Rh(II) and Rh(I) two-legged piano-stool complexes: structure,reactivity, and electronic properties

The ligand 1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene, 3, was used to synthesize a mononuclear Rh(II) complex [(eta(1):eta(6):eta(1)-1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh][PF(6)](2), 6+, in a two-legged piano-stool geometry. The structural and electronic properties of this novel complex including a single-crystal EPR analysis are reported. The complex can be cleanly interconverted with its Rh(I) form, allowing for a comparison of the structural properties and reactivity of both oxidation states. The Rh(I) form 6 reacts with CO, tert-butyl isocyanide, and acetonitrile to form a series of 15-membered mononuclear cyclophanes [(eta(1):eta(1)-1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh(CO)(3)][PF(6)] (8), [(eta(1):eta(1)-1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh(CNC(CH(3))(3))(2)][PF(6)] (10), and [(eta(1):eta(1)-1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh(CO)(CH(3)CN)][PF(6)] (11). The Rh(II) complex 6+ reacts with the same small molecules, but over shorter periods of time, to form the same Rh(I) products. In addition, a model two-legged piano-stool complex [(eta(1):eta(6):eta(1)-1,4-bis[3-(diphenylphosphino)propoxy]-2,3,5,6-tetramethylbenzene)Rh][B(C(6)F(5))(4)], 5, has been synthesized and characterized for comparison purposes. The solid-state structures of complexes 5, 6, 6+, and 11 are reported. Structure data for 5: triclinic; P(-)1; a = 10.1587(7) A; b = 11.5228(8) A; c = 17.2381(12) A; alpha = 96.4379(13) degrees; beta = 91.1870(12) degrees; gamma = 106.1470(13) degrees; Z = 2. 6: triclinic; P(-)1; a = 11.1934(5) A; b = 12.4807(6) A; c = 16.1771(7) A; alpha = 81.935(7) degrees; beta = 89.943(1) degrees; gamma = 78.292(1) degrees; Z = 2. 6+: monoclinic; P2(1)/n; a = 11.9371(18) A; b = 32.401(5) A; c = 12.782(2) A; beta = 102.890(3) degrees; Z = 4. 11: triclinic; P(-)1; a = 13.5476(7) A; b = 13.8306(7) A; c = 14.9948(8) A; alpha = 74.551(1) degrees; beta = 73.895(1) degrees; gamma = 66.046(1) degrees; Z = 2.     

Redox-associated eta(1) to eta(2) conversion of disulfide ligands in dinuclear ruthenium complexes

Disulfide-bridged dinuclear ruthenium complexes [[Ru(MeCN)(P(OMe)(3))(2)](2)(mu-X)(mu,eta(2)-S(2))][ZnX(3)(MeCN)] (X = Cl (2), Br (4)), [[Ru(MeCN)(P(OMe)(3))(2)](2)(mu-Cl)(2)(mu,eta(1)-S(2))](CF(3)SO(3)) (5), [[Ru(MeCN)(P(OMe)(3))(2)](2)(mu-Cl)(mu,eta(2)-S(2))](BF(4)) (6), and [[Ru(MeCN)(2)(P(OMe)(3))(2)](2)(mu-Cl)(mu,eta(1)-S(2))](CF(3)SO(3))(3) (7) were synthesized, and the crystal structures of 2 and 4 were determined. Crystal data: 2, triclinic, P1, a = 15.921(4) A, b = 17.484(4) A, c = 8.774(2) A, alpha = 103.14(2) degrees, beta = 102.30(2) degrees, gamma = 109.68(2) degrees, V = 2124(1) A(3), Z = 2, R (R(w)) = 0.055 (0.074); 4, triclinic, P1 a = 15.943(4) A, b = 17.703(4) A, c = 8.883(1) A, alpha = 102.96(2) degrees, beta = 102.02(2) degrees, gamma = 109.10(2) degrees, V = 2198.4(9) A(3), Z = 2, R (R(w)) = 0.048 (0.067). Complexes 2 and 4 were obtained by reduction of the disulfide-bridged ruthenium complexes [[RuX(P(OMe)(3))(2)](2)(mu-X)(2)(mu,eta(1)-S(2))] (X = Cl (1), Br (3)) with zinc, respectively. Complex 5 was synthesized by oxidation of 2 with AgCF(3)SO(3). Through these redox steps, the coordination mode of the disulfide ligand was converted from mu,eta(1) in 1 and 3 to mu,eta(2) in 2 and 4 and further reverted to mu,eta(1) in 5. Electrochemical studies of 6 indicated that similar conversion of the coordination mode occurs also in electrochemical redox reactions.     

Cobalt-complexed conjugated diyne salts: a family of rigid masked dielectrophiles. Syntheses, structures, and double nucleophilic substitutions

A family of dicationic diyne salts of the general formula [(Co2(CO)6)2-mu,eta2,eta2-(Nu-CH2C(triple bond)C-C(triple bond)CCH2-Nu)][BF4]2 [Nu = SMe2 (3); Nu = NC6H7, 3-picoline, (5); Nu = NC9H7, quinoline (7)] were prepared and fully characterized. Three X-ray molecular structures of 3, 5, and the neutral starting material 2,4-hexadiyne-1,6-diol complex [(Co2(CO)6)2-mu,eta2,eta2-(HO-CH2C(triple bond)C-C(triple bond)CCH2-OH)] (1) are presented. Complex 1 crystallizes in the triclinic space group P1 with a = 14.722(2) A, b = 14.571(3) A, c = 14.722(2) A, alpha = 105.17(1) degrees, beta = 113.30(1) degrees, gamma = 99.20(1) degrees, and Z = 4. Complex 3 crystallizes in the monoclinic space group P2(1)/n with a = 12.758(3) A, b = 13.360(3) A, c = 20.494(3) A, beta = 91.44(1) degrees, and Z = 4, and compound 5 also crystallizes in the monoclinic space group P2(1)/n with a = 9.426(2) A, b = 21.739(5) A, c = 18.704(3) A, beta = 94.86(1) degrees, and Z = 4. The X-ray structures provide us with valuable information on the arrangement of the Co2-alkyne units, which have a cis geometry and are in sharp contrast to that observed generally for diyne-tetracobalt compounds. Complex [(Co2(CO)6)2-mu,eta2,eta2-(Me2S-CH2C(triple bond)C-C(triple bond)CCH2-SMe2)][BF4]2 (3) reacts with N-, S-, and P-centered nucleophiles and affords the related substituted complexes in high yields. The stability and reactivity of the disulfonium diyne complex 3 toward nucleophiles are compared to those of the analogous disulfonium-yne complex [(Co2(CO)6)2-mu,eta2,eta2-(Me2S-CH2-C(triple bond)C-CH2-SMe2)][BF4]2 (4).     

Rhenium(I) carbonyl complexes of 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPT). Rhenium(I)-promoted methoxylation of the triazine ring carbon atom in dinuclear rhenium complexes

2,4,6-Tris(2-pyridyl)-1,3,5-triazine (TPT) bridged dinuclear rhenium(I) tricarbonyl halide complexes with the composition (mu-TPT)[ReX(CO)(3)](2) (3, X = Cl; 4, X = Br) can be made either by one-pot reaction of TPT with 2 equiv of [ReX(CO)(5)] (X = Cl and Br) in chloroform or by reacting mononuclear [ReX(CO)(3)(TPT)] (2) (1, X = Cl; 2, X = Br) with an excess amount of [ReX(CO)(5)]. Crystal data are as follows. 1: monoclinic, P2(1)/c, a = 11.751(1) A, b = 11.376(1) A, c = 15.562(2) A, beta = 103.584(2) degrees, V = 2022.0(4) A(3), Z = 4. 2: monoclinic, P2(1)/c, a = 11.896(1) A, b = 11.396(1) A, c = 15.655(1) A, beta = 104.474(2) degrees, V = 2054.9(3) A(3), Z = 4. 3: triclinic, P1, a = 11.541(2) A, b = 12.119(2) A, c = 13.199(2) A, alpha = 80.377(2) degrees, beta = 76.204(3) degrees, gamma = 66.826(2) degrees, V = 1642.5(4) A(3), Z = 2. Crystals of 4 crystallized from acetone: triclinic, P1, a = 11.586(5) A, b = 12.144(5) A, c = 13.364(6) A, alpha = 80.599(7) degrees, beta = 76.271(8) degrees, gamma = 67.158(8) degrees, V = 1678.0(12) A(3), Z = 2. Crystals of 4' are obtained from CH(2)Cl(2)-pentane solution: monoclinic, C2/c, a = 17.555(4) A, b = 15.277(3) A, c = 13.093(3) A, beta = 111.179(3) degrees, V = 3274.0(12) A(3), Z = 4. By contrast, similar reactions in the presence of methanol yielded complexes with the composition [mu-C(3)N(3)(OMe)(py)(2)(pyH)][ReX(CO)(3)](2) (5, X = Cl; 6, X = Br). Crystal data for 5: monoclinic, C2/c, a = 26.952(2) A, b = 16.602(1) A, c = 14.641(1) A, beta = 116.147(1) degrees, V = 5880.5(8) A(3), Z = 8. 6: monoclinic, C2/c, a = 27.513(3) A, b = 16.740(2) A, c = 14.837(2) A, beta = 116.925(2) degrees, V = 6092.8(10) A(3), Z = 8. An unusual metal-induced methoxylation at the carbon atom of the triazine ring of the bridging TPT ligand was observed. The nucleophilic attack of MeO(-) on C(3) results in a tetrahedral geometry around the carbon atom. Concomitantly, the uncoordinated pyridyl ring is protonated and rotated into a perpendicular orientation relative to the central C(3)N(3) ring. Reaction of TPT with [NEt(4)](2)[ReBr(3)(CO)(3)] in benzene-methanol resulted in an unexpected dinuclear complex 7, with formulation [mu-C(3)N(3)(OMe)(py)(3)][Re(CO)(3)][ReBr(CO)(3)]. The methoxylated TPT ligand functions simultaneously as a tridentate and bidentate ligand with two fac-Re(CO)(3)(+) cores. Crystal data for 7: monoclinic, P2(1)/n, a = 12.114(1) A, b = 14.878(1) A, c = 15.807(1) A, beta = 104.601(1) degrees, V = 2756.9(3) A(3), Z = 4.     

Structural Chemistry of Poly(ethylene glycol) Complexes of Lead(II) Nitrate and Lead(II) Bromide

The reaction of 1:1 stoichiometries (1:1.5 for the nitrate/tetraethylene glycol (EO4) and pentaethylene glycol (EO5) complexes) of PbX(2) (X = NO(3), Br) with five- to eight-donor poly(ethylene glycols) (PEGs) in 3:1 CH(3)CN/CH(3)OH (CH(3)CN only for the nitrate/EO5 complex) followed by solvent evaporation resulted in six crystalline materials upon which X-ray structural analyses were carried out: [Pb(NO(3))(2)(EO4)](n)(), [Pb(NO(3))(2)(EO5)], [Pb(NO(3))(2)(EO6)], [PbBr(EO5)(&mgr;-Br)PbBr(2)].H(2)O, [PbBr(NCMe)(EO6)](2)[PbBr(2)(EO6)][PbBr(3)](2), and [PbBr(EO7)][PbBr(3)]. The nitrates crystallize as tight ion pairs with the PEG ligands coordinating in an equatorial plane around the Pb(2+) ions. Because EO4 has only five oxygen donors, this complex exhibits steric unsaturation which is overcome by a monodentate interaction with a third nitrate anion that is also coordinated to a neighboring Pb(2+) ion. The six donors of EO5 coordinate in an equatorial plane resulting in a 10-coordinate complex with trans, twisted, bidentate nitrate anions. The seven-donor hexaethylene glycol (EO6) only uses six of its oxygen donors to coordinate Pb(2+). [Pb(NO(3))(2)(EO4)](n)() is monoclinic, P2(1)/c, with a = 7.902(3) ?, b = 22.136(6) ?, c = 8.910(2) ?, beta = 90.96(3) degrees, and Z = 4. [Pb(NO(3))(2)(EO5)] is triclinic P&onemacr;, with a = 9.332(3) ?, b = 10.025(3) ?, c = 11.688(4) ?, alpha = 68.41(3) degrees, beta = 68.39(3) degrees, gamma = 68.58(3) degrees, and Z = 2. [Pb(NO(3))(2)(EO6)] is monoclinic P2(1)/c, with a = 16.289(4) ?, b = 10.773(4) ?, c = 12.329(4) ?, beta = 106.77(2) degrees, and Z = 4. Lead(II) bromide complexes with PEGs tend to crystallize as PEG complexed cations with polymeric lead(II) bromide anions. In the EO5 complex, bromide anions in the polymer also coordinate to the PEG-wrapped Pb(2+) cations. The hexa- and heptaethylene glycol (EO6 and EO7, respectively) complexes contain discreet ions. In these halide complexes, EO7 is the only PEG to expand the Pb(2+) coordination number from eight to nine. [PbBr(EO5)(&mgr;-Br)PbBr(2)].H(2)O is triclinic P&onemacr;, with a = 7.922(6) ?,b = 15.802(9) ?, c = 19.001(9) ?, alpha = 73.19(8) degrees, beta = 88.91(9) degrees, gamma = 87.22(9) degrees, and Z = 4. [PbBr(NCMe)(EO6)](2)[PbBr(2)(EO6)][PbBr(3)](2) is monoclinic P2(1)/c, with a = 14.389(4) ?, b = 31.931(9) ?, c = 8.029(2) ?, beta = 97.76(3) degrees, and Z = 2. [PbBr(EO7)][PbBr(3)] is monoclinic Cc, with a = 13.165(3) ?, b = 24.732(5) ?, c = 8.007(1) ?, beta = 94.58(2) degrees, and Z = 4.     

New antitumor-active azole-bridged dinuclear platinum(II) complexes: synthesis, characterization, crystal structures, and cytotoxic studies

Three new derivatives of the cytotoxic azole-bridged dinuclear platinum(II) complex [(cis-Pt(NH3)2)2(mu-OH)(mu-pz)][NO3]2 (1) have been prepared and structurally characterized. Their formulas are [(cis-Pt(NH3)2)2(mu-OH)(mu-1,2,3-ta)][NO3]2 (2) (1,2,3-ta = 1,2,3-triazolate), [(Pt(R,R-dach))(mu-OH)(mu-pz)(Pt(S,S- dach))][NO3]2 (3) (dach = 1,2-diaminocyclohexane, pz = pyrazolate), and [(Pt(R,R-dach))(mu-1,2,3- ta)2(Pt(S,S-dach))][NO3]2 (4). The compounds were characterized by 1H, 13C, and 195Pt NMR spectroscopy, and elemental analysis, and their crystal structures were determined. Relevant data for 2: triclinic, space group P1, a = 8.5225(15) A, b = 9.1977(18) A, c = 9.9771(7) A, alpha = 66.988(10) degrees, beta = 75.423(9) degrees, gamma = 67.321(13) degrees, Z = 2. 3: orthorhombic, space group Pca2(1), a = 17.7653(3) A, b = 12.4076(3) A, c = 10.7091(3) A, Z = 4. 4: orthorhombic, space group Pbca, a = 13.8944(1) A, b = 17.8668(1) A, c = 20.7647(2) A, Z = 8. In the crystal structures of 2, and 3, the intramolecular distances between the two Pt atoms are 3.4411(6) and 3.4873(5) A, and the dihedral angles between the platinum coordination planes are 14.1(3) and 9.3(4) degrees, respectively. In 2, an intramolecular hydrogen bond is observed between N9 of the ammine ligand and the noncoordinated nitrogen atom (N3) of the triazole ring (N9...N3: 2.962(10) A). 4 has a boat-form structure, and the two coordination planes cross at 83.64(10) degrees. A cytotoxicity assay of these dinuclear platinum(II) compounds on human tumor cell lines was performed. In most of the cell lines, 1 and 2 showed much higher cytotoxicity than those of cisplatin. On the other hand, 3 was found to be moderately active, and 4 was found only marginally cytotoxic. Implications of these findings are discussed in the context of a structure-activity relationship.     

Amine-templated linear vanadium sulfates with different chain structures

Amine-templated vanadium sulfates of the formula [HN(CH(2))(6)NH][(V(IV)O)(2)(OH)(2)(SO(4))(2)].H(2)O, I, [H(3)N(CH(2))(2)NH(3)][V(III)(OH)(SO(4))(2)].H(2)O, II, and [H(2)N(CH(2))(4)NH(2)][(V(IV)O)(H(2)O)(SO(4))(2)], III, have been prepared under hydrothermal conditions. These vanadium sulfates add to the new emerging family of organically templated metal sulfates. Compound I has a linear chain structure consisting of V(2)O(8) square-pyramid dimers connected by corner-sharing SO(4) tetrahedra, creating four-membered rings along the chain. Both II and III possess simple linear chain topologies formed by VO(6) octahedra and SO(4) tetrahedra, with II having the tancoite chain structure. Compound I crystallizes in the triclinic space group P1 (No. 2) with a = 7.4852(4) A, b = 9.5373(5) A, c = 11.9177(6) A, alpha = 77.22 degrees, beta = 76.47(2) degrees, gamma = 80.86 degrees, Z = 2. Compound II: monoclinic, space group P2(1)/c (No. 14), a = 6.942(2) A, b = 10.317(3) A, c = 15.102(6) A, beta = 90.64(4) degrees, Z = 4. Compound III: triclinic, space group P1 (No. 2) with a = 6.2558(10) A, b = 7.0663(14) A, c = 15.592(4) A, alpha = 90.46(2) degrees, beta = 90.47(2) degrees, gamma = 115.68(2) degrees, Z = 2. Magnetic susceptibility measurements reveal weak antiferromagnetic interactions in I and III and ferromagnetic interactions in II.     

Controlling substitution chemistry in ruthenium(II) systems. Synthesis of heteroleptic complexes incorporating the [Ru([9]aneS3)]2+ metal center

The complex [Ru(py)3([9]aneS3)][PF6]2, 1 (py = pyridine), has proved to be a suitable starting material for the synthesis of heteroleptic Ru(II) complexes. By exploiting unfavorable steric interactions between 2-H and 6-H hydrogens of coordinated pyridyl ligands, we have synthesized half-sandwich complexes incorporating the thiocrown [9]aneS3 and a variety of facially coordinated N-donor ligands. Such complexes are easily prepared: Stirring 1 at room temperature in the presence of a suitable nitrile ligand leads to the exclusive substitution of one py ligand to produce complexes such as [([9]aneS3)Ru(py)2(NCMe)][PF6]2, 2. However, if the same reaction is carried out at higher temperatures, two py ligands are substituted, leading to complexes such as [([9]aneS3)Ru(py)(NCMe)2][PF6]2, 3. An alternative approach to such heteroleptic species has also been developed which exploits the restricted ability of thioethers to neutralize positive charges through sigma-donation. This phenomenon allows the synthesis of heteroleptic complexes in a two-step procedure via monocationic species. By variation of the donor/acceptor properties of ligands incorporated into the [Ru([9]aneS3)]2+ metal center, it is possible to tune the Ru(III)/Ru(II) redox couple over a range of > 700 mV. The solid-state structures of 1-3 were confirmed by X-ray crystallography studies. Crystal data: C22H30F12N4O2P2RuS3 (1.CH3NO2), monoclinic, Cc, a = 23.267(5) A, b = 11.5457(18) A, c = 26.192(5) A, alpha = 90 degrees, beta = 114.836(10) degrees, gamma = 90 degrees, Z = 8; C18H25F12N3P2RuS3 (2), triclinic, P1, a = 11.3958(19) A, b = 11.4280(19) A, c = 11.930(2) A, alpha = 100.518(3) degrees, beta = 100.542(3) degrees, gamma = 112,493(3) degrees, Z = 2; C15H23F12N3P2RuS3 (3), orthorhombic, Pna2(1)), a = 14.748(5) A, b = 18.037(18) A, c = 10.341(5) A, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, Z = 4.     

Syntheses, structures, and stabilities of [PPh(4)][WS(3)(SR)](R=(i)Bu,(i)Pr,(i)Bu, benzyl, allyl) and [PPh(4)][MoS(3)(S(t)Bu)

Intermediates in the condensation process of [MS(4)](2)(-) (M = Mo, W) to polythiometalates, in the presence of alkyl halides, had not been reported prior to our communication of [PPh(4)][WS(3)(SEt)] (Boorman, P. M.; Wang, M.; Parvez, M. J. Chem. Soc., Chem. Commun. 1995, 999-1000). We now report the isolation of a range of related compounds, with 1 degrees, 2 degrees, and 3 degrees alkyl thiolate ligands, including one Mo example. [PPh(4)][WS(3)(SR)] (R = (i)Bu (1), (i)Pr (2), (t)Bu (3), benzyl (5), allyl (6)) and [PPh(4)][MoS(3)(S(t)Bu)] (4) have been isolated in fair to good yields from the reaction of [PPh(4)](2)[MS(4)] with the appropriate alkyl halide in acetonitrile and subjected to analysis by X-ray crystallography. Crystal data are as follows: for 1, triclinic space group P1 (No. 2), a = 11.0377(6) A, b = 11.1307(5) A, c = 13.6286(7) A, alpha = 82.941(1) degrees, beta = 84.877(1) degrees, gamma = 60.826(1) degrees, Z = 2; for 2, monoclinic space group P2(1)/c (No. 14), a = 9.499(6) A, b = 15.913(5) A, c = 18.582(6) A, beta = 99.29(4) degrees, Z = 4; for 3, monoclinic space group P2(1)/n (No. 14), a = 10.667(2) A, b = 17.578(2) A, c = 16.117(3) A, beta = 101.67(1) degrees, Z = 4; for 4, monoclinic space group P2(1)/n (No. 14), a = 10.558(3) A, b = 17.477(3) A, c = 15.954(3) A, beta = 101.18(2) degrees, Z = 4; for 5, monoclinic space group P2(1)/n (No. 14), a = 16.2111(9) A, b = 11.0080(6) A, c = 18.1339(10) A, beta = 111.722(1) degrees, Z = 4; for 6, triclinic space group P1 (No. 2), a = 9.4716(9) A, b = 10.4336(10) A, c = 14.4186(14) A, alpha = 100.183(2) degrees, beta = 90.457(2) degrees, gamma = 91.747(2) degrees, Z = 2. Structures 3 and 4 are isomorphous, and 1 exhibits disorder about the tertiary carbon. 6 has been shown to exhibit fluxionality in solution by variable-temperature (1)H NMR studies, and an allyl migration mechanism is implicated in this process. The kinetics for the reaction of [WS(4)](2)(-) and EtBr were measured and suggest an associative nucleophilic substitution (S(N)2) mechanism. The decomposition of the [WS(3)(SEt)](-) ion is shown to be second order with respect to this ion, suggesting the formation of a transient binuclear intermediate. M-S bond cleavage is the predominant step in decomposition of 1-6 to yield alkyl sulfides, alkyl thiols, and polythiometalates such as [PPh(4)](2)[M(3)S(9)]. In contrast, reactions of [PPh(4)](2)[WO(x)()S(4)(-)(x)()] (x = 1, 2) with (t)BuBr result in the additional decomposition product of isobutene, presumably by C-S bond cleavage and beta-hydrogen transfer. Interestingly, the reaction of [PPh(4)](2)[WOS(3)] with BzCl yields 5 as the only isolable W thiolate species.     

Synthesis and structural characterization of quaternary thorium selenophosphates: A2ThP3Se9 (A = K, Rb) and Cs4Th2P5Se17

Single crystals of A2ThP3Se9 (A = K (I), Rb (II)) and Cs4Th2PsSe17 (III) form from the reaction of Th and P in a molten A2Se3/Se (A = K, Rb, Cs) flux at 750 degrees C for 100 h. Compound I crystallizes in the triclinic space group P1 (No. 2) with unit cell parameters a = 10.4582(5) A, b = 16.5384(8) A, c = 10.2245(5) A, alpha = 107.637(1); beta = 91.652(1); gamma = 90.343(1) degrees, and Z = 2. Compound II crystallizes in the triclinic space group P1 (No. 2) with the unit cell parameters a = 10.5369(5) A, b = 16.6914(8) A, c = 10.2864(5) A, alpha = 107.614(1) degrees, beta = 92.059(1) degrees, gamma = 90.409(1) degrees, and Z = 2. These structures consist of infinite chains of corner-sharing [Th2Se14] units linked by (P2Se6)4- anions in two directions to form a ribbonlike structure along the [100] direction. Compounds I and II are isostructural with the previously reported K2UP3Se9. Compound III crystallizes in the monoclinic space group P2(1)/c (No. 14) with unit cell parameters a = 10.238(1) A, b = 32.182(2) A, c = 10.749(1) A; beta = 95.832(1) degrees, and Z = 4. Cs4Th2P5Se17 consists of infinite chains of corner-sharing, polyhedral [Th2Se13] units that are also linked by (P2Se6)4- anions in the [100] and [010] directions to form a layered structure. The structure of III features an (Se2)2- anion that is bound eta 2 to Th(2) and eta 1 to Th(1). This anion influences the coordination sphere of the 9-coordinate Th(2) atom such that it is best described as bicapped trigonal prismatic where the eta 2-bound anion occupies one coordination site. The composition of III may be formulated as Cs4Th2(P2Se6)5/2(Se2) due to the presence of the (Se2)2- unit. Raman spectra for these compounds and their interpretation are reported.     

Sandwich-type germanotungstates: structure and magnetic properties of the dimeric polyoxoanions [M4(H2O)2(GeW9O34)2]12 - (M = Mn2+, Cu2+, Zn2+, Cd2+)

The novel dimeric germanotungstates [M(4)(H(2)O)(2)(GeW(9)O(34))(2)](12)(-) (M = Mn(2+), Cu(2+), Zn(2+), Cd(2+)) have been synthesized and characterized by IR spectroscopy, elemental analysis, magnetic measurements, and (183)W-NMR spectroscopy. X-ray single-crystal analyses were carried out on Na(12)[Mn(4)(H(2)O)(2)(GeW(9)O(34))(2)].38H(2)O (Na(12)()-1), which crystallizes in the monoclinic system, space group P2(1)/n, with a = 13.0419(8) A, b = 17.8422(10) A, c = 21.1626(12) A, beta = 93.3120(10) degrees, and Z = 2; Na(11)Cs(2)[Cu(4)(H(2)O)(2)(GeW(9)O(34))(2)]Cl.31H(2)O (Na(11)()Cs-2) crystallizes in the triclinic system, space group P, with a = 12.2338(17) A, b = 12.3833(17) A, c = 15.449(2) A, alpha = 100.041(2) degrees, beta = 97.034(2) degrees, gamma = 101.153(2) degrees, and Z = 1; Na(12)[Zn(4)(H(2)O)(2)(GeW(9)O(34))(2)].32H(2)O (Na(12)()-3) crystallizes in the triclinic system, space group P, with a = 11.589(3) A, b = 12.811(3) A, c = 17.221(4) A, alpha = 97.828(6) degrees, beta = 106.169(6) degrees, gamma = 112.113(5) degrees, and Z = 1; Na(12)[Cd(4)(H(2)O)(2)(GeW(9)O(34))(2)].32.2H(2)O (Na(12)()-4) crystallizes also in the triclinic system, space group P, with a = 11.6923(17) A, b = 12.8464(18) A, c = 17.616(2) A, alpha = 98.149(3) degrees, beta = 105.677(3) degrees, gamma = 112.233(2) degrees, and Z = 1. The polyanions consist of two lacunary B-alpha-[GeW(9)O(34)](10)(-) Keggin moieties linked via a rhomblike M(4)O(16) (M = Mn, Cu, Zn, Cd) group leading to a sandwich-type structure. (183)W-NMR studies of the diamagnetic Zn and Cd derivatives indicate that the solid-state polyoxoanion structures are preserved in solution. EPR measurements on Na(12)()-1 at frequencies up to 188 GHz and temperatures down to 4 K yield a single, exchange-narrowed peak, at g(iso) = 1.9949, typical of Mn systems, and an upper limit of |D| = 20.0 mT; its magnetization studies still await further theoretical treatment. Detailed EPR studies on Na(11)()Cs-2 over temperatures down to 2 K and variable frequencies yield g( parallel ) = 2.4303 and g( perpendicular ) = 2.0567 and A( parallel ) = 4.4 mT (delocalized over the Cu(4) framework), with |D| = 12.1 mT. Magnetization studies in addition yield the exchange parameters J(1) = -11 and J(2) = -82 cm(-)(1), in agreement with the EPR studies.     

Europium(II) and ytterbium(II) cyclic organohydroborates: an europium(II) complex with an agostic interaction

Lanthanide bis((cyclooctane-1,5-diyl)dihydroborate) complexes (THF)(4)Ln[(micro-H)(2)BC(8)H(14)](2) (Ln = Eu, 1; Yb, 2) were synthesized by a metathesis reaction between (THF)(x)()LnCl(2) and K[H(2)BC(8)H(14)] in THF in a 1:2 molar ratio. Attempts to prepare the monosubstituted lanthanide cyclic organohydroborates (THF)(x)LnCl[(micro-H)(2)BC(8)H(14)] were unsuccessful. On the basis of the molecular structure and IR spectrum of 1, there is an agostic interaction between Eu(II) and one of the alpha-C-H hydrogens from the [(micro-H)(2)BC(8)H(14)] unit. No such interaction was observed for 2. The coordinated THF in 1 and 2 can be removed under dynamic vacuum, but the solvent ligands remain bound to Yb when 2 is directly dissolved in Et(2)O or toluene. In strong Lewis basic solvents, such as pyridine or CH(3)CN, attack of the Yb-H-B bridge bonds results. Decomposition of 2 to the 9-BBN dimer in CD(2)Cl(2) was observed by (11)B and (1)H NMR spectroscopies. Compound 2 was reacted with 2 equiv of the hydride ion abstracting reagent B(C(6)F(5))(3) to afford the solvent-separated ion pair [Yb(THF)(6)][HB(C(6)F(5))(3)](2) (3). Complexes 1, 2, and 3 were characterized by single-crystal X-ray diffraction analysis. Crystal data: 1 is orthorhombic, Pna2(1), a = 21.975(1) A, b = 9.310(1) A, c = 16.816(1) A, Z = 4; 2 is triclinic, P1, a = 9.862(1) A, b = 10.227(1) A, c = 10.476(1) A, alpha = 69.87(1) degrees, beta = 76.63(1) degrees, gamma = 66.12(1) degrees, Z = 1; 3.Et(2)O is triclinic, P1, a = 13.708(1) A, b = 14.946(1) A, c = 17.177(1) A, alpha = 81.01(1) degrees, beta = 88.32(1) degrees, gamma = 88.54(1) degrees, Z = 2.     

Bis(pyrazol-1-yl)acetates as tripodal heteroscorpionate ligands in iron chemistry: syntheses and structures of iron(II) and iron(III) complexes with bpza, bdmpza, and bdtbpza ligands

The molecular structure of the previously reported species "[Fe(bdtbpza)Cl]" has been revealed by X-ray structure determination to be a ferrous dimer [Fe(bdtbpza)Cl](2) (2c) [bdtbpza = bis(3,5-di-tert-butylpyrazol-1-yl)acetate]. The syntheses of ferrous 2:1 complexes [Fe(bpza)(2)] (3a) and [Fe(bdtbpza)(2)] (3c) as well as ferric 1:1 complexes [NEt(4)][Fe(bpza)Cl(3)] (4a) and [NEt(4)][Fe(bdmpza)Cl(3)] (4b) [bpza = bis(pyrazol-1-yl)acetate, bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate] are reported. Complexes 3a, previously reported [Fe(bdmpza)(2)] (3b), and 3c are high-spin. No spin crossover to the low-spin state was observed in the temperature range of 5-350 K. 4a and 4b are synthesized in one step and in high yield from [NEt(4)](2)[Cl(3)FeOFeCl(3)]. 4a and 4b are iron(III) high-spin complexes. Crystallographic information: 2c (C(24)H(39)ClFeN(4)O(2).CH(2)Cl(2).CH(3)CN) is triclinic, P1, a = 12.171(16) A, b = 12.851(14) A, c = 13.390(13) A, alpha = 98.61(9) degrees, beta = 113.51(11) degrees, gamma = 108.10(5) degrees, Z = 2; 3a (C(8)H(7)Fe(0.5)N(4)O(2)) is monoclinic, P2(1)/n, a = 7.4784(19) A, b = 7.604(3) A, c = 16.196(4) A, beta = 95.397(9) degrees, Z = 4; 3c (C(24)H(39)Fe(0.5)N(4)O(2)) is monoclinic, P2(1)/n, a = 9.939(6) A, b = 18.161(10) A, c = 13.722(8) A, beta = 97.67(7) degrees, Z = 4; 4b (C(20)H(35)Cl(3)FeN(5)O(2)) is monoclinic, C2/c, a = 30.45(6) A, b = 12.33(2) A, c = 16.17(3) A, beta = 118.47(5) degrees, Z = 8.     

Coexistence of long-range ferromagnetic ordering and glassy behavior in one-dimensional bimetallic cyano-bridged polymers

Two new one-dimensional (1-D) 3d-5d cyano-bridged bimetallic assemblies, ([Co(3)(II)(DMF)(12)][W(V)(CN)(8)](2)])(infinity) (1) and ([Mn(3)(II)(bipy)(2)(DMF)(8)][W(V)(CN)(8)](2))(infinity) (2), have been synthesized and characterized, where bipy stands for 2,2'-bipyridine and DMF represents N,N-dimethylformamide. The X-ray analyses show that the two complexes belong to the P(-)1 space group with Z = 1 and C(52)H(84)N(28)O(12)Co(3)W(2), a = 11.690(3) A, b = 12.703(3) A, c = 13.712(3) A, alpha = 86.889(4) degrees, beta = 73.256(4) degrees, and gamma = 77.033(4) degrees for 1 and C(60)H(72)N(28)O(8)Mn(3)W(2), a = 10.672(2) A, b = 13.024(3) A, c = 16.000(3) A, alpha = 78.32(3) degrees, beta = 75.69(3) degrees, and gamma = 66.63(3) degrees for 2. The structures of the two complexes are similar and consist of 12-atom rhombic M(2)W(2)(CN)(4) (M = Co (1), Mn (2)) units, which act as a basic component to be repeatedly connected through W-C-N-M-N-C-W linkages to form a one-dimensional infinite 3,2-chain; these chains are well separated by the DMF molecules or 2,2'-bipyridines coordinated to the metal ions Co(2+) for 1 and Mn(2+) for 2. Magnetic studies, including linear and nonlinear ac susceptibility measurements, demonstrate that the long-range magnetic ordering and spin glass behavior coexist in the two 1-D compounds.     

Adduct formation between alkali metal ions and divalent metal salicylaldimine complexes having methoxy substituents. A structural investigation

Sodium, potassium, and cesium salts (iodides, nitrates, acetates, and tetraphenylborates) form 1/1, 1/2 and 2/3 adducts with MLn [M = Co, Ni, Cu, and Zn; n = 1-4; H2L1 = N,N'-(3-methoxysalicyliden)ethane-1,2-diamine; H2L2, H2L3, and H2L4 are the -propane-1,2-diamine, -o-phenylenediamine, and -propane-1,3-diamine analogues of H2L1). Metal salicyladimine, alkali metal, and anion all exert influence on stoichiometry and reactivity. Sodium ions tend to reside within the planes of the salicylaldimine oxygens, as in Na(NO3)(MeOH).NiL4 (1), Na(NO3)(MeOH).CuL1 (2; both with unusual seven-coordinated sodium), and Na.(NiL4)2I.EtOH.H2O (3; with dodecahedral sodium coordination geometry). Potassium and cesium tend to locate between salicylaldimine ligands as in KI.NiL4 (4) and [Cs(NO3).NiL4]3.MeOH (5; structures with infinite sandwich assemblies), CsI.(NiL2)2.H2O (6), CsI3.(NiL4)2 (7; simple sandwich structures), and [K(MeCN)]2.(NiL4)3 (8; a triple-decker sandwich structure). Crystal data for 1 are the following: triclinic, P1, a = 7.3554(6) A, b = 11.2778(10) A, c = 13.562(2) A, alpha = 96.364(10) degrees, beta = 101.924(9) degrees, gamma = 96.809(10) degrees, Z = 2. For 2, triclinic, P1, a = 7.2247(7) A, b = 11.0427(6) A, c = 13.5610(12) A, alpha = 94.804(5) degrees, beta = 98.669(7) degrees, gamma = 99.26(6) Z = 2. For 3, orthorhombic, Pbca, a = 14.4648(19) A, b = 20.968(3) A, c = 28.404(3) A, Z = 8. For 4, triclinic, P1, a = 12.4904(17) A, b = 13.9363(13) A, c = 14.1060(12) A, alpha = 61.033(7) degrees, beta = 89.567(9) degrees, gamma = 71.579(10) degrees, Z = 2. For 5, monoclinic. P2(1)/n, a = 12.5910(2) A, b = 23.4880(2) A, c = 22.6660(2) A, beta = 99.3500(1) degree, Z = 4. For 6, orthorhombic, Pbca, a = 15.752(3) A, b = 23.276(8) A, c = 25.206(6) A, Z = 8. For 7, triclinic, P1, a = 9.6809(11) A, b = 10.0015(13) A, c = 11.2686(13) A, alpha = 101.03 degrees, beta = 90.97 degrees, gamma = 100.55 degrees, Z = 2. For 8, monoclinic, C2/c, a = 29.573(5) A, b = 18.047(3) A, c = 23.184(3) A, beta = 122.860(10) degrees, Z = 8.     

Octahedral coordination of halide ions (I-, Br-, Cl-) sandwich bonded with tridentate mercuracarborand-3 receptors

The "anti-crown" B-hexamethyl 9-mercuracarborand-3 (1) was shown to complex halide ions (I-, Br-, Cl-) in an eta(3)-sandwich fashion. Symmetry-allowed interactions of the filled halide ion p-orbitals and the corresponding empty mercury p-orbitals result in three equivalent p(Hg)-p(halide)-p(Hg) three-center two-electron bonds and a sandwich structure. The molecular structures of [Li.(H(2)O)(4)][1(2).I].2CH(3)CN, MePPh(3)[1(2).Br].((CH(3))(2)CO)(2).(H(2)O)(2), and PPN[1(2).Cl] were determined by single-crystal X-ray diffraction studies. Compound [Li.(H(2)O)(4)][1(2).I].2CH(3)CN crystallized in the triclinic space group P-1, a = 13.312(8) A, b = 13.983(9) A, c = 13.996(9) A, alpha = 61.16(2) degrees, beta = 82.34(2) degrees, gamma = 86.58(2) degrees, V = 4365(2) A(3), Z = 1, R = 0.063, and R(w) = 0.171. Compound MePPh(3)[1(2).Br].((CH(3))(2)CO)(2).(H(2)O)(2) crystallized in the monoclinic space group C2/c, a = 24.671(8) A, b = 17.576(6) A, c = 26.079(8) A, beta = 106.424(6) degrees, V = 10847(6) A(3), Z = 8, R = 0.0607, and R(w) = 0.1506. Compound PPN[1(2).Cl] crystallized in the monoclinic space group C2/m, a = 37.27(2) A, b = 29.25(1) A, c = 10.990(4) A, beta = 100.659(7) degrees, V = 11774(8) A(3), Z = 4, R = 0.0911, and R(w) = 0.2369.     

A novel three-dimensional network constructed from tetramolybdate clusters linked via two types of copper complex fragments: synthesis, characterization, and magnetic behavior of [[CuII(2,2'-bpy)][CuII(IN)2][Mo4O12(OH)2]

A novel three-dimensional copper molybdate with mixed ligands, [[Cu(II)(2,2'-bpy)][Cu(II)(IN)(2)][Mo(4)O(12)(OH)(2)]] (IN(-) = isonicotinate ion, 2,2'-bpy = 2,2'-bipyridine), 1, has been hydrothermally synthesized and structurally characterized, and this compound is built from an unprecedented tetranuclear molybdenum oxide cluster covalently bonded to two types of copper complex fragments, [Cu(II)(2,2'-bpy)](2+) and [Cu(II)(IN)(2)], via terminal oxygen atoms of [MoO(6)] octahedra. Crystal data for compound 1: monoclinic, space group C2/c, a = 16.4755 A, b = 10.3714 A, c = 17.4382 A, alpha = 90.0000 degrees, beta = 94.8098 degrees, gamma = 90.0000 degrees; V = 2969.24 A(3); Z = 2. Variable temperature magnetic susceptibility indicates that both ferromagnetic and antiferromagnetic interactions exist in 1.     

Supramolecular Mn(II) and Mn(II)/Mn(III) grid complexes with [Mn9(mu2-O)12] core structures. Structural, magnetic, and redox properties and surface studies

A series of [3 x 3] Mn(II)(9), antiferromagnetically coupled, alkoxide-bridged, square grid complexes, derived from a group of "tritopic" dihydrazide ligands, is described. The outer ring of eight Mn(II) centers in the grids is isolated magnetically from the central Mn(II) ion, leading to an S = 0 ground state for the ring, and an S = 5/2 ground state overall in each case. Exchange in the Mn(II)(8) ring can be represented by a 1D chain exchange model. Rich electrochemistry displayed by these systems has led to the production of Mn(II)/Mn(III) mixed-oxidation-state grids by both electrochemical and chemical means. Structures are reported for [Mn(9)(2poap)(6)](C(2)N(3))(6).10H(2)O (1), [Mn(9)(2poap)(6)](2)[Mn(NCS)(4)(H(2)O)](2)(NCS)(8).10H(2)O (2), [Mn(9)(2poapz)(6)](NO(3))(6).14.5H(2)O (3), [Mn(9)(2popp)(6)](NO(3))(6).12H(2)O (4), [Mn(9)(2pomp)(6)](MnCl(4))(2)Cl(2).2CH(3)OH.7H(2)O (5), and [Mn(9)(Cl2poap)(6)](ClO(4))(9).7H(2)O (6). Compound 1 crystallized in the tetragonal system, space group P4(2)/n, with a = 21.568(1) A, c = 16.275(1) A, and Z = 2. Compound 2 crystallized in the triclinic system, space group P, with a = 25.043(1) A, b = 27.413(1) A, c = 27.538(2) A, alpha = 91.586(2) degrees, beta = 113.9200(9) degrees, gamma = 111.9470(8) degrees, and Z = 2. Compound 3 crystallized in the triclinic system, space group P, with a = 18.1578(12) A, b = 18.2887(12) A, c = 26.764(2) A, alpha = 105.7880(12) degrees, beta = 101.547(2) degrees, gamma = 91.1250(11) degrees, and Z = 2. Compound 4 crystallized in the tetragonal system, space group P4(1)2(1)2, with a = 20.279(1) A, c = 54.873(6) A, and Z = 4. Compound 5 crystallized in the tetragonal system, space group I, with a = 18.2700(2) A, c = 26.753(2) A, and Z = 2. Compound 6 crystallized in the triclinic system, space group P, with a = 19.044(2) A, b = 19.457(2) A, c = 23.978(3) A, alpha = 84.518(3) degrees, beta = 81.227(3) degrees, gamma = 60.954(2) degrees, and Z = 2. Preliminary surface studies on Au(111), with a Mn(II) grid complex derived from a sulfur-derivatized ligand, indicate monolayer coverage via gold-sulfur interactions, and the potential for information storage at high-density levels.     

Homologous series of redox-active, dinuclear cations [M(2)(O(2)CCH(3))(2)(pynp)(2)](2+) (M = Mo, Ru, Rh) with the bridging ligand 2-(2-pyridyl)-1,8-naphthyridine (pynp)

A homologous series of dinuclear compounds with the bridging ligand 2-(2-pyridyl)-1,8-naphthyridine (pynp) has been prepared and characterized by X-ray crystallographic and spectroscopic methods. [Mo(2)(O(2)CCH(3))(2)(pynp)(2)][BF(4)](2) x 3CH(3)CN (1) crystallizes in the monoclinic space group P2(1)/c with a = 15.134(5) A, b = 14.301(6) A, c = 19.990(6) A, beta = 108.06(2) degrees, V = 4113(3) A(3), and Z = 4. [Ru(2)(O(2)CCH(3))(2)(pynp)(2)][PF(6)](2) x 2CH(3)OH (2) crystallizes in the monoclinic space group C2/c with a = 14.2228(7) A, b = 20.3204(9) A, c = 14.1022(7) A, beta = 95.144(1) degrees, V = 4059.3(3) A(3), and Z = 4. [Rh(2)(O(2)CCH(3))(2)(pynp)(2)][BF(4)](2) x C(7)H(8) (3) crystallizes in the monoclinic space group C2/c with a = 13.409(2) A, b = 21.670(3) A, c = 13.726(2) A, beta = 94.865(2) degrees, V = 3973.9(8) A(3), and Z = 4. A minor product, [Rh(2)(O(2)CCH(3))(2)(pynp)(2)(CH(3)CN)(2)][BF(4)][PF(6)] x 2CH(3)CN (4), was isolated from the mother liquor after crystals of 3 had been harvested; this compound crystallizes in the triclinic space group, P1 with a = 12.535(3) A, b = 13.116(3) A, c = 13.785(3) A, alpha = 82.52(3) degrees, beta = 77.70(3) degrees, gamma = 85.76(3) degrees, V = 2193.0(8) A(3), and Z = 2. Compounds 1-3 constitute a convenient series for probing the influence of the electronic configuration on the extent of mixing of the M-M orbitals with the pi system of the pynp ligand. Single point energy calculations performed on 1-3 at the B3LYP level of theory lend insight into the bonding in these compounds and allow for correlations to be made with electronic spectral data. Although purely qualitative in nature, the values for normalized change in orbital energies (NCOE) of the frontier orbitals before and after reduction are in agreement with the observed differences in reduction potentials as determined by cyclic voltammetry.     

Synthesis and characterization of new coordination polymers generated from oxadiazole-containing organic ligands and inorganic silver(I) salts

The coordination chemistry of the oxadiazole-containing rigid bidentate ligands 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L2) and 2,5-bis(4-aminophenyl)-1,3,4-oxadiazole (L3) with inorganic Ag(I) salts has been investigated. Four new coordination polymers were prepared by solution reactions and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. [[Ag(L2)]SO3CF3]n (1)(triclinic, P1; a = 10.1231(7) A, b = 13.9340-(10) A, c = 13.9284(10) A, alpha = 116.7300(10) degrees, beta = 94.6890(10) degrees, gamma = 108.7540(10) degrees, Z = 4) was obtained by the combination of L2 with AgOTf in a CH2Cl2/CH3OH mixed-solvent system and features a unique one-dimensional elliptical macrocycle-containing chain motif. The approximate dimensions of the rings are ca. 22 x 11 A. [[Ag-(L2)](ClO4)(CH3OH)0.5(H2O)0.5]n (2) (triclinic, P1; a = 8.4894(5) A, b = 13.9092(8) A, c = 14.1596(8) A, alpha = 71.1410(10) degrees, beta = 77.3350(10) degrees, gamma = 81.5370(10) degrees, Z = 4) was generated from the reaction of L2 with AgClO4 in a H2O/CH3OH mixed-solvent system and consists of one-dimensional chains that are linked to each other by weak noncovalent pi-pi interactions into two-dimensional sheets. Uncoordinated ClO4-counterions and guest solvent molecules are located between the layers. [[Ag(L2)]NO3]n (3) was obtained by the combination of L2 with Ag(NO3)2 in a MeOH/H2O mixed-solvent system (triclinic, P1; a = 8.3155(6) A, b = 8.8521(6) A, c = 9.8070(7) A, alpha = 74.8420(10) degrees, beta = 77.2800(10) degrees, gamma = 68.6760(10) degrees, Z = 2). In the solid state, it exhibits an interesting pair of chains associated with C-H...O hydrogen bonds. [[Ag(L3)]SO3CF3]n (4) is generated from L3 and AgSO3CF3 in a CH2Cl2/MeOH mixed-solvent system and crystallizes in the unusual space group Pnnm, with a = 7.9341(4) A, b = 11.5500(5) A, c = 18.1157(8) A, and Z = 4. It adopts a novel three-dimensional structural motif in the solid state with big rhombic channels (ca. 15 x 10 A).