Tertiary arsine-stabilised arsenium salts: syntheses and comparisons with phosphine analogues

The first tertiary arsine-stabilised arsenium salts, [(L)AsMePh]OTf (L = Ph3As, Me2PhAs, [2-(MeOCH2)C6H4]Ph2As, [2-(MeOCH2)C6H4]Me2As), have been prepared by chloride abstraction from chloromethylphenylarsine with trimethylsilyl triflate in the presence of the arsine. The complexes have been characterised by crystallography and 1H NMR spectroscopy. The chiral cations in the complexes have structures based on the trigonal pyramid in which the arsine is coordinated orthogonally to the prochiral, six-electron MePhAs+ ion that forms the base of the pyramid. The NMR data for the complexes in dichloromethane-d2 are consistent with rapid exchange of the arsine on the arsenium ion, even at 183 K. The corresponding phosphine-stabilised complexes are considerably more stable than their arsine counterparts in dichloromethane-d2 with the free energy of activation DeltaG = ca. 60 kJ mol(-1) being calculated for phosphine exchange in [(Me2PhP)AsMePh]OTf at 281 K; for [(Me2[2-(MeOCH2)C6H4]P)AsMePh]OTf in the same solvent, DeltaG = ca. 70 kJ mol(-1) at 323 K.     

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.     

Diastereoselectivity and molecular recognition in the self-assembly of double-stranded dinuclear metal complexes of the type [M2[(R,S)-tetraphos]2](PF6)2 (M = Ag and Au)

The ligand (R,S)-Ph(2)PCH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)PPh(2), (R,S)-tetraphos, combines with silver(I) and gold(I) ions in the presence of hexafluorophosphate to diastereoselectively self-assemble the head-to-head (H,H) diastereomers of the double-stranded, dinuclear metal complexes [M(2)[(R,S)-tetraphos](2)](PF(6))(2) in which the two chiral metal centers in the complexes have M (R end of phosphine) and P (S end of phosphine) configurations. The crystal and molecular structures of the compounds have been determined: (H,H)-(M,P) -[Ag(2)[(R,S)-tetraphos](2)](PF(6))(2), monoclinic, P2(1)/c, a = 10.3784(2), b = 47.320(1), c = 17.3385(4) A, beta = 103.8963(5) degrees, Z = 4; (H,H)-(M,P)-[Au(2)[(R,S)-tetraphos](2)](PF(6))(2), monoclinic, P.2(1) (No. 4, c unique axis), a = 24.385(4), b = 46.175(3), c = 14.820(4) A, Z = 8. The complexes crystallize as racemic compounds in which the unit cell in each case contains equal numbers of enantiomorphic molecules of the cation and associated anions. The cations in both structures have similar side-by-side structures of idealized C(2) symmetry, the bulk helicity of each molecule in the solid state being due solely to the twist of the central ten-membered ring containing the two metal ions of opposite configuration, which has the chiral twist-boat-chair-boat conformation. When 1 equiv each of (R,S)-tetraphos, (R,R)-(+/-)-tetraphos, (S,S)-(+)-tetraphos, 2 equiv of Ph(2)PCH(2)CH(2)PPh(2) (dppe), and 7 equiv of [AuCl(SMe(2))] in dichloromethane are allowed to react for several minutes in the presence of an excess of ammonium hexafluorophosphate in water (two phases), the products are the double-stranded digold(I) complexes in which each ligand strand has recognized itself by stereoselective self-assembly, together with [Au(dppe)(2)]PF(6).     

Reduction of the pertechnetate anion with bidentate phosphine ligands

The reduction of ammonium pertechnetate with bis(diphenylphosphino)methane (dppm), and with diphenyl-2-pyridyl phosphine (Ph(2)Ppy), has been investigated. The neutral Tc(II) complex, trans-TcCl(2)(dppm)(2) (1), has been isolated from the reaction of (NH(4))[TcO(4)] with excess dppm in refluxing EtOH/HCl. Chemical oxidation with ferricinium hexafluorophosphate results in formation of the cationic Tc(III) analogue, trans-[TcCl(2)(dppm)(2)](PF(6)) (2). The dppm ligands adopt the chelating bonding mode in both complexes, resulting in strained four member metallocycles. With excess PhPpy, the reduction of (NH(4))[TcO(4)] in refluxing EtOH/HCl yields a complex with one chelating Ph(2)Ppy ligand and one unidentate Ph(2)Ppy ligand, mer-TcCl(3)(Ph(2)Ppy-P,N)(Ph(2)Ppy-P) (3). The cationic Tc(III) complexes, trans-[TcCl(2)(Ph(2)P(O)py-N,O)(2)](PF(6)) (4) and trans-[TcCl(2)(dppmO-P,O)(2)](PF(6)) (5) (Ph(2)P(O)py = diphenyl-2-pyridyl phosphine monoxide and dppmO = bis(diphenylphosphino)methane monoxide), have been isolated as byproducts from the reactions of (NH(4))[TcO(4)] with the corresponding phosphine. The products have been characterized in the solid state and in solution via a combination of single-crystal X-ray crystallography and spectroscopic techniques. The solution state spectroscopic results are consistent with the retention of the bonding modes revealed in the crystal structures.     

Chemistry of metal-bound anion radicals. A family of mono- and bis(azopyridine) chelates of bivalent ruthenium

The reaction of the dihydride [RuII(H)2(CO)(PPh3)3], 3, with excess azo-2,2'-bipyridine (abp) in boiling dry benzene has afforded the diradical bischelate [RuII(abp.-)2(CO)(PPh3)], 4, and the hydridic monochelate monoradical [RuII(abp.-)(H)(CO)(PPh3)2], 5. A similar reaction between 3 and 2-(p-chlorophenylazo)pyridine (Clpap) did not yield a bischelate, but the hydridic monoradical [RuII(Clpap.-)(H)(CO)(PPh3)2], 6, has been isolated. Upon treatment of 4-6 with NH4PF6 in a wet dichloromethane-acetonitrile medium, the one-electron-oxidized salts 4+PF6-, 5+PF6-, and 6+PF6- are isolated, H+ being the oxidizing agent. The X-ray structures of 4+PF6-.CH2Cl2, 5+PF6-.H2O, and 6+PF6- have been determined. In the monoradical 4+ the azo N-N bond lengths in the two chelate rings are 1.284(6) and 1.336(6) A, showing that the radical electron is localized in the latter ring. The half-filled extended Hückel HOMO is indeed found to be so localized, and it has a large azo character. Complexes 4-6 display radical redox couples with E1/2 in the range -0.5 to +0.10 V vs SCE. The E1/2 values qualitatively correlate with corresponding vco values (1900-2000 cm-1). The monoradicals (S = 1/2) 4+, 5, and 6 uniformly display a strong EPR signal near g = 2.00. Metal-mediated magnetic interaction makes the EPR-silent diradical 4 strongly antiferromagnetic with J = -299 cm-1. Crystal data are as follows: (4+PF6-.CH2Cl2, C40H33Cl2F6N8-OP2Ru) monoclinic, space group P2(1)/c (no. 14), a = 14.174(6) A, b = 16.451(4) A, c = 18.381(4) A, beta = 98.00(3) degrees, Z = 4; (5+PF6-.H2O, C47H41F6N4O2P3Ru) monoclinic, space group P2(1)/n (no. 14), a = 9.433(2) A, b = 38.914(17) A, c = 13.084(3) A, beta = 103.47(2) degrees, Z = 4; (6+PF6-, C48H39ClF6N3OP3Ru) monoclinic, space group P2(1)/n (no. 14), a = 10.496(5) A, b = 22.389(8) A, c = 19.720(6) A, beta = 90.53(3) degrees, Z = 4.     

A trigonal planar mu 3-fluorido coinage metal complex from a dicationic (diphosphinomethane)copper(I) dimer: syntheses,structures, and bonding

The triflate and hexafluorophosphate salts of [Cu2(mu-dtbpm)2]2+ (1(2+)) [dtbpm = bis(di-tert-butylphosphino)methane, tBu2PCH2PtBu2] and of [Cu3(mu 3-F)(mu-dtbpm)3]2+ (2(2+)) were synthesized and characterized. Coordination of solvent or counterions to 1(2+) is observed neither in solution nor in the solid state. The two copper(I) centers in 1(2+) indicate weak d10-d10 closed-shell interactions. 1(2+) reacts slowly with PF6- anions in acetone or KF in CH2Cl2 to yield the mu 3-fluorido complex 2(2+) with idealized D3 symmetry, containing a trigonal planar Cu3F core, as shown by single-crystal X-ray diffraction. Distinct structural differences are observed compared to monocationic bicapped, trinuclear copper(I) dppm halide complexes [dppm = bis(diphenylphosphino)methane, Ph2PCH2PPh2]. The average Cu-Cu, Cu-F, and Cu-P distances and the P-Cu-P' angle in 2(2+) are 3.85, 2.22, and 2.28 A and 144.3 degrees, respectively. The P2Cu units are twisted out of the Cu3F plane by an average angle of 18.4 degrees. DFT calculations (BPW91/LANL2DZ) for the model [Cu3(mu 3-F)(mu-dhpm)3]2+ (dhpm = diphosphinomethane, H2PCH2PH2) are used to explain the formation, structure, and bonding pattern of 2(2+).     

Syntheses of new ionic technetium(III) complexes containing four monodentate phosphine ligands. Crystal structures of trans-[Tc(PMe2Ph)4Cl2]PF6, trans-[Tc(PMe3)4Cl2]BPh4, and trans-[Tc(PMe3)4Cl2]PF6

New ionic technetium complexes of the type trans-[Tc(PR3)4Cl2]+ are synthesized by various methods. The simplest method is the reaction of [TcO4]- with the phosphine in methanol in the presence of a chloride salt. Compounds containing PMe2Ph and PMe3 are synthesized and characterized by crystallographic methods. The complexes containing the less bulky phosphine can be prepared from complexes containing the bulker phosphine. The compounds are paramagnetic, with two unpaired electrons. The complexes studied by X-ray diffraction methods are the trans isomers. [Tc(PMe2Ph)4Cl2]PF6 crystallizes in the monoclinic space group P2(1)/c, with a = 11.511(2) A, b = 26.713(7) A, c = 12.688(3) A, beta = 92.79(1) degrees, Z = 4, and R1 = 0.0574. [Tc(PMe3)4Cl2]BPh4 (II) crystallizes in the orthorhombic space group Pbcn, with a = 18.213(5) A, b = 22.950(5) A, c = 19.428(6) A, Z = 8, and R1 = 0.0691. [Tc(PMe3)4Cl2]PF6 crystallizes in the monoclinic space group P2(1)/c, with a = 18.152(7) A, b = 16.838(9) A, c = 18.090(6) A, beta = 106.63(1) degrees, Z = 8, and R1 = 0.0670. The compounds all have octahedral coordination, but an important tetrahedral deformation of the plane containing the Tc and the four P atoms is observed in each case. In II, the two independent Tc atoms are both located on 2-fold axes.     

The F/Ph rearrangement reaction of [(Ph3P)3RhF], the fluoride congener of Wilkinson's catalyst

The fluoride congener of Wilkinson's catalyst, [(Ph(3)P)(3)RhF] (1), has been synthesized and fully characterized. Unlike Wilkinson's catalyst, 1 easily activates the inert C-Cl bond of ArCl (Ar = Ph, p-tolyl) under mild conditions (3 h at 80 degrees C) to produce trans-[(Ph(3)P)(2)Rh(Ph(2)PF)(Cl)] (2) and ArPh as a result of C-Cl, Rh-F, and P-C bond cleavage and C-C, Rh-Cl, and P-F bond formation. In benzene (2-3 h at 80 degrees C), 1 decomposes to a 1:1 mixture of trans-[(Ph(3)P)(2)Rh(Ph(2)PF)(F)] (3) and the cyclometalated complex [(Ph(3)P)(2)Rh(Ph(2)PC(6)H(4))] (4). Both the chloroarene activation and the thermal decomposition reactions have been shown to occur via the facile and reversible F/Ph rearrangement reaction of 1 to cis-[(Ph(3)P)(2)Rh(Ph)(Ph(2)PF)] (5), which has been isolated and fully characterized. Kinetic studies of the F/Ph rearrangement, an intramolecular process not influenced by extra phosphine, have led to the determination of E(a) = 22.7 +/- 1.2 kcal mol(-)(1), DeltaH(++) = 22.0 +/- 1.2 kcal mol(-)(1), and DeltaS(++) = -10.0 +/- 3.7 eu. Theoretical studies of F/Ph exchange with the [(PH(3))(2)(PH(2)Ph)RhF] model system pointed to two possible mechanisms: (i) Ph transfer to Rh followed by F transfer to P (formally oxidative addition followed by reductive elimination, pathway 1) and (ii) F transfer to produce a metallophosphorane with subsequent Ph transfer to Rh (pathway 2). Although pathway 1 cannot be ruled out completely, the metallophosphorane mechanism finds more support from both our own and previously reported observations. Possible involvement of metallophosphorane intermediates in various P-F, P-O, and P-C bond-forming reactions at a metal center is discussed.     

A luminescent platinum(II) 2,6-bis(N-pyrazolyl)pyridine complex

Four platinum(II) cationic complexes were prepared with the mer-coordinating tridentate ligands 2,6-bis(N-pyrazolyl)pyridine (bpp) and 2,6-bis(3,5-dimethyl-N-pyrazolyl)pyridine (bdmpp): [Pt(bpp)Cl]Cl.H(2)O; [Pt(bdmpp)Cl]Cl.H(2)O; [Pt(bpp)(Ph)](PF(6)); [Pt(bdmpp)(Ph)](PF(6)). The complexes were characterized by (1)H NMR spectroscopy, elemental analysis, and mass spectrometry, and the structures of the bpp derivatives were determined by X-ray crystallography. [Pt(bpp)Cl]Cl.2H(2)O: monoclinic, P2(1)/n, a = 11.3218(5) A, b = 6.7716(3) A, c = 20.6501(6) A, beta = 105.883(2) degrees, V = 1522.73(11) A(3), Z = 4. The square planar cations stack in a head-to-tail fashion to form a linear chain structure with alternating Pt...Pt distances of 3.39 and 3.41 A. [Pt(bpp)(Ph)](PF(6)).CH(3)CN: triclinic, P, a = 8.3620(3) A, b = 10.7185(4) A, c = 13.4273(5) A, alpha = 96.057(1) degrees, beta = 104.175(1) degrees, gamma = 110.046(1) degrees, V = 1072.16(7) A(3), Z = 2. Cyclic voltammograms indicate all four complexes undergo irreversible reductions between -1.0 and -1.3 V vs Ag/AgCl (0.1 M TBAPF(6)/CH(3)CN), attributable to ligand- and/or metal-centered processes. By comparison to related 2,2':6',2' '-terpyridine complexes, the electrochemical and UV-visible absorption data are consistent with bpp being both a weaker sigma-donor and pi-acceptor than terpyridine. Solid samples of [Pt(bpp)(Ph)](PF(6)) at 77 K exhibit a remarkably intense, narrow emission centered at 655 nm, whereas the other three complexes exhibit only very weak emission.     

Substituent effects on indium-phosphorus bonding in (4-RC6H4S)3In.PR'3 adducts (R = H, Me, F; R' = Et, Cy, Ph): a spectroscopic, structural, and thermal decomposition study

The tris(arylthiolate)indium(III) complexes (4-RC(6)H(4)S)(3)In [R = H (5), Me (6), F (7)] were prepared from the 2:3 reaction of elemental indium and the corresponding aryl disulfide in methanol. Reaction of 5-7 with 2 equiv of the appropriate triorganylphosphine in benzene or toluene resulted in isolation of the indium-phosphine adduct series (4-RC(6)H(4)S)(3)In.PR'(3) [R = H, R' = Et (5a), Cy (5b), Ph (5c); R = Me, R' = Et (6a), Cy (6b), Ph (6c); R = F, R' = Et (7a), Cy (7b), Ph (7c)]. These compounds were characterized via elemental analysis, FT-IR, FT-Raman, solution (1)H, (13)C{(1)H}, (31)P{(1)H}, and (19)F (7a-c) NMR spectroscopy, and X-ray crystallography (5c, 6a, 6c, and 7a). NMR spectra show retention of the In-P bond in benzene-d(6) solution, with phosphine (31)P{(1)H} signals shifted downfield compared to the uncoordinated ligand. The X-ray structures show monomeric 1:1 adduct complexes in all cases. The In-P bond distance [2.5863(5)-2.6493(12) A] is influenced significantly by the phosphine substituents but is unaffected by the substituted phenylthiolate ligand. Relatively low melting points (88-130 degrees C) are observed for all adducts, while high-temperature thermal decomposition is observed for the indium thiolate reactants 5-7. DSC/TGA and EI-MS data show a two-step thermal decomposition process, involving an initial loss of the phosphine moiety followed by loss of thiolate ligand.     

Synthesis, Structure, and Reactivity of [Zr(6)Cl(18)H(5)](2)(-), the First Paramagnetic Species of Its Class

Reaction of [Zr(6)Cl(18)H(5)](3)(-) (1) with 1 equiv of TiCl(4) yields a new cluster anion, [Zr(6)Cl(18)H(5)](2)(-) (2), which can be converted back into [Zr(6)Cl(18)H(5)](3)(-) (1) upon addition of 1 equiv of Na/Hg. Cluster 2 is paramagnetic and unstable in the presence of donor molecules. It undergoes a disproportionation reaction to form 1, some Zr(IV) compounds, and H(2). It also reacts with TiCl(4) to form [Zr(2)Cl(9)](-) (4) and a tetranuclear mixed-metal species, [Zr(2)Ti(2)Cl(16)](2)(-) (3). The oxidation reaction of 1 with TiCl(4) is unique. Oxidation of 1 with H(+) in CH(2)Cl(2) solution results in the formation of [ZrCl(6)](2)(-) (5) and H(2), while in py solution the oxidation product is [ZrCl(5)(py)](-) (6). There is no reaction between 1 and TiI(4), ZrCl(4), [TiCl(6)](2)(-), [ZrCl(6)](2)(-), or CrCl(3). Compounds [Ph(4)P](2)[Zr(6)Cl(18)H(5)] (2a), [Ph(4)P](2)[Zr(2)Ti(2)Cl(16)] (3a), [Ph(4)P](2)[Zr(2)Cl(9)] (4a), [Ph(4)P](2)[ZrCl(6)].4MeCN (5a.4MeCN), and [Ph(4)P][ZrCl(5)(py)] (6a) were characterized by X-ray crystallography. Compound 2a crystallized in the trigonal space group R&thremacr; with cell dimensions (20 degrees C) of a = 28.546(3) ?, b = 28.546(3) ?, c = 27.679(2) ?, V = 19533(3) ?(3), and Z = 12. Compound 3a crystallized in the triclinic space group P&onemacr; with cell dimensions (-60 degrees C) of a = 11.375(3) ?, b = 13.357(3) ?, c = 11.336(3) ?, alpha = 106.07(1) degrees, beta = 114.77(1) degrees, gamma = 88.50(1) degrees, V = 1494.8(7) ?(3), and Z = 1. Compound 4a crystallized in the triclinic space group P&onemacr; with cell dimensions (-60 degrees C) of a = 12.380(5) ?, b = 12.883(5) ?, c = 11.000(4) ?, alpha = 110.39(7) degrees, beta = 98.29(7) degrees, gamma = 73.12(4) degrees, V = 1572(1) ?(3), and Z = 2. Compound 5a.4MeCN crystallized in the monoclinic space group P2(1)/c with cell dimensions (-60 degrees C) of a = 9.595(1) ?, b = 19.566(3) ?, c = 15.049(1) ?, beta = 98.50(1) degrees, V = 2794.2(6) ?(3), and Z = 2. Compound 6a crystallized in the monoclinic space group P2(1)/c with cell dimensions (20 degrees C) of a = 10.3390(7) ?, b = 16.491(2) ?, c = 17.654(2) ?, beta = 91.542(6) degrees, V = 3026.4(5) ?(3), and Z = 4.     

Metal(II) hexafluorophosphates(V) (M = Sr, Pb) containing XeF(2)-coordinated metal ions [M(XeF(2))(3)](PF(6))(2), [Pb(3)(XeF(2))(11)](PF(6))(6), and [Sr(3)(XeF(2))(10)](PF(6))(6)

From the system MF(2)/PF(5)/XeF(2)/anhydrous hydrogen fluoride (aHF), four compounds [Sr(XeF(2))(3)](PF(6))(2), [Pb(XeF(2))(3)](PF(6))(2), [Sr(3)(XeF(2))(10)](PF(6))(6), and [Pb(3)(XeF(2))(11)](PF(6))(6) were isolated and characterized by Raman spectroscopy and X-ray single-crystal diffraction. The [M(XeF(2))(3)](PF(6))(2) (M = Sr, Pb) compounds are isostructural with the previously reported [Sr(XeF(2))(3)](AsF(6))(2). The structure of [Sr(3)(XeF(2))(10)](PF(6))(6) (space group C2/c; a = 11.778(6) Angstrom, b = 12.497(6) Angstrom, c = 34.60(2) Angstrom, beta = 95.574(4) degrees, V = 5069(4) Angstrom(3), Z = 4) contains two crystallographically independent metal centers with a coordination number of 10 and rather unusual coordination spheres in the shape of tetracapped trigonal prisms. The bridging XeF(2) molecules and one bridging PF(6)- anion, which connect the metal centers, form complicated 3D structures. The structure of [Pb(3)(XeF(2))(11)](PF(6))(6) (space group C2/m; a = 13.01(3) Angstrom, b = 11.437(4) Angstrom, c = 18.487(7) Angstrom, beta = 104.374(9) degrees, V = 2665(6) Angstrom(3), Z = 2) consists of a 3D network of the general formula {[Pb(3)(XeF(2))(10)](PF(6))(6)}n and a noncoordinated XeF(2) molecule fixed in the crystal structure only by weak electrostatic interactions. This structure also contains two crystallographically independent Pb atoms. One of them possesses a unique homoleptic environment built up by eight F atoms from eight XeF(2) molecules in the shape of a cube, whereas the second Pb atom with a coordination number of 9 adopts the shape of a tricapped trigonal prism common for lead compounds. [Pb(3)(XeF(2))(11)](PF(6))(6) and [Sr(3)(XeF(2))(10)](PF(6))(6) are formed when an excess of XeF(2) is used during the process of the crystallization of [M(XeF(2))(3)](PF(6))(2) from their aHF solutions.     

Chemistry of Thiobenzoates: Syntheses, Structures, and NMR Spectra of Salts of [M(SOCPh)(3)](-) (M = Zn, Cd, Hg)

The salts (Ph(4)E)[M(SOCPh)(3)] (M = Zn, Cd, or Hg; E = P or As) are produced by the reaction of Zn(NO(3))(2).6 H(2)O, Cd(NO(3))(2).4H(2)O or HgCl(2) with Et(3)NH(+)PhCOS(-) and (Ph(4)E)X (E = P, X = Br; E = As, X = Cl) in aqueous MeOH in the ratios M(II):PhCOS(-):Ph(4)E(+) = 1:>/=3:>/=1. The crystal structures of (Ph(4)P)[Zn(SOCPh)(3)] (1), (Ph(4)As)[Cd(SOCPh)(3)] (2) and (Ph(4)P)[Hg(SOCPh)(3)] (3) have been determined by single-crystal X-ray diffraction experiments. Crystal data for 1: triclinic; space group P&onemacr;; Z = 2; a = 10.819(2) ?, b = 13.219(3) ?, c = 15.951(3) ?; alpha = 101.75(2) degrees, beta = 97.92(1) degrees, gamma = 109.18(2) degrees. Crystal data for 2: triclinic; space group P&onemacr;; Z= 2; a = 10.741(2) ?, b = 13.168(2) ?, c = 15.809(2) ?; alpha = 101.00(1) degrees, beta = 97.65(1) degrees, gamma = 109.88(1) degrees. Crystal data for 3: monoclinic; space group P2(1)/n; Z = 4; a = 13.302(2) ?, b = 14.276(2) ?, c = 21.108(2) ?; beta = 90.92(1) degrees. The compounds 1 and 2 are isomorphous and isostructural. In the anions [M(SOCPh)(3)](-) the metal atoms have trigonal planar coordination by three sulfur atoms. The metal atoms are further more weakly coordinated intramolecularly to one (M = Hg) or two (M = Zn, Cd) thiobenzoate oxygen atom(s). Using the Bond Valence approach it is found that the contribution of M.O bonding to the total bonding is in the order Cd > Zn > Hg. The metal ((113)Cd, (199)Hg) NMR signals of [M(SOCPh)(3)](-) (M = Cd, Hg) are more shielded than those found for MS(3) kernels in thiolate complexes, a difference attributed to the M(.)O bonding in the thiobenzoate complexes. The (113)Cd resonance of [Cd(SOCPh)(3)](-) in dilute solution is in the region anticipated from dilution data for [Na(Cd{SOCPh}(3))(2)](-).     

Versatility of dithiophosphates in the syntheses of copper(I) complexes with bis(diphenylphosphino)alkanes: abstraction of chloride from dichloromethane

Reactions of [Cu(CH(3)CN)(4)]X (X = PF(6), BF(4)) with bis(diphenylphosphino)methane (dppm = Ph(2)PCH(2)PPh(2)) and ammonium dialkyldithiophosphates, (NH(4))[S(2)P(OR)(2)] (R = Et, (i)Pr), yield a series of novel Cu(I) polynuclear complexes, trinuclear [Cu(3)(mu-dppm)(3)(mu(3)-Cl){S(2)P(OEt)(2)}] (PF(6)) 1 and [Cu(3)(mu-dppm)(2){S(2)P(OR)(2)}(2)](PF(6)) (R = Et, 2; (i)Pr, 3), tetranuclear [Cu(4)(mu-dppm)(2) {S(2)P(OEt)(2)}(4)] 4, and hexanuclear [Cu(6)(mu-dppm)(2)(mu(4)-Cl){S(2)P(O(i)()Pr)(2)}(4)](BF(4)) 5. Similarly, the reaction of [Cu(2)(mu-L-L)(2)(CH(3)CN)(2)](PF(6))(2) (L-L, dppm, dppe = Ph(2)PCH(2)CH(2)PPh(2)) with (NH(4))[S(2)P(OR)(2)] yields dinuclear [Cu(2)(mu-dppm)(2){S(2)P(OR)(2)}(2)] 6 (R= (i)Pr, 6A; Et, 6B), trinuclear [Cu(3)(mu-dppe)(3)(mu-Cl)(2){S(2)P(O(i)Pr)(2)}] 9, and polymeric [Cu(mu(2)-dppe){S(2)P(OR)(2)}](n) (R = Et, 7; (i)Pr, 8) complexes. The formation of 1 and 5 involved the abstraction of chloride from dichloromethane when the Cu/S(2)P(OR)(2) ratio exceeded 1, but when ratio was 1:1, no Cl abstraction occurred, as in compound 4. Compound 9, however, was obtained as a 12% byproduct in the synthesis of 8 using a 1:1:1 ratio of Cu/dppe/S(2)P(O(i)Pr)(2). The chloride binds to Cu atoms in a mu(3)-Cl mode by capping one face of the Cu(3) triangle of cluster 1. A mu(4)-Cl caps a single tetragonal face of the trigonal prism of cluster 5, and in the cluster 9, two chlorides bond in mu(2)-Cl modes. Both clusters 2 and 3 exhibit the mu(3)-S mode of bonding for dtp ligands. Only cluster 5 exhibited close Cu...Cu contacts (2.997-3.0238 A). All of compounds were characterized by single-crystal X-ray diffraction and pertinent crystallographic data for 1, 5, and 9 are are follows: (1) C(79)H(76)ClCu(3)F(6)O(2)P(8)S(2), triclinic, P, a = 11.213(1) A, b = 14.142(1) A, c = 25.910(2) A, alpha = 95.328(2) degrees , beta = 99.594(2) degrees , gamma = 102.581(2) degrees , V = 3918.2(6) A(3), Z = 2; (5) C(74)H(100)BClCu(6)F(4)O(8)P(8)S(8), monoclinic, P2(1)/n, a = 25.198(4) A, b = 15.990(3) A, c = 25.421(4) A, beta = 106.027(3) degrees , V = 9845(3)A(3), Z = 4; (9) C(84)H(86)Cl(2)Cu(3)O(2)P(7)S(2), monoclinic, C2/c, with a = 24.965(3) A, b = 17.058(2) A, c = 20.253(2) A, beta = 95.351(4) degrees , V = 8587.4(17)A(3), Z = 4.     

Structural, dynamic, and theoretical studies of [AunPt2(PPh3)4(mu-S)2-n(mu 3-S)nL][PF6]n [n = 1, L = PPh3; n = 2, L = Ph2PCH2PPh2, (C5H4PPh2)2Fe

Three heterometallic Au-Pt complexes [Pt2(PPh3)4(mu-S)(mu 3-S)Au(PPh3)][PF6] (2), [Pt2(PPh3)4(mu 3-S)2Au2(mu-dppm)]-[PF6]2 (3), and [Pt2(PPh3)4(mu 3-S)2Au2(mu-dppf)][PF6]2 (4) have been synthesized from Pt2(PPh3)4(mu-S)2 (1) [dppm = Ph2PCH2PPh2; dppf = (C5H4PPh2)2Fe] and characterized by single-crystal X-ray crystallography. In 2, the Au(I) atom is anchored on only one of the sulfur centers. In 3 and 4, both sulfur atoms are aurated, showing the ability of 1 to support an overhead bridge structure, viz. [Au2(P-P)], with or without the presence of Au-Au bond. The change of dppf to dppm facilitates such active interactions. Two stereoisomers of complex 3 (3a,b) have been obtained and characterized by single-crystal X-ray crystallography. NLDFT calculations on 2 show that the linear coordination mode is stabilized with respect to the trigonal planar mode by 14.0 kJ/mol. All complexes (2-4) are fluxional in solution with different mechanisms. In 2, the [Au(PPh3)] fragment switches rapidly between the two sulfur sites. Our hybrid MM-NLDFT calculations found a transition state in which the Au(I) bears an irregular trigonal planar geometry (delta G++ = 19.9 kJ/mol), as well as an intermediate in which Au(I) adopts a regular trigonal planar geometry. Complexes 3a,b are roughly diastereoisomeric and related by sigma (mirror plane) conversion. This symmetry operation can be broken down to two mutually dependent fluxional processes: (i) rapid flipping of the dppm methylene group across the molecular plane defined by the overhead bridge; (ii) rocking motion of the two Au atoms across the S...S axis of the (Pt2S2) core. Modeling of the former by molecular mechanics yields a steric barrier of 29.0 kJ/mol, close to that obtained from variable-temperature 31P(1Hz) NMR study (33.7 kJ/mol). In 4, the twisting of the ferrocenyl moiety across the S...S axis is in concert with a rocking motion of the two gold atoms. The movement of dppf is sterically most demanding, and hence, 4 is the only complex that shows a static structure at lower temperatures. Pertinent crystallographic data: (2) space group P1, a = 15.0340(5) A, b = 15.5009(5) A, c = 21.9604(7) A, alpha = 74.805(1) degrees, beta = 85.733(1) degrees, gamma = 78.553(1) degrees, R = 0.0500; (3a) space group Pna2(1), a = 32.0538(4) A, b = 16.0822(3) A, c = 18.9388(3) A, R = 0.0347; (3b) space group Pna2(1), a = 31.950(2) A, b = 16.0157(8) A, c = 18.8460(9) A, R = 0.0478; (4) space group P2(1)/c, a = 13.8668(2) A, b = 51.7754(4) A, c = 15.9660(2) A, beta = 113.786(1) degrees, R = 0.0649.     

Synthesis and Electrochemistry of Heterobimetallic Ruthenium/Platinum and Molybdenum/Platinum Complexes

As starting materials for heterobimetallic complexes, [RuCp(PPh(3))CO(PPh(2)H)]PF(6) and [RuCp(PPh(3))CO(eta(1)-dppm)]PF(6) were prepared from RuCp(PPh(3))(CO)Cl. In the course of preparing [RuCp(eta(2)-dppm)(eta(1)-dppm)]Cl from RuCp(Ph(3)P)(eta(1)-dppm)Cl, the new monomer RuCpCl(eta(1)-dppm)(2) was isolated. The uncommon coordination mode of the two monodentate bis(phosphines) was confirmed by X-ray crystallography [a = 11.490(1) ?, b = 14.869(2) ?, c = 15.447(2) ?, alpha = 84.63(1) degrees, beta = 70.55(1) degrees, gamma = 72.92(1) degrees, V = 2378.7(5) ?(3), d(calc) = 1.355 g cm(-)(3) (298 K), triclinic, P&onemacr;, Z = 2]. The dppm-bridged bimetallic complexes RuCp(PPh(3))Cl(&mgr;-dppm)PtCl(2), RuCpCl(&mgr;-dppm)(2)PtCl(2), and [RuCp(PPh(3))CO(&mgr;-dppm)PtCl(2)]PF(6) each exhibit electrochemistry consistent with varying degrees of metal-metal interaction. The cationic heterobimetallic complexes [Mo(CO)(3)(&mgr;-dppm)(2)Pt(H)]PF(6) and [MoCp(CO)(2)(&mgr;-PPh(2))(&mgr;-H)Pt(PPh(3))(MeCN)]PF(6) were prepared by chloride abstraction from the corresponding neutral bimetallic species and show electrochemical behavior similar to the analogous Ru/Pt complexes.     

Luminescent chains formed from neutral, triangular gold complexes sandwiching TlI and AgI. Structures of (Ag([Au(mu-C2,N3-bzim)]3)2)BF4.CH2Cl2, (Tl([Au(mu-C2,N3-bzim)]3)2)PF(6).0.5THF (bzim = 1-benzylimidazolate), and (Tl([Au(mu-C(OEt)=NC6H4CH3)]3)2)PF6.THF, with MAu6 (M = Ag+, Tl+) cluster cores

It has been found that several trinuclear complexes of AuI interact with silver and thallium salts to intercalate Ag+ and Tl+ cations, thereby forming chains. The resulting sandwich clusters center the cations between the planar trinuclear moieties producing structures in which six AuI atoms interact with each cation in a distorted trigonal prismatic coordination. The resultant (B3AB3B3AB3)infinity pattern of metal atoms also shows short (approximately 3.0 A) aurophilic interactions between BAB molecular centers. These compounds display a strong visible luminescence, under UV excitation, which is sensitive to temperature and the metal ion interacting with the gold. X-ray crystal structures are reported for Ag([Au(mu-C2,N3-bzim)]3)2BF4CH2Cl2 (P1, Z = 2, a = 14.4505(1) A; b = 15.098(2)A; c = 15.957(1)A; alpha = 106.189(3) degrees; beta = 103.551(5) degrees; gamma = 101.310(5) degrees); Tl([Au(mu-C2,N3-bzim)]3)2PF(6)05C4H8O (P1, Z = 2, a = 15.2093(1)A; b = 15.3931(4)A; c = 16.1599(4)A; alpha = 106.018(1) degrees; beta = 101.585(2) degrees; gamma = 102.068(2) degrees); and Tl([Au(mu-C(OEt)=NC6H4CH3)]3)2PF6.C4H8O (P2(1)/n, Z = 4, a = 16.4136(3)A; b = 27.6277(4)A; c = 16.7182(1)A; beta = 105.644(1) degrees). Each compound shows that the intercalated cation, Ag+ or Tl+, coordinates to a distorted trigonal prism of six AuI atoms. The counteranions reside well apart from the cations between the cluster chains.     

Synthesis,structure, and reactivity of some sterically hindered (Silylamino)phosphines

A series of new (silylamino)phosphines that contain sterically bulky silyl groups on nitrogen were prepared by deprotonation/substitution reactions of the hindered disilylamines t-BuR(2)Si(Me(3)Si)NH (1, R = Me; 2, R = Ph) and (Et(3)Si)(2)NH (3). Sequential treatment of the N-lithio derivatives of 1-3 with PCl(3) or PhPCl(2) and MeLi gave the corresponding (silylamino)phosphines t-BuR(2)Si(Me(3)Si)NP(R')Me (5, R = Me, R' = Ph; 6, R = Ph, R' = Me) and (Et(3)Si)(2)NP(R)Me (11, R = Me; 12, R = Ph) in high yields. Two of the P-chloro intermediates t-BuR(2)Si(Me(3)Si)NP(Ph)Cl (7, R = Ph; 9, R = Me) were also isolated and fully characterized. Hydrolysis of 7 afforded the crystalline PH-substituted aminophosphine oxide t-BuPh(2)SiN(H)P(Ph)(=O)H (10). Thermal decomposition of 7 occurred with elimination of Me(3)SiCl and formation of a novel P(2)N(2) four-membered ring system (36) that contains both P(III) and P(V) centers. Reactions of the N-lithio derivatives of amines 1 and 2 with phosphorus trihalides afforded the thermally stable -PF(2) derivatives t-BuR(2)Si(Me(3)Si)NPF(2) (13, R = Me; 14, R = Ph) and the unstable -PCl(2) analogue 17 (R = Ph). Reduction (using LiAlH(4)) of the SiPh-substituted dihalophosphines 14 and 17 gave the unstable parent phosphine t-BuPh(2)Si(Me(3)Si)NPH(2) (15). The P-organo-substituted (silylamino)phosphines underwent oxidative bromination to afford high yields of the corresponding N-silyl-P-bromophosphoranimines t-BuR(2)SiN=P(R')(Me)Br (18, R = R' = Me; 19, R = Me, R' = Ph; 20, R = Ph, R' = Me) and Et(3)SiN=P(R)(Me)Br (23, R = Me; 24, R = Ph). Subsequent treatment of these reactive PBr compounds with lithium trifluoroethoxide or phenoxide produced the corresponding PO derivatives t-BuR(2)SiN=P(R')(Me)OR' ' (25 and 26, R' ' = CH(2)CF(3); 28-30, R' ' = Ph) and Et(3)SiN=P(R)(Me)OR' (31 and 33, R' = CH(2)CF(3); 32 and 34, R = Ph), respectively. Many of the new compounds containing the bulky tert-butyldiphenylsilyl group, t-BuPh(2)Si, were solids that gave crystals suitable for X-ray diffraction studies. Consequently, the crystal structures of three (silylamino)phosphines (6, 7, and 14), one (silylamino)phosphine oxide (10), one N-silylphosphoranimine (30), and the cyclic compound 36 were determined. Among the (silylamino)phosphines, the P-N bond distances [6, N-PMe(2), 1.725(3) A; 7, N-P(Ph)Cl, 1.68(1) A, 14, N-PF(2), 1.652(4) A] decreased significantly as the electron-withdrawing nature of the phosphorus substituents increased. The N-silylphosphoranimine t-BuPh(2)SiN=PMe(2)OPh (30), which is a model system for poly(phosphazene) precursors, had a much shorter P=N distance of 1.512(6) A and a wide Si-N-P bond angle of 166.4(3) degrees. A similar P=N bond distance [1.514(7) A] and Si-N-P angle [169.9(6) degrees ] were observed for the exocyclic P=N-Si linkage in the ring compound 36, while the phosphine oxide 10 had P-N and P=O distances of 1.637(4) and 1.496(3) A, respectively, and a Si-N-P angle of 134.3(2) degrees.     

Synthesis, Structure, and Characterization of a Novel Manganese(IV) Monomer, [Mn(IV)(Me(3)TACN)(OMe)(3)](PF(6)) (Me(3)TACN = N,N',N"-Trimethyl-1,4,7-triazacyclononane), and Its Activity toward Olefin Oxidation with Hydrogen Peroxide

A novel manganese(IV) monomer, [Mn(IV)(Me(3)TACN)(OMe)(3)](PF(6)), has been synthesized in methanol by the reaction of MnCl(2) with the ligand, N,N',N"-trimethyl-1,4,7-triazacyclononane (Me(3)TACN), in the presence of Na(2)O(2). The resulting product was isolated as the red/brown crystalline hexafluorophosphate salt. The compound crystallizes in the space group P2/c with the cell dimensions a = 15.652(2) ?, b = 8.740(1) ?, c = 15.208(2) ?, beta = 108.81(1) degrees, V = 1969.4(4) ?(3), and Z = 4. The structure was solved by the heavy-atom method and was refined by full-matrix least-squares techniques to a final value of R = 0.067 (R(w) = 0.097) based upon 3087 observations. The manganese atom in the molecule is six-coordinate in an N(3)O(3) ligand environment with the triazacyclononane facially coordinated. Pertinent average bond distances and angles are as follows: Mn-O, 1.797(5) ?; Mn-N, 2.116(5) ?; O-Mn-O, 97.8(2) degrees; N-Mn-N, 81.4(2) degrees; O-Mn-N, 167.8 degrees (2); O-Mn-N, 86.8(2) degrees; O-Mn-N, 92.8(2) degrees. The complex was further characterized by UV-vis and EPR spectroscopies, solution magnetic susceptibility measurements, FAB-MS, and electrochemistry. [Mn(IV)(Me(3)TACN)(OMe)(3)](PF(6)) was found to catalyze the oxidation of water-soluble olefins using hydrogen peroxide as the oxidant in an aqueous medium. The catalyzed rates of oxidation of these olefins indicate at least a 12-fold rate enhancement over oxidant alone. The unusual stability of the catalytic species was demonstrated by the repeated additions of substrate and oxidant while maintaining a constant catalytic rate of oxidation.     

Antiferromagnetic coupling in a six-coordinate high spin cobalt(II)-semiquinonato complex

The 3,5-di-tert-butyl-catecholato and 9,10-phenanthrenecatecholato adducts of the cobalt-tetraazamacrocycle complex Co(Me(4)cyclam)(2+) (Me(4)cyclam = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) were synthesized and oxidized. The oxidation reaction products were isolated in the solid state as hexafluorophosphate derivatives. Both these complexes can be formulated as 1:1 cobalt(II)-semiquinonato complexes, that is, Co(Me(4)cyclam)(DBSQ)PF(6) (1) and Co(Me(4)cyclam)(PhSQ)PF(6) (2), in the temperature range 4-300 K, in striking contrast with the charge distribution found in similar adducts formed by related tetraazamacrocycles. The synthesis strategy and the structural, spectroscopic, and magnetic properties are reported and discussed. The crystallographic data for 2 are as follows: monoclinic, space group P2(1)/a, nomicron. 14, a = 14.087(4) A, b = 15.873(4) A, c = 14.263 (7) A, alpha = 89.91(3) degrees, beta = 107.34(2) degrees, gamma = 90.08(2) degrees, Z = 4. Both these complexes are characterized by triplet electronic ground states arising from the antiferromagnetic coupling between the high-spin d(7) metal ion and the radical ligand.