Co(II)/Zn(II) Coordination Polymers with Angular Dicarboxylate and Flexible N-Donor Struts: Structural and Photoluminescence Studies

Abstract

Four mixed ligand coordination polymers [Co(BrIP)(4-BPMP)1.5·H2O]n (1), [{Zn2(BrIP)2 (HBrIP)(H3-BPMP)}·4H2O]n (2), [{Co(SDB)(3-BPMP)}·(C4H8O)·H2O]n (3) and [{Co(SDB)(4-BPMP)}·2H2O]n (4) (where 4-BPMP = 1,4-bis(4-pyridylmethyl)piperazine, 3-BPMP = 1,4-bis(3-pyridylmethyl)piperazine, H2BrIP = 5-bromoisophthalic acid, and H2SDB = 4,4′-sulfonyldibenzoic acid) have been synthesized by solvothermal methods. Crystal structure of 1 revealed that 4-BPMP ligands (present in different conformations) in conjunction with BrIP and metal nodes engender an interpenetrated two-dimensional (2D) grid-type network. Compound 2 comprises of one-dimensional metal organic ladder patterns with pendent carboxylic acid sites on HBrIP moieties. Coordination polymers 3 and 4 exhibit [Co2(SDB)2]n double chain loops containing “paddle-wheel” secondary building units tethered by 3-BPMP and 4-BPMP respectively, generating (4,4) grid-type 2D nets. Comprehensive characterization, structural analysis, and photoluminescence behavior of 1–4 are discussed.