First Paramagnetic 4d Transition-Metal Complex with a Redox-Active Tetrathiafulvalene Derivative, [Ru(salen)(PPh₃)(TTF-CHCH-Py)]BF₄ [salen²⁻ = N,N′-Ethan-1,2-diylbis(salicylidenamine), PPh₃ = Triphenylphosphine, TTF-CHCH-Py = 4-(2-Tetrathiafulvalenylethenyl)pyridine]

The first paramagnetic 4d transition-metal complex with a redox-active tetrathiafulvalene ligand has been synthesized. The preparation, X-ray structure, electrochemistry, and electron paramagnetic resonance measurements of [Ru(salen)(PPh₃)(TTF-CHCH-Py)](BF₄) [1(BF₄)] are reported. The crystal structure reveals that the paramagnetic Ru^III (s = ¹/₂) center is in a tetragonally elongated octahedral geometry and the TTF-CHCH-Py ligand is coordinated to the axial position of the Ru^III ion through the nitrogen atom of the pyridine group. Thus, 1(BF₄) is an attractive precursor to study future π−4d interactions in dual-property conducting and magnetic materials.