Prediction of the Existence of LiCH, a Carbene-like Organometallic Molecule

TL;DR

This paper predicts the existence of LiCH, a novel carbene-like organometallic molecule, using advanced computational methods, revealing its triplet ground state, linear geometry, and stability relative to dissociation channels.

Contribution

The study introduces LiCH as a new molecule and demonstrates its properties using 2-RDM methods capable of capturing multireference correlation effects.

Findings

LiCH has a triplet ground state with a 15.8 kcal/mol singlet-triplet gap.

LiCH is linear in both triplet and singlet states.

LiCH is stable by approximately 77 kcal/mol against dissociation.

Abstract

Carbenes comprise a well-known class of organometallic compounds consisting of a neutral, divalent carbon and two unshared electrons. Carbenes can have singlet or triplet ground states, each giving rise to a distinct reactivity. Methylene, CH$_2$, the parent hydride, is well-known to be bent in its triplet ground state. Here we predict the existence of LiCH, a carbene-like organometallic molecule. Computationally, we treat the electronic structure with parametric and variational two-electron reduced density matrix (2-RDM) methods, which are capable of capturing multireference correlation typically associated with the singlet state of a diradical. Similar to methylene, LiCH is a triplet ground state with a predicted 15.8 kcal/mol singlet-triplet gap. However, unlike methylene, LiCH is linear in both the triplet state and the lowest excited singlet state. Furthermore, the singlet state is found to exhibit strong electron correlation as a diradical. In comparison to dissociation channels Li + CH and Li$^+$ + CH$^-$, the LiCH was found to be stable by approximately 77 kcal/mol.