Synthesis and crystal structure of coinage metal(I) complexes with tetrazole (Htetz) and triphenylphosphine ligands, and their antimicrobial activities. A helical polymer of silver(I) complex [Ag(tetz)(PPh3)2]n and a monomeric gold(I) complex [Au(tetz)(PP

Two novel coinage metal(I)-triphenylphosphine complexes with a heterocyclic ligand, [Ag(tetz)(PPh3)2]n (1) and [Au(tetz)(PPh3)] (2) (Htetz=tetrazole) were synthesized from a reaction in dichloromethane of the precursor complex [Ag(tetz)]n with PPh3 and from a reaction in acetone of [AuCl(PPh3)] with Htetz in the presence of aqueous NaOH, respectively, and isolated as colorless needle crystals for both 1 and 2. The crystal structures of 1 and 2 were determined by single-crystal X-ray diffraction. These d10 complexes were also fully characterized by elemental analyses, TG/DTA and FT-IR in the solid-state, solution NMR (31P, 1H and 13C, as well as 109Ag for 1) spectroscopies and solution molecular weight measurements. Complex 1, is composed of a helical polymer, a 21 helix with a pitch 9.471 Å, formed by a bridged tetrazolate of an AgNP2 core in the solid-state, but it was present as a monomer in solution. In contrast to 1, complex 2 consisted of a monomeric two-coordinate AuNP core without gold(I)–gold(I) interaction both in the solid-state and in solution. The molecular structures of 1 and 2 were compared with those of the corresponding triazole complexes, i.e. silver(I) complexes [Ag(1,2,3-triz)(PPh3)2]n (3) and [Ag(1,2,4-triz)(PPh3)2]n (4) both as helical polymers, a monomeric gold(I) complex [Au(1,2,3-triz)(PPh3)] (5) and a dimeric gold(I) complex [Au(1,2,4-triz)(PPh3)]2 (6) through an intramolecular gold(I)–gold(I) bond; the structures of complexes 3–6 being recently determined by X-ray crystallography. The antimicrobial activities of 1, its precursor [Ag(tetz)]n and 2 were compared and key factors affecting them discussed.