ANIONIC COORDINATION COMPLEXES OF Mo AND W WHICH CRYSTALLIZE FROM LIQUID CLATHRATE MEDIA WITH OXONIUM ION-CROWN ETHER CATIONS

Abstract

The complexes H₃O⁺·18-crown-6]MoOCl₄(H₂O)^?], 1, and H₂O·aza-18-crown-6·(H⁺)] MoOCl₄(H₂O)^?], 3, were synthesized from a mixture of Mo(CO)₆, HCl(g), H₂O and either 18-crown-6 for 1 or mono-aza-18-crown-6 for 3, in toluene. For complex 4, H₂O·aza-18-crown-6·(H⁺)]₂WOCl₄(H₂O)^?]Cl^?], reaction conditions were as for 3 except W(CO)₆ was used in place of Mo(CO)₆. Similarly, for complex 2, H₃O⁺·18-crown-6]WOBr₄(H₂O)^?], W(CO)₆ and HBr were used in the reaction mixture. These reactions were promoted by UV radiation and formed liquid clathrates almost immediately upon reaction. X-ray crystal structures were performed on each compound. Complex 1 crystallizes in the triclinic space group P/i with a = 10.206(1), b = 10.486(1), c = 11.701(1) Å, α = 71.11(1), β = 74.60(1), γ = 75.08(1)°, and D _c = 1.649 g cm^?3 for Z = 2. Refinement based on 3925 observed reflections led to a final R value of 0.078. Complex 2 crystallizes in the monoclinic space group P2₁/c with a = 9.710(1), b = 19.824(1), c = 12.399(1) Å, β = 104.58(1)°, and D _c = 2.369 g cm^?3 for Z = 4. Refinement based on 2008 observed reflections led to a final R value of 0.090. Complex 3 crystallizes in the orthorhombic space group Pnmn with a = 16.927(1), b = 12.226(1), c = 11.167(1) Å, and D _c = 1.598 g cm^?3 for Z = 4. Refinement based on 1486 observed reflections led to a final R value of 0.040. Complex 4 crystallizes in the monoclinic space group C2/m with a = 11.761(2), b = 12.096(2), c = 14.966(1) Å, β = 132.91(1)°, and D _c = 1.502 g cm^?3 for Z = 4. Refinement based on 2021 observed reflections led to a final R value of 0.051. In all cases the metal coordination sphere was essentially octahedral with the water ligand trans to the oxo species.