Organometallic Chemistry of Heterocycles

During recent years some remarkable publications have appeared in the field of organometallic complexes of heterocycles, which might predetermine new future developments, related to new applications in synthetic chemistry, catalysis, and various aspects of materials chemistry, and nanotechnological applications in particular. This chapter outlines some of the recent development in the chemistry of organomettalic compounds, foucusing on five-membered monoheterocycles, azoles, pyridines, six-membered heterocycles with two or more heteroatoms, and five-and six-membered rings with transition metal heteroatoms. Derivatized furan and thiophene containing phosphine moieties in cluster-formation cleave their C–P bonds but remain intact in the furyne and thiophyne clusters, which allow the study of the nature and reactivity of these heterorings. Phosphametallocene chemistry has been marked by the discovery of a new pattern of acetylation and creation of the ligands combining phosphametallocene and imidazol-2-ylidene carbene functions. Azole chemistry is also characterized by a combinatorial approach when two principally different donor functions are linked in a ligand in search of new efficient catalytic systems. The chapter emphasizes that pyridines and some azines provide a reactivity pattern that allows the preparation of a variety of new derivatives of aromatic and dearomatized six-membered heterocycles. Reactions of ring expansion and ring contraction allow the preparation of such rings with a variety of substituents.