Doubly-linked 1D coordination polymers derived from 2:2 metallamacrocyclic Ni(II) complexes with bipodal acylthiourea and exo-bidentate N-donor bridging ligands:toward potentially selective chemical sensors?

摘要

The square planar 2:2 metallamacrocyclic Ni(II) complex of 3,3,3',3'-tetraethyl-1,1'-isophthaloylbis(thiourea) readily forms coordination polymers by axial coordination of various exo-bidentate N-donor linkers:pyrazine,4,4'-bipyridine,1,2-bis(4-pyridyl)ethane and l,2-di(4-pyridyl)ethylene.Steric constraints,together with coordination limited to the axial directions,result in the self-assembly of double-linked 1D ladder structures.One compound in particular,with the bridging ligand 1,2-di(4-pyridyl)ethylene,is found to exist as a quasi-polymer,realising only one-third of its potential linkages.On exposure to various solvents,this compound appears to undergo complete polymerisation,both rapidly and fully reversibly with an associated colour change,making it a potential chemical sensor.