M-II(C4H12N2)[B2P3O12(OH)] (M-II = Co, Zn): Synthesis and crystal structure of novel open framework borophosphates

Two novel borophosphates. M-II(C4H12N2)-[B2P3O12(OH)] (M-II = CO, Zn), exhi biting open frameworks, have been synthesized by hydrothermal reactions (T = 165 degreesC). The crystal structures of the isotypic compounds have been determined both at 293 K (orthorhombic, Ima2 (no. 46), Z = 4; M-II = Co: a = 12.4635(4) Angstrom, b = 9.4021(4) Angstrom, c = 11.4513(5) Angstrom, V = 1341.90 Angstrom (3), R-1 = 0.0202, wR(2) = 0.0452, 2225 observed reflect ions with I > 2 sigma (I); M-II = Zn: a = 12.4110(9) Angstrom, b = 9.4550(5 ) Angstrom, c = 11.4542(4) Angstrom, V = 1344.69 Angstrom (3), R-1 = 0.0621 , wR(2) = 0.0926, 1497 observed reflections with I > 2 sigma (I)). Distorte d CoO6-octahedra and ZnO5-square-pyramids, respectively, share common oxyge n-corners with BO4-, PO4- and (HO)PO3-tetrahcdra. The tetrahedral groups ar e linked via common corners to form infinite loop-branched borophosphate ch ains 1 infinity [B2P3O12(OH)(4-)]. The open framework of M-II-coordination polyhedra and tetrahedral borophosphate chains contains a three-dimensional system of interconnected structural channels running along [100], [011] an d [011], respectively, which are occupied by di-protonated piperazinium ion s.