Coordination frameworks constructed from bipyridyl piperazine and MCl₂(M = Co, Ni, Zn): structural characterization and optical properties

Abstract

Three metal-organic polymers, [CoCl2(bpfp)]n 1, {[NiCl2(bpfp)2](H2O)3}n 2 and [ZnCl2(bpfp)]n 3 (bpfp = N,N'-bis(3-pyridylformyl)piperazine), are formed by the self-assembly of the flexible bpfp with MCl2 (M = Co, Ni, Zn), respectively. X-Ray single-crystal structural analysis reveals that polymer 1 exhibits a novel grid network, in which the grid is composed of segments of bpfp and cobalt ions. Polymer 2 consists of 2D rhombohedral grids, the dimensions of the grid are 15.782 x 12.434 A2 and the diagonal-to-diagonal distances are 13.186 x 25.169 A2. In polymer 3, infinite wavelike chains are extended to 2D supramolecular arrays via C-H...Cl hydrogen bonds. The third-order nonlinear optical (NLO) behaviors of 1-3 and bpfp were investigated in dilute DMF solution by Z-scan measurement. The results show that 1, 2 and 3 exhibit good third-order NLO properties, which are quite different from bpfp that shows weak NLO behavior. This paper demonstrates that metal ions can strongly influence the crystal structures and third-order NLO properties of polymers.

Synthesis, structure and electrochemical properties of a polyoxometalate-templated compound with 2D twofold interpenetrating network

“…In addition, there exist two kinds of weak C-HÁÁÁO hydrogen bonding interactions in the structure (Table S2) The construction of the title compound with 2D interpenetrating network can be attributed to not only the coordination pattern of the Cu(II) center and the L ligand but also the template effect of PW 12 anion. Hou and coworkers [38] used the same L ligand and various inorganic anions such as SO 4 2-, N 3 -, I -, SCN -, NO 3 -, Cl -to generate many new coordination polymers, which exhibited non-interpenetrating structures. Compared with the above anions, Keggin-type PW 12 polyanions show larger size (ca.…”

A Series of Coordination Polymers Exhibiting Dual Chiral Features and Diverse Interhelical Interactions

“…The overall net chiralities of compounds 3 – 5 are largely derived from the inherent chiralities of the ligand (chiral carbon atoms). The above-mentioned difference in the five complexes might be caused by the nature of different metal ions, including the different electronic configuration and the thus resulted in different coordination environments of metal ions . The Co(II) and Ni(II) ions in 1 and 2 exhibit nearly regular six-coordinate MN 3 O 3 octahedral geometry with one pyridine molecule in the equatorial position and the other in the axial position.…”

Studies on two coordination polymers [M(μ4-pz25dc)]n (M=Cd or Zn, pz25dc=pyrazine-2,5-dicarboxylato) with three-dimensional pillared-layer three-nodal framework: Synthesis, structural characterization, strong optical non-linearities and optical limiting properties

“…Given the polydispersity indexes very close to 1, the dissolved polymers are broken into small pieces of the same size, which do not further dissociate into smaller species, and stable oligomers with a constant polymerization degree (43 and 57, respectively, for polymers 1 and 2) are thus formed. This fact is that solution processing is known to have some unique advantages including better molecular weight control [41,64]. Coordination polymers with very narrow molecular weight distributions and strong optical non-linearities are also observed in some reported metal-organic polymers, such as [NiCl 2 (bpfp) 2 …”