The synthesis and characterization of a series of heavier group 14 element (Ge, Sn, and Pb) carbene homologues based on the electronically modified, 2,6-dimesityl substituted terphenyl ligands Ar # -3,5-i Pr 2 , Ar # -4-SiMe 3 , and Ar # -4-Cl (Ar # -3,5-i Pr 2 = C 6 H 2 -2,6-Mes 2 -3,5-i Pr 2 ; Ar # -4-Cl = C 6 H 2 -2,6-Mes 2 -4-Cl; Ar # -4-SiMe 3 = C 6 H 2 -2,6-Mes 2 -4-SiMe 3 ; Mes = C 6 H 2 -2,4,6-Me 3 ) are presented. The consequences of introducing electron withdrawing and -releasing substituents on the solid state structures of the newly synthesized germylenes, stannylenes, and plumbylenes as well as their Mossbauer, NMR and UV−vis spectroscopic properties are presented and discussed in the context of a second order Jahn−Teller type mixing of frontier orbitals with appropriate symmetry. Experimental findings were supported by DFT calculations. More electron withdrawing ligands lead to a bonding situation with higher contribution of p-orbitals from the central heavier group 14 element in σ-bonding toward the ligands and thus increased s-electron character of the lone pair. Furthermore, this results in an increase in the energy separation between the frontier orbitals. Experimentally, these changes are manifested in narrower bending angles at the heavy tetrel atoms and hypsochromic in their UV−vis spectra. In contrast, derivatives of more electron rich m-terphenyl ligands are characterized by a smaller HOMO− LUMO gap and wider interligand angles.

Despite the fact that sterically demanding 1,2-dihydrodistannanes are versatile synthons, their synthesis is typically a tedious, low-yield procedure, which limits synthetic applications. Looking for generally applicable and high-yield routes, we examined the dehydrogenative coupling of sterically crowded diorganotindihydrides. Herein, we report the application of lanthanide diamide-based catalysts (CH 2 ) 3 -1,3-[N(Dipp)] 2 LnBr (Ln=La,Ce,Nd,Dy) to generate polystannanes and distannanes, depending on the size of the aromatic substituents. Reaction of t Bu 2 SnH 2 resulted in the quantitative formation of 1,1,2,2-tetra-tertbutyldistannane while conversion of sterically encumbered Mes 2 SnH 2 yielded 1,1,2,2-tetramesityldistannane.