Copper(II) complexes based on a new chelating 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine ligand: Synthesis and crystal structures. Lone pair–π, C–H···π, π–π and C–H·

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• 作者：Mark B. Bushuev ; Viktor P. Krivopalov ; Natalia V. Pervukhina ; Dmitrii Yu. Naumov ; Gennadii G. Moskalenko ; Katerina A. Vinogradova ; Lilia A. Sheludyakova ; Stanislav V. Larionov
• 关键词：Copper(II) complexes ; Pyrazolylpyrimidines ; Crystal structures ; Non-covalent (lone pair– ; &#x3c0 ; C– ; H· ; · ; · ; &#x3c0 ; &#x3c0 ; – ; &#x3c0 ; C– ; H· ; · ; · ; N and C– ; H· ; · ; · ; Cl) interactions
• 刊名：Inorganica Chimica Acta
• 出版年：2010
• 出版时间：20 April 2010
• 年：2010
• 卷：363
• 期：7
• 页码：1547-1555
• 全文大小：716 K

文摘

A new bidentate chelating pyrazolylpyrimidine ligand bearing a strong electron-donating substituent, i.e. 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine (L) (Scheme 1), has been synthesized and used to obtain the copper(II) complexes by reaction with CuCl₂. The molar ratio Cu:L = 1:2 leads to isolation of a complex having CuL₂Cl₂ empirical formula, while the molar ratio Cu:L = 1:1 gives a complex with CuLCl₂ empirical formula. The crystal structure of L as well as the structures of both complexes were studied by single crystal X-ray diffraction. The crystal structure of CuL₂Cl₂ compound is formed by trans-[CuL₂Cl₂] mononuclear molecules. Surprisingly, in contrast to the previous compound having molecular structure, the crystal structure of CuLCl₂ consists of mononuclear [CuL₂Cl]⁺ complex cations and dinuclear [Cu₂Cl₆]²⁻ anions. Thus, formula of CuLCl₂ complex can be represented as [CuL₂Cl]₂[Cu₂Cl₆]. In both complexes molecules of L adopt bidentate chelating coordination mode through N² atom of pyrazole and N³ atom of pyrimidine rings forming five-membered CuN₃C metallocycles. Owing to C–H···N interactions and π–π-stacking L molecules form 2D network. In the structure of trans-[CuL₂Cl₂] there exist double lone pair(N(piperidine))–π(pyrimidine) interactions and C–H···Cl contacts resulting in the formation of 1D chains. Layered 2D structure of [CuL₂Cl]₂[Cu₂Cl₆] results from C–H···Cl, C–H···π and double lone pair(Cl([CuL₂Cl]⁺ complex cation)–π(pyrimidine) interactions.