Syntheses and characterizations of zinc phosphites with new templates generated by N-alkylation transformations

• New templates were generated in situ by direct N-methylation reactions.
• Two new open-framework zinc phosphites were solvothermally synthesized.
• A complex double layered structure was found in compound 1.
• The 3D network of 2 was constructed from heptameric [Zn3(HPO3)4] clusters.

Two new organically templated zinc phosphites, [tmpip]0.5[Zn2(HPO3)2(H2PO3)] (1) and [dmdabco][Zn3(HPO3)4]·(H2O) (2), have been synthesized under solvothermal conditions, where tmpip = N,N,N′,N′-tetramethyl-piperazinium and dmdabco = N,N′-dimethyl-1,4-diazabicyclo[2,2,2]octane. Note that the templating agents tmpip2 + and dmdabco2 + originated from in situ N-methylation transformations between CH3OH solvent and corresponding cyclic aliphatic amine precursors, i.e. piperazine, 1-methylpiperazine or 1,4-dimethylpiperazine in 1, and 1,4-diazabicyclo[2,2,2]octane in 2. Distinct from conventional Eschweiler–Clarke methylation with excess formic acid and formaldehyde, such direct methylation transformation from methanol molecules is unique. Compound 1 consists of ZnO4 tetrahedra, HPO3 and HPO2(OH) pseudopyramids, exhibiting a complex double layered structure with 12-ring windows. Compound 2 is constructed from strictly alternating ZnO4 tetrahedra and HPO3 pseudopyramids, and possesses a (3,4)-connected interrupted architecture with intersecting 8- and 12-ring channels.

Two new templates were generated in situ by direct N-methylation transformations between CH3OH and organic amines. Two organically templated zinc phosphites were synthesized and structurally characterized. Compound 1 possesses a double layered structure, while 2 exhibits a (3, 4)-connected interrupted 3D architecture.Figure optionsDownload as PowerPoint slide