Addition of adamantylidene to La2@C78: isolation and single-crystal X-ray structural determination of the monoadducts.

Thermal and photochemical reactions of La2@C78 with 2-admantane-2,3-[3H]-diazirine are investigated. Four isomers of the monoadduct (La2@C78Ad) synthesized by the photoreaction are isolated by HPLC and characterized by mass, UV−vis-NIR absorption, cyclic voltammogram and differential pulse voltammogram spectroscopy, proton and 13C NMR spectroscopic analysis, single-crystal X-ray diffraction analysis, and theoretical approaches. The addition reactions occur at both the [5,6] and [6,6] positions. X-ray and theoretical studies indicate that one of the monoadduct isomers has an open structure with two La atoms on the C3 axis of the D3h cage of La2@C78.