Probing the imine silylenoid HN=SiNaF and its insertions reaction with R–H (R=F, OH, NH2, CH3) using DFT

Abstract

The geometries and isomerization of the imine silylenoid HN=SiNaF as well as its insertion reactions with some R-H molecules have been systematically investigated theoretically, where R=F, OH, NH 2 , and CH 3 , respectively. The barrier heights for the four insertion reactions are 67.7, 115.6, 153.5, and 271.5 kJ/mol at the B3LYP/6-311+G* level of theory, respectively. Here, all the mechanisms of the four reactions are identical to each other, i.e., a stable intermediate has been formed during the insertion reaction. Then, the intermediate could dissociate into the substituted silylene (HN=SiHR) and NaF with a barrier corresponding to their respective dissociation energies. Correspondingly, the reaction energies for the four reactions are 71.8, 95.5, 123.3, and 207.6 kJ/mol, respectively, which are linearly correlated with the calculated barrier heights. Furthermore, the effects of halogen substitutions (F, Cl, and Br) on the reaction activity have also been discussed. As a result, the relative reactivity among the four insertion reactions should be as follows: H-F [ H-OH [ H-NH 2 [ H-CH 3 .

Theoretical Studies on the Alkylidene Silylenoid H2C = SiLiF and Its Insertion Reaction with R-H (R = F, OH, NH2)

“…Similar to the unsaturated carbene H2C = C:, silylene HN = Si:, 25 the most stable alkylidene silylene H2C = Si: is also in singlet, where the singlet state is more favorable about 246.8 kJ/mol in energy relative to that of triplet state at the B3LYP/ 6-311+G* level of theory. Thus, the singlet state of H2C = Si: has been discussed in the following study.…”

“…At present, their existence, structures, and chemical properties have not been studied experimentally. Recently, Li et al have studied the geometries and isomerization reaction of unsaturated silylenoid H2C = SiNaF 23 and H 2 C = SiNaBr theoretically, 24 Wang et al 25 have studied the geometries and insertion reaction with R-H of HN = SiMX.…”

Interplay of thermochemistry and Structural Chemistry, the journal (volume 19, 2008) and the discipline

“…In the further study, Wang et al [180] studied silylenes, which are one of the significant and highly reactive organosilicon compounds. They report the use of DFT to study the geometries and isomerization of the imine silylenoid HN=SiNaF as well as systematic investigation of insertion reactions of R-H molecules (R = F, OH, NH 2 , CH 3 ).…”

Insight into the substitution reactions of silylenoid H2SiLiF with GeH3X (X = F, Cl, Br): a theoretical study

“…On the other hand, since Clark et al [37] studied the isomers of lithoflurosilylenoid H 2 SiLiF theoretically using ab initio calculations for the first time in 1980, many silylenoids such as R 1 R 2 SiMX (R 1 , R 2 =H, F, OH, NH 2 , Me, Et; M=Li, Na, K, Be, Mg, etc. ; X=F, Cl, Br) [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] have been investigated by quantum chemistry methods. Such theoretical studies show that R 1 R 2 SiMX has four possible structures (see Scheme 1): a p-complex (I), a three-membered-ring (ii), an σ-complex (iii), and a 'classical' tetrahedral (iv).…”