Thiophenes in Organotransition Metal Chemistry:  Patterns of Reactivity

Abstract

Thiophenes, including benzothiophenes and dibenzothiophenes, undergo a variety of reactions with transition metal complexes that lead to products in which the thiophene is partially reduced or cleaved at a C−S bond. The specific types of reactivity depend on the modes of thiophene coordination to the metal, which in turn depend on the particular metal and its associated ligands. It is the intent of this review to organize these numerous reactions of thiophenes into categories that illustrate distinct patterns of reactivity. It is hoped that an understanding of such patterns will stimulate the use of thiophene−organotransition metal chemistry in synthetic organic chemistry.

Photosubstitution of (Fulvalene)tetracarbonyldiruthenium by Alkenes and Alkynes: First Observation of Alkyne Coupling on Fulvalene Dimetals and Synthesis of a (Fulvalene)dimetallacyclopentadiene(alkene) Complex

“…32 Stable µ 1 (S) complexes of thiophene are rare and most contain a positively charged metal nucleus. 33 Dinuclear ruthenium activation of thiophene is known to cause C-S bond cleavage, 34 but none was observed here. Rather, heating 9 (THF, 65 °C) with the appropriate ligands led to 8 (82%) and 10 (85%), respectively.…”

“…33 Phosphine independent rates were established by measurement of the disappearance of 9 (and appearance of 10) in C 6 D 6 at 86 °C using one, two, and four equivalents of PPh 3 , k obs = 7.4 x 10 37 and the Ru-S bond appreciably strong.…”

Gas-phase oon-molecule reactions of transition metal complexes: The effect of different coordination spheres on complex reactivity

“…The 1 (S) binding mode, however, is generally fairly weak. In fact, it has been established that thiophene units in rigid macrocyclic ligands coordinate poorly or not at all in most transition metal complexes [65][66][67]. Molecular orbital calculations by Sargent et al [68] involving sulfur-rich multidentate ligands designed to bind metals in a 1 (S) fashion, indicate that the magnitude and polarizability of the electronic density of sulfur's lone pairs determine the coordination strength of the ligand.…”

Carbon-Hydrogen Bond Activation of Phenyldi(2- Thienyl)Phosphine at A Triruthenium Cluster Center

“…[1][2][3][4] Thiophene and its benzoderivatives normally do not bind strongly with transition metals which is a major drawback to study their behaviors on metal surface. In order to circumvent this problem thienylphosphine has been employed to bring the thiophenes into the coordination sphere of transition metals through the phosphine moiety of the ligand.…”