Synthesis and structure of an open-framework cobalt zincophosphate

摘要

Introducing cobalt into a Zn-P-O-amine system and using oxalates as starting materials, in amine containing openframework cobalt zincophosphate, [C_4N_2H_(12)][Co_(0.14)Zn_(1.86)(PO_4)(H_(1.5)PO_4)_2] (1), has been hydrothermally synthesized and structurally determined. It crystallizes in the monoclinic space group C2/c (No.15) with cell parameters (a = 13.374(3) A, b = 12.827(3) A, c = 8.1940(16) A, beta = 94.77 (3) deg, V = 1400.9(5) A~3, Z = 4, D_(cal) = 2.399 g cm~(-3). The linkages of ZnO_4 and PO_4 give rise to four-membered rings, which serve as the secondary building unit for compound 1. The four-membrered rings (four-MR) share their corners leading to chains. Connection of these chains results in a complex three-dimensional channel systel. Eight-MR, twelve -MR and highly distorted twelve-MR channels can be observed along the [010], [110] and [101] directions, respectively. The prominent facture of compound 1 is the cloverlike 16-MR channel along the [001] direction. The channel space are occupied by the diprotonated piperazine molecules with H-bonds to the framework.