Two Novel Cationic Frameworks Based on Cadmium(II) Vinylphosphonate with 4,4′-Bipyridine as Coligand

Abstract

The reaction of cadmium nitrate and vinylphosphonic acid (H2L) with 4,4′-bipyridine (bipy) as coligand led to two novel cadmium(II) vinylphosphonates, namely, [Cd4(L)3(NO3)(bipy)4(H2O)3]·(NO3)·3(H2O) (1) and [Cd3(HL)3(L)(bipy)3(H2O)4]·(NO3)·3.5(H2O) (2). Both compounds feature a cationic framework which encloses charge-balanced nitrate anions as well as guest water molecules. They represent the first examples of metal-organic frameworks based on mixed bridging ligands that contain a low-carbon-number alkylphosphonate. Notably, the cationic framework of 2 manifests an unprecedented (4,5)-connected net topology with point symbol of (42·6·83)·(43·65·82)2. Two novel cationic frameworks based on cadmium(II) vinylphosphonate with 4,4′-bipyridine as coligand are reported here.