The ambiphilic Ge(II) and Sn(II) cationic species have been reported to be isolated through kinetic or thermodynamic stabilizations. Nonetheless, steric congestion or excessive coordination of donor atoms to the cationic center concurrently disfavors its prompt reactivity. Our research in this field revolves around the utilization of structurally non-rigid bis(imine) based tetradentate supporting ligands for the stabilization of Ge(II) and Sn(II) cationic species. Such E(II) cationic systems have been advantaged due to inherent flexibility present at the ligand backbone allowing disposal of E(II) orbitals through geometric rearrangements for further reactivity. The bifunctionality present in the ligand enables the first examples of Ge(II) bismonocations. Furthermore, the redox-active nature of the ligand encourages participation in chemical transformations. In this personal account we have provided a detailed discussion of our published work in this direction in the last five years.

Dedicated to Prof. Dr. Rainer Streubel on his 64 th birthday N,N'-Diboryl-4,4'-bipyridinylidene ( B BiPy) has been utilized in sub-stoichiometric amounts along with anionic base as one electron donor species for both transition metal-free borylation of aryl halides and arene CÀ H functionalization with aryl iodides for biaryl syntheses. Reaction between B BiPy and potassium tertbutoxide or methoxide has led to the formation of 4,4'bipyridine radical anion (BiPy •À ) with the release of an electron. The BiPy •À has been structurally characterized. The single electron released is transferred to aryl halides generating aryl radicals, which then react with diboron in the presence of methoxide to form aryl boronate and with unactivated benzene in the presence of tert-butoxide to form biaryls. Substrate scopes studies showed that aryl iodides and bromides undergo borylation (1B-12B), while only aryl iodides undergo CÀ C bond formation with arene CÀ H (1C-8C) through radical chain reaction. Mechanisms for CÀ B and CÀ C bond formation have been proposed based on the experimental findings.