کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1327756 977502 2009 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The role of ancillary ligands and of electron poor alkenes and alkynes in stabilizing Pd(0) derivatives: A comparative study
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
The role of ancillary ligands and of electron poor alkenes and alkynes in stabilizing Pd(0) derivatives: A comparative study
چکیده انگلیسی

The peculiar characteristics of the ligand neocuproine (2,9-dimethylphenanthroline) allow a number of exchange equilibrium studies between the low valence complex [Pd(η2-nq)(Neocup)] (nq = naphthoquinone; Neocup = neocuproine) and several alkenes and alkynes. A new order of stability which compares differently unsaturated molecules was established. An overview of the factors governing the stability of palladium(0) alkene and alkyne derivatives as a function of the steric and electronic characteristics of both the unsaturated molecule and the ligand becomes accessible and a comparison with the previously determined order was therefore feasible. Such a comparison enlightens the importance of the substituent methyl groups in ortho position of the hetero-aromatic ring which represents the molecular fragment common to all the ligands considered. Taking advantage of the steric requirements of the alkene tmetc (tmetc = tetramethylethylenetetracarboxylate) a kinetic investigation of the reaction between the olefin itself and the complexes [Pd(η2-dmfu)(L-L′)] (dmfu = dimethylfumarate; L–L′ = 8-diphenylphosphanyl-2-methyl-quinoline, neocuproine, phenanthroline) was carried out. The structures of the complexes [Pd(η2-dmfu)(DPPQ)] and [Pd(η2-deta)(Neocup)] (deta = but-2-ynedioc acid diethyl ester) were also reported in the present paper. The structure of the latter represents the first example of a palladium(0) complex in which the N2C2 donor set around the metal centre is supported by a chelating η2-alkyne.

The characteristics of the ligand neocuproine (2,9-dimethylphenathroline) allow a number of exchange equilibrium studies between the low valence complex [Pd(η2-nq)(Neocup)] (nq = naphthoquinone; Neocup = neocuproine) and several alkenes and alkynes. A new order of stability which compares differently unsaturated molecules was therefore established.The structures of the complexes [Pd(η2-dmfu)(DPPQ)] (dmfu = dimethylfumarate) and of the first di-nitrogen palladium(0) alkyne derivative [Pd(η2-deta)(Neocup)] (deta = but-2-ynedioc acid diethyl ester) were also reported.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Organometallic Chemistry - Volume 694, Issue 3, 1 February 2009, Pages 411–419
نویسندگان
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