SiI₂—A Novel Triatomic Molecule with a Relativistic Touch

Abstract

Reaction of pure SiI4 with elemental silicon in a short‐path thermolysis furnace at 1200K affords SiI2, one of the few still unknown of the 1638 triatomic molecules of the 13 most important non‐metals. The assignment of the photoelectron spectrum used for the characterization, which contained seven bands; was accomplished with the help of a quasirelativistic two‐component pseudo‐potential SCF calcuation with DZP basis set; the Koopmans' defects are less than ± 0.33 eV.

Organosilicon Radical Cations

“…The spin/orbit coupling effects are calculated to be negligibly small. 35 The optimized structural parameters of c/su = 250 pm and ZlSil = 103°as well as the charges of Si +0.54 and I -0.27 fit nicely into the dihalogen silylene series (Figure 12), which is dominated by the decreasing effective nuclear charges of the halogen substituents. 39 The other silylene story, published in 1994, is also breathtaking: Following the surprising discovery of the first "bottlable" carbenes by Arduengo and col-laborators40 as well as of the subsequent analogous germanium derivatives,41 the first isoelectronic silylene has been synthesized and crystallized and its structure determined.42…”

“…19 H3CSiCl is presumably the intermediate in the Rochow/Miiller process for methylchlorosilanes.37 Gas-phase structures have been determined for SiCl2 and for SiBr2 by electron diffraction. 1 The PE spectroscopic studies of silylenes, confined so far to the dihalogen derivatives SiX2, with X = F, Cl, and Br1'18 35 (Figure 12), have now been extended to the kinetically unstable SH2 (Figure 12) and to the surprisingly stable five-membered ring derivative (HC)2(NC(CH3)2)2Si (Figure 13). In addition, H3CSiH has been investigated by Fourier transform ion cyclotron resonance spectroscopy.…”

Structural Distortions in Diiodine-Substituted Unsaturated Hydrocarbons

“…(1)], for which calculations using a highly correlated relativistic pseudopotential wavefunction were carried out [27] to all the interesting novel organic compounds published day by day, such as 2,5,7,10-tetraiodo-1,6-methano [10]annulene (Scheme 10). [28] SiI 4 [Si] x 3 2 SiI 2…”

Theoretical study of I2O

“…Bock et al [1] have suggested that one could construct 1638 triatomic molecules from 13 nonmetallic elements (H, B, C, Si, N, P, O, S, F, Cl, Br, I, and Xe). Most of these compounds have already been characterized, but for a few exceptions.…”