Double piperazinediium and 1,4-diazabicyclo[2.2.2] octanediium MII selenates (MII = CoII, NiII, CuII, ZnII) as effective catalysts for Henry reaction

New organically templated complexes {(C4H12N2)[MII(H2O) 4(SeO4)(2)]}center dot 2H(2)O [M-II = Co (1), Cu (2) and Zn (3)] were prepared by slow evaporation of aqueous solution containing metal(II) carbonate, selenic acid and piperazine taken in 1: 2: 1 M ratio. The compounds 1-3 were characterized by IR spectroscopy, ESIMS, elemental and single-crystal X-ray diffraction analyses. The structures of the compounds contain [C4H12N2](2+) cation, H2O molecules and the [MII(H2O)(4)(SeO4)(2)](2) anions interlinked by Ow-Hw center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonding. 1-3 and known analogous mixed salts (C6H14N2)[MII(H2O)(6)](SeO4)(2) [MII = Ni (4), Zn (5)] (C6H12N2 = 1,4-diazabicyclo[2.2.2] octane) are effective catalysts in the synthesis of b-nitroalkanols from nitroethane and aliphatic or aromatic aldehydes with yields up to 93% and threo/erythro ratio up to 79: 21. Crown Copyright (C) 2013 Published by Elsevier B. V. All rights reserved.