Syntheses and structures of two low-dimensional beryllium phosphate compounds: [C5H14N2]2[Be3(HPO4)5].H2O and [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5H2O.

The first two low-dimensional beryllium phosphates, [C5H14N2]2[Be3(HPO4)5].H2O (BePO-CJ29) and [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5 H2O (BePO-CJ30), have been successfully synthesized under mild hydrothermal/solvothermal conditions. BePO-CJ29 is built up from strict alternation of BeO4 and HPO4 tetrahedra forming a unique one-dimensional double chains with 12-ring apertures. There are pseudo-10-ring apertures enclosed by two double chains through H-bonds. BePO-CJ29 can also be viewed as a pseudo 2-D layered structure stabilized by strong H-bonds. The diprotonated 2-methylpiperazium cations are located at three positions (i.e., inside the 12-ring aperture, inside the pseudo-10-ring aperture, and in the interlayer of the inorganic pseudo-layers. BePO-CJ30 is constructed by the alternation of Be-centered tetrahedra (including BeO4 and HBeO4) and P-centered tetrahedra (including PO4 and HPO4) resulting in a two-dimensional layered structure parallel to the (0 1 1) direction. The complex layer is composed of coupled 4.8 net sheets. The diprotonated 1,6-hexandiamine cations and water molecules reside in the interlayer regions and interact with the inorganic layers through H-bonds. Crystal data are as follows: [C5H14N2]2[Be3(HPO4)5].H2O (BePO-CJ29), triclinic, P1 (No. 2), a = 8.1000(9) A, b = 8.4841(14) A, c = 19.665(2) A, alpha = 89.683(10) degrees, beta = 78.182(8) degrees, gamma = 87.932(9) degrees, V = 1321.9(3) A3, Z = 2, R1 = 0.0523 (I > 2sigma(I)), and wR2 = 0.1643 (all data); [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5 H2O (BePO-CJ30), orthorhombic, Pccn (No. 56), a = 26.01(4) A, b = 8.431(12) A, c = 9.598(13) A, V = 2105(5) A3, Z = 8, R1 = 0.0833 (I > 2sigma(I)), and wR2 = 0.2278 (all data).