Detection and characterization of singly deuterated silylene, SiHD, via optical spectroscopy

Abstract

Singly deuterated silylene has been detected and characterized in the gas-phase using high-resolution, two-dimensional, optical spectroscopy. Rotationally resolved lines in the 0 0 0X 1 A ′ →à 1 A ′′ band are assigned to both c-type perpendicular transition and additional parallel, axis-switching induced bands. The extracted rotational constants were combined with those for SiH 2 and SiD 2 to determine an improved equilibrium bond length, r SiH , and bond angle, θ, of 1.5137 ± 0.0003 Å and 92.04 • ± 0.05 • , and 1.4853 ± 0.0005 Å and 122.48 • ± 0.08 • for theX 1 A ′ (0, 0, 0) andà 1 A ′′ (0, 0, 0) state respectively. The dispersed fluorescence consists of a long progression in theà 1 A ′′ (0, 0, 0) →X 1 A ′ (0, ν 2 , 0) emission which was analyzed to produce vibrational parameters. A strong quantum level dependence of the rotationally resolved radiative decay curves is analyzed. Published by AIP Publishing. [http://dx

Molecular Main Group Metal Hydrides

“…We would like to draw specific attention to the review by Hadlington, Driess, and Jones who document the use of modern molecular design principles and synthetic methods to access low-coordinate Group 14 hydride complexes, while discussing important pioneering work relating to the use of such species in catalysis . The parent inorganic silylene SiH 2 is often touted as a key intermediate formed during the decomposition of SiH 4 into thin films of Si. , As shown in Scheme , SiH 2 can be generated as a transient species by the flash photolysis of PhSiH 3 , while photolysis of Me 2 SiH 2 and 1-chloro-1-silacyclopent-3-ene ( 738 ) yield MeSiH and ClSiH, respectively. , The reactivity of SiH 2 with small molecules, such as O 2 , H 2 O, HCl, CO 2 , MeC­(O)­H, Me 2 O, alkenes, , alkynes, N 2 (the H 2 Si·N 2 adduct is stable at 10 K), NO, or silanes (e.g., MeSiH 3 ), can lead to E–H bond insertion, oxidative addition, hydride migration, or Lewis acid–base adduct formation, depending on the nature of the substrate (Scheme ). Furthermore, SiH 2 also has been the subject of numerous computational investigations. − Laser flash photolysis of germacyclopentenes at 193 nm (Scheme ) yields GeH 2 , either in the gas phase or solution, , and reactivity paths that mirror those exhibited by SiH 2 with small molecules have been observed. − In related work, gas phase laser flash photolysis of 1,3,4-trimethyl­germacyclopent-3-ene ( 739 ) yields transient MeGeH (Scheme ), while passage of an electric discharge through H 3 GeCl vapor affords the reactive halogermylene HGeCl .…”

“…977,978 As shown in Scheme 119, SiH 2 can be generated as a transient species by the flash photolysis of PhSiH 3 , while photolysis of Me 2 SiH 2 and 1-chloro-1- silacyclopent-3-ene (738) yield MeSiH and ClSiH, respectively. 979,980 The reactivity of SiH 2 with small molecules, such as O 2 , 981 H 2 O, 982 HCl, 983 CO 2 , 984 MeC(O)H, 985 Me 2 O, 986 alkenes, 987,988 alkynes, 989 N 2 (the H 2 Si•N 2 adduct is stable at 10 K), 990 NO, 991 or silanes (e.g., MeSiH 3 ), 992 can lead to E−H bond insertion, oxidative addition, hydride migration, or Lewis acid−base adduct formation, depending on the nature of the substrate (Scheme 120). Furthermore, SiH 2 also has been the subject of numerous computational investigations.…”

Direct observation of vibrational energy dispersal via methyl torsions

“…It has been used to analyze mixtures by Neij et al 45 and Kable and coworkers, 46 and also as a detailed probe of rovibronic structure. 44 , 47 , 48 More recently, it has given highly informative information on the role of internal rotation in vibrational energy dispersal by Lawrance, Gascooke and coworkers. 14 , 17 , 23 , 34 , 44 Although DF and LIF spectra can be recorded separately, each can be obtained from a 2D-LIF spectrum; and indeed, there is much more information in a 2D-LIF spectrum than in the separate cases.…”

Modelling the non-local thermodynamic equilibrium spectra of silylene (SiH2)

“…Naturally, this is a very deformed geometry comparing to the equilibrium structure of the gas phase SiH 2 , r e = 1.5137 AE 0.003 Å and a e = 92.04 AE 0.051. 107 After being dissociated, in relaxing to be a free molecule, the fragment SiH 2 has added vibrational energy and is hence in a situation when it's vibrational populations do not match the LTE distribution for corresponding temperature of the surroundings, at least for the vibrational degrees of freedom.…”