Use of metal carbonyls in the formation of [H5O2+•15-crown-5][MOCl4(H2O)-], (M = Mo, W), and a second sphere coordination complex in [mer-CrCl3(H2O)3•15-crown-5]

The reactions of M(CO)(6) (M = Mo, W) with HCl(g) in the presence of 15-crown-5 and H2O in toluene have been explored. These reactions were promoted with the use of UV radiation and formed liquid clathrates almost immediately upon reaction. For each metal species, oxidation of the metal center from either [0] to [ +3] in the case of Cr or from [0] to [+5] in the case of both Mo and W occurred. For chromium, a new isomer of CrCl3(H2O)(3) was generated in the second-sphere coordination complex, [mer-CrCl3(H2O)(3) . 15-crown-5] (1), which crystallized from the liquid clathrate layer in the reaction mixture. For molybdenum and tungsten the isostructural complexes, [H5O2+ . 15-crown-5][MOCl4(H2O)(-)], (M = Mo (2), M = W, (3)) rapidly formed where the H5O2+ oxonium ion was stabilized within the liquid clathrate layer. The structures of each of these complexes were established by X-ray crystallography. Complex 1 crystallizes in the monoclinic space group P2(1)/n with a=9.261(3), b=16.182(3), c=12.899(5) Angstrom, beta=107.87(1)degrees, V=1839 Angstrom(3) and D-calc.= 1.568 g cm(-3) for Z=4. Refinement based on 3217 observed reflections led to a final R value of 0.085. Complex 2 crystallizes in the monoclinic space group P2(1)/n with a=12.840(3), b=12.053(1), c=13.290(2) Angstrom, beta=94.26(3)degrees, V=2051 Angstrom(3) and D-calc.=1.720 g cm(-3) for Z=4. Refinement based on 3208 observed reflections led to a final R value of 0.051. Complex 3 is isostructural with 2 with a=12.805(2), b=12.024(1), c=13.293(2) Angstrom, beta=94.25(1)degrees, V=2041 Angstrom(3) and D-calc.=2.015 g cm(-3) for Z=4. Refinement based on 2543 observed reflections led to a final R value of 0.045. (C) 1998 Elsevier Science S.A. All rights reserved.