Two layered gallophosphates assembled about the chiral metal complexes: Co(en) 3·Ga 3P 4O 16·5H 2O and trans−Co(dien) 2·Ga 3P 4O 16·3H 2O

Abstract

Two new layered gallophosphates Co(en) 3·Ga 3P 4O 16·5H 2O ( 1) and trans-Co(dien) 2·Ga 3P 4O 16·3H 2O ( 2) have been hydrothermally synthesized using the racemic mixture of chiral metal complex Co(en) 3Cl 3 and Co(dien) 2Cl 3 as the structure-directing agent, respectively. Their structures are determined by single-crystal X-ray diffraction analysis and further characterized by X-ray power diffraction, ICP, elemental, and TG analyses. The structures of 1 and 2 consist of vertex-linking GaO 4 and PO 3(=O) tetrahedral units forming macroanionic [Ga 3P 4O 16] 3− sheets with a 4.6-net. The 4.6-net is characteristic of chiral [3.3.3] propellane-like structural motifs. The sheets of 1 stack in an ABAB sequence, with a pair of enantiomers of chiral Co(en) 3 3+ cations residing in the interlayer region. The sheets of 2 array in a helical fashion with an ABCDEF stacking sequence, with only one enantiomer of chiral Co(dien) 2 3+ cations residing in the interlayer region. Structural elucidation of 1 and 2 reveals that there exist stereo-specific correspondence between the metal complex template and the structure of the inorganic host. Crystal data: 1, Co(en) 3·Ga 3P 4O 16·5H 2O, orthorhombic, Pnna (No. 52), a=8.6618(2) Å, b=21.6071(5) Å, c=13.7426(4) Å, Z=4, R 1=0.0337 ( I>2 σ( I)), w R 2=0.0985 (all data); 2, Co(dien) 2·Ga 3P 4O 16·3H 2O, hexagonal, P6 522 (No. 179), a=8.5152(7) Å, b=8.5152(7) Å, c=63.278(8) Å, R 1=0.1183 ( I>2 σ( I)), w R 2=0.2864 (all data) and Z=6.