Survey Of Long d10鈥揹10 Metallophilic Contacts in Four-Membered Rings of Ag(I) and Au(I) Supported by Carbene鈥揚yrazole Mixed Ligands

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• 作者：Raul Guajardo Maturana ; Miguel Ponce Vargas ; Alvaro Mu帽oz-Castro
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：August 30, 2012
• 年：2012
• 卷：116
• 期：34
• 页码：8737-8743
• 全文大小：324K
• 年卷期：v.116,no.34(August 30, 2012)
• ISSN：1520-5215

文摘

The interesting case of long intramolecular d¹⁰鈥揹¹⁰ contacts has been studied through [Ag₄L₂]²⁺ and [Au₄L₂]²⁺ (L = 3,5-bis((N-methylimidazolyl)methyl)pyrazole) systems, showing interesting features gained by analysis of the electronic structure and the overall shielding tensor in the molecular domain, in terms of its components. The long intramolecular closed-shell separations are attributed to the population of the bonding, nonbonding, and antibonding combinations of the ns atomic shells in the [M₄]⁴⁺ core, contrasting with that observed in systems with shorter d¹⁰鈥揹¹⁰ distances. This point allows to concludeb that separations shorter then the sum of the van der Waals radii (3.4 脜 for Ag鈥揂g, and 3.2 脜 for Au鈥揂u) of the nucleus involved requires a net bonding population between ns and np atomic shells of the d¹⁰ closed-shell centers. Moreover, [Au₄L₂]²⁺ exhibits an increased covalency observed for the enhanced charge-donation due to the stabilization of the ns and destabilization of the (n 鈥?1)d driven by the relativistic effects. The magnetic response denotes a slight interaction between the closed-shell centers at distances in the range of their sum of van der Waals radii because the observed remote effect (or anisotropic effect) caused by each d¹⁰ nucleus does not influence considerably the neighbor center. The analysis of 未 in terms of its components allows to conclude that the [Au₄L₂]²⁺ system exhibits an increased magnetic response due to the increase in the number of the inner-electrons in comparison to [Ag₄L₂]²⁺.