Synthese von Wolframkomplexen des Typs [LW(CO)3X]+ (X = H, F, Br; L = 1,4,7-Triazacyclononan). Die Kristallstrukturen von [LW(CO)3Br]BF4 und [LW(CO)3H]2[WOCl5]·H2O / Synthesis of Tungsten Complexes of the Type [LW(CO)3X]+ (X=H, F, Br; L=1,4,7-triazacyclononane). The Crystal Structures of [LW(CO)3Br]BF4 and [LW(CO)3H]2[WOCl5]·H2O

Abstract

The reaction of LW(CO)3 (L = 1,4,7-triazacyclononane) with Br2 in CHCl3 yields orange [LW(CO)3Br](Br3) which was converted to its BF4 - salt. [LW(CO)3Br]BF4 crystallizes in the triclinic space group P1̅ (a = 8.273(3), b = 8.628(2), c = 13.034(3) Å , α = 80.10(2), β = 72.69(2), γ = 61.14(2)°, Z = 2); it consists of cations [LW(CO)3Br]+ , with seven-coordinate W atoms, and BF4 - anions. The corresponding salt [LW(CO)3F](PF6) was obtained from LW(CO)3 with 20% aqueous HF in the presence of air and addition of NaPF6. The analogous reaction with 37% aqueous HCl affords green crystals of [LW(CO)3H]2[WOCl5]·H2O which crystallize in the monoclinic space group P21/c (a = 12.234(4), b = 18.853(7), c = 14.609(5) Å, β = 105.65(3)°, Z = 4). The W atoms in the [LW(CO)3H]+ cations are seven-coordinate; the six-coordinate [WOCl5]2- anions are not disordered. The W = O distance is short (1.72(1) Å ), the mean equatorial W-Cl distance is 2.390 Å whereas the W-Cl bond distance trans to the W = O group is 2.562(5) Å.