Chinese chemists have synthesized a number of molecules that contain in its structure four condensed aromatic rings with the Central atom of osmium. The yields of the reaction was more than 85 percent, and one of the substances were able to identify 92% yield. A study published in the journal Science Advances.
Organic compounds that contain in its structure several benzene rings connected to each other along one of the sides, called polycyclic aromatic hydrocarbons. A carbon atom as the Central can contain no more than three condensed aromatic rings. To create more complex structures it can be replaced by an atom of a transition metal, the presence of d-orbitals which in theory should hold around her for more than three condensed aromatic rings. However, to experimentally synthesize such molecules have been only two or three rings.
Jenui Lou (Zhengyu Lu) with colleagues from Xiamen University suggested that the reaction metallorganicheskie active compounds with three condensed five-membered rings are ideal as a substrate for cycloaddition of unsaturated organic substances, thus forming a molecule with four fused rings. Synthetics introduced into the reaction tricyclic substance with a single atom of osmium in the centre, forming one of the carbons of the triple bond. According to the authors of the article, the small size of the aromatic ring with an atom of the transition metal-promoted activation of a triple connection. It was to pick a molecule of azide — compounds with three nitrogen atoms connected by double bonds, which in the reaction form a fourth five-membered cycle.