Trovacene chemistry. 2. [5-5]bitrovacene, (mu-eta(5):eta(5)-fulvalenediyl)bis[(eta(7)-cycloheptatrienyl)vanadium]: Synthesis, structure, and intermetallic communication

Lithiation of trovacene, (eta(7)-C7H7)V(eta(5)-C5H5), Li/I exchange, and Pd (dppf)Cl-2-catalyzed homocoupling affords [5-5]bitrovacene 5(2.). Intermeta llic communication manifests itself in typical biradical features of the EP R spectrum and in the resolution of redox splittings of 147 mV for the two subsequent oxidations and 224 mV for the reductions, respectively. 5(2.) ad opts a trans conformation in the single crystal (X-ray diffraction) as well as in rigid solution (EPR spectroscopy). A magnetic susceptibility study o f 5(2.) reveals weak antiferromagnetic coupling (J = -2.78 cm(-1)) of the t wo V(d(5)) centers.