2225-30-1Relevant academic research and scientific papers
The effect of the oxidation state of molybdenum complexes on the catalytic transformation of terminal alkynes: Cyclotrimerization vs. polymerization
Czelu?niak, Izabela,Kociecka, Paulina,Szymańska-Buzar, Teresa
, p. 70 - 78 (2012/11/13)
Reactions of monosubstituted alkynes (PhC≡CH, tBuC≡ CH, nBuC≡CH, HOCH2C≡CH, HO(CH 3)2CC≡CH) in the presence of molybdenum(0) and molybdenum(II) carbonyl complexes (Mo(CO)6/hv, [Mo(CO) 4(pip)2] (pip = piperidine), [Mo(CO)4(pip) 2]/SnCl4, [Rpip]2[{(μ-Cl)Mo(μ-Cl) (SnCl3)(CO)3}2] (R = C3H 5, H)) lead to the formation of cyclotrimerization and polymerization products, which were characterized by chromatography (GC-MS, GPC) and by 1H and 13C NMR spectroscopy. The effect of the oxidation state of the molybdenum catalyst on the transformation of the terminal alkynes was observed: cyclotrimerization vs. polymerization. Only molybdenum(II) complexes lead to the formation of polyenic polymers. Moreover, reaction of prop-2-yn-1-ol initiated by [Mo(CO)4(pip)2] in dichloromethane leads to the formation of oligomers containing the vinylidene unit. Mechanistic NMR studies show that η2-alkyne complex formation is the principal feature of all transformations of alkynes catalyzed by molybdenum complexes.
LIGANDEIGENSCHAFTS- UND -KONZENTRATIONSSTEUERUNGEN IM SYSTEM 3-METHYLBUT-1-IN-3-OL/Ni(COD)2/P-LIGANDEN
Hartmann, W.,Preuss, K. D.,Singer, H.
, p. 235 - 246 (2007/10/02)
The phosphorus/nickel ratio for 18 P ligands was varied over several orders of magnitude and the effect upon the oligomerisation of 3-methylbut-1-yn-3-ol with Ni(COD)2 as catalyst was examined.Some conclusions could be drawn concerning association phenomena.The resulting changes in product composition were correlated with steric and electronic characteristics of the ligands.Steric control dominated and contributed ca. 70percent of the observed effects.
A SYSTEMATIC STUDI OF THE CATALYTIC ACTIVITY OF BIS(PHOSPHINE)NICKEL(II) COMPLEXES IN THE CYCLOTRIMERIZATION REACTION OF ACETYLENES. III. CATALYTIC ACTIVITY OF ACETYLIDES
Bicev, Peter,Furlani, Anita,Russo, Maria Vittoria
, p. 25 - 30 (2007/10/02)
The catalytic activities of CR)L2> complexes (L = Bu3P, Ph3P; R = Ph or C(CH3)2OH) and of analogous complexes in the cyclotrimerization reactions of phenylacetylene (PA) and 2-methyl-3-butyn-2-ol (MB) have been compared.In agreement with previous proposal, the monoacetylide complexes are reaction intermediates: in fact, the induction periods are reduced and the distributions of reaction products are very similar.The complexes CR)2L2> are also active catalysts and the catalytic activity is influenced by the ligand L.Reactions carried out in NH(C2H5)2 as solvent are also reported.
