Evidence for Bidirectional Noninnocent Behavior of a Formazanate Ligand in Ruthenium Complexes
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- 作者：Abhishek Mandal ; Brigitte Schwederski ; Jan Fiedler ; Wolfgang Kaim ; Goutam Kumar Lahiri
- 刊名：Inorganic Chemistry
- 出版年：2015
- 出版时间：August 17, 2015
- 年：2015
- 卷：54
- 期：16
- 页码：8126-8135
- 全文大小：580K
- ISSN：1520-510X
文摘
Redox series of the complexes [Ru(L)(L鈥?2]n, L = 1,5-diphenyl-3-(4-tolyl)-formazanate and L鈥?= 2,4-pentanedionate (acac鈥?/sup>), 2,2鈥?bipyridine (bpy), or 2-phenylazopyridine (pap), were studied by cyclic and differential pulse voltammetry and by TD-DFT-supported spectroelectrochemistry (UV鈥搗is鈥揘IR, EPR). The precursors [RuIII(L鈥?/sup>)(acac鈥?/sup>)2], [RuII(L鈥?/sup>)(bpy)2]ClO4, and [RuII(L鈥?/sup>)(pap)2]ClO4 were identified in their indicated oxidation states by X-ray crystal structure determination. The six-membered formazanato-ruthenium chelate rings have an envelope conformation with puckering of the metal. DFT calculations indicate a pronounced sensitivity of the N鈥揘 bond lengths toward the ligand oxidation state. Several electrochemically accessible charge states were analyzed, and the derived oxidation numbers RuII, RuIII, or RuIV, L鈥?or (L鈥?鈥⑩€?/sup>, and L鈥?/sup>, L鈥?鈥?/sup>, or the new formazanyl ligand L鈥?/sup> for the two-way noninnocent formazanate reflect the increasing acceptor effect of the ancillary ligands L鈥?in the series acac鈥?/sup> < bpy < pap.