Roles of halide anions in the structural diversity of Zn(ii) complexes containing the flexible N,N′-di(4-pyridyl)adipoamide ligand

Abstract

A series of Zn(II) complexes with N,N 0 -di(4-pyridyl)adipoamide ligands, {[ZnX 2 (L)]$H 2 O} N (X ¼ Cl, 1, Br, 2 and I, 3; L ¼ N,N 0 -di(4-pyridyl)adipoamide), [Zn 2 X 4 (L) 2 ]$2DMF (X ¼ Cl, 4 and Br, 5) and [Zn 2 I 4 (L) 2 ]$4DMF$C 4 H 10 O, 6, were prepared and their structures determined by X-ray crystallography. Complexes 1 and 2 form double-stranded helical chains which are supported by the N-H/O and O-H/X hydrogen bonds involving the guest water molecules and the halide anions, whereas 3 shows sinusoidal chains which are interlinked by the N-H/O hydrogen bonds and p-p interactions. Complexes 1-3 represent a unique example that the halide anions show significant effect on folding and unfolding of the Zn(II) double-stranded helical coordination polymers. Complexes 1-3 can be transformed to the corresponding complexes 4-6, which are dinuclear with 34-membered metallocycles. In these complexes, the chloride and bromide anions play the same role in the crystal structures, while the iodide anion is distinct.

Self-Catenated Coordination Polymers Involving Bis-pyridyl-bis-amide

“…The reagents CdBr 2 ·4H 2 O, 1,2-benzenedicarboxylic acid (1,2-H 2 bdc), 1,3-benzenedicarboxylic acid (1,3-H 2 bdc), 1,4-benzenedicarboxylic acid (1,4-H 2 bdc), and benzene-1,2,3-tricarboxylic acid (1,2,3-H 3 btc) were purchased from Aldrich Chemical Co., Cd­(CH 3 COO) 2 ·2H 2 O was purchased from Alfa Aesar, and 1,4-phenylenediacetic acids were purchased from ACROS Co. The ligands N,N ′-di­(3-pyridyl)­suberoamide ( L 1 ) and N,N ′-di­(3-pyridyl)­adipoamide ( L 2 ) were prepared according to published procedures. − …”

Synthesis, crystal structures and reversible solid-state crystal-to-crystal transformation of three isostructural lead(ii) halide coordination polymers with different luminescence properties in bulk and nanoscale

“…The emission behaviors of compounds 1 and 2 are the same, which can most probably be ascribed to similar polarizations of chloride and bromide anions. 61 The photoluminescence peaks of CPs 1 and 2 are clearly red-shifted, featuring an LMCT (ligand-to-metal charge transfer) character from the ligand to Pb 2+ . 62 The distinct behaviour of compound 3 can be attributed to its bigger size and lower electronegativity.…”

Metal cation- and anion-induced assembly: structures and luminescent properties

“…for C 53 H 40 CoN 10 OS 2 : C,66.59;H,4.22;N,14.65. Found: C,66.96;H,4.58;N,14. 1041(m), 1126(w), 1168(m), 1195(s), 1245(s), 1333(m), 1363(s), 1398(s), 1440(s), 1494(s), 1523(s), 1571(w), 1603(s), 2065(s), 3455(s).…”

“…Compared with 1 and 3, no hydrogen bonding interactions based on the anion can be found in 2, which may be attributed to the greater size and smaller electronegativity of the iodide anion. 14 As a result, only the C-H … N hydrogen bonding interactions based on the pyrazolyl nitrogen atom link the molecules to form a 1-D structure.…”