Formation of a Carbon Dioxide Complex of Rhenium <i>via</i> Formal Oxidation of a Carbon Monoxide Ligand
作者:Tein-Fu Wang、Chong-Chen Hwu、Chia-Wen Tsai、Kuan-Jiuh Lin
DOI:10.1021/om9702845
日期:1997.7.1
The reaction of aminorhenium carbonyl complex 1 with MCPBA provides the aminorhenium η2-CO2 complex 2 in 97% yield. Bromination of 1 followed by treatment of the resultant bromide with NaOH also provides 2 in 90% yield.
The aminorhenium complex (CO)(2)ReNH(CH3)CH2CH2(eta(5)-C5H4) (3), in which the ligating amino group is connected to the cyclopentadienyl ligand, was prepared by irradiation of (eta(5)-C5H4CH2CH2NHCH3)Re(CO)(3) (2) in THF. Alkylation of the corresponding anion [(CO)(2)ReN(CH3)CH2CH2(eta(5)-C5H4)]Li--(+) (4) as well as the neutral aminorhenium complex 3 with a variety of electrophiles has been studied. The anion 4 reacted with electrophiles, such as CH3I, CH2=CHCH2Br, C6H5CH2Br, and HC drop CCH2Br, at the nitrogen center to provide (CO)(2)ReNR(CH3)CH2CH2(eta(5)-C5H4) (5a-d). However, 4 reacted with electrophiles having a carbonyl group or a nitrile group next to the electrophilic carbon, such as BrCH2CO2CH3, BrCH2CO2C2H5, and BrCH2CN, to give rhenium alkylation compounds [(CO)(2)(R)ReNH(CH3)CH2CH2(eta(5)-C5H4)]Br-+(-) (7e-g) after protonation. The neutral aminorhenium complex 3 reacted with the electrophiles mentioned above to provide exclusive Re-alkylation compounds 7a-g. The structure of the tetraphenylborate salt of 7c, [(CO)(2)(C6H5CH2)ReNH(CH3)CH2CH2(eta(5)-C5H4)](+)BPh(4)(-) (8), has been determined by X-ray diffraction.