A crystallographic and spectroscopic study on the reactions of WCl6 with carbonyl compounds

WCl6, 1, reacted with two equivalents of HC(O)NR2 (R = Me, Et) in CH2Cl2 to afford the W((VI)) oxo-derivatives WOCl4(OCHNR2) (R = Me, 2a; R = Et, 2b) as main products. The hexachlorotungstate(V) salts [{O-C-N(Me)CH2CH2CH2}(2)(mu-H)][WCl6], 3, and [PhNHC(Me)N(Ph)C(O)Me][WCl6], 4, were isolated in moderate yields from the 1 : 2 molar reactions of 1 with N-methyl-2-pyrrolidone (in CH2Cl2) and acetanilide (in CDCl3), respectively. The additions of two equivalents of ketones/aldehydes to 1/CH2Cl2 yielded the complexes WOCl4[OC(R)(R')] (R = Me, R' = Ph, 5a; R = R' = Ph, 5b; R = R' = Me, 5c; R = R' = Et, 5d; R = H, R' = 2-Me-C6H4, 5e) and equimolar amounts of C(R)(R')Cl-2. Analogously, WOCl3[kappa(2)-{1,2-C6H4(O)(CHO)}], 5f, and 1,2-C6H4(OH)(CHCl2) were obtained from 1 and salicylaldehyde. The 1 : 1 reaction of 1 with acetone in CH2Cl2 resulted in the clean formation of WOCl4 and 2,2-dichloropropane. Compounds 5a, b, f were isolated as crystalline solids, whereas 5c, d, e could be detected by solution NMR only. The interaction of 1/CH2Cl2 with isatin, in a 1 : 1 molar ratio, revealed to be a new, convenient route for the synthesis of 3,3-dichloro-2,3-dihydro-1H-indol-2-one, 6. The 1 : 1 reactions of 1 with R'OCH(R)CO2Me (R = H, R' = Me; R = Me, R' = H) in a chlorinated solvent afforded the tungsten(V) adducts WCl4[kappa(2)-OCH(R)(COMe)-Me-2] (R = H, 7a; R = Me, 7b). 1/CH2Cl2 reacted sluggishly with equimolar quantities of trans-(CO2Et)CH=CH(CO2Et) and CH2(CO2Me)(2) to give, respectively, the W(IV) derivatives WCl4[kappa(2)-CH2(CO2Me)(2)], 8a, and [WCl4-kappa(2)-{trans-(CO2Et)CH-CH (CO2Et)}](n), 8b, in about 70% yields. The molecular structures of 2a, 3, 4, 5a, 5f, 7a and 7b were ascertained by X-ray diffraction studies.