Gamil A. Guirgis

Gamil A. Guirgis
College of Charleston | C of C · Department of Chemistry and Biochemistry

Ph D, FRSC

About

364
Publications
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Publications

Publications (364)
Article
Cyclopropylchloromethyldifluorosilane, c-C3H5SiF2CH2Cl, has been synthesized, and its rotational spectrum has been recorded by chirped-pulse Fourier transform microwave spectroscopy. The spectral analysis of several isotopologues indicates the presence of two distinct conformations in the free-jet expansion, which are interconvertible through a rot...
Conference Paper
Full-text available
The rotational spectrum of 1-ethylsilacyclopentane (1ESCP) and 1-ethyl-1-fluorosilacyclopentane (1E1FSCP) were collected and assigned in the 5.0-19.0 GHz region of the electromagnetic spectrum. In collaboration with Dr. Gamil Guirgis of the College of Charleston, the title molecules were synthesized in Charleston, SC and rotational spectra were rec...
Article
The broadband microwave spectra of two related organosilicon molecules, cyclopentylsilane and 1,1,1-trifluorocyclopentylsilane, have been measured and assigned. Both molecules exhibit a Cs-symmetric “envelope” structure, which is confirmed by a determination of the heavy atom backbone rs substitution structures using isotopic substitution in natura...
Article
The ground state, pure rotational spectrum of 1,1-difluoro-1-silacyclopentane has been studied using chirped-pulse, Fourier transform microwave (CP-FTMW) spectroscopy and observed in the 6-20.3 GHz region of the electromagnetic spectrum. This spectrum was acquired leveraging the deep averaging capability of the technique. The parent species, ¹³C, ²...
Article
High level theoretical CCSD/cc-pVTZ computations have been carried out to calculate the structures and ring-puckering potential energy functions (PEFs) for 1,1-difluorosilacyclopent-2-ene (2SiCPF2) and 1,1-dichlorosilacyclopent-2-ene (2SiCPCl2). The structure and PEF for 1,1-dibromosilacyclopent-2-ene (2SiCPBr2) was obtained by ab initio MP2/cc-pVT...
Article
Since 1-chloromethyl-1-fluorosilacyclohexane is a newly synthesized molecular compound its structural parameters and conformational stability is unknown. Raman and infrared vibrational spectroscopy methods were employed for analysis of this molecule. IR spectra were recorded for both gas phase and liquid sample, whereas the Raman experiments were p...
Article
Full-text available
The rotational spectrum of 1,3,5-trisilapentane has been observed on a chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer and is reported. During assignment, multiple conformations of the molecule were identified in the molecular beam. Prior quantum chemical calculations performed on the molecule show that the identified spectra corre...
Article
Raman spectra of 1,1-dicyclopropyl-2,2-dimethylethene (c-C3H5)2C = C(CH3)2) as a liquid were obtained at 293 K and polarization data recorded. Additional Raman spectra were observed at various temperatures between 293 and 143 K, and intensity changes of certain bands with temperature detected. When the sample was cooled to 153 K an amorphous solid...
Thesis
Full-text available
The sila-alicycles 1,1-dichloro-1-silacycloheptane [1,1-dichlorosilepane] (1), 1-chloro-1-(chloromethyl)-1-silacyclohexane [1-chloro-1-(chloromethyl)silinane] (5), and 1-chloro-1-methyl-1-silacyclohexane [1-chloro-1-methylsilinane] were prepared via Grignard reactions of the appropriate (α,ω-alkylidene)dimagnesium bromide with a silyl chloride. Sub...
Poster
Full-text available
Conformational preferences of novel 1,1-difluorosilepane were investigated theoretically via individual ab initio calculations of probable conformers. 1,1-Difluorosilepane was produced via a Grignard reaction of (hexan-1,6-diyl)dimagnesium bromide and SiCl4, followed by difluorination via halogen exchange. The product was analyzed with gas-phase FT...
Poster
Full-text available
This investigation was conducted to determine conformational preferences of relatively unexplored silepane derivatives. Probable conformers of 1,1-difluorosilepane were characterized via individual ab initio molecular orbital calculations. Furthermore, 1,1-dichlorosilepane was successfully synthesized via reaction of a difunctional Grignard reagent...
Article
The molecular structures of two conformers (cis and gauche forms)of C3H5-SiH2-NCO, alternatively known as cyclopropylsilyl isocyanate, have been deduced by a combination of microwave (MW) spectra, including data from 12,13C and 28,29,30Si isotopomers, and ab initio calculations. The MW rotational constants (RC) for the most abundant isotopes are (a...
Article
The infrared spectrum (3100-300 cm-1) in the gas phase and Raman spectrum (3100-150 cm-1) of the liquid of cyclobutyldichlorosilane (c-C4H7SiHCl2) have been recorded. Variable temperature (-143 °C to -123 °C) studies of the Raman spectra (3100-300 cm-1) dissolved in liquid krypton have been carried out. From these data, the experimental stabilities...
Article
Raman spectra of liquid, and infrared spectra of gaseous as well as matrix isolated 1,1,2,2-tetrachloro-1,3-disilacyclopentane were recorded and analyzed with the aid of DFT calculations. Complete assignment of the experimental vibrational spectral bands is made. Experimental results and DFT calculations confirm that 1,1,2,2-tetrachloro-1,3-disilac...
Article
The FT-microwave spectrum (6.5 - 26 GHz) of (chloromethyl)fluorosilane, ClCH2-SiH2F has been recorded and 200 transitions for the normal species along with (13)C, (37)Cl, (29)Si and (30)Si isotopomers have been assigned for trans conformer. Infrared spectra (3,100 to 400 cm(-1)) of gas, solid and the variable temperature (-60 to -100 °C) studies of...
Article
Rotational spectra for two conformers of c-C3H5SiHFCH3 (cyclopropylfluoromethyl silane, CFMS) and one conformer of c-C3H5SiF2CH3 (cyclopropyldifluoromethyl silane, CDFMS) have been observed by a combination of chirped-pulse and resonant cavity Fourier-transform microwave spectroscopy in the 7.5-16.5 GHz range. All rotational transitions were double...
Article
The infrared and Raman spectra of 1,1,3,3,5,5-hexafluoro-1,3,5-trisilacyclohexane (c-C3H6Si3F6) as a solid powder have been recorded. The vibrational spectra reveal that the crystalline compound exists as a chair conformer with C3v symmetry at ambient temperature. Additional conformers such as twist or boat were not detected although quantum chemic...
Conference Paper
Full-text available
Raman spectra of germacyclohexane in liquid and solid states were recorded and depolarization data obtained. Infrared absorption spectra of the vapor and liquid have been studied. The wavenumbers of the vibrational modes were derived in the harmonic and anharmonic approximation in B3LYP/ccpVTZ calculations. According to the calculations, germacyclo...
Article
Raman spectra of 1,1-difluoro-1-silacyclohexane as a liquid, and as a solid at 78 K were recorded and depolarization data obtained. The infrared spectra of the vapour, liquid and amorphous and crystalline solids have been studied. In the low temperature IR and Raman spectra eight and three bands, respectively, were shifted a few cm-1 when the sampl...
Article
Raman spectra of 1,1-difluoro-1-silacyclohexane as a liquid, and as a solid at 78 K were recorded and depolarization data obtained. The infrared spectra of the vapour, liquid and amorphous and crystalline solids have been studied. In the low temperature IR and Raman spectra eight and three bands, respectively, were shifted a few cm⁻¹ when the sampl...
Article
(Chemical Equation Presented) The structure of methylfluoroisocyanato silane (Me-SiHF-NCO) has been deduced by a combination of microwave (MW) spectra including data from 12,13C, 14,15N, and 28,29,30Si isotopomers, and ab initio calculations. The rotational constants (RC) for the most abundant isotopes are A = 6301.415(45), B = 1535.078(39), and C...
Article
Infrared spectra of gaseous, liquid and matrix isolated samples of newly synthesized 1,1-dimethyl-2-oxy-1-silacyclohexane were recorded. Raman spectra of 1,1-dimethyl-2-oxy-1-silacyclohexane in liquid and solid states were obtained in the temperature range from 170 to 340 K. Ab initio HF and DFT B3LYP calculations were performed in order to determi...
Article
The FT-microwave spectrum (6000–19,800 MHz) of cyclopropylcyanosilane, c-C3H5SiH2CN has been recorded and 773 transitions for the 28Si, 29Si, 30Si, 13C and 15N isotopomers have been assigned for cis and gauche conformers. Infrared spectra (3200–220 cm−1) of gas and Raman spectra (3200–40 cm−1) of the liquid have been recorded as well as the variabl...
Article
The infrared and Raman spectra of 1,1,3,3,5,5-hexafluoro-1,3,5-trisilacyclohexane (c-C3H6Si3F6) as a solid powder have been recorded. The vibrational spectra reveal that the crystalline compound exists as a chair conformer with C3v symmetry at ambient temperature. Additional conformers such as twist or boat were not detected although quantum chemic...
Article
A 1,1-disubstituted silacyclohexane, 1-chloro-1-methyl-1-silacyclohexane, C5H10SiClCH3, was synthesized and studied by infrared and Raman spectroscopy. The infrared spectra of the vapor and liquid were recorded at ambient temperature and the solid sample investigated at 78 K. Negligible spectral changes ocurred at 78 K compared with the fluid state...
Article
Variable temperature (−50 to −100 °C) Raman spectra (3500–136 cm−1) were recorded of ethynylcyclopentane, c-C5H9CCH in liquid xenon. The envelope-equatorial (Eq) conformer was determined more stable than envelope-axial (Ax) form with enthalpy difference of 94 ± 9 cm−1 (1.12 ± 0.11 kJ/mol) and 39 ± 2% Ax conformer present at ambient temperature. The...
Article
The FT-microwave spectrum of 1,1,3,3-tetrafluoro-1,3-disilacyclopentane (c-C3H6Si2F4) has been recorded and 339 transitions for 6 isotopologues have been assigned for the twist conformation. The ground state rotational constants were determined with values for the normal species: A = 2102.74026(68), B = 751.34319(32), C = 736.51478(31). Adjusted r0...
Article
spectra, structural parameters, vibrational assignments and theoretical calculations of 1,3-disilacyclopentane, Journal of Molecular Structure (2013), doi: http://dx.doi.org/10.1016/j.molstruc.2013.06.042 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early ve...
Article
FT-microwave, infrared spectra of gas and Raman spectra of liquid for cyclopropylfluorosilane, c-C3H5SiH2F have been recorded. 51 transitions for the 28Si, 29Si, and 30Si isotopomers have been assigned for the gauche conformer. Enthalpy differences in xenon solution by variable temperature infrared spectra between the more stable gauche and lesser...
Article
Raman spectra of of 1-methyl-1-silacyclohexane as a liquid were recorded at 293 K and depolarization data obtained. Additional Raman spectra were recorded at various temperatures between 293 and 143 K, and intensity changes with temperature of certain Raman bands were detected. A supercooled liquid appeared after slow cooling, but an amorphous phas...
Article
The microwave spectrum of cyclobutylisocyanate, c-C4H7NCO, has been investigated from 21,000 to 11,000 MHz and 11 transitions for the more stable equatorial-trans conformer were assigned. The rotational constants of the ground vibrational state have been determined and the molecule has been shown to be a near symmetric prolate rotor (К = −0.99). Th...
Article
The infrared spectra (3500–220 cm−1) in the gas phase of cyclobutylsilane, c-C4H7SiH3 has been recorded. Variable temperature (−65 to −100 °C) studies of the infrared spectra (3500–400 cm−1) dissolved in liquid xenon have been carried out. From these data, both the equatorial and axial conformers have been identified and their relative stability ob...
Article
The structures of CH$_{3}$SiHF-NCO, 1-X-silacyclopropane (X $=$ cyano, isocyanato), 1,1,3,3-tetrafluoro-1,3-disilacyclopentane and its hydrogen analogue (1,3-disilacyclopentane), and 1-isocyanato-silacyclohexane have been studied by chirped pulse FTMW spectroscopy in the 6-18 GHz band. Multiple conformers for some of the species were also detected:...
Article
The infrared spectra (3500-220cm(-1)) of cyclobutylgermane, c-C(4)H(7)GeH(3) have been recorded of the gas. Also variable temperature (-65 to -100°C) studies of the infrared spectra (3500-400cm(-1)) of the sample dissolved in liquid xenon were recorded and both the equatorial and axial conformers were identified. The enthalpy difference has been de...
Article
Chlorodifluoromethylsilane Chirped-pulse broadband microwave spectroscopy (CP-FTMW) structure Ab initio a b s t r a c t The rotational spectrum of methyl(difluoro)silyl chloride, CH 3 SiF 2 Cl, has been obtained using chirped-pulse Fourier transform microwave spectroscopy. The spectrum is complicated by hyperfine structure contributed by the chlori...
Article
Raman spectra of silacyclohexane as a liquid was recorded and depolarization data obtained. The infrared spectra of the vapour and liquid have been studied.The compound exists in the stable chair conformation, whereas a possible twist form should have more than 15 kJ mol−1 higher energies for silacyclohexane derived from numerous calculations. The...
Article
Ab initio calculations of the relative energies, optimized geometries and vibrational spectrum of the four conformers of n-pentane have been completed, and a normal coordinate calculation performed to establish the nature of the observed molecular vibrations. From the Raman spectrum of the annealed crystal, in which only aa conformer bands are obse...
Article
The structure of methyldifluoroisocyanato silane, MeF(2)SiNCO (2), has been studied by molecular rotational spectroscopy. The rotational spectrum has a complicated structure from (14)N nuclear quadrupole coupling and internal rotation of the methyl group. Cavity Fourier-transform microwave spectroscopy measurements were important for providing high...
Article
The infrared spectra of 1-chloro-1-silacyclohexane have been studied as a vapour and liquid at ambient temperature and as amorphous and annealed crystalline solids at 78 K. Various infrared bands present in the vapour and liquid states vanished in the crystalline state upon cooling. Raman spectra of the liquid were recorded at 293 K and polarizatio...
Article
The structures of CH_3SiF_2-NCO and CH_3SiF_2-Cl have been studied by molecular rotational spectroscopy in the 6.5-18 GHz band. The rotational spectrum was measured by cavity Fourier transform microwave (FTMW) and chirped-pulse FTMW spectroscopy. The experiment targeted the study of CH_3SiF_2-NCO, but CH_3SiF_2-Cl was also observed as an impurity....
Article
The infrared spectra of gaseous and solid N-bromo-hexafluoro-2-propanimine, (CF(3))(2)CNBr, have been obtained from 2000 to 50 cm(-1). The vibrational assignment for the normal modes is proposed based on infrared band contours, group frequencies and normal coordinate calculations utilizing C(s) symmetry. The structural parameters have been obtained...
Article
Raman spectra of 1-fluoro-1-silacyclohexane as a liquid were recorded at 293 K and polarization data obtained. Additional Raman spectra were recorded at various temperatures between 293 and 143 K, and intensity changes of certain bands with temperature were investigated. An apparently plastic phase was observed around 170 K, but no definite crystal...
Article
The microwave spectrum (6500–18 500 MHz) of 1-fluoro-1-silacyclopentane, c-C4H8SiHF has been recorded and 87 transitions for the 28Si, 29Si, 30Si, and 13C isotopomers have been assigned for a single conformer. Infrared spectra (3050-350 cm−1) of the gas and solid and Raman spectrum (3100-40 cm−1) of the liquid have also been recorded. The vibration...
Article
The Raman and infrared spectra (3500–50 cm−1) of the gas, liquid or solution, and solid were recorded of 2,2,3,3,3-pentafluoropropylamine (CF3CF2CH2NH2) and the ND2 isotopomer. Variable temperature (−55 to − 100 °C) studies of the infrared spectra (3600–400 cm−1) of samples dissolved in liquid xenon have been carried out. From these data, two of th...
Article
The FT-microwave spectrum of n-butylgermane, CH3CH2CH2CH2GeH3 has been investigated from 4000 to 18,000 MHz and the microwave spectra have been observed for all of the five naturally occurring germanium isotopologues for the anti–anti (aa) conformer. The dipole moment for the 74Ge containing species has been measured, giving a total dipole moment o...
Article
Raman spectra of cyclopropylmethyl dichlorosilane (c-C3H5)SiCl2CH3 as a liquid were recorded at 293K and polarization data were obtained. Additional Raman spectra were recorded at various temperatures between 293 and 163K, and intensity changes of certain bands with temperature were detected. No crystallization was ever obtained in the Raman cryost...
Article
Full-text available
Infrared and Raman spectra (3500-60 cm(-1)) of gas and/or liquid and solid 1-bromo-1-silacyclopentane (c-C4H8SiBrH) have been recorded and the vibrational data indicate the presence of a single conformer with no symmetry which is consistent with the twisted form. Ab initio calculations with a variety of basis sets up to MP2(full)/6-311+G(2df,2pd) p...
Article
Variable temperature (−55 to −100°C) studies of the infrared spectra (4000–400cm−1) of 2,2-difluoroethylamine, F2CHCH2NH2 dissolved in liquid xenon have been carried out. From these data three of the five possible conformers have been identified and their relative stabilities obtained. The enthalpy differences have been determined among the most st...
Article
The infrared spectrum (3200–400cm−1) of the gas and the Raman spectrum (3200–50cm−1) of liquid and solid 1,1-difluoro-1-silacyclopentane and 1,1-dichloro-1-silacyclopentane have been recorded. In all of these physical states only the twisted (C2) conformer was detected. The conformational energies have been calculated with the Moller–Plesset pertur...
Article
Infrared and Raman spectra (3500–60 cm−1) of gas and/or liquid and solid 1-chloro-1-silacyclopentane (c-C4H8SiClH) have been recorded and the vibrational data indicate the presence of a single conformer with no symmetry which is consistent with the twisted form. Ab initio calculations with a variety of basis sets up to MP2(full)/aug-cc-pVTZ predict...
Article
Infrared spectra (4000 to 400 cm(-1)) of the gas and variable temperature xenon solutions, and the Raman spectrum of the liquid have been recorded for cyclopropylisocyanate. The enthalpy difference has been determined to be 77 ± 8 cm(-1) (0.92 ± 0.10 kJ/mol) with the trans form more stable than the cis conformer with 59 ± 2% present at ambient temp...
Article
The infrared spectra (3200-30 cm(-1)) of ethyl bromogermane, CH3CH2GeH2Br, in the gaseous phase and of amorphous and annealed solid samples as well as the Raman spectrum (3200-100 cm(-1)) of the liquid have been recorded. Variable-temperature (-105 to -150 degreesC) studies of the infrared spectra of a sample dissolved in liquid krypton have been c...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
The microwave (MW) spectrum of HF2SiNCO (1) has been obtained and analyzed in the Ir representation for CS symmetry. The rotational constants (RC) are: A 7111.28104(179), B 1565.77581(49) and C 1347.52275(77) MHz; the centrifugal distortion constants are: ΔJ 2.661(11), ΔJK 455.44(25), δJ 0.4237(51), ϕK −54.96(29) kHz; the 14N nuclear quadrupole cou...
Article
The FT-microwave spectrum of germylcyclohexane, c-C(6)H(11)GeH(3), has been recorded, and more than 40 transitions for the (70)Ge, (72)Ge, and (74)Ge isotopomers (isotopologues) have been assigned for the chair-equatorial conformer. The heavy atom adjusted r(0) structural parameters have been determined [distances, C(gamma)-C(delta) = 1.533(3) A, C...
Article
Rotational spectra have been measured for five naturally occurring isotopologues of germanium in the gauche conformer of the cyclopropylmethylgermane molecule by Fourier-transform microwave spectroscopy. Internal rotation of the methyl group caused all rotational transitions to be doubled and analysis of these A and E states with an internal rotati...
Article
The infrared spectra of ethylmethylgermane (CH3CH2GeH2CH3) have been studied as a vapour in the 4000–400 and 500–100 cm−1 regions and as an amorphous solid at 78 K. Raman spectra of the sample as a liquid were recorded at 293 K and polarization data were obtained. Additional Raman spectra were recorded at various temperatures between 293 and 143 K,...
Article
Variable temperature (-55 to -100°C) studies of the infrared spectra (3500-400 cm(-1)) of fluorocyclobutane, c-C(4)H(7)F, dissolved in liquid xenon have been carried out as well as the infrared spectra of the gas. By utilizing eight pairs of conformers at 10 different temperatures, the enthalpy difference between the more stable equatorial conforme...
Article
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Article
The Raman (3200 to 10 cm−1) and IR spectra (3200 to 30 cm−1) of propionyl bromide, CH3CH2CBrO, of the gas and solid have been recorded. Additionally, the Raman spectrum of the liquid has been recorded with qualitative depolarization measurements. All of these data indicate that propionyl bromide exists as a mixture of two conformers in the fluid ph...
Article
Raman spectra of ethylmethyldichlorogermane (CH3CH2GeCl2CH3) as a liquid were recorded at 293 K and polarization data were obtained. Additional Raman spectra were recorded at various temperatures between 293 and 154 K, and intensity changes of certain bands with temperature were detected. The sample was also investigated as amorphous and crystallin...
Article
The microwave spectrum of allyldifluorosilane (H(2)C=CHCH(2)SiF(2)H) has been investigated for the first time in the 28-80 GHz spectral interval at a temperature of -30 degrees C. The spectrum of the ground vibrational state of one conformer characterized by an anticlinal orientation for the C=C-C-Si chain of atoms and a synclinal conformation for...
Article
The rotational spectrum for the normal isotopologue of difluorosilyl isocyanate, HF_2SiNCO, has been measured in the 5--15 GHz range using a 480 MHz bandwidth chirped-pulse Fourier-transform (CP-FTMW) microwave spectrometer and a Balle-Flygare resonant cavity FT-microwave spectrometer. Clearly resolved nuclear quadrupole hyperfine splittings arisin...
Article
A chirped-pulse Fourier-transform microwave (CP-FTMW) spectrometer based on the original Pate design has been constructed to allow analysis of any 480 MHz region in the 7 - 18 GHz range. A 1 μs chirped-pulse (0 - 240 MHz) from an arbitrary function generator is mixed with output from a microwave synthesizer and used to polarize a supersonic gas exp...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
The rotational spectra for three conformers of 3,3-difluoropentane have been measured using both a newly constructed narrow bandwidth chirped-pulse Fourier-transform microwave spectrometer and a Balle–Flygare resonant cavity Fourier-transform microwave spectrometer. The chirped-pulse instrument produces a microwave pulse spanning up to 480 MHz band...
Article
The infrared spectra (3100–40 cm−1) of gaseous and amorphous solid and Raman spectra (3200–20 cm−1) of the liquid at various temperatures for methylgermylcyclopropane, c-C3H5GeH2CH3, have been obtained. Additionally, variable temperature (−55 to −100 °C) studies of the infrared spectra of the sample dissolved in xenon have been recorded. From these...
Article
The far-IR spectrum has been recorded from 50 to 360 cm−1 at a resolution of 0.10 cm−1 for acetyl cyanide, CH3C(O)CN. The fundamental methyl torsion is observed at 126.06 cm−1 from which a periodic barrier to internal rotation is calculated to be 400 cm−1 (1144 cal mol−1). Utilizing previously reported rotational constants for eight isotopic specie...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
The Raman spectra (3500–50 cm−1) of the liquid and solid methylcyclohexane and the infrared spectra of the gas and solid methylcyclohexane have been recorded. The Raman band at 754 cm−1 in the liquid has been confidently assigned to the less stable axial conformer and its intensity was recorded as a function of temperature from 25 to −95 °C. By the...
Article
Infrared spectra of 1,2-bis(trifluorosilyl)ethane (SiF3CH2CH2SiF3) were obtained in the vapour and liquid phases, in argon matrices and in the solid phase. Raman spectra of the compound as a liquid were recorded at various temperatures between 293 and 270 K and spectra of an apparently crystalline solid were observed. The spectra revealed the exist...
Article
The Raman (3200-30 cm−1) and/or infrared spectra (3500 to 400 cm−1) of gaseous, liquid and solid dimethylsilylisocyanate, (CH3)2 Si(H)NCO, have been recorded. The MP2(full) calculations, employing a variety of basis sets with and without diffusion functions, have been used to predict the structural parameters, conformational stability, vibrational...
Article
The infrared spectra (3200-50 cm(-1)) of the gas and solid and the Raman spectrum (3200-30 cm(-1)) of liquid and solid fluorocyclopentane, c-C5H9F, have been recorded. Additionally the infrared spectra (3200-400 cm(-1)) of liquid xenon solutions have been recorded at -65 and -95 degrees C. In all of the physical states, only the twisted C(1) confor...
Article
The infrared spectra (4,000–30 cm−1) of the gas and solid and the Raman spectrum of liquid 2,2-difluoroethanol as well as variable temperature infrared spectra of krypton/xenon solutions have been recorded. From all these data, two (Gg and Tg) out of the five possible stable conformers have been confidently identified. The order of the stabilities...
Article
Rotational spectra for 3 silicon isotopologues (28Si, 29Si, 30Si) of cyclopropylmethylsilane (c-C3H5SiH2CH3) have been observed in natural abundance using Fourier-transform microwave spectroscopy, and the dipole moment of the most abundant (28Si) isotopologue has been determined using the Stark effect. The observed rotational constants (A = 8800.59...
Article
Rotational spectra for the five naturally occurring germanium isotopologues of the anti-anti conformer of n-butylgermane have been measured using a Fourier-transform microwave spectrometer operating in the 4-18 GHz range. This conformer, determined by ab initio calculations at the MP2/6-311++G(2d,2p) level to be the most stable of five possible con...
Article
The rotational spectrum of diethylsilane has been assigned using broadband chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy. Previously, Fourier-transform microwave rotational spectra were observed using a Balle-Flygare type instrument for the ^{28}Si isotopologues of the gauche-gauche, trans-gauche, and trans-trans conformers. In t...
Article
Variable temperature (−55 to −100 °C) studies of the infrared spectra (3500–400 cm−1) of cyanocyclobutane, c-C4H7CN, dissolved in liquid xenon have been carried out. The infrared spectra of the gas and solid, as well as, the Raman spectrum of the liquid have also been recorded. By utilizing eight pairs of conformers at 10 different temperatures, th...
Article
The infrared spectra (3100–40 cm−1) of gaseous and solid and Raman spectra (3200–20 cm−1) of liquid and solid c-C3H5SiH2CH3, methylsilylcyclopropane, have been recorded. Additionally, variable temperature (−55 to −100 °C) studies of the infrared spectra of the sample dissolved in xenon have been recorded. From these spectral data, two conformers ha...
Article
Variable temperature (−55 to −145 °C) studies of the infrared spectra (4000–50 cm−1) of allyl alcohol (3-hydroxypropene), CH2CHCH2OH, dissolved in liquid krypton and/or liquid xenon have been carried out. The infrared spectra of the gas and solid have also been recorded. From these data four of the five possible stable conformers have been identifi...
Article
The rotational spectra belonging to the (28)Si isotopologue for three conformers of diethyldifluorosilane (Et(2)SiF(2)) and three conformers of diethylsilane (Et(2)SiH(2)) have been measured between 4 and 17 GHz by using pulsed-jet Fourier-transform microwave spectroscopy. Rotational spectra for the gauche-gauche, trans-trans, and trans-gauche conf...
Article
The infrared (3200–400 cm−1) and Raman spectra (3500–40 cm−1) of gas/or liquid and solid chloromethylsilane, ClCH2SiH3, dichloromethylsilane, Cl2CHSiH3, chloromethyltrifluorosilane, ClCH2SiF3, and dichloromethyltrifluorosilane, Cl2CHSiF3, have been recorded and complete vibrational assignments are given for all four molecules. To support the spectr...
Article
The Raman (3300-10 cm(-1)) and infrared (3300-40 cm(-1)) spectra of gaseous and solid vinyl silyl fluoride, CH(2)=CHSiH(2)F, have been recorded. Raman spectrum of the liquid has also been recorded and depolarization values obtained. Variable-temperature studies of the infrared spectra of the sample dissolved in liquid krypton (-110 to -150 degrees...
Article
The infrared spectra (3600–100 cm−1) of gaseous and solid cyclobutylamine, c-C4H7NH2 have been recorded, as well as, the infrared (3600–60 cm−1) spectra in xenon or krypton solutions at variable temperatures. From the latter studies, the enthalpy differences have been determined to be 225 ± 26 cm−1 (2.69 ± 0.31 kJ/mol) between the most stable equat...
Article
Variable temperature (−55 to −105 °C) studies of the infrared spectra (4000–400 cm−1) of chlorocyclohexane (c-C6H11Cl) dissolved in liquefied xenon have been carried out. The infrared spectra of the gas and solid have also been recorded from 4000–100 cm−1. By analyzing six conformer pairs in the xenon solution, a standard enthalpy difference of 132...
Article
Variable temperature (−55 to −100°C) studies of the infrared spectra (4,000–400cm−1) of chlorocyclobutane, c-C4H7Cl, dissolved in liquid xenon have been carried out. The infrared spectrum (4,000–100cm–1) of the gas has also been recorded. For this puckered ring molecule the enthalpy difference between the more stable equatorial conformer and the ax...