Gas-Phase Characterization by Photoelectron Spectroscopy of Unhindered, Low-Coordinate Germanium Compounds:  Germaimines, Germylenes, and Germaisonitriles¹

Abstract

Low-coordinate, unhindered germanium compounds, germaimines, germylenes, and germaisonitriles, have been generated and characterized by the combination of flash vacuum thermolysis (FVT) of appropriately substituted germacyclopentenes and ultraviolet photoelectron spectroscopy (UV−PES). These products have characteristic ionization potentials (IPs) at low energy consistent with their great kinetic instability and their high reactivity. The ionization potentials associated with the ejection of an electron from the πGe  N orbital for germaimines and the nGe lone pair for germylenes are useful fingerprints of these compounds. At higher temperature these transient species lead to the formation of germaisonitriles that show two characteristic IPs associated with the πGe  N and the nGe orbital ionizations. Characterization of these three unhindered species is supported by ab initio calculations of the geometrical and electronic structures by using the B3LYP density functional hybrid with LANL2DZ(d) and 6-311G(d) basis sets.

A Route to a Germanium-Carbon Triple Bond: First Chemical Evidence for a Germyne

“…However, some compounds with triple bonds to Si were identified by spectroscopy or by various other methods 4. Germaisocyanides :Ge≡NR have only been detected by photoelectron spectroscopy,5 whereas in coordination chemistry, stable transition metal germylyne complexes have been reported and structurally characterized since 1996 6. No triple bond to tin has yet been described.…”

Fast and scalable solvent-free access to Lappert's heavier tetrylenes E{N(SiMe3)2}2 (E = Ge, Sn, Pb) and ECl{N(SiMe3)2} (E = Ge, Sn)

“…Lastly, in contrast to the lighter Ge and Sn counterparts, which identities have been fully confirmed 39 and proposed using photoelectron spectroscopy, 41 respectively, chloroplumbylene 6 is unknown, to the best of our knowledge.…”

“…20a,c Chlorogermylene 4 has never been isolated, although it has been proposed as a reaction intermediate during the thermal decomposition of germacyclopentenes as a route to germaisonitriles. 41 Lastly, in contrast to the lighter Ge and Sn counterparts, which identities have been fully conrmed 39 and proposed using photoelectron spectroscopy, 41 respectively, chloroplumbylene 6 is unknown, to the best of our knowledge.…”

“…Chlorogermylene 4 has never been isolated, although it has been proposed as a reaction intermediate during the thermal decomposition of germacyclopentenes as a route to germaisonitriles. 41…”

Theoretical studies on the imine germylenoid HNGeNaF and its insertion reaction with R–H (R=F, OH, NH2, CH3)

“…Similarly, imine germylenoid HN@GeMX is one of the simplest unsaturated germylenoids, which is the complex of imine germylene HN@Ge: and MX (M = Li, Na, X = F, Cl). Imine germylene have been first characterized indirectly using various trapping reagents [32], and have been reported both experimentally [33,34] and theoretically [35,36] in recent years. However, relevant geometries of imine germylenoid and its reaction activities with R-H type molecules are still lack.…”