92473-06-8Relevant articles and documents
On the trail of dichlorodinitrosyltungsten: A tale of two reactions
Hunter, Allen D.,Legzdins, Peter
, p. 4198 - 4204 (2008/10/08)
Polymeric [W(NO)2Cl2]n may be synthesized in high yields by two preparative methods. The first method involves treatment of WCl6 in CH2Cl2 with an excess of NO followed by complete purging of the ClNO byproduct from the system. It has been established that this reductive nitrosylation proceeds via the isolable intermediate complexes, dark violet cis-W(NO)2Cl4 and bright green fac-W(NO)3Cl3. The second method involves controlled reaction of W(CO)6 with 2 equiv of ClNO in CH2Cl2 after initiation of the conversion with traces of an oxidant. Evidence is presented that this reaction probably proceeds via a catalytic, radical chain mechanism, the initiation step being the formation of substitutionally labile W(CO)6+· and the final propagation step being the reduction of W(NO)2Cl2+· by W(CO)6, which affords the final product and regenerates W(CO)6+·. If either synthesis is effected in the presence of 2 equiv of CH3CN, the only nitrosyl-containing product formed is yellow-green W(NO)Cl3(CH3CN)2, a solid complex also obtainable by reaction of W(NO)2Cl4 or W(NO)3Cl3 with CH3CN. A variety of hard and soft Lewis bases, L, cleave polymeric [W(NO)2Cl2]n to produce new, monomeric W(NO)2Cl2L2 compounds that can be isolated in good yields. The stereochemistries of these octahedral complexes can generally be established by conventional spectroscopic methods. The complexes having L = THF, Et2O, or CH3CN undergo metathesis with n-Bu3Sn(C5H5) to form the known (η5-C5H5)W(NO)2Cl in moderate yields.
