Mixed-Ligand Approach to Changing the Metal Ratio in Bismuth–Transition Metal Heterometallic Precursors

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• 作者：Craig M. Lieberman ; Zheng Wei ; Alexander S. Filatov ; Evgeny V. Dikarev
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：April 18, 2016
• 年：2016
• 卷：55
• 期：8
• 页码：3946-3951
• 全文大小：310K
• 年卷期：0
• ISSN：1520-510X

文摘

A new series of heteroleptic bismuth–transition metal β-diketonates [BiM(hfac)₃(thd)₂] (M = Mn (1), Co (2), and Ni (3); hfac = hexafluoroacetylacetonate, thd = tetramethylheptanedionate) with Bi:M = 1:1 ratio have been synthesized by stoichiometric reactions between homometallic reagents [Bi^III(hfac)₃] and [M^II(thd)₂]. On the basis of analysis of the metal–ligand interactions in heterometallic structures, the title compounds were formulated as ion-pair {[Bi^III(thd)₂]⁺[M^II(hfac)₃]⁻} complexes. The direct reaction between homometallic reagents proceeds with a full ligand exchange between main group and transition metal centers, yielding dinuclear heterometallic molecules. In heteroleptic molecules 1–3, the Lewis acidic, coordinatively unsaturated Bi^III centers are chelated by two bulky, electron-donating thd ligands and maintain bridging interactions with three oxygen atoms of small, electron-withdrawing hfac groups that chelate the neighboring divalent transition metals. Application of the mixed-ligand approach allows one to change the connectivity pattern within the heterometallic assembly and to isolate highly volatile precursors with the proper Bi:M = 1:1 ratio. The mixed-ligand approach employed in this work opens broad opportunities for the synthesis of heterometallic (main group–transition metal) molecular precursors with specific M:M′ ratio in the case when homoleptic counterparts either do not exist or afford products with an incorrect metal:metal ratio for the target materials. Heteroleptic complexes obtained in the course of this study represent prospective single-source precursors for the low-temperature preparation of multiferroic perovskite-type oxides.