An overview of the development of compounds with heavier low-valent group 14 elements (known as tetrylenes) as single component catalyst for organic transformation has been provided. Compounds with heavier group 14 elements possess stereochemically active lone pairs and energetically accessible π-antibonding orbitals, thereby resembling the electronic configuration of transition-metal compounds. Such compounds with low-valent group 14 elements has been known for small molecule activation since Power's report of dihydrogen activation by a digermyne, but their utilization in catalysis remained as a "Holy Grail" in main group chemistry. In recent years, numerous methodologies have been discovered epitomizing the use of Si(II), Ge(II) and Sn(II) compounds as single site catalysts for hydroboration of aldehydes, ketones, pyridines, cyanosilylation of aldehydes and ketones, N-formylations aromatic amines, dehydrocoupling reactions. This mini-review highlights these significant developments with an emphasis on the mechanistic investigation.

The reactivity of NOBF4 towards silylene, disilene, germylene, stannylenes has been described. Smooth syntheses of compounds of composition [PhC(NtBu)2E(=O→BF3)N(SiMe3)2, E = Si (3) and Ge (4)] was accomplished from the...

In this paper, we have demonstrated the unique reactivity of a previously reported disilene [(TMS)2N­(η1-Me5C5)­SiSi­(η1-Me5C5)­N­(TMS)2] (1) with the halides of groups 13–15, which resulted in the formation of silicon–E (E = B, Al, Ge, P) bonds. Treatment of 1 with Lewis acidic BCl3 led to the formation of a cationic boron species [Cp*BSi­(Cl)2N­(TMS)2)]­[BCl3SiCl3] (2). In contrast, the reaction of 1 with BCy2Cl afforded an oxidative addition product [(TMS)2N­(η1-Me5C5)­Si­(BCy2)­(Cl)] (3) via the insertion of a Si­(II) atom into the B–Cl bond. Extending the reaction with its higher congener led to classical Lewis acid-base adducts, (TMS)2N­(η1-Me5C5)­Si→AlCl3 (4) and (TMS)2N­(η1-Me5C5)­Si→AlBr3 (5), respectively. The reaction of GeCl2 with 1 proceeded in a completely different manner and resulted in a hybrid dendrimeric compound [HGe­(Si­(Cl)2N­(TMS)2)3] (6), whereas, with SnCl2, it led to Cp*SnCl (7). Lastly, the reaction of Ph2PCl followed the same pattern like Cy2BCl and led to the formation of an oxidative addition product [(TMS)2N­(η1-Me5C5)­Si­(PPh2)­(Cl)] (9) with a Si–P bond.

Group 11 metal (M = Cu, Ag, Au) complexes of heavier tetrylenes (namely, germylene and stannylene) have been studied for several years now. However, the field is mainly unexplored for their potential application either in homogeneous catalysis or in photophysical properties regardless of how the current reports allude to the rich and fascinating chemistry of group 14 elements. In this mini-review, we attempted to summarize the recent advances of heavier tetrylene-stabilized coinage metal complexes, which are majorly dominated by structure elucidation studies. This comprehensive summary intends to help researchers design and fine-tune the tetrylene ligand framework that can lead to coinage metal complexes for future applications as photoemitters in organic light-emitting diode fabrication and efficient catalysts in homogeneous catalysis.

In this paper, we have used 2-aminopyridinato ligands (1 and 2) to stabilize two four-coordinated tin(II) aminopyridinato compounds ([Sn{NPh(py)} 2 ] (3) and [Sn{N(SiMe 3 )py} 2 ] (4)) (py=pyridine) through a salt elimination reaction. The reactions of 3 and 4 with elemental sulfur and selenium resulted in the formation of compounds (5-8) with Sn 2 E 2 (E = S and Se)