monoclinic, space group P2(1)/c with a = 12.448(3) ?, b = 13.200(7) ?, c = 17.973(4) ?, beta = 104.28(2) degrees, V = 2862(2) ?(3), and Z = 4; 3, RuCl(4)O(0.5)N(4)C(6)H(20), monoclinic, space group P2(1)/a with a = 13.731(2) ?, b = 14.319(4) ?, c = 13.949(2) ?, beta = 90.77(1) degrees, V = 2742(1) ?(3), and Z = 8; 4, RuKCl(6)O(4)N(4)C(6)H(28), trigonal, space group R&thremacr; with a = 10.254(4), c = 35.03(1) ?, V = 3190(2) ?(3), and Z = 6; 5, RuCl(2)O(5.5)N(4)C(8)H(22), triclinic, space group P&onemacr; with a = 10.336(2) ?, b = 14.835(2) ?, c = 10.234(1) ?, alpha = 90.28(1) degrees, beta = 90.99(1) degrees, gamma = 92.07(1) degrees, V = 1567.9(4) ?(3), and Z = 4; 6, RuF(8)N(6)C(16)B(2)H(24), monoclinic, space group P2(1)/c, a = 10.779(2) ?, b = 14.416(3) ?, c = 14.190(2) ?, beta = 93.75(2) degrees, V = 2200.3(7) ?(3), and Z = 4. Compound 4 possesses a very unique layered structure made up of both anionic and cationic slabs, {[K(tren)](2)[Ru(III)Cl(6)]}(n)()(n)()(-) and {(H(5)O(2))(4)[Ru(III)Cl(6)]}(n)()(n)()(+) (n = infinity), in which both sheets {[K(tren)](2)}(n)()(2)(n)()(+) and {(H(5)O(2))(4)}(n)()(4)(n)()(+) offer cylindrical pores that are occupied with the [Ru(III)Cl(6)](3)(-) anions. The presence of a C=N double bond of baia in 6 is judged from the C-N distance of 1.28(2) ?. It is suggested that the structural restraint enhanced by the attachment of alkylene chelates at the nitrogen donors of amines results in either the mislocation or misdirection of the donors, leading to the elongation of the Ru-N(amine) distances and to the weakening of their trans influence. Such structural strain is also discussed as related to the spectroscopic and electrochemical properties of the cis-[Ru(II)L(4)(bpy)](2+) complexes (L(4) = (NH(3))(4), (ethylenediamine)(2), and cyclam).     

Metal Complexes of Dithiolate Ligands: 5,6-Dihydro-1,4-dithiin-2,3-dithiolato (dddt(2-)), 5,7-Dihydro-1,4,6-trithiin-2,3-dithiolato (dtdt(2-)), and 2-Thioxo-1,3-dithiole-4,5-dithiolato (dmit(2-)). Synthesis, Electrochemical Studies, Crystal and Electronic Structures, and Conducting Properties

New precursors to potentially conductive noninteger oxidation state (NIOS) compounds based on metal complexes [ML(2)](n)()(-) [M = Ni, Pd, Pt; L = 5,6-dihydro-1,4-dithiin-2,3-dithiolato (dddt(2)(-)), 5,7-dihydro-1,4,6-trithiin-2,3-dithiolato (dtdt(2)(-)), and 2-thioxo-1,3-dithiole-4,5-dithiolato (dmit(2)(-)); n = 2, 1, 0] have been investigated. Complexes of the series (NR(4))[ML(2)] (R = Me, Et, Bu; L = dddt(2)(-), dtdt(2)(-)) have been isolated and characterized, and the crystal structure of (NBu(4))[Pt(dtdt)(2)] (1) has been determined {1 = C(24)H(44)NPtS(10), a = 12.064(2) ?, b = 17.201(3) ?, c = 16.878(2) ?, beta = 102.22(2) degrees, V = 3423(1) ?(3), monoclinic, P2(1)/n, Z = 4}. Oxidation of these complexes affords the corresponding neutral species [ML(2)](0). Another series of general formula (cation)(n)()[M(dmit)(2)] [cation = PPN(+), BTP(+), and (SMe(y)()Et(3)(-)(y)())(+) with y = 0, 1, 2, and 3, n = 2, 1, M = Ni, Pd] has also been studied. All of these (cation)(n)()[M(dmit)(2)] complexes have been isolated and characterized [with the exception of (cation)[Pd(dmit)(2)] for cation = (SMe(y)()Et(3)(-)(y)())(+)]. The crystal structures of (PPN)[Ni(dmit)(2)].(CH(3))(2)CO (2) and (SMeEt(2))[Ni(dmit)(2)] (3) have been determined {2 = C(45)H(36)NNiS(10)P(2)O, a = 12.310(2) ?, b = 13.328(3) ?, c = 15.850(3) ?, alpha = 108.19(3) degrees, beta = 96.64(2) degrees, gamma = 99.67(2) degrees, V = 2373(1) ?(3), triclinic, P&onemacr;, Z = 2; 3 = C(11)H(13)NiS(11), a = 7.171(9) ?, b = 17.802(3) ?, c = 16.251(3) ?, beta = 94.39(4) degrees, V = 2068(2) ?(3), monoclinic, P2(1)/n, Z = 4} NIOS salts derived from the preceding precursors were obtained by electrochemical oxidation. Electrochemical studies of the [M(dddt)(2)] complexes show that they may be used for the preparation of NIOS radical cation salts and [M(dddt)(2)][M'(dmit)(2)](x)() compounds, but not for the preparation of (cation)[M(dddt)(2)](z)() NIOS radical anion salts. The electrochemical oxidation of the [M(dtdt)(2)](-) complexes always yields the neutral [M(dtdt)(2)](0) species. The crystal structure of [Pt(dddt)(2)][Ni(dmit)(2)](2) (4) has been determined and is consistent with the low compaction powder conductivity (5 x 10(-)(5) S cm(-)(1) at room temperature) {4 = C(20)H(8)Ni(2)PtS(28), a = 20.336(4) ?, b = 7.189(2) ?, c = 14.181(2) ?, beta = 97.16(2) degrees, V = 2057(1) ?(3), monoclinic, C2/m, Z = 2}. The crystal structures of the semiconducting NIOS compounds (BTP)[Ni(dmit)(2)](3) (5) and (SMe(3))[Ni(dmit)(2)](2) (6) have been determined {5 = C(43)H(22)PNi(3)S(30), a = 11.927(2) ?, b = 24.919(2) ?, c = 11.829(3) ?, alpha = 93.11(1) degrees, beta = 110.22(1) degrees, gamma = 83.94(1) degrees, V = 3284(1) ?(3), triclinic, P&onemacr;, Z = 2; 6 = C(15)H(9)Ni(2)S(21), a = 7.882(1) ?, b = 11.603(2) ?, c = 17.731(2) ?, alpha = 77.44(1) degrees, beta = 94.39(1) degrees, gamma = 81.27(1) degrees, V = 1563(1) ?(3), triclinic, P&onemacr;, Z = 2}. The parent compound (SEt(3))[Ni(dmit)(2)](z) (unknown stoichiometry) is also a semiconductor with a single-crystal conductivity at room temperature of 10 S cm(-)(1). By contrast, the single-crystal conductivity at room temperature of (SMeEt(2))[Pd(dmit)(2)](2) (7) is rather high (100 S cm(-)(1)). 7 behaves as a pseudometal down to 150 K and undergoes an irreversible metal-insulator transition below this temperature. The crystal structure of 7 has been determined {7 = C(17)H(13)NPd(2)S(21), a = 7.804(4) ?, b = 36.171(18) ?, c = 6.284(2) ?, alpha = 91.68(4) degrees, beta = 112.08(4) degrees, gamma = 88.79(5) degrees, V = 1643(1) ?(3), triclinic, P&onemacr;, Z = 2}. The electronic structure of (SMeEt(2))[Pd(dmit)(2)](2) (7) and the possible origin of the metal-insulator transition at 150 K are discussed on the basis of tight-binding band structure calculations.     

Regulation of geometry around the ruthenium center of bis(2-pyridinecarboxylato) complexes by the nitrosyl moiety: syntheses, structures, and theoretical studies

cis-[Ru(NO)Cl(pyca)(2)] (pyca = 2-pyridinecarboxylato), in which the two pyridyl nitrogen atoms of the two pyca ligands coordinate at the trans position to each other and the two carboxylic oxygen atoms at the trans position to the nitrosyl ligand and the chloro ligand, respectively (type I shown as in Chart 1), reacted with NaOCH(3) to generate cis-[Ru(NO)(OCH(3))(pyca)(2)] (type I). The geometry of this complex was confirmed to be the same as the starting complex by X-ray crystallography: C(13.5)H(13)N(3)O(6.5)Ru; monoclinic, P2(1)/n; a = 8.120(1), b = 16.650(1), c = 11.510(1) A; beta = 99.07(1) degrees; V = 1536.7(2) A(3); Z = 4. The cis-trans geometrical change reaction occurred in the reactions of cis-[Ru(NO)(OCH(3))(pyca)(2)] (type I) in water and alcohol (ROH, R = CH(3), C(2)H(5)) to form [[trans-Ru(NO)(pyca)(2)](2)(H(3)O(2))](+) (type V) and trans-[Ru(NO)(OR)(pyca)(2)] (type V). The reactions of the trans-form complexes, trans-[Ru(NO)(H(2)O)(pyca)(2)](+) (type V) and trans-[Ru(NO)(OCH(3))(pyca)(2)] (type V), with Cl(-) in hydrochloric acid solution afforded the cis-form complex, cis-[Ru(NO)Cl(pyca)(2)] (type I). The favorable geometry of [Ru(NO)X(pyca)(2)](n)(+) depended on the nature of the coexisting ligand X. This conclusion was confirmed by theoretical, synthetic, and structural studies. The mono-pyca-containing nitrosylruthenium complex (C(2)H(5))(4)N[Ru(NO)Cl(3)(pyca)] was synthesized by the reaction of [Ru(NO)Cl(5)](2)(-) with Hpyca and characterized by X-ray structural analysis: C(14)H(24)N(3)O(3)Cl(3)Ru; triclinic, Ponemacr;, a = 7.631(1), b = 9.669(1), c = 13.627(1) A; alpha = 83.05(2), beta = 82.23(1), gamma = 81.94(1) degrees; V = 981.1(1) A(3); Z = 2. The type II complex of cis-[Ru(NO)Cl(pyca)(2)] was synthesized by the reaction of [Ru(NO)Cl(3)(pyca)](-) or [Ru(NO)Cl(5)](2)(-) with Hpyca and isolated by column chromatography. The structure was determined by X-ray structural analysis: C(12)H(8)N(3)O(5)ClRu; monoclinic, P2(1)/n; a = 10.010(1), b = 13.280(1), c = 11.335(1) A; beta = 113.45(1) degrees; V = 1382.4(2) A(3); Z = 4.