Reactivity of Low-Valent Iridium, Rhodium, and Platinum Complexes with Di- and Tetrasubstituted Hydrazines
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- 作者：Jessica M. Hoover ; John Freudenthal ; Forrest E. Michael ; James M. Mayer
- 刊名：Organometallics
- 出版年：2008
- 出版时间：May 26, 2008
- 年：2008
- 卷：27
- 期：10
- 页码：2238 - 2245
- 全文大小：394K
- 年卷期：v.27,no.10(May 26, 2008)
- ISSN：1520-6041
文摘
Three complexes, IrCl(PEt3)3, Rh(NNN)Cl (NNN = 2,6-(CyNmg src="http://pubs.acs.org/images/entities/dbd_2.gif">CH)2C5H3N), and (NN)PtMe2 [NN = 1,10-phenanthroline (phen) or 2,2′-bipyridine (bpy)], have been investigated for N−N oxidative addition reactivity with di- and tetrasubstituted hydrazines. The reaction of IrCl(PEt3)3with 1,2-diphenylhydrazine (PhNHNHPh) forms the cyclometalated azobenzene complex (Et3P)2Cl(H)Ir(C6H4Nmg src="http://pubs.acs.org/images/entities/dbd_2.gif">NPh) (1) and the 2:1 complex [(Et3P)2Cl(H)Ir]2(μ-C6H4Nmg src="http://pubs.acs.org/images/entities/dbd_2.gif">NC6H4) (2). The Rh(NNN)Cl pincer complex catalyzes the disproportionation of PhNHNHPh to azobenzene and aniline with no change in the Rh complex. The reaction of (bpy)PtMe2 with the hydrazine AcNHNHC(O)CH2CH2CHmg src="http://pubs.acs.org/images/entities/dbd_2.gif">CH2 (3) yields the platinum metallacycle (bpy)Pt(η2-AcN-NC(O)(CH2)2CHCH2 (4). Although IrCl(PEt3)3, Rh(NNN)Cl, and (NN)PtMe2 all undergo facile oxidative addition of other X−Y bonds, such reactivity is not observed for hydrazines; in the Ir and Pt systems there is a clear preference for cleavage of the stronger N−H bond over the N−N bond. The tetrasubstituted hydrazines tetraphenylhydrazine, 1,2-diphenyl-1,2-dimethylhydrazine, bisuccinimide, biphthalimide, and N-dimethylamino phthalimide do not react with IrCl(PEt3)3, Rh(NNN)Cl, and (NN)PtMe2. This lack of reactivity appears to be due to kinetic rather than thermochemical factors.