Inorganic Chemistry Communications (v.3, #4)

Crystals of a cyanide-bridged nickel(II) complex [Ni(TIM)][Ni(CN)4] (1) (TIM=2,3,9,10-tetramethyl-1,4,8,11-tetraazacyclotetradeca-1,3,8,10-tetraene) were formed by diffusion of [Ni(TIM)](ClO4)2 in MeCN and K3[Cr(CN)5(NO)] in H2O for two months. Complex 1 crystallized in the triclinic space group P-1 with a=7.610(2), b=8.096(2), c=9.392(2) Å, α=69.56(1), β=71.44(1), γ=84.66(2)°. The crystal structure confirmed the presence of cyanide-bridged nickel(II) chains. The [Ni(CN)4]2− moieties were shown to derive from the dissociation of [Cr(CN)5(NO)]3− and [Ni(TIM)]2+ owing to the stability of the [Ni(CN)4]2− ion. The coordination geometry around the six-coordinate nickel(II) ion is axially elongated octahedral with four nitrogen atoms of the macrocycle (Ni–N=2.008(2) Å) and two nitrogen atoms of the bridging cyanides (Ni–N=2.123(2) Å). The four-coordinate nickel(II) groups are square-planar with the Ni–C bond distances ranging from 1.858(2) to 1.861(3) Å.
Keywords: Crystal structures; Nickel(II) complexes; Macrocyclic complexes; Cyanide bridging;

The new ligand 3-(2-pyridyl)-1,2-benzisoxazole (3) was prepared in five steps from readily available starting materials. It represents the first example of a chelating ligand containing a 1,2-benzisoxazole group and readily forms complexes with palladium(II), copper(II) and ruthenium(II). An X-ray crystal structure of the copper complex, trans-Cu(3)2(NO3)2, is the first reported structure of a complex containing a 1,2-benzisoxazole.
Keywords: Crystal structures; Palladium complexes; Benzisoxazole complexes;

Synthesis and structure of the pentanuclear mixed-metal cluster [Co4MoCp(μ3-SBut)(μ3-S)(μ3-CO)(μ-CO)2(CO)6] by Jason D. King; Martin J. Mays; Mary McPartlin; Sanja Radojevic; Vallipuram Sarveswaran; Gregory A. Solan (159-162).
The pentanuclear mixed-metal cluster [Co4MoCp(μ3-SBut)(μ3-S)(μ3-CO)(μ-CO)2(CO)6] (1) has been synthesised by reaction of [CoMoCp(CO)7] with ButSSBut. X-ray structural analysis identified an asymmetric unit with three cobalt atoms and one molybdenum forming an irregular tetrahedron while one cobalt–molybdenum edge is bridged by a cobalt atom. Crystal data: space group P2(1)/n, a=10.162(2), b=13.722(3), c=17.69(5) Å, β=91.44(2)°, Z=4.
Keywords: Crystal structures; Mixed-metal complexes; Cobalt complexes; Molybdenum complexes; Sulfur complexes; Cluster complexes;

NBu4[{Au(C6F5)3}2(μ-PPh2)]: a gold(III) phosphide with a single atom bridging the metallic centers by M.Carmen Blanco; Eduardo J Fernández; Axel K Fischer; Peter G Jones; Antonio Laguna; M.Elena Olmos; M.Dolores Villacampa (163-165).
Reaction of [Au(C6F5)3(PPh2H)] with [Au(C6F5)3(tht)] and NBu4(acac) (acac=acetylacetonate) leads to the synthesis of NBu4[{Au(C6F5)3}2(μ-PPh2)] (1), an unprecedented complex with two gold(III) centers bonded to a unique bridging atom without any other stabilizing effect. The novel di-bridged gold(III) phosphide [Au2(C6F5)4(μ-PPh2)2] (2) is obtained by treatment of diphenylphosphine with [Au2(C6F5)4(μ-Cl)2]. The crystal structures of both derivatives have been determined by X-ray diffraction.
Keywords: Crystal structures; Dinuclear complexes; Gold complexes; Phosphides;

We discuss the critical role of the counter anion in the hydroxycarbonylation of styrene for different phosphorus-modified palladium systems. The regioselectivity can be controlled by the phosphorus ligand and the counter anion.
Keywords: Catalysis; Carbonylation; Styrene; Palladium complexes; Phosphine ligands; Counter anion;

Reaction of syn-B18H20 with [(η 5-C5Me5)IrCl2]2 and base results in multiple metal-centre addition, allied with oxidative cluster closure by multiple dihydrogen loss, giving the twenty-one-vertex globular cluster compound [(η 5-C5Me5)3Ir3B18H15(OH)] based on twelve-vertex closo {IrB11} and isonido {Ir2B10} clusters fused with a common five-atom {IrB4} unit that contains a central tetrahedral {IrB3} core.
Keywords: Globular borane cluster; Iridaborane cluster; Macropolyhedral assembly; Crystal structures; NMR spectroscopy; Metallaborane Aufbau;

The reaction of [Ru3(CO)12] with (SPR2)2NH produced, initially, [(μ2-H)Ru33-S){μ2-S,S,P′-(SPPh2)(PPh2)N}(CO)8 and [(μ2-H)Ru32-S,S,P′-(SPPh2)(PPh2)N}(CO)9] in which for both compounds one of the PS bonds of the ligand has been broken while the other PS group is bonded through the sulfur atom to two ruthenium atoms. In one of the compounds described, the lost sulfur atom moves to a triply bridging position bonded to the triangle of metal atoms. In the second compound, the sulfur atom is lost.
Keywords: Crystal structures; Disulfurimidophosphinate; Ruthenium clusters;

The reaction between Na2[nido-6,9-C2B8H10] (glyme, RT, 24 h) and PCl3 produced the neutral phoshadicarbaborane nido-7,8,11-PC2B8H11 (35%), which can be quantitatively deprotonated by proton sponge to give the corresponding [7,8,11-nido-PC2B8H10] anion. A similar reaction using PhPCl2 as the phosphorus source yielded the isomeric compound 7-Ph-7,8,10-nido-PC2B8H10 (64%), as well as nido-7,8,11-PC2B8H11 (14%) resulting from an accompanying dephenylation process.
Keywords: Boron-11 NMR; DFT/GIAO calculations; Dicarbaheteroboranes; Phosphacarboranes; Phosphadicarbaborane isomers; Triheteroboranes;

Reaction of 1,2-phenylenediamine with 2-pyridinecarboxaldehyde gave the new compound 1-(2-pyridylmethyl)-2-(2-pyridyl)benzimidazole (L) which reacted with [Cu(CH3CN)4](BF4) to form the title complex. Although the imine/2-(2-pyridyl) (‘α-diimine’) coordination setting in L appears well suited for forming a five-membered chelate ring, the crystal structure analysis of the bis(methanol) solvate revealed that the system rather opts for the formation of a partially saturated eight-membered chelate ring involving both pyridyl groups with a twist angle of 61.8° between the benzimidazole and 2-(2-pyridyl) moieties. In addition, L acts as a tridentate ligand, effecting dimerization of two chelate rings through the imine nitrogen centers of the imidazole groups. This dimerization gives rise to a ten-membered dimetalla ring. Tetracoordination at copper(I) is complemented by acetonitrile. The preference for this structure is attributed to the formation of unstrained metal centers with N–Cu–N angles between 105° and 118° and Cu–N distances of 2.03–2.05 Å.
Keywords: Benzimidazole ligand; Chelate rings; Copper complexes; Crystal structures; Pyridyl ligand;

Stereoselective electron-transfer reactions of the optically active ruthenium(III) complexes with hydrophobic side-chains with azurin(I) from Alcaligenes xylosoxidans GIFU 1051 by Hideyuki Kumita; Nobuo Asai; Takeshi Sakurai* ; Koichiro Jitsukawa; Tomohiro Ozawa; Hideki Masuda* ; Hisahiko Einaga (185-187).
In order to investigate the electron-transfer site of azurin, one of the electron-transfer proteins, some optically active Ru(III) complexes bearing hydrophobic amino acid side-chains as the molecular recognition probe have been prepared, and have been applied for the reaction with azurin-1Cu(I) from Alcaligenes xylosoxidans GIFU 1051. The estimated second-order rate constants and activation parameters, ΔH and ΔS , have indicated enantio- and stereoselectivities. The comparison with that for azurin-2, another species isolated from the same source, has strongly suggested that the electron-transfer site of azurin is His117.
Keywords: Electron-transfer proteins; Azurin; Optically-active ruthenium complexes; Stereo- and enantioselectivities;

The complex Re(o-phen)(CO)3Cl is used as a photolyase model. The phosphorescence of the complex is quenched by the 1,3-dimethyluracil cyclobutane dimer with k q=5.4×107 M−1 s−1. The quenching is accompanied by the cleavage of the dimer. However, this sensitized photolysis cannot be driven very far because the regenerated monomer quenches the triplet of the complex more efficiently (k q=1.2×109). The sensitized monomerization is thus limited by self inhibition.
Keywords: Photochemistry; Electron transfer; Rhenium complexes; Carbonyl complexes; Photolyase model;

In alkaline solution (1 M NaOH) irradiation (λ ir=266 nm) of Pb(OH)3 leads to the formation of hydrated electron and oxidized complex in the primary photochemical step. The nascent hydrated electrons react with the ground-state trihydroxoplumbate(II) complexes to form the corresponding reduced Pb(I) compound. The main reaction of this latter species is recombination (synproportionation) with the oxidized (Pb(III)) complex, significantly diminishing the efficiency of the overall light-induced oxidation of Pb(OH)3 in air-saturated solution.
Keywords: Flash photolysis; Plumbate complexes; Hydroxo complexes; Transient absorbance; Photoredox;

Ag(CO2PhCO2)Ag reacts with hexamethylenetetramine (hmt) in acetonitrile solution in the ratio 1:2 to yield the network [Ag23-hmt)2(μ-O2CPhCO2)]·7H2O, in which AgCO2PhCO2Ag units intercalate between the two-dimensional honeycomb-like layers to give a three-dimensional open network, while Ag(MePhSO3) reacts with hmt in the ratio 2:1 to produce the coordination network Ag24-hmt)(MePhSO3)2, consisting of two-dimensional grids with square cavities. The X-ray diffraction studies show that these two metal complexes can be used as molecular building blocks in the synthesis of silver–hmt networks.
Keywords: Crystal structures; Coordination networks; Ag(I) complexes; Silver–hmt networks; Molecular building;

Optical, magnetic and spectroscopic characterization of a novel iron(II) spin-transition compound with a Schiff base ligand by Hong-Mei Wang; Peng Cheng* ; Li-Cun Li; Shi-Ping Yan; Zong-Hui Jiang; Dai-Zheng Liao* ; Geng-Lin Wang; Jean-Pierre Tuchagues (198-201).
A novel iron(II) compound [FeL3](BF4)2, where L is the Schiff base ligand derived from 4-amino-1,2,4-triazole and 3-chlorobenzaldehyde, has been synthesized. Optical detection and magnetic measurements suggested the spin transition occurred between 180 and 192 K. The microscopic parameters and the molar thermodynamic functions were obtained from a theoretical analysis using a domain model and a two level Ising model.
Keywords: Spin transition; Iron(II) compounds; Schiff base; Magnetism;