A Homologous Series of First-Row Transition-Metal Complexes of 2,2鈥?Bipyridine and their Ligand Radical Derivatives: Trends in Structure, Magnetism, and Bonding

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• 作者：Mark Irwin ; Laurence R. Doyle ; Tobias Kr盲mer ; Radovan Herchel ; John E. McGrady ; Jose M. Goicoechea
• 刊名：Inorganic Chemistry
• 出版年：2012
• 出版时间：November 19, 2012
• 年：2012
• 卷：51
• 期：22
• 页码：12301-12312
• 全文大小：532K
• 年卷期：v.51,no.22(November 19, 2012)
• ISSN：1520-510X

文摘

The organometallic first-row transition-metal complexes [M(2,2鈥?bipy)(mes)₂] (M = Cr (1), Mn (2), Co (4), Ni (5); 2,2鈥?bipy = 2,2鈥?bipyridine; mes = 2,4,6-Me₃C₆H₂) were reacted with potassium and a suitable alkali-metal sequestering agent to yield salts of the anionic species [M(2,2鈥?bipy)(mes)₂]^{鈭?/sup>. The neutral parent compounds and their corresponding anionic congeners were characterized by single-crystal X-ray diffraction in [Cr(2,2鈥?bipy)(mes)₂]路1.5C₆H₆, [Mn(2,2鈥?bipy)(mes)₂], [Co(2,2鈥?bipy)(mes)₂]路THF, [Ni(2,2鈥?bipy)(mes)₂], [K(dibenzo-18-crown-6)路THF][Cr(2,2鈥?bipy)(mes)₂]路2THF, [K(18-crown-6)][Mn(2,2鈥?bipy)(mes)₂]路2THF, [K(18-crown-6)][Mn(2,2鈥?bipy)(mes)₂]路0.67py路0.67tol, [K(2,2,2-crypt)][Co(2,2鈥?bipy)(mes)₂], and [K(2,2,2-crypt)][Ni(2,2鈥?bipy)(mes)₂]. These species, along with the previously reported neutral and anionic iron complexes [Fe(2,2鈥?bipy)(mes)₂]0/鈥?/sup> (3/3鈥?/b>), form a homologous series of compounds which allow for an in-depth study of the interactions between metals and ligands. Single-crystal X-ray diffraction data, DFT calculations, and various spectroscopic and magnetic measurements indicate that the anionic complexes (1鈥?/b>鈥?b>5鈥?/b>) can be best formulated as M(II) complexes of the 2,2鈥?bipyridyl radical anion. These findings complement recent studies which indicate that bond metric data from single-crystal X-ray diffraction may be employed as an important diagnostic tool in determining the oxidation states of bipyridyl ligands in transition-metal complexes.}