Cyanide-bridged Fe(III)-Cu(II) complexes: Jahn-Teller isomerism and its influence on the magnetic properties.
We report here the synthesis and characterization of four dinuclear cyanide-bridged Fe(III)-Cu(II) complexes, based on a tetra- or a pentadentate bispidine ligand (L(1) or L(2), respectively; bispidines are 3,7-diazabiyclo[3.3.1]nonane derivatives) coordinated to the Cu(II) center, and a tridentate bipyridineamide (bpca) coordinated to the low-spin Fe(III) site, with cyanide groups completing the two coordination spheres, one of them bridging between the two metal ions. The four structurally characterized complexes [{Fe(bpca)(CN)(3)}{Cu(L(1)·H(2)O)}]BF(4), [{Fe(bpca)(CN)(3)}{Cu(L(2))}][Fe(bpca)(CN)(3)]·5H(2)O, [{Fe(bpca)(CN)(3)}{Cu(L(2)·MeOH)}]PF(6)·MeOH·H(2)O, and [{Fe(bpca)(CN)(3)}{Cu(L(2))}]PF(6)·2H(2)O belong to different structural isomers. The most important differences are structurally and electronically enforced (direction of the pseudo-Jahn-Teller mode) strong or weak interactions of the copper(II) center with the cyanide bridge. The related strength of the magnetic coupling of the two centers is analyzed with a combination of experimental magnetic, electron paramagnetic resonance (EPR), electronic spectroscopic data together with a ligand-field theory- and density functional theory (DFT)-based analysis.
Anorganisch-Chemisches Institut, INF 270, Universität Heidelberg, D-69120 Heidelberg, Germany. Mihail.Atanasov@cec.mpg.de
Mihail
M
Atanasov
Peter
P
Comba
Stefan
S
Helmle
D003300:Copper / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D007536:Isomerism; D060328:Magnetic Phenomena; D008958:Models, Molecular; D008968:Molecular Conformation; D009570:Nitriles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory
D009570:Nitriles; D009942:Organometallic Compounds; D003300:Copper; D007501:Iron