Douglas M. Ho

New nickel(II) and palladium(II) complexes with unsymmetrical quadridentate Schiff bases derived from 8-amino-4-methyl-5-azaoct-3-en-2-one. Crystal and molecular structure of [4,10-dimethyl-3-(nitroso-χN)-5,9-(diaza-χ2N)-trideca-3,10-diene-2,12-(dionato-χO)(2–)]nickel(II)

A monocondensation product of pentane-2,4-dione and 1,3-diaminopropane, 8-amino-4-methyl-5-azaoct-3-en-2-one, has been used as a precursor in preparation of three new unsymmetrical quadridentate Schiff-base ligands comprising a trimethylenedi-imine moiety. Nickel(II) and palladium(II) complexes of these ligands have been obtained and characterized by spectroscopic techniques. They are of essentially square-planar geometry and diamagnetic. The single-crystal structure of (4,10-dimethyl-3-nitroso-5,9-diazatrideca-3,10-diene-2,12-dionato)nickel(II) has been determined and shows the co-ordination of nickel by a nitroso group through the nitrogen atom. Crystallographic data: space group P21/c(no. 14), a= 8.788(2), b= 7.562(2), c= 21.502(8)A, β= 98.49(2)°, final R and R′ 0.0422 and 0.0490, respectively.

Mono- and di-nuclear nickel(II) complexes with Schiff bases derived from 4-substituted 2,6-diformylphenol and 7-amino-4-methyl-5-azahept-3-en-2-one; crystal and molecular structure of [4-chloro-2,6-bis(4-methyl-2-oxo-5,8-diazanona-3,8-dienyl)phenolato(3-)]dinickel(II) bromide hemihydrate

The reaction of 4-chloro- or 4-methyl-2,6-diformylphenol with 7-amino-4-methyl-5-azahept-3-en-2-one leads to either quadridentate mononucleating or heptadentate binucleating Schiff-base ligands, depending on the reaction conditions. Nickel complexes with both types of ligands have been obtained and characterized by i.r., u.v.–visible, n.m.r., and mass spectrometry. An interesting example of impeded pseudo-rotation of a five-membered chelate ring in dinuclear nickel complexes is observed. The single-crystal X-ray structure of [4-chloro-2,6-bis(4-methyl-2-oxo-5,8-diazanona-3,8-dienyl)phenolato(3–)]dinickel(II) bromide hemihydrate has been determined. It consists of a dinuclear complex cation of twisted bifurcated shape and a bromide anion, with a half-equivalent of water incorporated into the crystal lattice. Crystallographic data: space group C2/c(no. 15), a= 22.082(4), b= 11.5, c= 22.368(4)A, β= 118.61 (1)°, R and R′ 0.0380 and 0.0318, respectively.

A reaction converting a w-w triple bond to a double bond: tetrakis-diethyldithiophosphate-disulfide-ditungsten, preparation and characterization

Abstract The reaction between W2X2(OR)4 compounds [X = CH2CMe3 or OBut] and HS2P(OEt)2 (6 equivalents) in hydrocarbon solvents, produces a molecule of formula W2S2[S2P(OEt)2]4 with corresponding elimination of alkane, alcohol and [(EtO)2PS]2. This tungsten compound has been characterized by IR,1H,13C, and13P NMR spectroscopy, electronic absorption spectroscopy and single-crystal X-ray crystallography. The molecule adopts a structure based on an edge-shared bioctahedron, with two bridging sulfides, two chelating dithiophosphate ligands and two dithiophosphate ligands bridging the metal- metal double bond. The W-W distance of 2.5987(11)Aalong with the acute W—S—W angles of 67.74(8)dg, are consistent with the metal metal double bond formulation Σ2 π2 . This structure is similar to the W2S2(S2CNEt2)4 molecule prepared by Cotton et al. (Inorg. Chem. 1978,17, 2946).

Electrochemical synthesis of a new gallium telluride containing one-dimensional chains: structure of [(C6H5)4P]GaTe2(en)2(en = ethane-1,2-diamine)

The cathodic dissolution of a Ga2 Te3 electrode in an ethane-1,2-diamine solution of tetraphenylphosphonium bromide yields the novel gallium telluride [(C6H5)4P]GaTe2(en)21 which consists of one-dimensional GaTe2(en)2– chains held together by NH ⋯ Te hydrogen bonds.