Darstellung und spektroskopische untersuchungen der beiden isomeren von tricarbonyl[tricarbonyl(methyl-ferracyclopentadien)]eisen, CH3C4H3Fe2(CO)6; kristallstruktur von tricarbonyl[tricarbonyl(methyl-ferrathiacyclohexadien)]eisen, CH3C4H3SFe2(CO)6

Ring-expansion and desulfurisation of thiophenes with an aluminium(I) reagent

Reactions of thiophene, 2-methylthiophene, 2-methoxythiophene, 2,3-dimethylthiophene, and benzothiophene with the aluminium(I) complex [{ArNC(Me)2H}Al] (Ar = 2,6-di-isopropylphenyl) are reported. In all cases, carbon-sulfur bond activation and ring-expansion of the heterocycle is observed. For thiophene, we identify a reaction network for desulfurisation that includes an unusual second carbon-sulfur bond activation step.

Recent advances in well-defined, late transition metal complexes that make and/or break C-N, C-O and C-S bonds

Chemical transformations that result in either the formation or cleavage of carbon-heteroatom bonds are among the most important processes in the chemical sciences. Herein, we present a review on the reactivity of well-defined, late-transition metal complexes that result in the making and breaking of C-N, C-O and C-S bonds via fundamental organometallic reactions, i.e. oxidative addition, reductive elimination, insertion and elimination reactions. When appropriate, emphasis is placed on structural and spectroscopic characterization techniques, as well as mechanistic data.

Transition-metal mediated heteroatom removal by reactions of FeL(+) [L=O, C 4H 6, c-C 5H 6, c-C 5H 5, C 6H 6, C 5H 4(=CH 2)] with furan, thiophene, and pyrrole in the gas phase

Reactions of Fe(+) and FeL(+) [L=O, C4H6, c-C5H6, C5H5, C6H6, C5H4(=CH2)] with thiophene, furan, and pyrrole in the gas phase by using Fourier transform mass spectrometry are described. Fe(+), Fe(C5H5)(+), and FeC6H 6 (+) yield exclusive rapid adduct formation with thiophene, furan, and pyrrole. In addition, the iron-diene complexes [FeC4H 6 (+) and Fe(c-C5H6)(+)], as well as FeC5H4(=CH2)(+) and FeO(+), are quite reactive. The most intriguing reaction is the predominant direct extrusion of CO from furan by FeC4H6 (+), Fe(c-C5H6)(+), and FeC5H4(=CH2)(+). In addition, FeC4H 6 (+) and Fe(c-C5H6)(+) cause minor amounts of HCN extrusion from pyrrole. Mechanisms are presented for these CO and HCN extrusion reactions. The absence of CS elimination from thiophene may be due to the higher energy requirements than those for CO extrusion from furan or HCN extrusion from pyrrole. The dominant reaction channel for reaction of Fe(c-C5H6)(+) with pyrrole and thiophene is hydrogen-atom displacement, which implies D(O)(Fa(N5H5)(+)-C4H4X)>D(O)(Fe(C5H5)(+)-H)=46±5 kcal mol(-1). D(O)(Fe(+)-C4H4S) and D(O)(Fe(+)-C4H5N)=D(O)(Fe(+)-C4H6)=48±5 kcal mol(-1). Finally, 55±5 kcal mol(-1)=D(O)(Fe(+)-C6H6)>D(O)(Fe(+)-C4H4O)>D(O)(Fe(+)-C2H4)=39.9±1.4 kcal mol(-1). FeO(+) reacts rapidly with thiophene, furan, and pyrrole to yield initial loss of CO followed by additional neutral losses. D(O)(Fe(+)-CS)>D(O)(Fe(+)-C4H4S)≈48±5 kcal mol(-1) and D(O)(Fe(+)-C4H5N)≈48±5 kcal mol(-1)>D(O)(Fe(+)-HCN)>D(O)(Fe(+)-C2H4)=39.9±1.4 kcal mil(-1).