De. Over et Jm. Mayer, AMINE COMPLEXES OF TUNGSTEN(II) AND MOLYBDENUM(II) - M(NH2R)CL2(PMEPH2)3 AND M(NH2CH2CH2NH2)CL2(PMEPH2)2, Polyhedron, 12(21), 1993, pp. 2593-2602
Addition of primary amines or ammonia to solutions of WCl2(PMePh2)4 (1
) or MoCl2(PMePh2)4 (6) results in the formation of [M(NH2R)Cl2(PMePh2
)3] (M=W (2), Mo (7); R=H, Me, (n)Pr, (i)Pr, C6H11, CH2CF3, or CH2CH=C
H2). With larger secondary amines, no reaction is observed, except for
a transient adduct of aziridine. Ethylenediamine substitutes for two
phosphines, forming M(en)Cl2(PMePh2)2, but further substitution has no
t been observed even in neat ligand. Reactions of [WCl2(CH2=CH2)2(PMeP
h2)2] (4) with NH2Me and NH2nPr yield equilibrium amounts of amine-eth
ylene complexes [W(NH2R)C]2(CH2=CH2)(PMePh2)2] (5) plus ethylene. The
characterization of these compounds by paramagnetic NMR, IR, and mass
spectra is described. The amine complexes do not lose hydrogen to form
imido complexes, in contrast to the analogous reactions of alcohols a
nd thiols with 1 which yield oxo and sulphido complexes. This appears
to be related to the lower acidity of amines versus alcohols and thiol
s.