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The synthesis of the new organoiron salt [(η5-C5Me5)(η2-dppe)Fe–C≡C–2,5-C4H2S–C≡C–Fe(η2-dppe)(η5-C5Me5)][PF6]2-(4[PF6]2, dppe = 1,2-bis(diphenylphosphino)ethane) is reported with its full spectroscopic characterizations (1H and 31P NMR, IR, UV–vis, EPR). The antiferromagnetic exchange interaction between the two iron centres that act as spin carriers (S = 1 2 ) was probed by VT magnetic susceptibility measurements and Mossbauer spectroscopy. The singlet triplet energy gap (J) was evaluated between –147 and –178 cm–1 from the magnetic data and found to be larger from the Mossbauer data (J = –300 cm–1). This discrepancy is analysed. We also report the synthesis and characterization of the mononuclear model compounds [(η5-C5Me5)(η2-dppe)Fe–C≡C–2-C4H3S] (5, 88%), [(η5-C5Me5)(η2-dppe)Fe–C≡C–2-C4H3S][PF6] (5[PF6], 75%), and [(η5-C5Me5)(η2-dppe)Fe=C=C(H)–2-C4H3S][BF4] (5H[BF4], 88%) and the binuclear (bis)vinylidene complex [(η5-C5Me5)(η2-dppe)Fe=C=C(H)–2,5-C4H2S–(H)C=C=Fe(η2-dppe)(η5-C5Me5)][BF4]2 (4H2[BF4]2, 99%). The X-ray single crystal analysis of 5 is also reported. To cite this article: S. Roue et al., C. R. Chimie 6 (2003). |
