Synthesis, structural characterization and photoluminescence property of four di(mono)acylhydrazidate-coordinated Cd2+ and Zn2+ compounds

Abstract

Under hydrothermal conditions, the simple reactions between metal salts, aromatic polycarboxylic acids (4,4′-diphthalic anhydride ketone, dphahk; 4,4′-sulfoyldiphthalic anhydride, sdpha; pyridine-2,3-dicarboxylic acid, pdca) and N₂H₄·H₂O with or without the presence of phenanthroline·H₂O (phen) yielded four di(mono)acylhydrazidate-coordinated Cd²⁺/Zn²⁺ compounds as [Cd(DPHKH)(phen)]·1.75H₂O 1, [Zn₃(DPHKH)₂(HDPHKH)₂(phen)₂]·8H₂O 2, [Cd(SDPTH)(phen)(H₂O)]·H₂O 3 and [Zn(PDH)₂(H₂O)₂] 4 (DPHKH = 4,4′-diphthalhydrazidatoketone hydrazone; SDPTH = 4,4′-sulfoyldiphthalhydrazidate; PDH = pyridine-2,3-dicarboxylhydrazidate). The di(mono)acylhydrazide molecules in the title compounds originated from the hydrothermal in situ acylation reactions of aromatic polycarboxylic acids with N₂H₄·H₂O. It is noteworthy that another kind of hydrothermal in situ reaction was also observed when preparing compounds 1 and 2, namely the nucleophilic addition reaction between the keto group (of dphahk) and N₂H₄. The photoluminescence analysis indicates that the compounds in the different states (in the solid state or in aqueous solution) may exhibit different emission behaviors.