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Low‐dimensional coordination polymeric structures in alkali metal complex salts of the herbicide (2,4‐dichlorophenoxy)acetic acid (2,4‐D)
Author(s) -
Smith Graham
Publication year - 2015
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s205322961500056x
Subject(s) - chemistry , carboxylate , denticity , crystallography , octahedron , hydrogen bond , ligand (biochemistry) , molecule , stereochemistry , bridging ligand , crystal structure , biochemistry , receptor , organic chemistry
The Li, Rb and Cs complexes with the herbicide (2,4‐dichlorophenoxy)acetic acid (2,4‐D), namely poly[[aqua[μ 3 ‐(2,4‐dichlorophenoxy)acetato‐κ 3 O 1 : O 1 : O 1′ ]lithium(I)] dihydrate], {[Li(C 8 H 5 Cl 2 O 3 )(H 2 O)]·2H 2 O} n , (I), poly[μ‐aqua‐bis[μ 3 ‐(2,4‐dichlorophenoxy)acetato‐κ 4 O 1 : O 1′ : O 1′ , Cl 2 ]dirubidium(I)], [Rb 2 (C 8 H 5 Cl 2 O 3 ) 2 (H 2 O)] n , (II), and poly[μ‐aqua‐bis[μ 3 ‐(2,4‐dichlorophenoxy)acetato‐κ 5 O 1 : O 1′ : O 1′ , O 2 , Cl 2 ]dicaesium(I)], [Cs 2 (C 8 H 5 Cl 2 O 3 ) 2 (H 2 O)] n , (III), respectively, have been determined and their two‐dimensional polymeric structures are described. In (I), the slightly distorted tetrahedral LiO 4 coordination involves three carboxylate O‐atom donors, of which two are bridging, and a monodentate aqua ligand, together with two water molecules of solvation. Conjoined six‐membered ring systems generate a one‐dimensional coordination polymeric chain which extends along b and interspecies water O—H...O hydrogen‐bonding interactions give the overall two‐dimensional layers which lie parallel to (001). In hemihydrate complex (II), the irregular octahedral RbO 5 Cl coordination about Rb + comprises a single bridging water molecule which lies on a twofold rotation axis, a bidentate O carboxy , Cl ‐chelate interaction and three bridging carboxylate O‐atom bonding interactions from the 2,4‐D ligand. A two‐dimensional coordination polymeric layer structure lying parallel to (100) is formed through a number of conjoined cyclic bridges, including a centrosymmetric four‐membered Rb 2 O 2 ring system with an Rb...Rb separation of 4.3312 (5) Å. The coordinated water molecule forms intralayer aqua–carboxylate O—H...O hydrogen bonds. Complex (III) comprises two crystallographically independent ( Z ′ = 2) irregular CsO 6 Cl coordination centres, each comprising two O‐atom donors (carboxylate and phenoxy) and a ring‐substituted Cl‐atom donor from the 2,4‐D ligand species in a tridentate chelate mode, two O‐atom donors from bridging carboxylate groups and one from a bridging water molecule. However, the two 2,4‐D ligands are conformationally very dissimilar, with one phenoxyacetate side chain being synclinal and the other being antiperiplanar. The minimum Cs...Cs separation is 4.4463 (5) Å. Structure extension gives coordination polymeric layers which lie parallel to (001) and are stabilized by intralayer water–carboxylate O—H...O hydrogen bonds.