INFRARED SPECTROSCOPIC CHARACTERIZATION OF MOLECULAR-COMPLEXES OF DIMETHYLCADMIUM WITH GROUP-V AND GROUP-VI HYDRIDES IN INERT MATRICES AND CRYOGENIC THIN-FILMS
Hb. Bai et Bs. Ault, INFRARED SPECTROSCOPIC CHARACTERIZATION OF MOLECULAR-COMPLEXES OF DIMETHYLCADMIUM WITH GROUP-V AND GROUP-VI HYDRIDES IN INERT MATRICES AND CRYOGENIC THIN-FILMS, Journal of molecular structure, 377(3), 1996, pp. 235-246
Molecular complexes of (CH3)(2)Cd with H2S, H2Se, NH3, PH3 and AsH3 ha
ve been formed, isolated and characterized in argon matrices and cryog
enic thin films. Infrared spectra of the 1:1 and, in some cases, the 1
:2 complexes showed perturbations to a number of vibrational modes of
the acid ((CH3)(2)Cd) and base subunits. Shifts between 6 and 22 cm(-1
) to the red of the CdC2 antisymmetric stretch were noted, suggesting
that these complexes are somewhat less strongly bound than analogous c
omplexes of (CH3)(2)Zn. This conclusion is supported by the relatively
small shift of the symmetric deformation mode of NH3 complexes to (CH
3)(2)Cd compared with many known complexes of NH3. Nonetheless, the ma
gnitudes of the shifts correlate well with the proton affinities of th
e bases employed here. Cryogenic thin film experiments involving (CH3)
(2)Cd and NH3 permitted initial formation and trapping of the 1:1 comp
lex, and warming the film from 14 K towards room temperature led to fo
rmation of the 1:2 complex and then ultimately dissociation. The disso
ciation temperature correlated well with the shift of the CdC2 antisym
metric stretch, suggesting that both are related to the bond strength
in the complex.