Access to Metal‐Bridged Osmathiazine Derivatives by a Formal [4+2] Cyclization. Issue 19 (8th March 2019)

• Record Type: Journal Article
• Authors: Li, Jinhua; Lin, Yu‐Mei; Zhang, Hong; Chen, Yuan; Lin, Zhenyang; Xia, Haiping
• Is Part Of: Chemistry. Volume 25:Issue 19(2019)
• Page Start: 5077
• Page End: 5085
• Publication Date: 2019-03-08
• Subjects: [4+2] cyclization -- 1, 3-thizaine -- heteroatoms -- metallacycles -- osmium; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201806354
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Treatment of osmacyclopentadiene derivatives1 with phenyl or isopropyl isothiocyanate gave the fused five and six‐membered osmacycles2 –5 by a formal [4+2] cyclization. The facile protonation of the newly generated exocyclic imine in complexes2 –5 afforded conjugation‐extended osmacycle derivatives6 –9 . Compounds2 –9 each contain two main‐group heteroatoms (N and S) in the fused six‐membered ring located at the ortho (for S) and para (for N) positions relative to the osmium centre; these species can be regarded as rare osma‐1, 3‐thiazine derivatives and represent the first fused metallathiazine derivatives. In contrast to the non‐planar organic 6 H ‐1, 3‐thiazine, nearly coplanar metallathiazines8 and9 can be achieved by tuning the groups on the two nitrogen atoms. These unique metal‐bridged osma‐1, 3‐thiazine derivatives exhibit remarkable stabilities, broad spectral absorptions spanning the visible spectra, and considerable photothermal properties, which suggests their potential applications in material science. Abstract : Heteroatom‐containing metallacycles : New metal‐bridged osma‐1, 3‐thiazine derivatives were generated by a formal [4+2] cyclization reaction between osmacyclopentadiene derivatives and isothiocyanates (see scheme).