Iron−Molybdenum Charge-Transfer Hybrids Containing Organometallic and Inorganic Fragments Bridged by Aryldiazenido Ligands in a μ-η6:η1 Coordination Mode:  Syntheses, Characterization, X-ray Structures, Electrochemistry, and Theoretical Investigation

• Published in: Inorganic chemistry Vol. 46; no. 4; pp. 1123 - 1134
• Main Authors: Manzur, Carolina, Millán, Lorena, Fuentealba, Mauricio, Hamon, Jean-René, Toupet, Loïc, Kahlal, Samia, Saillard, Jean-Yves, Carrillo, David
• Format: Journal Article
• Language: English
• Published: American Chemical Society 19.02.2007
• Subjects: Chemical Sciences; Inorganic chemistry; or physical chemistry; Theoretical and
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic0613098

Representative members of a new family of covalently bonded charge-transfer molecular hybrids, of general formula [(η5-C5H5)Fe(μ,η6:η1-p-RC6H4NN)Mo(η2-S2CNEt2)3] +PF6 - (R: H, 5 +PF6 -; Me, 6 +PF6 -; MeO, 7 +PF6 -) and [(η5-C5Me5)Fe(μ,η6:η1-C6H5NN)Mo(η2-S2CNEt2)3]+PF6 -, 8 +PF6 -, have been synthesized by reaction of the corresponding mixed-sandwich organometallic hydrazines [(η5-C5H5)Fe(η6-p-RC6H4NHNH2)]+PF6 - (R:  H, 1 +PF6 -; Me, 2 +PF6 -; MeO, 3 +PF6 -) and [(η5-C5Me5)Fe(η6-C6H5NHNH2)]+PF6 -, 4 +PF6 -, with cis-dioxomolybdenum(VI) bis(diethyldithiocarbamato) complex, [MoO2(S2CNEt2)2], in the presence of sodium diethyldithiocarbamato trihydrate, NaSC(S)NEt2·3H2O, in refluxing methanol. These iron−molybdenum complexes consist of organometallic and inorganic fragments linked each other through a π-conjugated aryldiazenido bridge coordinated in η6 and η1 modes, respectively. These complexes were fully characterized by FT-IR, UV−visible, and 1H NMR spectroscopies and, in the case of complex 7 +PF6 -, by single-crystal X-ray diffraction analysis. Likewise, the electrochemical and solvatochromic properties were studied by cyclic voltammetry and UV−visible spectroscopy, respectively. The electronic spectra of these hybrids show an absorption band in the 462−489 and 447−470 nm regions in CH2Cl2 and DMSO, respectively, indicating the existence of a charge-transfer transition from the inorganic donor to the organometallic acceptor fragments through the aryldiazenido spacer. A rationalization of the properties of 5 +PF6 -−8 +PF6 - is provided through DFT calculations on a simplified model of 7 +PF6 -. Besides the heterodinuclear complexes 5 +PF6 -−8 +PF6 -, the mononuclear molybdenum diazenido derivatives, [(η1-p-RC6H4NN)Mo(η2-S2CNEt2)3] (R: H, 9; Me, 10; MeO, 11), resulting from the decoordination of the [(η5-C5H5)Fe]+ moiety of complexes 5 +PF6 -−7 +PF6 -, were also isolated. For comparative studies, the crystalline and molecular structure of complex 10·Et2O was also determined by X-ray diffraction analysis and its electronic structure computed.