Preparation and crystal structures of two polymeric silver(I) complexes of betaine derivatives

Abstract

Polymeric silver(I) complexes of two betaine derivatives, namely [{Ag 2(L 1) 2(NO 3)(H 2O)} n ](NO 3) n ( 1) and [{ Ag 4( L 2) 3} n]( ClO 4) 4 4 · 3n H 2O ( 2) [L 1 = 4-dimethylaminopyridinio-acetate, p-Me 2NC 5H 4N +CH 2CO 2 −; L 2 = 1,4-diazoniabicyclo[2.2.2]octane-1,4-dipropionate; −O 2C(CH 2) 2N + (CH 2CH 2) 3N + (CH 2) 2CO 2 −], have been prepared and characterized by X-ray crystallography. Complex 1 exhibits a zigzag chain structure via comparatively weak metal-carboxylate linkages between adjacent bis(carboxylato- O, O′)-bridge dimers, in which the coordination spheres of two independent Ag I atoms are each completed by an unidentate nitrate or aqua ligand at a much longer contact. Complex 2 consists of three independent infinite zigzag chains running parallel to the b direction, in which the Ag I atoms are cross-linked by double betaine ligands in the end-to-end mode. The Ag ··· Ag separation [2.750(2)_Å] in one infinite chain based on bis(carboxylato- O, O′)-bridged centrosymmetric dimeric units is the shortest one hitherto found among silver(I) complexes and hence indicative of a significantly stronger metal-metal interaction.