Synthesis and Properties of V₆O₁₆Cu(C₄H₄N₂)₂·(H₂O)_0.22(1): Charge Density Matching of a Metal-Segregated Layer Structure

A metal-segregated layered compound, containing square nets of Cu(pyz)22+ and buckled V6O162- layers, has been synthesized using hydrothermal techniques to have the composition V6O16Cu(C4H4N2)2·(H2O)0.22(1) (C4H4N2 = pyrazine, pyz). The Cu(II) square nets are nearly regular and undergo an antiferromagnetic transition at 8 K. In contrast to the plethora of recently synthesized metal−oxide clusters, chains, and networks in the VOx/M/L (M = late transition element; L = organonitrogen ligand) system, this compound is a relatively rare example that contains two different metals distributed into distinct layers. An application of charge density matching to form layered structures is postulated

Synthesis and Properties of V₆O₁₆Cu(C₄H₄N₂)₂·(H₂O)_0.22(1): Charge Density Matching of a Metal-Segregated Layer Structure

A metal-segregated layered compound, containing square nets of Cu(pyz)22+ and buckled V6O162- layers, has been synthesized using hydrothermal techniques to have the composition V6O16Cu(C4H4N2)2·(H2O)0.22(1) (C4H4N2 = pyrazine, pyz). The Cu(II) square nets are nearly regular and undergo an antiferromagnetic transition at 8 K. In contrast to the plethora of recently synthesized metal−oxide clusters, chains, and networks in the VOx/M/L (M = late transition element; L = organonitrogen ligand) system, this compound is a relatively rare example that contains two different metals distributed into distinct layers. An application of charge density matching to form layered structures is postulated

[(Zr₆B)Cl_11-<i>_x</i>I₂₊<i>_x</i>] (0 ≤ <i>x</i> ≤ 6): A New Mixed-Halide Structure with Zigzag Chains of Clusters in Multiply Twinned Crystals

The new [(Zr6B)Cl11-xI2+x] phase (with 0 ≤ x ≤ 6) is obtained from reactions of ZrI4, ZrCl4, and elemental Zr and B for 2−4 weeks in sealed Ta tubing at 800−850 °C. Single crystals of [(Zr6B)Cl6.44(7)I6.56] have been characterized by X-ray diffraction at room temperature (orthorhombic Pbcn, Z = 4, a = 12.365(2) Å, b = 15.485(3) Å, c = 13.405(2) Å). This structure contains zigzag chains of boron-centered (Zr6B) octahedra that are interconnected by Cli-i halides. Further three-dimensional connectivity is achieved by Ia-a-a bridges. The noncluster interconnecting two-bonded Xi sites are occupied statistically by a mixture of Cl and I. For each site both positions were resolved. This structure forms within a phase width of 0 ≤ x ≤ 6 at temperatures between 800 and 850 °C. Crystals of this phase appear to be always multiply twinned

Synthesis of [NH₄]MnCl₂(OAc) and [NH₄]₂MnCl₄(H₂O)₂ by Solvothermal Dehydration and Structure/Property Correlations in a One-Dimensional Antiferromagnet

The utility of the solvothermal dehydration strategy whereby superheated acetonitrile reacts with water of hydration to form ammonium acetate is demonstrated in the synthesis of [NH4]MnCl2(OAc), I, and [NH4]2MnCl4(H2O)2, II, from MnCl2·4H2O. The structure of I is shown to crystallize in the monoclinic space group C2/c (No. 15) with a = 15.191(6) Å, b = 7.044(2) Å, c = 13.603(6) Å, β = 107.31°, V = 1389.7(9) cm-1, and Z = 8. The structure of II crystallizes in the space group I4/mmm (No. 139) with a = 7.5250(5) Å, b = 8.276(2) Å, V = 468.6(1) cm-1, and Z = 2. Both structures exhibit extensive hydrogen bonding that controls both local Mn−Cl bonding and the interchain organization. I is shown to be a one-dimensional Heisenberg antiferromagnet with an intrachain exchange constant J/k = −2.39 K. This structure exhibits exchange coupling intermediate between the well-studied triply and doubly chloride-bridged one-dimensional manganese Heisenberg antiferromagnets. The structure/property correlation demonstrates a linear dependence of the exchange constant on the Mn−Cl−Mn bond angle, α, for α < 94°

Synthesis and Crystal Structure of a Dinuclear Palladium Complex Containing C,O-Bridging Ester−Enolato Moieties

Palladium ester enolates have been prepared and characterized using IR, NMR, and single-crystal X-ray diffraction techniques. The X-ray diffraction established a dimeric crystal structure for complex {[N∧N]PdCH2C(O)OCH3}2 (N∧N = 1-[1-(5-methylpyrrole-2-yl)ethylidne]amino-2,6-diisopropylbenzene), 2, which contains C,O-bridging enolato groups. Upon reaction with donor molecules (acetonitrile, phosphines), the dimeric 2 cleaves to form monometallic C-bound enolate complexes, 3‘ and 4

Synthesis of [NH₄]MnCl₂(OAc) and [NH₄]₂MnCl₄(H₂O)₂ by Solvothermal Dehydration and Structure/Property Correlations in a One-Dimensional Antiferromagnet

The utility of the solvothermal dehydration strategy whereby superheated acetonitrile reacts with water of hydration to form ammonium acetate is demonstrated in the synthesis of [NH4]MnCl2(OAc), I, and [NH4]2MnCl4(H2O)2, II, from MnCl2·4H2O. The structure of I is shown to crystallize in the monoclinic space group C2/c (No. 15) with a = 15.191(6) Å, b = 7.044(2) Å, c = 13.603(6) Å, β = 107.31°, V = 1389.7(9) cm-1, and Z = 8. The structure of II crystallizes in the space group I4/mmm (No. 139) with a = 7.5250(5) Å, b = 8.276(2) Å, V = 468.6(1) cm-1, and Z = 2. Both structures exhibit extensive hydrogen bonding that controls both local Mn−Cl bonding and the interchain organization. I is shown to be a one-dimensional Heisenberg antiferromagnet with an intrachain exchange constant J/k = −2.39 K. This structure exhibits exchange coupling intermediate between the well-studied triply and doubly chloride-bridged one-dimensional manganese Heisenberg antiferromagnets. The structure/property correlation demonstrates a linear dependence of the exchange constant on the Mn−Cl−Mn bond angle, α, for α < 94°

Preparation of the Octahedral d⁶ Amido Complex TpRu(CO)(PPh₃)(NHPh) (Tp = Hydridotris(pyrazolyl)borate): Solid-State Structural Characterization and Reactivity

The reaction of TpRu(CO)(PPh3)(OTf) (2) with LiNHPh affords the amido complex TpRu(CO)(PPh3)(NHPh) (3) in 88% isolated yield. The amido complex 3 has been characterized by 1H NMR, 13C NMR, 31P NMR, elemental analysis, cyclic voltammetry, and a solid-state X-ray diffraction study. Variable temperature NMR studies have revealed a rotational barrier around the ruthenium−amido nitrogen bond of 3 of 12 kcal/mol (transformation of the major isomer to the minor isomer). The solid-state structure of 3 discloses a pyramidal amido moiety. Heating benzene solutions of the amido complex 3 and 1,4-cyclohexadiene or 9,10-dihydroanthracene results in no observable reaction. Reaction of complex 2 with excess aniline yields [TpRu(CO)(PPh3)(NH2Ph)][OTf] (4)

Ruthenium(II) Anilido Complex Containing a Bisphosphine Pincer Ligand: Reversible Formation of Amidinate Ligands via Intramolecular C−N Bond Formation

The reaction of the octahedral anilido complex (PCP)Ru(CO)(NHPh)(PMe3) with acetonitrile produces the amidinate complex (PCP)Ru(CO){N(H)C(Me)N(Ph)}. Mechanistic studies indicate that the reaction proceeds through coordination of the nitrile to the Ru(II) metal center, followed by intramolecular nucleophilic addition of the amido ligand

Organoplatinum Chemistry with a Dicarboxamide–Diphosphine Ligand: Hydrogen Bonding, Cyclometalation, and a Complex with Two Metal–Metal Donor–Acceptor Bonds

The chemistry of the ligand bis­(2-diphenylphosphinoethyl)­phthalamide, dpppa, with platinum­(II) is described. The reaction of dpppa with [Pt₂Me₄(μ-SMe₂)₂], <b>1</b>, in a 2:1 ratio gave a mixture of [PtMe₂(dpppa)] and [Pt₂Me₄(μ-dpppa)₂], both of which contain Pt···H–N hydrogen bonds. However, reaction in a 1:1 ratio gave a remarkable tetraplatinum complex, [Pt₄Me₆(μ-dpppa-H)₂], which is shown to contain two Pt–Pt donor–acceptor bonds and in which one arm of the dpppa ligand has been cyclometalated. The reaction of [PtCl₂(dpppa)] with silver trifluoroacetate, to abstract chloride, and triethylamine as base has given the bis­(cyclometalated) complex [Pt­(dpppa-2H)], and this has been crystallized in three different forms, in which one or both of the carbonyl groups act as donors to a proton or to silver­(I). The complex [Pt­(dpppa-2H)]·AgO₂CCF₃·dmso forms a dimer and [Pt­(dpppa-2H)]·(AgO₂CCF₃)₂ forms a coordination polymer in the solid state

Oxidation of a Vanadium(V)−Dithiolate Complex to a Vanadium(V)−η²,η²-Disulfenate Complex

Oxidation of a Vanadium(V)−Dithiolate Complex to a Vanadium(V)−η2,η2-Disulfenate Comple