Facile in situ syntheses of new templates and formations of three zinc phosphates

Abstract

Three new organically templated zinc phosphates, namely, [dmdabco][Zn2(HPO4)3]·(H2O) (1), [tmpip]0.5[Zn2(HPO4)2(H2PO4)] (2) and [tmpip][Zn3(HPO4)4] (3) (dmdabco=N,N′-dimethyl-1,4-diazabicyclo[2,2,2]octane, tmpip=N,N,N′,N′-tetramethyl-piperazinium), were successfully synthesized under solvothermal reactions and structurally characterized by single-crystal X-ray diffraction. The dmdabco2+ and tmpip2+ templating agents were derived respectively from simple in situ N-alkylation transformations between the methanol solvent and organic cyclic aliphatic diamines, 1,4-diazabicyclo[2,2,2]octane (dabco) in 1 and 1-methylpiperazine in 2 and 3. Such direct methylation feature is unique, and quite different from conventional Eschweiler–Clarke methylation in which an excess of formic acid and formaldehyde was required. Compound 1 exhibits a 4-connected 2D (4, 4) net with pentameric [Zn2(HPO4)3] clusters as secondary building units (SBUs); 2 possesses a complex double layered structure with 12-ring windows. Compound 3 has a (3, 4)-connected 3D pcu architecture with heptameric [Zn3(HPO4)4] clusters as SBUs, forming intersecting 8- and 12-ring channels.