Chiral three-dimensional microporous nickel aspartate with extended Ni-O-Ni bonding

In the course of our investigation aimed at the preparation of homochiral coordination polymers using readily available in optically pure form ligands and building blocks of condensed metal polyhedra, we recently reported a one-dimensional nickel aspartate compound [Ni2O(L-Asp)(H2O)(2)]center dot 4H(2)O (1) based on helical chains with extended Ni-O-Ni bonding. Here we report a new nickel aspartate [Ni-2.5(OH)(L-Asp)(2)]center dot 6.55H(2)O (2) with a three-dimensional Ni-O-Ni connectivity that forms at a higher pH and is based on the same helices as in 1 which are connected by additional nickel octahedra to generate a chiral open framework with one-dimensional channels with minimum van der Waals dimensions of 8 x 5 angstrom. The crystal structure of 2 was determined by synchrotron single-crystal X-ray diffraction on a 10 x 10 x 240 mu m crystal.