Reactions of Sc+, Ti+, V+, Fe+, Co+, and Ni+ with naphthalene halides. Study of the initial steps of a metal-catalyzed polymerization in the gas phase

Poly(naphthylene) is of interest, in particular, due to its intrinsic electrical conductivity. Reported here are the initial steps in the metal-catalyzed polymerization of naphthalene as observed in the gas-phase reactions of Sc+, Ti+, V+, Fe+, Co+, and Ni+ with 1-halonaphthalenes studied in a Fourier transform mass spectrometer. Sc+, Ti+, V+, and Fe+ were found to dehydrohalogenate all of the halides stepwise, to produce ions of the form M(C10H6)(n)(+). Up to 6 steps of dehydrohalogenations were observed in the case of the reactions of Fe+ with 1-chloronaphthalene. Co+ and Ni+ exhibited similar behavior except in the case of 1-fluoronaphthalene, where only condensation products were observed. Sc+ showed unusual reactivity by also being able to eliminate C2H2, this reaction being most prominent in the case of fluoronaphthalene. Aside from dehydrohalogenations, Ti+ was found to eliminate a hydrogen atom to form TiC(10)H(6)X(+) in its reactions with all of the halides. 2-Bromonaphthalene was also studied and compared with the results for 1-bromonaphthalene, but no significant differences were observed. Secondary and higher order reactions were investigated, and several ionic products from primary and secondary reactions were studied by collision-induced dissociation (CID). The formation of (C10H6)(n)(+) with n = 2 and 3 was observed and was in some cases formed by loss of M or MX from M(C10H6)(n)(+) and M(C10H6)(n)X(+), respectively, but also in direct reactions of M(C10H6)(n-1)(+) With the neutral halonaphthalene, which is in contrast with the behavior observed for the related phenyl halides in an earlier study. The ionization potentials of(C10H6)(n) with n = 2 and 3 are lower than that of iron (7.87 eV) as Fe was lost upon CID of Fe(C10H6)(n)(+) for n = 2 and 3. The thermodynamical consequences of the reactions are discussed, as well as deductions concerning the structure of several of the ionic reaction products.