Syntheses and Characterizations of Coordination Polymers Constructed from 4-Pyridylacetic Acid

Abstract

Assembly of 4-pyridylacetic acid hydrochloride (Hpya‚HCl) and Zn(CH 3 COO) 2 ‚2H 2 O, 3CdSO 4 ‚8H 2 O, or MnCl 2 ‚4H 2 O gave rise to five polymeric complexes {[Zn(C 7 H 6 NO 2 ) 2 ]‚7H 2 O} n (1), [trans-M(C 7 H 6 NO 2 ) 2 (H 2 O) 2 ] n (M ) Zn, 2; Cd, 3; Mn, 5), and [cis-Cd(C 7 H 6 NO 2 ) 2 (H 2 O) 2 ] n (4), respectively. X-ray diffraction analyses reveal that complex 1 has a two-dimensional (2D) framework comprising rhombic grids of cavity dimensions 13.965 × 12.475 Å, and the structure is extended into a three-dimensional network with large unique quasi-aperture by hydrogen bond and π-π stacking interactions. Complexes 2, 3, and 5 possess a 2D structure consisting of alternate left and right helical chains with rhombic grids of dimensions 15.933 × 5.692, 16.445 × 5.834, and 16.179 × 5.706 Å, respectively. Complex 4 has a 2D network constructed by right helical chains. Different crystallization conditions result in different coordination geometries of metal centers in zinc (1 and 2) and cadmium complexes (3 and 4). Thermogravimetric analyses of the complexes were performed.

Poly[trans-diaquabis(μ2-3-pyridylacetato)copper(II)]

“…The molecule of the title complex, which is similar to that previously described for [M(Hpya) 2 (H 2 O) 2 ] n (M = Cu, Co, Mn, Ni, Zn, Cd; Hpya = 4-pyridylacetic acid) (Li et al, 2004;Du et al, 2006) and [M(3-pyridylacetato) (Martin et al, 2007), is centrosymmetric, so pairs of equivalent ligands lie trans to each other in a slightly distorted octahedral geometry. The Cu II center is six-coordinated by two water molecules in the axial positions, two pyridyl nitrogen atoms and two carboxylate oxygen atoms from four 3-pyridylacetate ligands in the equatorial plane.…”

“…The six-coordinate complex with 4-pyridylacetate and 3-pyridylacetate ligands have similar octahedral geometry (Li et al, 2004;Du et al, 2006;Martin et al, 2007).…”

“…These ligands can connect different metal ions to form robust networks or some porous coordination polymers. Though various metal-pyridinepolycarboxylate complexes have been reported (Evans et al, 2002;Aakeröy et al, 1999;Tong et al, 2003;Li et al, 2004;Du et al, 2006), complexes of 3-pyridylacetate are very limited. Only complexes of nickel and cobalt have been published recently up to now (Martin et al, 2007).…”

A new manganese(II) complex with the m-aminobenzoate anion: [aqua(3-aminobenzoato-κO)bis(1,10-phenanthroline-κ2 N,N′)manganese(II)] 3-aminobenzoate 4.5-hydrate

“…The manganese(II) ion is six-coordinated by four N atoms from two distinct phen molecules, one carboxylate O atom from an m-aminobenzoate anion and one O atom from a water molecule. The Mn-O(carboxylate) distance of 2.114 (2) Å is significantly shorter than the value found in the polymeric compound [trans-Mn(C 7 H 6 NO 2 ) 2 (H 2 O) 2 ] n (Li et al, 2004). In (I), in constras to what is observed in the bis(oaminobenzoato)copper(II) complex (Lange & Haendler, 1975), the amine group of the m-aminobenzoate ligand is not coordinated to the manganese(II) ion.…”

Recent advances in the design and construction of helical coordination polymers

“…Hong et al [64][65][66][67][68][69] are currently taking an approach of self-assembly reaction between metal ions and flexible twisted pyridinecarboxylate ligands to form helical or chiral frameworks. 4-Pyridylacetic acid (17) possesses two interesting characteristics: (a) it possesses flexibility owing to the presence of a -CH 2 -spacer between the pyridyl ring and carboxylate moiety; (b) it holds three Fig.…”