Rs. Czernuszewicz et al., ORIGIN OF THE UNUSUAL BENDING DISTORTION IN THE (MU-OXO)DIVANADIUM(III) COMPLEX [V2O(L-HIS)(4)] - A REINVESTIGATION, Inorganic chemistry, 33(26), 1994, pp. 6116-6119
The title compound, [V2O(l-his)(4)].2H(2)O (1), originally reported by
Kanamori et al. (Chem. Lett. 1993, 1731-1734), has been reinvestigate
d using both X-ray crystallography and resonance Raman spectroscopy. R
edetermination of the structure in the higher symmetry monoclinic spac
e group C2 gives the following crystallographic parameters: C24H34N12O
11V2, fw = 786.5, a = 14.583(2) Angstrom, b = 14.024(2) Angstrom, c =
10.659(1) Angstrom, beta = 129.71(1)degrees, V = 1676.9(2) Angstrom(3)
, Z = 2, R = 0.0399 and R(w) = 0.0548 for 249 least-squares parameters
refined against 3504 unique, observed (F > 4 sigma(F)) data. The X-ra
y structure reveals two strong intramolecular hydrogen bonds that acco
unt for the unusually small V-O-V angle (153.9 degrees) in this unsupp
orated mu-oxo divanadium complex. Resonance Raman spectroscopy in the
solid-state confirms the presence of the intramolecular hydrogen bondi
ng and the acute V-O-V angle. Comparison of resonance Raman spectra of
1 in solid and solution indicates that the V-O-V angle opens up to si
milar to 180 degrees upon dissolution due to a breaking of the intramo
lecular hydrogen bonds in the solid.