New Details Concerning the Reactions of Nitric Oxide with Vanadium Tetrachloride

The slow addition of NO to a CCl4 solution of VCl4 reproducibly forms the known polymer [V(NO)3Cl2]n as a dark
brown powder. Treatment of a CH2Cl2 suspension of [V(NO)3Cl2]n with excess THF generates mer-(THF)3V(NO)Cl2
(1) which can be isolated as an orange crystalline material in 55% yield. The reaction of 1 with excess MeCN or
1 equiv of trimpsi (trimpsi = tBuSi(CH2PMe2)3) provides yellow-orange (MeCN)3V(NO)Cl2·MeCN (2·MeCN) and
yellow (trimpsi)V(NO)Cl2 (3), respectively. A black, crystalline complex formulated as [NO][VCl5] (4) is formed by
the slow addition of NO to neat VCl4 or by the reaction of excess ClNO with neat VCl4. Complex 4 is extremely
air- and moisture-sensitive, and IR spectroscopy suggests that in solutions and in the gas phase it dissociates
back into VCl4 and ClNO. Reaction of 4 with excess [NEt3(CH2Ph)]Cl generates [NEt3(CH2Ph)]2[VCl6]·2CH2Cl2
(5·2CH2Cl2), which can be isolated as deep-red crystals in 51% yield. All new complexes have been characterized
by conventional spectroscopic methods, and the solid-state molecular structures of 1, 2·MeCN, and 5·2CH2Cl2
have been established by single-crystal X-ray diffraction analyses.