STABLE (ETA(2)-ALKYNE)MCL2 COMPLEXES - SY NTHESIS AND REACTIVITY

The synthesis and reactivity of {(eta5-C5H4SiMe3)2Ti(C=CSiMe3)2} MCl2 (M = Fe: 3a; M = Co: 3b; M = Ni: 3c) is described. The complexes 3 are accessible by the reaction of (eta5-C5H4SiMe3)2Ti(C=CSiMe3)2 (1) with equimolar amounts of MCl2 (2) (M = Fe, Co, Ni). 3a reacts with the or ganic chelat ligands 2,2'-dipyridyl (dipy) (4a) or 1,10-phenanthroline (phen) (4b) in THF at 25-degrees-C to afford in quantitative yields ( eta5-C5H4SiMe3)2Ti(C=CSiMe3)2 (1) and [Fe(dipy)2]Cl2 (5a) or [Fe(phen) 2]Cl2 (5b). 1/n[Cu(I)Hal]n (6) or 1/n[Ag(I)Hal]n (7) (Hal = Cl, Br) re act with {[eta5-C5H4SiMe3)2Ti(C=CSiMe3)2}FeCl2 (3a), by replacement of the FeCl2 building block in 3a, to yield the compounds {(eta5-C5H4SiM e3)2Ti(C=CSiMe3)2{Cu(I)Hal (8) or {(eta5-C5H4SiMe3)2Ti(C=CSiMe3)2}Ag(I )Hal (9) (Hal = Cl, Br), respectively. In 8 and 9 each of the two Me3S iC=C-units is eta2-coordinated to monomeric Cu(I)Hal or Ag(I)Hal moiet ies. Compounds 8 and 9 can also be synthesized by the reaction of (eta 5-C5H4SiMe3)2Ti(C=CSiMe3)2 (1) with 1/n[Cu(I)Hal]n (6) or 1/n[Ag(I)Hal ]n (7) in excellent yields. All new compounds have been characterized by anlaytical and spectroscopic data (IR, H-1NMR, MS). The magnetic mo ments of compounds 3 were measured.