Polymeric Complexes with “Piperazine−Pyridine” Building Blocks:  Synthesis, Network Structures, and Third-Order Nonlinear Optical Properties

Abstract

A new bidentate "building block", N, N′-bis(3-pyridylformyl)piperazine (bpfp), was synthesized. X-ray diffraction studies reveal that the piperazine ring in bpfp forms a chairlike structure conformation. bpfp self-assembled into two-dimensional layered rhombohedral grid polymers {[Mn(H2O)2-(SO4)(bpfp)](H2O)3(CH3OH)}n (1) and {[Zn(NCS)2(bpfp)2]‚2H2O}n (2) with Mn(II) and Zn(II), a threedimensional polymer [Cd(N3)2(bpfp)]n (3) with Cd(II), and a one-dimensional zigzag polymer [HgI2(bpfp)]n (4) with Hg(II). Each rhombohedral grid in polymer 1 is composed of four Mn, two bpfp, and two SO4 2-; the dimensions of the grid are 6.537 × 12.843 Å. In polymer 2, each rhombohedral grid consists of 60membered rings Zn4(bpfp)4 showing the dimensions of 14.231 × 15.586 Å. Zn4(bpfp)4 grids are bridged by Zn ions and all pyridyl-N atoms of bpfp ligands into the 2-D network structure along a and c directions. Polymer 3 exhibits a 3-D layered structure with tetragonal prism channel viewing from a direction. The bpfp ligands occupy the four edges of tetragonal prism channel, which is cut off by layers consisting of rhombohedral grids Cd 4(N3)4. Polymer 4 is quite different from polymers 1-3; it exhibits a 1-D zigzag framework extending along the c axis. Polymers 1-3 possess a very strong NLO absorption and selffocusing effect. Their third-order NLO absorptive coefficients R2 are 9.2 × 10 -9 , 6.9 × 10 -9 , and 7.1 × 10 -9 m W -1 . The third-order NLO hyperpolarizabilities γ are 1.79 × 10 -28 , 9.10 × 10 -29 , and 9.66 × 10 -29 esu, respectively. The γ values are comparable to those of the best NLO materials and coordination polymers. We found that the valence shell structures of central metal ions can influence the NLO properties of coordination polymers.

Metal‐Dependent Topologies and Water Aggregations in Copper and Nickel Carboxycinnamate Coordination Polymers with a Long‐Spanning Dipyridylamide Ligand

“…The dipyridylamide ligand bis(4-pyridylformyl)piperazine (4-bpfp) was prepared by a literature procedure. [15] Water was deionized above 3 MΩ per cm in-house. Elemental analysis was carried out with a Perkin-Elmer 2400 Series II CHNS/ O Analyzer.…”

Syntheses, Structures and Electrochemical Properties of Two New Copper(II) Complexes Based on Isomeric Bis(pyridylformyl)piperazine Ligands and Rigid=Flexible Organic Dicarboxylates

“…Ligands 3-bpfp and 4-bpfp were synthesized by the literature method [34]. All other reagents employed were commercially available and used as received without further purification.…”

Structures and enhanced third-order nonlinear optical performance of four complexes investigated by thin film Z-scan technique

“…Before the preparation of compound films, we measured the XRD patterns of the complexes and compared them Although the third-order nonlinear properties of some CPs have been reported [13][14][15][16][17]27], these data were from the solution state. Therefore, we studied the third-order NLO properties of these neat compounds in thin films by Zscan techniques.…”