Darstellung,Kristallstrukturen und Schwingungsspektren von [(Mo6X)Y]2–; Xi = Cl,Br; Ya = NO3, NO2

Synthesis, Crystal Structures, and Vibrational Spectra of (Mo₆X)Y]^2–; Xⁱ = Cl, Br; Y^a = NO₃, NO₂ By treatment of (Mo₆X)Y]^2–; Xⁱ = Y^a = Cl, Br with AgNO₃ or AgNO₂ by strictly exclusion of oxygene in acetone the hexanitrato and hexanitrito cluster anions (Mo₆X)Y]^2–, Y^a = NO₂, NO₃ are formed. X-ray structure determinations of (Ph₄As)₂(Mo₆Cl)(NO₃)] · 2 Me₂CO ( 1 ) (monoclinic, space group P2₁/n, a = 12.696(3), b = 21.526(1), c = 14.275(5) Å, β = 115.02(2)°, Z = 2), (n-Bu₄N)₂(Mo₆Br)(NO₃)] · 2 CH₂Cl₂ ( 2 ) (monoclinic, space group P2₁/n, a = 14.390(5), b = 11.216(5), c = 21.179(5)Å, β = 96.475(5)°, Z = 2) and (Ph₄P)₂(Mo₆Cl)(NO₂)] (3) (monoclinic, space group P2₁/n, a = 11.823(5), b = 13.415(5), c = 19.286(5) Å, β = 105.090(5)°, Z = 2) reveal the coordination of the ligands via O atoms with (Mo–O) bond lengths of 2.11–2.13 Å, and (MoON) angles of 122–131°. The vibrational spectra of the nitrato compounds show the typical innerligand vibrations ν_as(NO₂) (～ 1500), ν_s(NO₂) (～ 1270) and ν(NO) (～ 980 cm^–1). The stretching vibrations ν(N=O) at 1460–1490 cm^–1 and ν(N–O) in the range of 950–1000 cm^–1 are characteristic for nitrito ligands coordinated via O atoms.