Antti Kivinen

Fluoroalcohols—XXV. Matrix i.r. spectrum and normal coordinate analysis of 2-fluoroethanol

Abstract The i.r. spectra of 2-fluoroethanol and its OD-deuterated analogue have been recorded in argon, nitrogen and mixed argon-nitrogen matrices. A vibrational assignment, supported by normal coordinate calculations, is presented. A conformational change from gauche to trans isomer occurs in the argon matrix due to the i.r. beam

Fluoroalcohols—XX: Infrared and Raman spectra of hexafluoro-2-propanol and its deuterated analogues

Abstract The infrared spectra of hexafluoro-2-propanol and its three deuterated analogues in the gaseous, liquid and solid states and the Raman spectra of the compounds in the liquid state were recorded. Assignments of the vibration bands are made, and especially the vibrations related to the OH and OD groups are discussed. Two bands due to C 1 and C 3 , conformers are found in the OH stretching region; several pairs of sum and difference bands related to the lower-frequency ( C 3 ) band are seen in the vapour spectra. Association “fingers” occur in the spectra of the condensed phases between 2600 and 2900 cm −1 . Two association bands due to in-plane OH bending were found in the spectra of (CF 3 ) 2 CHOH. No association band due to OH torsion was found with certainty in the liquid phase spectra of any of the compounds.

Fluoroalcohols—XXI. Infrared, matrix infrared and Raman spectra of 1,1,1-trifluoro-2-propanol and its three deuterated analogues

Abstract The i.r. spectra of CF 3 CHOHCH 3 , CF 3 CHODCH 3 , CF 3 CDOHCH 3 and CF 3 CDODCH 3 have been recorded for gaseous, liquid and solid states, and in argon and nitrogen matrices (the spectrum of CF 3 CHOHCH 3 in a krypton matrix as well). Raman spectra of the compounds in the liquid state were also recorded. Vibrational assignments are made, and discussed with particular reference to OH and OD groups. The influence of association on the vibration bands was studied in detail by the matrix isolation technique. Only one conformer was found for the alcohols in question. The monomeric νOH band is a singlet for spectra in argon and krypton matrices; for spectra in nitrogen matrices it is a doublet. Two monomeric OD bending bands were found for the OD deuterated alcohols between 800 and 1000 cm −1 . CF 3 CHOHCH 3 seems to have two polymeric δOH bands. The monomeric OH and OD torsion bands are very intense and narrow in argon matrices (τOH band at about 300 cm −1 , τOD band at about 250 cm −1 ). In nitrogen matrices these are broader, less intense, and occur at considerably higher frequencies (τOH at about 380 cm −1 ). The OH torsion bands of a few other fluoroalcohols in argon were also studied. Some data are reported for trifluoroacetone in an argon matrix.

Infrared, matrix i.r. and Raman spectra of hexachloro-2-propanol

Abstract The i.r. spectra of the alcohol CCl 3 CHOHCCl 3 have been recorded in the gaseous and solid phases, in argon, krypton, nitrogen and carbon monoxide matrices and in various solutions. Raman spectra of the solid alcohol and its solutions were also recorded. Assignments of the vibration bands are made on the basis of an approximate normal coordinate calculation. The alcohol exhibits two conformers in the vapour phase and in solutions; the relative stabilities of these conformers are discussed. When the temperature is varied, a reversible interconversion between two species of the alcohol occurs in nitrogen matrices. The self-association tendency of the alcohol is very weak.

Reversible temperature effects in the matrix IR spectra of halogenated 2-propanols

Abstract The reversible temperature effects in the IR spectra of CCl 3 CHOHCCl 3 and of a few other halogenated 2-propanols in N 2 , CO and mixed N 2 -Ar matrices have been studied. Alcohol-nitrogen complexes are formed reversibly and irreversibly in matrices containing nitrogen.

Polarized infrared spectra: Part 2. Fundamental vibrations of tetrachloroethylene, some mono-, di- and trihalogenated methanes and carbon disulfide

Abstract Polarized IR transmission spectra, using the stretched film method, have been measured for tetrachloroethylene, iodomethane, dibromomethane, dichloromethane, bromochloromethane, chloroform, bromoform and iodoform, and for some of their deuterated analogues, as well as carbon disulphide. All of these molecules are asymmetric enough to be oriented by the polymer stretching method and fundamental vibrations are assigned according to their symmetry species. The orientation of the molecules studied can be described as being either rod-like or disc-like.

Polarized infrared spectra: Part 1. Stretched polymer method. Fundamental vibrations of some mono- and di-substituted benzenes

Abstract Polarized IR spectra of five benzene derivatives (four of C2v symmetry and one of D2h symmetry) have been recorded using the stretched polymer method. It has been found that the values of the dichroic ratios depend systematically on the symmetry class of the vibration in question. The IR-active vibrations can thus be unambiguously divided into the correct symmetry classes. The general validity of the method, as well as its value for vibrational analysis, is discussed.

Polarized infrared spectra: Part 3. The use of perdeuterated polyethylene film. The spectrum of nitrobenzene

Abstract A simple laboratory method for the preparation of perdeuterated polyethylene sheets from powder is described. These sheets have been used as matrix material to obtain polarized IR spectra by the stretched polymer method. The properties of the perdeuterated film are compared with those of ordinary polyethylene film. The perdeuterated film can be stretched equally well as the undeuterated analogue. The orientation of the molecules dissolved in the stretched perdeuterated sheets is somewhat better than in undeuterated sheets. The concentration seems to affect, to some extent, the magnitude of the orientation of dissolved molecules. Both undeuterated and perdeuterated polyethylene films have been used to study the polarized IR spectra of nitrobenzene- d 0 and nitrobenzene- d 5 . Some disputed points in the assignments are discussed.

Fluoroalcohol—XXII. Infrared, matrix infrared and Raman spectra and normal coordinate calculations for hexafluoro-2,2-propanediol and its deuterated analogues

Abstract Infrared spectra of the geminal diol (CF3)2C(OH)2 (hexafluoroacetone hydrate) and of its deuterated analogue (CF3)2C(OD)2 were recorded for the gaseous and liquid states and for argon and nitrogen matrices. Some i.r. data were obtained also for CF3(HO)C(OD)CF3 in argon. Raman spectra were recorded for hexafluoroacetone trihydrate and trideuterate. Vibrational assignments are made, and discussed with particular reference to OH and OD groups. Normal coordinate calculations were carried out to aid in the assignments of bands. The calculations indicated that the CF stretchings and bendings are strongly coupled with the skeletal modes, and thus the group frequency approximation is not good in the case of the compounds studied. This is true especially in the case of the CO bendings. The influence of association on the vibration bands was studied in detail by the matrix isolation technique. Monomeric hexafluoroacetone hydrate occurs obviously in the form of one conformer only, which is of C2v symmetry. The frequencies of the two νOH (νOD) fundamentals seems to be approximately equal. For the alcohol dimer we propose an eight-membered cyclic structure. The liquid monohydrate seems to consist mainly of dimers.

Fluoroalcohols—XXVI. Vibrational spectra of pentafluoroprop-1-en-2-ol (enolic pentafluoroacetone)

Abstract Infrared spectra of pentafluoroprop-1-en-2-ol, the enol form of pentafluoroacetone, were recorded in the gaseous state and in argon and nitrogen matrices. Two different species, which interconverted upon warming, were found in the matrices. The Raman spectrum of the liquid alcohol was recorded. An approximate vibrational assignment is given.