Isolated Magnetic Clusters of Co(ll) and Ni(ll) within 3-Dimensional Organic Frameworks of 6-Mercaptonicotinic Acid: Unique Structural Topologies Based on Selectivity for Hard and Soft Coordination Environments

摘要

Hydrothermal reaction of the mixed thiolate-carboxylate-aromatic amine ligand,6-mercaptonicotinic acid (6-mnaH_2) with Co(ll) and Ni(ll) leads to two network coordination solids [M_9(6-mna)_8(mu_3-0_)2-(OH_3)_2(OH_2)_6] (M = Co,Ni),1,and [M_2Ni_(12)(6-mna)_(12)(mu_3-OH)_2-(OH_2)_6] centre dot 8H_20 (M = K,Rb,Cs),2.These compounds are unusual for two reasons: they are thiolate-bridged networks and they are three-dimensional lattices which contain isolated metal clusters and chains.The magnetic behavior of these compounds has been studied,showing that 2 contains ferromagnetically coupled Ni_6 wheels.