Cyclopalladated azido complexes containing C,N-donor (HC approximately N = 2-(2'-thienyl)pyridine, azobenzene, 3,3'-dimethyl azobenzene, N,N'-dimethylbenzylamine, 2-phenylpyridine) ligands: reactivity towards organic unsaturated compounds and catalytic properties.
Cyclopalladated azido dimers having various C,N-donor ligands, [Pd(mu-N3)(C,N-Ln)]2 (L1H = 2-(2'-thienyl)pyridine; L2H = azobenzene; L3H = 3,3'-dimethylazobenzene; L4H = N,N'-dimethylbenzylamine; L5H = 2-phenylpyridine), underwent cleavage with tertiary (or chelating) phosphines to form the cyclopalladated [Pd(N3)(PR3)(C,N-L)], the sigma-bonded [Pd(N3)(PR3)2(C-L)], or the dinuclear-cyclopalladated [PdN3(PR3)(C,N-L)]2(mu-P approximately P) complexes. In particular, treating [Pd(mu-N3)(C,N-L)]2 with the basic chelating phosphine (depe or dmpe) produced the homoleptic bis(chelating) complex [Pd(C,N-Ln)2] (n = 1-3). Complex [Pd(N3)(PR3)(C,N-L4)] or [Pd(N3)(PR3)2(C-L4)] reacted with aryl isocyanides to selectively give the imidoyl [Pd(N3)(-C=N-Ar)(PR3)(N-L4)] or the imidoyl carbodiimido complex [Pd(N=C=N-Ar)(-C=N-Ar)(PR3)(N-L4)], which was formed by the CN-Ar insertion into the orthometallated Pd-C bond on the phenyl moiety or the interaction into the Pd-N3 bond of the supporting ligand. In addition, reactions of [Pd(N3)(PR3)2(C-Ln)] (n = 1, 2, 4) with R-NCS {R = i-Pr, C6H4-NCS, (CH3)3Si} gave the S-coordinated tetrazole-thiolato Pd(II) complexes. Finally, the catalytic activity of the cyclopalladated azido complexes was evaluated.
Lee
Kyung-Eun
KE
Department of Chemistry, Kangnung National University, Gangneung 210-702, Korea.
Jeon
Hyeong-Tak
HT
Han
Sam-Yong
SY
Ham
Jungyeob
J
Kim
Yong-Joo
YJ
Lee
Soon W
SW