Recent topics in the chemistry of heavier congeners of carbenes

Approaches to the study and description of metal cation binding on functional fragments of high-molecular weight substances in aqueous systems

“…We also found a rather strong interaction between the LEP of the nitrogen atoms in the NMe 2 groups and the In performing NBO analysis of dimers 4c and 5c both molecules were treated as two monomer subunits bound through donor acceptor rather than covalent interactions that were described in terms of second order perturbation theory ∆E i→j* (2) . The main nonvalent interactions within subunits in dimers 4c and 5c are of the same nature as the nonvalent interactions in monomers 4b and 5b.…”

“…The orbital interactions between two subunits in dimers 4c and 5c can be analyzed in terms of the second order perturbation theory ∆E i→j* (2) in the NBO basis set. The sum of the ∆E i→j* (2) energies corresponding to the inter actions between subunits is 232.8 kcal mol -1 for dimer 5c (the ∆E i→j* (2) energies lower than 0.1 kcal mol -1 were ignored) and only 183.4 kcal mol -1 for 4c.…”

“…to the atom M causes the LUMO to be shielded; 6 this orbital can also be shielded against external attack by involving in the formation of a stable aromatic system (π electron sextet). 7-8 Recently, we have synthesized a number of germanium(II) and tin(II) derivatives without bulky sub stituents at the metal atom, namely, M(OCH 2 CH 2 NMe 2 ) 2 (1) (M = Ge, Sn), 9 X-Ge-OCH 2 CH 2 NMe 2 (2) (X = Cl, OAc), 10 [N 3 -M-OCH 2 CH 2 NMe 2 ] 2 (3) (M = Ge, Sn), 11 and (Me 3 Si) 2 N-Ge-OCH 2 CH 2 NMe 2 (4), and [(Me 3 Si) 2 N-Sn-OCH 2 CH 2 NMe 2 ] 2 (5) (Fig. 1).…”

Germylenes derived from pyridine-containing diols: reactions with diphenylphosphoryl azide and 9,10-phenanthrenequinone*

“…In this case, the structure of the product was also confirmed by X-ray structural analysis. On the other hand, dimeric germylene [MeN(CH 2 CH 2 O) 2 Ge] 2 and stannylene [MeN(CH 2 CH 2 O) 2 Sn] 2 derived from dialkanolamines undergo this reaction to give a mixture of products, which are difficult to identify [12,13]. It should be noted that the extent of oligomericity of the "heavy carbene" (whether it is a monomer or dimer) is very important in this reaction.…”

“…The study of derivatives of divalent Group IVA elements (Si, Ge, Sn, Pb) is currently one of the most rapidly developing fields in organometallic chemistry [1][2][3]. These compounds, which are called "heavy carbenes", have long been considered unstable, but the pioneering work of M. Lappert et al became a starting point for the active investigation of these unusual compounds [4,5].…”