The magnetic study of a binuclear Cu(ii) complex with pi-pi stacking interactions.
An anomalous magnetic interaction is observed in a very common and unpublished binuclear copper(ii) complex, [Cu(2)(micro(2)-OOCCH(3))(2)(bpydiol-H)(2)(H(2)O)(2)] (bpydiol-H = mono deprotonated 2,2'-bypyridine-3,3'-diol). In the complex, the two Cu(ii) ions are bridged by two acetate anions and there is a pi-pi stacking interaction between the adjacent pyridine rings. Theoretical calculations reveal that the acetate bridge ligand leads to an antiferromagnetic coupling with 2J = -166.72 cm(-1), whereas the pi-pi stacking developed a ferromagnetic interaction with 2J = 21.0 cm(-1). The offset from the antiferromagnetic interaction and the ferromagnetic interaction may be one of main factors that resulted in the weaker magnetic coupling with experimental fitting 2J = -59.61 cm(-1). This is the first example using theoretical calculations that evaluate the magnetic coupling intensity for a pi-pi stacking system.
Hou
Chao
C
College of Chemistry, Chemical Engineering and Materials Science, Engineering Research Center of Pesticide and Medicine Intermediate Clean Production, Ministry of Education, Shandong Normal University, Jinan 250014, P. R. China.
Shi
Jing-Min
JM
Sun
You-Min
YM
Shi
Wei
W
Cheng
Peng
P
Liu
Lian-Dong
LD
D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008280:Magnetics; D008958:Models, Molecular; D015394:Molecular Structure; D014867:Water / Q000737:chemistry
D014867:Water; D003300:Copper