A halogenophilic pathway in the reactions of transition metal carbonyl anions with [(η⁶-iodobenzene)Cr(CO)₃].

The paper provides the first example of formal nucleophilic substitution by the halogenophilic pathway in Cr(CO)3 complexes of haloarenes with metal carbonyl anions. All metal carbonyl anions examined attack [(η(6)-iodobenzene)Cr(CO)3] at halogen, which is shown by aryl carbanion scavenging with t-BuOH. The reaction with K[CpFe(CO)2] gives only the dehalogenated arene, but the reaction with K[Cp*Fe(CO)2] (Cp* = η(5)-C5Me5) results in nucleophilic substitution to give [(η(6)-C6H5FeCp*(CO)2)Cr(CO)3].

Radical-chain oxidative addition mechanism for the reaction of an [Re(CO)5]- anion with α-bromostilbene.

E-α-Bromostilbene spontaneously reacts with Na[Re(CO)(5)] at 22 °C in THF to give Na[ReBr(CO)(4){Z-C(Ph)=CHPh}] and Na[Re(2)(CO)(9){Z-C(Ph)=CHPh}] as the main products. Z-α-Bromostilbene is less reactive, but gives the same products. The reaction is stimulated by visible light or a source of solvated electrons (NaK(2.

Lariat ethers with fluoroaryl side-arms: a study of CFmetal cation interaction in the complexes of N-(o-fluoroaryl)azacrown ethers.

New lariat ethers, N-(o-fluorophenyl)aza-15-crown-5 (F-A15C5) and N,N'-bis(o-fluorophenyl)diaza-18-crown-6 (F(2)-A(2)18C6), were prepared by the N-arylation of the corresponding azacrown ethers. The interaction of the ligands with metal cations was studied in solution by (1)H and (19)F NMR (in acetone-d(6)) and UV spectroscopy (MeOH) confirming the formation of complexes of F(2)-A(2)18C6 with K(+), Na(+), Ag(+), Ba(2+), Pb(2+) and of F-A15C5 with Na(+) and giving evidence of CFmetal cation interaction. Cation binding constants (beta, evaluated by UV titration method), demonstrate that F-A15C5 and F(2)-A(2)18C6 form more stable complexes than their fluorine-free analogs.