Monovalent lanthanide(I) in borozene complexes
Wan‐Lu Li, Teng‐Teng Chen, Weijia Chen, Jun Li, Lai‐Sheng Wang
Abstract
Abstract Lanthanide (Ln) elements are generally found in the oxidation state +II or +III, and a few examples of +IV and +V compounds have also been reported. In contrast, monovalent Ln(+I) complexes remain scarce. Here we combine photoelectron spectroscopy and theoretical calculations to study Ln-doped octa-boron clusters (LnB 8 − , Ln = La, Pr, Tb, Tm, Yb) with the rare +I oxidation state. The global minimum of the LnB 8 − species changes from C s to C 7v symmetry accompanied by an oxidation-state change from +III to +I from the early to late lanthanides. All the C 7v -LnB 8 − clusters can be viewed as a monovalent Ln(I) coordinated by a η 8 -B 8 2− doubly aromatic ligand. The B 7 3− , B 8 2− , and B 9 − series of aromatic boron clusters are analogous to the classical aromatic hydrocarbon molecules, C 5 H 5 − , C 6 H 6 , and C 7 H 7 + , respectively, with similar trends of size and charge state and they are named collectively as “borozenes”. Lanthanides with variable oxidation states and magnetic properties may be formed with different borozenes.