Synthesis and Characterization of Photothermal Osmium Carbolong Complexes

Metallacycles with chelating polydentate conjugated-carbon chain ligands are called carbolong complexes, which are expected to have interesting properties. In this work, the preparation of 12-carbon carbolong complexes in which all of the coordinated atoms in the equatorial plane are carbon atoms was studied. With the help of the well-established mechanism, a new approach to prepare coplanar carbolong complexes bearing different organic functional groups was developed by adding different terminal alkynes in sequence. In the presence of HBF₄ , these coplanar carbolong complexes were converted to η³ -allyl osmapentalene derivatives, which can be produced directly from the reaction of cyclopropaosmapentalene 1 with terminal alkynes in the presence of AgBF₄ under anhydrous conditions. This study offers a new route for the preparation of functional osmium carbolong complexes with excellent photothermal properties, which can be used to prepare photothermal materials.