名称:
Preparation, properties and crystal structure of two isomers of R,R,S,S- and R,S,R,S-[chloro(1,3,10,12,16,19-hexaazatetracyclo[17,3,1,112,16,04,9]tetracosane)copper(II)]+
摘要:
Two isomers (R, S, R, S- and R, R, S, S-) of five coordinate complex [Cu(L)Cl](divided by) have been separated and characterised. These two isomers have significantly different spectrochemical and electrochemical properties. Absorption maximum of R, S R, S-[Cu(L)Cl](divided by) shifts to longer wavelength and its reduction potential shifts to more positive direction comparing those of R,R,S,S-[Cu(L)Cl](divided by). R. S, R, S-[Cu(L)Cl](divided by) is significantly distorted to trigonal-bipyramidal structure, whereas R, R, S, S-[Cu(L)Cl](divided by) retains almost square-planar geometry. The average bond distance of Cu-N in basal plane of R, S, R, S-[Cu(L)Cl](divided by) I is longer by 0.024 A than that of R, R, S, S-[Cu(L)Cl](+), whereas the bond distance of Cu-Cl in former is shorter by 0.200 A than that in latter. The isolated square-planar complexes of R, R S, S- and R, S. R, S-[Cu(L)](ClO4)(2) are converted to the R, R S, S- and R, S R, S-[Cu(L)Cl](divided by) by the addition of Cl- in nitromethane solution with the rate constants, k = 1.70 (+/-0.02) and 8.31 (+/-0.07) M-1 s(-1). respectively. (C) 2003 Elsevier B.V. All rights reserved.