Azidokomplexe von Vanadium(IV) und Vanadium(V): (Ph₄P)₂[VOCl₂(μ‐N₃)]₂ und (Ph₄P)₂[VOCl(μ‐N₃)(N₃)₂]₂

Abstract

Abstract Azido Complexes of Vanadium(IV) and Vanadium(V): (Ph 4 P) 2 [VOCl 2 (μ‐N 3 )] 2 and (Ph 4 P) 2 [VOCl(μ‐N 3 )(N 3 ) 2 ] 2 (Ph 4 P) 2 [VOCl 2 (μ‐N 3 )] 2 ( 1 ) was prepared by reaction of (Ph 4 P)[VO 2 Cl 2 ] with trimethylsilylazide in the molar ratio 1:2 in dichloromethane solution to give dark green, moisture sensitive, non‐explosive single crystals. The reaction is accompanied by the formation of the dark blue side‐product (Ph 4 P) 2 [VOCl(μ‐N 3 )(N 3 ) 2 ] 2 ( 2a ), which can be obtained as the main product by application of a large excess of Me 3 SiN 3 . Dark blue needles of 2a crystallize spontaneously from the CH 2 Cl 2 solution within one hour at 4 °C. After standing at 4 °C under its mother liquid within 24 hours a first‐order phase transition of 2a occurs forming dark blue prismatic single crystals of 2b . According to single crystal X‐ray structure determinations, 2a and 2b crystallize in the same type of space group $\rm P{\bar 1}$ , however, with different lattice dimensions. The vanadium(IV) complex 1 is characterized by X‐ray structure determination and by vibrational spectroscopy (IR, Raman) as well as by EPR spectroscopy, whereas 2b is characterized by IR spectroscopy. 1 : Space group P2 1 /n, Z = 2, a = 1009.5(1), b = 1226.6(2), c = 1943.0(2) pm, β = 98.42(1)°, R 1 = 0.0672. The complex anion $\rm [VOCl_{2}(\mu-N_{3})]^{2-}_{{2}/{2}}$ forms centrosymmetric units with V 2 N 2 ‐four‐membered rings with a V···V distance of 335.6(1) pm and coordination number five on the vanadium(IV) atoms. 2a : Space group $\rm P{\bar 1}$ , Z = 1, a = 1089.0(2), b = 1097.1(2), c = 1310.1(2) pm, α = 92.99(1)°, β = 106.12(2)°, γ = 117.05(2)°, V = 1309.8(4) Å 3 , d calc. = 1.440 g·cm −3 , R 1 = 0.0384. The complex anion forms centrosymmetric units of symmetry C i with V 2 N 2 four‐membered rings and VN bond lengths of 200.4(3) and 234.4(2) pm, respectively. The non‐bonding V···V distance amounts to 356.2(1) pm. 2b : Space group $\rm P{\bar 1}$ , Z = 1, a = 1037.3(2), b = 1157.6(2), c = 1177.2(2) pm, α = 98.48(2)°, ° = 103.82(2)°, γ = 106.33(2)°, V = 1281.8(4) Å 3 , d calc. = 1.471 g·cm −3 , R 1 = 0.0724. The structure of the complex anion $\rm [VOCl(\mu-N_{3})(N_{3})_{2}]^{2-}_{{2}/{2}}$ is similar to the anion of 2a with VN bond lengths of the four‐membered V 2 N 2 ring of 203.3(4) and 235.2(4) pm, respectively, and a non‐bonding V···V distance of 357.5(1) pm.