A study of dynamic behavior of transition metal complexes with fullerene C₆₀ using density function theory

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• 作者：Yuri F. Oprunenko ; ^{oprunenko@mail.ru} ; Igor P. Gloriozov
• 关键词：Haptotropic rearrangements ; DFT ; Fullerene ; Transition metals
• 出版年：2013
• 出版时间：15 May, 2013
• 年：2013
• 卷：732
• 期：Complete
• 页码：116-121
• 全文大小：765 K

文摘

Dynamic processes in the complexes of a general formula of [M(NO)H_n(PPh₃)₂(¦Ç²-C₆₀)] (M?=?Co, Rh, n?=?0; 1, 2, respectively, and Ru, n?=?1; 3) were studied theoretically by means of density functional theory (DFT). Earlier two distinct dynamic processes were established for 1-3, namely a low barrier of organometallic group (OMG) rotation around the axis of C₆₀ double bond with the metal (?=?9, 10, 14?kcal/mol, respectively) and ¦Ç²,¦Ç²-haptotropic rearrangements (HR) consisting of a metal shifting over the whole surface of C₆₀ with activation barrier approximately 2-4?kcal/mol higher than the corresponding barriers for rotation ( were not measured quantitatively). Mechanisms of these both experimentally observed dynamic processes were theoretically modeled in our paper and activation barriers for rotation (¦¤G?=?8.5, 10.5, 15.1?kcal/mol) and HR (¦¤G?=?12.2, 12.2, 18.2?kcal/mol) for 1-3, respectively, were calculated, discussed and compared with experimental barriers from ¹³C EXCY and dynamic NMR at variable temperatures. Rotation of OMG for 1 and 2 has quite a straightforward mechanism and proceeds through ¦Ç²-transition states TS_rot(1, 2). For 3 the process of rotation is much more complicated and involves the intermediate IM_rot(3) and two non-equivalent transition states, TS1_rot(3) and TS2_rot(3), with all stationary states on potential energy surface (PES) possessing ¦Ç²-hapticity. HR rearrangements proceed via consequent intra- and inter-ring shifts of OMG over the whole surface of C₆₀. Process occurs through the structurally similar for 1-3 ¦Ç²-intermediates (IM) in which OMG coordinated to buckminsterfullerene at 6-5 ring fusion and ¦Ç¹-transition states (TS), respectively.