Synthesis and crystal structure of tetranuclear copper(I) and silver(I) complexes bridged by 2-amino-1,3,4-thiadiazole (atdz): [Cu-4(atdz)(6)](ClO4)(4) center dot 2CH(3)OH and [Ag-4(atdz)(6)](ClO4)(4)

Two novel tetracopper(I) and tetrasilver(I) complexes [Cu-4(atdz)(6)](ClO4) (4). 2CH(3)OH (1) and [Ag-4(atdz)(6)](ClO4)(4) (2), have been prepared usin g 2-amino-1,3,4-thiadiazole (atdz), and their crystal structures and proper ties have been determined. On each tetranuclear complex, two Cu or Ag atoms (M) are bridged by two atdz ligands to form a six-membered N2M2N2 framewor k. The two N2M2N2 frameworks are in parallel linked by another atdz ligand to provide the tetranuclear structure with a rectangular M-4 core. The four Cu or Ag atoms possess a trigonal-square geometry. The two adjacent M...M separations are (3.096(1) and 3.412(1) Angstrom) and (3.316(2) and 3.658(2) Angstrom) for 1 and 2, respectively. On both tetranuclear complexes there are two species of hydrogen bonds between the ClO4- anions and the NH2 grou p of atdz ligands. It is proposed that the hydrogen bonds are related to th e stabilization of the tetranuclear structure during the crystallization pr ocess. (C) 1999 Elsevier Science S.A. All rights reserved.