(1) Two novel polymeric silver (I)-triphenylphosphine complexes with nitrogen-containing heterocycles, [Ag (1,2,3-triz) (PPh_3)_2]_n 3 and [Ag (1,2,4-triz) (PPh_3)_2]_n 4 (Htriz=triazole) were synthesized from reactions of polymeric precursors [Ag (1,2,3-triz)]_n 1 and [Ag (1,2,4-triz)]_n 2 with 3 equiv of PPh_3 in CH_2Cl_2,respectively. The polymeric precursors 1 and 2 have been obtained as a non-crystalline, colorless powder-solid : 2 showed a wide spectrum of excellent antibacterial activities, but 1 did not. The antimicrobial activities of the complexes 1-4,evaluated by MIC (minimum inhibitory concentration), were compared and key factors affecting them were discussed. The crystal structures of the complexes 3 and 4 were determined by single-crystal X-ray diffraction. The complexes 3 and 4 in the solid-state were helical polymers consisting of AgN_2P_2 cores formed by bridging triazolate anions and two PPh_3 ligands. The complexes 3 and 4 were also fully characterized by elemental analyses, TG/DTA and FT-IR in the solid-state and by various solution NMR (^P, ^Ag, ^1H and ^C) spectroscopies and molecular weight measurements in solution. (2) Two novel gold (I)-triphenylphosphine complexes with nitrogen-containing heterocycles, [Au (1,2,3-L) (PPh_3)] 1 and [Au (1,2,4-L) (PPh_3)]_2・xH_2O (x=0.5-1.0) 2 (HL=triazole) were synthesized from stoichiometric reactions of a precursor complex [AuCl (PPh_3)] with HL in acetone in the presence of aqueous NaOH, and isolated as colorless needles and cubic crystals, respectively. The crystal structures of 1 and 2 were determined by single-crystal X-ray diffraction. 1 and 2 were also fully characterized by complete elemental analyses, TG/DTA and FT-IR in the solid-state and by solution NMR (^P, ^1H and ^C) spectroscopies and solution molecular-weight measurements. 1 consisted of a monomeric 2-coordinate AuNP core both in the solid-state and in solution, while, in contrast, 2 comprised a dimeric (AuNP)_2 core through an Au-Au bond in the solid-state, but a monomeric AuNP core in solution. Within the two gold (I) complexes composed of very closely related nitrogen-containing heterocycles and a common bulky PPh_3,ligand, it was found that the aggregation through the Au…Au interaction in 2 was overruled in 1. The molecular structures of 1 and 2 were also compared with those of the corresponding silver (I) analogs, [Ag (1,2,3-L) (PPh_3)_2]_n 3 and [Ag (1,2,4-L) (PPh_3)_2]_n 4,the molecular structures of both of which have been recently determined as helical polymers in the solid-state. (3) Polymeric silver (I) imidazolate [Ag (imd)]_n (1; Himd=imidazole, C_3H_4N_2) showing a wide spectrum of excellent antimicrobial activities against bacteria, yeast and mold, which has been obtained as non-crystalline, colorless powder, was successfully converted to molecular, crystalline complex [Ag (imd) (PPh_3)_3] 2 by a reaction of 1 with 3 equivalents of PPh_3 in CH_2Cl_2. This novel complex 2 was not obtained from reactions in solutions of the precursors [AgCl (PPh_3)_3] and/or [AgCl(PPh_3)_2]_2 with Himd in the presence of NaOH or with sodium salt of imd. On the contrary, the corresponding gold (I) complex [Au (imd) (PPh_3)] 3 was formed by a reaction of the precursor [AuCl (PPh_3)] and Himd in the presence of NaOH. From a synthetic viewpoint, these facts show the ordering of ligand replacement in these complexes to be Ag-P>>Ag-Cl>Ag-N, while Au-P>>Au-N>Au-Cl. This ordering also exhibits the different reactivity of silver (I) and gold (I) complexes with biological ligands such as proteins, enzymes, nucleic acids and amino acids. The complex 2 was fully characterized by complete elemental analyses, TG/DTA, FT-IR, solution molecular weight measurement and various solution NMR (^1H, ^C, ^P and ^Ag) spectroscopies. The complex 2 in solution was present in a rapid equilibrium with the dissociated species of two PPh_3 ligands, i. e., [Ag (imd) (PPh_3)]. The ^P NMR measurements at low temperature showed that (i) all PPh_3 ligands in 2 in CHCl_3 solution migrated at room temperature between the two isotopes ^Ag and ^Ag, in addition to the dissociation of two PPh_3 ligands, and (ii) there were present the 4-coordinate tetrahedral complex 2 and the dissociated complex [Ag (imd) (PPh_3)] in solution
