The effect of organic linkers on the supramolecular structures of two new Ni(II) cyclen complexes (cyclen = 1,4,7,10-tetraazadodecane)

Two new nickel(II)(cyclen) coordination polymers, {Ni(cyclen)·(bipy)]·(ClO₄)₂}_n (1) and Ni(cyclen)]₂·(squa)·(ClO₄)₂ (2) have been synthesized and characterized structurally, where cyclen is 1,4,7,10-tetraazadodecane. Compound 1 crystallizes in the monoclinic system, space group C2/c, with a = 10.5339(17) ?, b = 14.565(2) ?, c = 16.133(3) ?, β = 102.799(2)°, V = 2413.4(7) ?³. Compound 2 crystallizes in the orthorhombic system, space group P _{nm a} with a = 25.722(3) ?, b = 11.1168(12) ?, c = 11.4580(13) ?, V = 3276.3(6) ?³. In both compounds, each Ni^II center is in a distorted octahedral coordinated environment with four N_cyclen atoms and two N_pyridine atoms from 4,4′-bipyridine linker for 1 and two O_aqueou atoms from the coordinated water for 2, respectively. The complex 1 exhibits infinite zigzag 1D chains by linking of 4,4′-bipyridine coordinated. In complex 2, 2D sheet supramolecule generated through self-assembling by hydrogen bond.