The reaction of the group-13 alkyls ER₃ (E = Al, Ga, In; R = CH₂t-Bu, CH₂ SiMe₃) with the platinum-complex [(dcpe)Pt(H)(CH₂t-Bu)]

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• 作者：Fischer ; Roland A. ; Wei脙脙 ; Dana ; Winter ; Manuela ; M脙脙ller ; Iris ; Kaesz ; Herbert D. ; Fr脙脙hlich ; Nikolaus ; et. al.
• 刊名：Journal of Organometallic Chemistry
• 出版年：2004
• 期刊代码：64_0022328x
• 类别：ch
• 出版时间：November 29, 2004
• 卷：689
• 期：24
• 页码：4611-4623
• 文件大小：566 K

摘要

The reactions of the sterically demanding group-13 alkyls ER₃ (E=Al, Ga, In; R=CH₂ t-Bu, CH₂SiMe₃) with the platinum-complex [(dcpe)Pt(H)(CH₂t-Bu)] were re-investigated. The bimetallic compounds [(dcpe)Pt(ER₂)(R)] (3: E=Ga, R=CH₂SiMe₃; 5: E=In, R=CH₂t-Bu; dcpe=bis(dicyclohexylphosphino)ethane) with direct 脧脧(Pt脧脧脧E) bonds were obtained by oxidative addition of an E-C bond to the coordinatively unsaturated fragment [(dcpe)Pt] produced in situ by thermolysis of the starting complex [(dcpe)Pt(CH₂t-Bu)(H)]. The single crystal structure determination reveals a Pt脧脧脧Ga bond length of 2.376(2) 脧脧脧 and a Pt脧脧脧In bond length of 2.608(1) 脧脧脧. All new compounds were characterised by elemental analysis, ³¹P and ¹⁹⁵Pt NMR spectroscopy. Interestingly, the Pt脧脧脧Ga compound 3 slowly transforms into the platinum alkyl/hydride isomer {(dcpe)Pt(脧脧₂-H)[CH₂Si(CH₃)₂ CH₂Ga(CH₂SiMe₃)₂]} (4) during crystallization from solution at room temperature. The X-ray single crystal structure analysis revealed both complexes 3 and 4 coexisting in the unit cell in a 1:1 relation. The inaccessibility of analytically pure samples of the Pt脧脧脧Al complex {(dcpe)Pt[Al(CH₂t-Bu)₂](CH₂t-Bu)} (6), postulated as intermediate of the reaction of [(dcpe)Pt(H)(CH₂t-Bu)] with Al(CH₂t-Bu) on the basis of ³¹P and ¹⁹⁵Pt NMR data, is attributed to an enhanced tendency to isomerisation into the alkyl/hydride Pt/Al congener of 4. A brief DFT analysis of the bonding situation of the model complex [(dhpe)Pt(GaMe₂)(Me)] (1M) revealed, that the contribution of 脧脧(Pt脧脧脧Ga) back-bonding is negligible.