Synthesis and X-ray crystal structures of novel silver(I) complexes of (N-carboxymethyl) dimethylammonioacetate

Two novel silver(I) coordination polymers [{Ag(L)}(n)] (1) and [{Ag-3(L)(2)}(n)][ClO4](n) (2) (L = (N-carboxymethyl)dimethylammonioacetate anion: Me(2)N(+)(CH2CO3-)(2)), have been synthesized and characterized by X-ray crystallography. Complex 1 (space group P2(1)/c with a = 5.524(1), b = 10.007(2), c = 14.406(2) Angstrom, beta = 91.11(1)degrees, U = 796.2(2) Angstrom(3) and Z = 4) possesses a dimeric subunit in which the silver atoms are doubly bridged by a pair of syn-syn mu-carboxylato-O,O' groups. The dimeric subunits are inter-linked to form a three-dimensional framework via coordination of each silver center by a carboxylato oxygen atom from an adjacent dimer. The coordination geometry of the silver(I) atom is a distorted tetrahedron, and the [Ag-2(carboxylato-O,O')(2)] dimer exhibits a modified type D structure. Complex 2 (space group Ima2 with a = 28.438(8), b = 7.366(2), c = 9.878(3) Angstrom, U = 2069.1(10) Angstrom(3) and Z = 8) comprises discrete perchlorate anions and a tetrakis(carboxylato-O,O')-bridged trimeric subunit of C-2 symmetry. The trimeric subunits are extended into an unusual infinite zigzag (Ag ... Ag ... Ag ...)(n). chain running along the b direction. Such chains are cross-linked by metal-carboxylate linkages, generating a two-dimensional network corresponding to the plane (200). Compound 2 is the first example among silver(I) carboxylates that has a polymeric structure based on the linkage of trimeric subunits.