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Title: EPR evidence for magnetic exchange through a four-carbon aliphatic bridge in a binuclear copper(II) complex. Single crystal x-ray structure of 7,7'-(1,4-butanediyl)-bis(2,12-dimethyl-3,7,11,17-tetraazabicyclo(11. 3. 1)heptadeca-1(17),2,11,13,15-pentaene)nickel(II)) perchlorate monohydrate

Journal Article · · J. Coord. Chem.; (United States)

The single crystal x-ray structure of the title, binuclear nickel(II) complex has been determined and the compound used as a host for EPR investigations of the analogous copper(II) complex. The impetus for this work was an earlier suggestion that magnetic exchange interactions detected by EPR spectroscopy on frozen solutions of the biscopper(II) complex were a result of a direct copper-copper interaction in a closed conformation of the binuclear species. Results reported here suggest that the complex exists in the open conformation where the distance between metal centres is maximized and that the magnetic exchange occurs by a super-exchange mechanism through the aliphatic chain. The /vert bar/J/vert bar/ value for the exchange interaction is greater than 0.018 cm/sup /minus/1/. Crystal data for (Ni/sub 2/C/sub 34/H/sub 50/N/sub 8/)(ClO/sub 4/)/sub 4/ /center dot/ H/sub 2/O (298 K): monoclinic, space group P2/sub 1//n, a = 13.560(3), b = 11.678(2), c = 15.377(3) /angstrom/, /beta/ = = 108.48(2)/degree/, /rho//sub calcd/ = 1.588 g cm/sup /minus/3/ for Z = 2 and M/sub r/ = 1104.1, R = 0.068, R/sub w/ = 0.76. The intramolecular Ni-Ni distance is 9.13 /angstrom/. The analogous copper complex is isomorphorus with the nickel complex.

Research Organization:
Georgia Institute of Technology, Atlanta (USA)
DOE Contract Number:
FG22-84PC70782
OSTI ID:
5837760
Journal Information:
J. Coord. Chem.; (United States), Vol. 19:1-3, Issue 1-3
Country of Publication:
United States
Language:
English