Using the new β-diketimine 1a (PhCH(PhC═N-Dip)2, Dip = 2,6-iPr2C6H3), which possesses three phenyl groups at the ligand backbone, we synthesized the β-diketiminato germylene chloride 2 (LGeCl, L = [PhC(PhCN-Dip)2]−). The β-diketiminato germanium radical complex 3 (•LGe:, •L = •[PhC(PhCN-Dip)2]2–) has been isolated by reduction of LGeCl with sodium/naphthalene in 64% yield. X-ray diffraction, HR-MS, and electron paramagnetic resonance analyses together with DFT calculations reveal that 3 exhibits a remarkably different structure in comparison with the reported Ge(I) radical C (L′•Ge:, L′ = [HC(tBuCN-Dip)2]−). The inductive effect of three phenyl groups leads to the backbone of ligand 1 being more electron deficient, and therefore the singly occupied molecular orbital (SOMO) of radical 3 is mainly composed of a π-antibonding orbital between the N and C atoms. This results in ca. 0.14 Å shorter N–Ge bonds and ca. 0.1 Å longer C–N bonds in 3 in comparison to those observed in C. Thus, the radical 3 is a two-coordinate germylene stabilized by an N-heterocyclic radical ligand.

The roaming mechanism in the reaction H + MgH →Mg + HH is investigated by classical and quantum dynamics employing an accurate ab initio three-dimensional ground electronic state potential energy surface. The reaction dynamics are explored by running trajectories initialized on a four-dimensional dividing surface anchored on three-dimensional normally hyperbolic invariant manifold associated with a family of unstable orbiting periodic orbits in the entrance channel of the reaction (H + MgH). By locating periodic orbits localized in the HMgH well or involving H orbiting around the MgH diatom, and following their continuation with the total energy, regions in phase space where reactive or nonreactive trajectories may be trapped are found. In this way roaming reaction pathways are deduced in phase space. Patterns similar to periodic orbits projected into configuration space are found for the quantum bound and resonance eigenstates. Roaming is attributed to the capture of the trajectories in the neighborhood of certain periodic orbits. The complex forming trajectories in the HMgH well can either return to the radical channel or “roam” to the MgHH minimum from where the molecule may react.