Premium
Copper(II) Complexes of ω ‐Hydroxy‐Functionalized N ‐Salicylidenehydrazides show pH‐Controlled Switching between Dicationic Dimers and Neutral One‐Dimensional Coordination Polymers
Author(s) -
Roth Arne,
Buchholz Axel,
Plass Winfried
Publication year - 2007
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200600309
Subject(s) - chemistry , salicylaldehyde , copper , perchlorate , ligand (biochemistry) , crystallography , antiferromagnetism , polymer , dimer , inorganic chemistry , stereochemistry , polymer chemistry , ion , schiff base , organic chemistry , biochemistry , receptor , physics , condensed matter physics
Abstract New copper(II) complexes of the hydrazone ligands H 2 salhyhb, H 2 salhyhp, and H 2 salhyhh, derived from salicylaldehyde and ω ‐hydroxy carbonic acid hydrazides, have been synthesized and physically characterized. Two fundamental structures were found in solid state depending on the pH‐value of the reaction solution. Acidic conditions lead to the formation of the di‐ μ ‐phenoxo‐bridged dicationic complex dimers [{Cu(Hsalhyhb)} 2 ] 2+ ( 1a ), [{Cu(Hsalhyhp)} 2 ] 2+ ( 2a ), and [{Cu(Hsalhyhh)} 2 ] 2+ ( 3a ), isolated as perchlorate salts. The dimeric complexes show strong antiferromagnetic coupling with J = −399 ( 1a ), −410 ( 2a ), and −311 cm −1 ( 3a ). Higher pH‐values resulted in the aggregation of neutral copper ligand fragments to the one‐dimensional coordination polymers [{Cu(salhyhb)} n ] ( 1b ), [{Cu(salhyhp)} n ] ( 2b ), and [{Cu(salhyhh)} n ] ( 3b ). 3b has been examined by means of X‐ray crystallography and represents the first example of a structurally characterized neutral copper(II) N ‐salicylidenehydrazide complex without additional ligands. The magnetic interactions in the polymers are also antiferromagnetic with J = −125 ( 1b ), −136 ( 2b ), and −148 cm −1 ( 3b ), but strongly reduced compared to the corresponding dimeric complexes. The two basic structure types can be reversibly interconverted simply by pH‐control.