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Abstract: The aim of this work was to extend the small library of existing compounds of gold(I) that contain pentafluorophenyl and thiazole ligands and to determine the biological activity of such compounds against a well-known cancer cell line. Seven mono and dinuclear new compounds that contain imidazole, thiazole and tetrazole rings were isolated and characterised. Three of the crystal structures determined indicated Au…Au interactions between constituent complex molecules. A simple adduct, [Au(C6F5)(N-methyl-imidazole)], exhibits a relatively high anti-tumour specificity indicating the viability of selected phosphine-free gold complexes as cytotoxic agents. [Copyright &y& Elsevier]

Lithiation of 1-benzyl-1H-tetrazole followed by transmetallation with [AuCl(PPh3)], [Au(C6F5)(tht)] or [AuCl(tht)] (tht = tetrahydrothiophene) and subsequent alkylation afforded cationic 1-benzyl-4-methyl-4,5-dihydro-1H-1,2,3,4-tetrazol-5-ylidene(triphenylphosphine)gold(i), 1, neutral 1-benzyl-4-methyl-4,5-dihydro-1H-1,2,3,4-tetrazol-5-ylidene(pentafluorophenyl)gold(i), 2, and a cationic biscarbene complex, bis(1-benzyl-4-methyl-4,5-dihydro-1H-1,2,3,4-tetrazol-5-ylidene)gold(i), 3. The first complex underwent a homoleptic rearrangement in solution to form 3. Reaction of [Au(N3)PPh3] with the three isocyanides (CH3)2C6H3NC, tBuNC and CyNC, respectively, yielded the corresponding neutral tetrazolyl(phosphine) complexes of gold, [1-(2,6-dimethylphenyl)-1H-tetrazol-5-yl](triphenylphosphine)gold(i), 4, [1-(tert-butyl)-1H-tetrazol-5-yl](triphenylphosphine)gold(i), 6, and [1-(cyclohexyl)-1H-tetrazol-5-yl](triphenylphosphine)gold(i), 7. Alkylation of 4with methyl triflate on N4allowed isolation of the crystalline carbene complex 1-(2,6-dimethylphenyl)-4-methyl-4,5-dihydro-1H-1,2,3,4-tetrazol-5-ylidene)(triphenylphosphine)gold(i), 5. Complex 7was not isolable in pure form but converts by isocyanide substitution of triphenylphosphine into [1-cyclohexylisocyanide][1-(cyclohexyl)-1H-tetrazol-5-yl]gold(i), 8. From a product mixture of 7and 8the transformed molecules [(cyclohexylamino)(ethoxy)carbene](1-cyclohexyl-1H-tetrazol-5-yl)gold(i), 9, and [bis(cyclohexylamino)carbene](1-cyclohexyltetrazol-5-yl)gold(i), 10, co-crystallised spontaneously after a long time at −20 °C. [ABSTRACT FROM AUTHOR]

Dichlorogallane (HGaCI[sub 2])[sub 2] is readily prepared from gallium trichloride and triethylsilane in quantitative yield. Its crystal structure has been determined by single crystal X-ray diffraction. In the chlorine-bridged dimers of crystallographically imposed C[sub 2h] symmetry, the terminal hydrogen atoms are in trans positions. In the reaction with 2 equiv of triethylphosphine, the mononuclear complex (Et[sub 3]P)GaHCI[sub 2] is formed. Thermal decomposition of (HGaCI[sub 2])[sub 2] affords hydrogen gas and quantitative yields of "GaCI[sub 2]" as mixed-valent Ga[GaCI[sub 4]]. Treatment of this product with triethylphosphine gives the symmetrical, Ga-Ga-bonded gallium(ll) complex [GaCI[sub 2](PEt[sub 3])][sub 2] with an ethane-type structure and with the phosphine ligands in a single-trans conformation. The corresponding [GaBr[sub 2](PEt[sub 3])][sub 2] complex is prepared from Ga[GaBr[sub 4]] and has an analogous structure. (Et[sub 3]P)GaCl[sub 3] has been synthesized and structurally characterized as a reference compound. [ABSTRACT FROM AUTHOR]