Heteroleptic Phenylcalcium Derivatives via Metathesis Reactions of PhCa(thf)4I with Potassium Compounds

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• 作者：Martin G&auml ; rtner ; Helmar Gö ; rls ; Matthias Westerhausen
• 刊名：Organometallics
• 出版年：2007
• 出版时间：February 12, 2007
• 年：2007
• 卷：26
• 期：4
• 页码：1077 - 1083
• 全文大小：147K
• 年卷期：v.26,no.4(February 12, 2007)
• ISSN：1520-6041

文摘

The metathesis reactions of (thf)₄Ca(Ph)I with the corresponding potassium compounds KR yield theheteroleptic arylcalcium derivatives (thf)₃Ca(Ph)[N(SiMe₃)₂] (1) and (thf)₄Ca(Ph)PPh₂ (2), due to theinsolubility of KI in common organic solvents. However, the reaction of KCp and KOC₆H₂-2,6-tBu-4-Me with (thf)₄Ca(Ph)I give the homoleptic compounds (thf)₂CaCp₂ (3) and (dme)CaCp₂ (4) (dependingon the solvent) as well as (thf)₃Ca(OC₆H₂-2,6-tBu-4-Me)₂ (5). Diphenylcalcium decomposed under thesereaction conditions. The reaction of K[(Me₃SiN)₂CPh] with (thf)₄Ca(Ph)I yields [{(thf)₃Ca}₂{4,4-Ph₂-2,6-(C₆H₄)₂C₃N₃}(ges/entities/mgr.gif">-I)] (6). This dihydrotriazine derivative forms due to a slow liberation of benzonitrilefrom the starting N,N'-bis(trimethylsilyl)benzamidinate. A solvent change in order to shift the Schlenkequilibrium (2 PhCaI=CaPh₂ + CaI₂) toward the homoleptic diphenylcalcium leads immediately to ethercleavage reactions and the formation of [{(Et₂O)CaPh₂}₄·(Et₂O)CaO] (7), which precipitates from diethylether. This cage compound contains an oxygen-centered Ca₅ square pyramid with the phenyl groupsbridging all Ca···Ca edges.