ISSN:
0009-2940
Keywords:
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Description / Table of Contents:
On the Lewis Acidity of Nickel(0), II. Methylenetriorganylphosphorane Complexes of Nickel(0)Methylenetriorganylphosphoranes R3P = CH2 (R = CH3, C6H5) react with Ni(CDT) and Ni(C2H4)3 to form the (methylenetriorganylphosphorane)(alkene)nickel(0) complexes (R3PCH2)Ni(CDT) (R = CH3, 2) and (R3PCH2)Ni(C2H4)2) (R = CH3, C6H5, 4, 5). On treatment with CO the ethene complexes give the known carbonyl complexes (R3PCH2)Ni(CO)3 (R = CH3, C6H5, 9, 10) in pure form. 2 and 4 decompose at room temperature to give Me3PNi(CDT) and Me3PNi(C2H4)2; cyclopropane is produced in the presence of ethene. - The stability of the CH2—Ni0 bond in the methylenetriorganylphosphorane complexes falls in the series Ni(CO)3 〉 Ni(C2H4)2 〉 Ni(CDT), corresponding to declining Lewis acidity of the nickel atom. 13C NMR evidence indicates that in the same sequence the P—CH2 bond also becomes weakened. The thermally induced elimination of methylene shows that the nickel bonded methylene group has appreciable carbenoid character.
Notes:
Methylentriorganylphosphorane R3P = CH2 (R = CH3, C6H5) reagieren mit Ni(CDT) und Ni(C2H4)3 zu den (Methylentriorganylphosphoran)(alken)nickel(0)-Komplexen (R3PCH2) Ni(CDT) (R = CH3, 2) und (R3PCH2)Ni(C2H4)2(R = CH3, C6H5, 4, 5). Die Ethen-Komplexe ergeben mit CO die bereits bekannten Carbonyl-Komplexe (R3PCH2)Ni(CO)3(R = CH3, C6H5, 9, 10) in reiner Form. 2 und 4 gehen bei Raumtemperatur in Me3PNi(CDT) und Me3PNi(C2H4)2 über, wobei sich in Gegenwart von Ethen Cyclopropan bildet. - Die Stabilität der CH2—Ni0-Bindung in den Methylentriorganylphosphoran-Komplexen verringert sich mit der in der Reihe Ni(CO)3 〉 Ni(C2H4)2 〉 Ni(CDT) abfallenden Lewis-Acidität des Nickels. Aus den 13C-NMR-Spektren ist ableitbar, daß sich in gleicher Sequenz auch die P—CH2-Bindungsordnung vermindert. Die thermisch induzierte Methylen-Abspaltung läßt auf einen carbenoiden Charakter der an Nickel(0) gebundenen Methylengruppen schließen.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19851180127
