Recognition of S···Cl Chalcogen Bonding in Metal-Bound Alkylthiocyanates

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• 作者：Ekaterina S. Yandanova ; Daniil M. Ivanov ; Maxim L. Kuznetsov ; Andrey G. Starikov ; Galina L. Starova ; Vadim Yu. Kukushkin
• 刊名：Crystal Growth & Design
• 出版年：2016
• 出版时间：May 4, 2016
• 年：2016
• 卷：16
• 期：5
• 页码：2979-2987
• 全文大小：582K
• 年卷期：0
• ISSN：1528-7505

文摘

Reaction of K₂[PtCl₄] with excess AlkSCN in water gives the alkylthiocyanate complexes trans-[PtCl₂(AlkSCN)₂] (Alk = Et 1, ⁿPr 2; 80–85%). These species were studied, in particular, by X-ray crystallography. In the solid state, both 1 and 2 exhibit the previously unreported S···Cl chalcogen bonding, which consolidates the complexes into networks and leads to layered structures. Theoretical density functional theory calculations and Bader’s atoms in molecules analysis demonstrated two types of intermolecular interactions in tetramer (1)₄, viz. the S···Cl chalcogen and the H···Cl hydrogen bonds. Despite that each particular S···Cl or H···Cl bonding is weak with the estimated energy of 1–2 kcal/mol, altogether they play a crucial role in the stabilization of the S₂Cl₂ fragment in (1)₄, the basis set of superposition error corrected interaction energy being −12.8 kcal/mol per monomer complex molecule. The chalcogen bonding and the rhomboidal structure of the S₂Cl₂ fragment can be interpreted in terms of electrostatic arguments as a result of the interaction between the belt of negative electrostatic potential around the Cl atoms and the sulfur σ-holes. The natural bond orbital analysis revealed that both LP(S) → LP*(Pt)/σ*(Pt–N)/σ*(Pt–Cl) and LP(Cl) → σ*(S–C) types of hyperconjugative charge transfers are important in the chalcogen bonding.