ISSN:
0009-2940
Keywords:
Alkynylnickel halides
;
Nickel complexes
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Oxidative Linear Trimerization of Alkynyl Groups in (Trimethylphosphane)nickel Complexes: Structures and the Role of Ligand-Rich Precursors NiX(C≡CR)(PMe3)n (n = 2-4)Oxidative additions of 1-halogenoalkynes XC≡CR; to Ni(PMe3)4 afford high yields of pentacoordinate ionic alkynylnickel compounds [Ni(C≡CR)(PMe3)4]+X- [R = SiMe3, X = I (1); R = CMe3, X = I (2), Br (3); R = SiEt3, X = I (6), Br (7); R = SiiPr3, X = I (10), Br (11), R = Ph, X = I (21), Br (22)] or complex molecules Ni(C≡CR)X(PMe3)3 [R = SiPh3, X = I (14), Br (15); R = Ph, X = I (19), Br (20)]. Dissociation of trimethylphosphane gives square planar trans-Ni(C≡CR)X-(PMe3)2 [R = CMe3, X = Br (4), Cl (5); R = SiEt3, X = Br (8), Cl (9); R = SiiPr3, X = Br (12), Cl (13); R = SiPh3, X = I (16), Br (17), Cl (18); R = Ph, X = I (23), Br (24), Cl (25)] but with R = SiR'3, X = I the title reaction dominates with formation of trans-Ni[C(C≡CR)=CR(C≡CR)]I(PMe3)2 [R = CMe3 (26), SiEt3 (29), SiiPr3 (32)]. Thermal activation is necessary in order to obtain trans-Ni[C≡CR)=CR(C≡CR)]X(PMe3)2 [R = CMe3, X = Br (27), Cl (28); R = SiEt3, X = Br (30), Cl (31); R = SiiPr3, X = Br (33), Cl (34)], while only thermal decomposition is observed with trans-Ni(C≡CR)X(PMe3)2 (R = Ph, SiPh3). Examples for both types of reactivity including structural data are given: trans-Ni(C≡CRSiMe3)Br(PMe3)2 and 25 crystallize in the space group P1. Pentacoordinate 19 (space group P21) adopts a trigonal pipyramid of ligand donor atoms with equatorial phenylethynyl and iodo ligands.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19941270904
