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Metal-ion selectivity by macrocyclic ligands. Part 3. The interaction of Mn II and Co II with pyridinyl-derived N3O2 macrocycles; X-ray structures of endomacrocyclic complexes of Mn II and Co II

1991; Royal Society of Chemistry; Issue: 11 Linguagem: Inglês

10.1039/dt9910002989

2050-5671

Neil A. Bailey, David E. Fenton, Simon J. Kitchen, Terence H. Lilley, Mark Williams, Peter A. Tasker, Anthony J. Leong, Leonard F. Lindoy,

Molecular Sensors and Ion Detection

The interaction of MnII and CoII with the macrocycles L1 and L2, each containing an N3O2-donor set, has been investigated. Conductometric titration of the 1 : 1 MnII complexes with chloride indicated the formation of a 2 : 1 complex presumably through bridging of a chloride ion. The stability constants of the complexes have been determined in 95% methanol. The X-ray crystal structures of the 1 : 1 complexes [MnL1Br(EtOH)]ClO4 and [CoL1(NO3)]NO3, have been determined. The metal in [MnL1Br(EtOH)]ClO4 is seven-co-ordinate and lies within the macrocyclic cavity. The donor set comprises the five macrocyclic donor atoms, a bromide anion and an ethanol molecule. Overall, the co-ordination sphere corresponds to a distorted pentagonal-bipyramidal arrangement. The complex [CoL1(NO3)]NO3 also has all donors of the macrocycle co-ordinated together with a nitrate anion. The cobalt is seven-co-ordinated and the co-ordination polyhedron is intermediate between a capped trigonal prism and a pentagonal bipyramid.