Vibrational spectroscopy investigation using density functional theory on 7‐chloro‐3‐methyl‐2H‐1,2,4‐ benzothiadiazine 1,1‐dioxide

Abstract

The solid phase Fourier transform infrared (FTIR) and Fourier transform (FT) Raman spectral analysis of 7-chloro-3-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide (diazoxide), an antihypertensive agent was carried out along with density functional computations. The optimized geometry, wavenumber and intensity of the vibrational bands of diazoxide were obtained by DFT-B3LYP level of theory with complete relaxation in the potential energy surface using 6-31G(d,p) basis set. A complete vibrational assignment aided by the theoretical harmonic frequency analysis has been proposed. The harmonic vibrational wavenumbers calculated have been compared with experimental FTIR and FT Raman spectra. The observed and the calculated wavenumbers are found to be in good agreement. The experimental spectra coincide satisfactorily with those of calculated spectra.

Investigation of Tautomeric Structures of 6-Aza-2-Thiouracil-5-Carboxylic Acid Using Vibrational Spectroscopy Along With DFT Theoretical Method

“…CN stretching vibrations of the title molecule were observed at 1270, 1164 cm -1 in the FT-IR, at 1270 and 1176 cm -1 in the Raman spectrum and calculated as 1247 and 1182 cm -1 , respectively. These vibration wavenumbers are in agreement with the literature [37]. CN stretching modes and their TED values are collected in Table 3.…”

Vibrational and Molecular Structural Investigations of Pioglitazone Combined Study of Experimental and Quantum Chemical Calculations (Density Functional Theory)

“…From the literature survey, the bands appeared at 1305 cm -1 in FTIR and 1307 cm -1 in FT-Raman spectra of 7-choloro-3-methyl-2H-1,2,4-benzothiadiazine 1, 1-dioxide assigned to C-N stretching vibrations by Seshadri etal. [27].The C-N stretching vibrations are observed at 1375 cm -1 by Krishnakumar [28]. In this present investigation, the bands appeared at 1037,1147,and 1175 cm -1 in FT-IR and 1039,1150 and 1207 cm -1 in FT-Raman have been assigned to C-N stretching vibrations.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part IV

“…Anyone interested in the exact methodology used is invited to view the abstract of the paper at the Journal website or to download and read the paper in its entirety. The molecules for which vibrational analysis has been carried out through the standard methods of quantum chemistry are: 4‐chloro‐ and 4‐bromophenylboronic acid,276 4‐( N , N ‐dimethylamino)‐ N ‐methyl‐4′‐toluene sulfonate,277 C 7 H 15 CONH 2 ‐ valpromide,278 L ‐arginine nitrate hemihydrate,279 Azure A chloride, 3‐amino‐7‐(dimethylamino) phenothiazin‐5‐ium chloride,280 8‐( n ‐butylaminophenylmethyliden)‐1,2,3,4,5,6,7‐heptathiocane which contains a CS7 ring,281 N ‐acetyl‐ L ‐Asp and N ‐acetyl‐ L ‐Glu in the solid state,282 N ‐acetyl‐ L ‐Asp‐ L ‐Glu in the solid state,283 7‐chloro‐3‐methyl‐2 H ‐1,2,4‐benzothiadiazine 1,1‐dioxide,284 strontium tartrate (C 4 H 4 O 6 Sr),285 flavonoid derivatives baicalein and naringenin,2863‐{[(4‐fluorophenyl)methylene]amino}‐2‐phenylquinazolin‐4(3 H )‐one,287 1‐benzyl‐1 H ‐imidazole,288 hydrated platinum(II), palladium(II) and cis ‐diammineplatinum(II) ions in acidic solution,289 ibuprofen‐cyclodextrin inclusion complexes,290 the anticancer drug combretastatin‐A2,291 the grossular garnet Ca 3 Al 2 Si 3 O 12 ,292 2‐fluoro‐6‐nitrotoluene,293 (CH 3 ) 3 GeBr,294 benzoic acid and 3,5‐dichloro salicylic acid,295 PCCMB 2,5 dimethyl‐1‐phenylpyrazolium‐3‐carboxylate and its isomer the CCMB 1,3‐dimethyl‐2‐phenylpyrazolium‐4 carboxylate,296 the nonpeptide antagonist irbesartan,297 3‐{[(2‐hydroxyphenyl)methylene]amino}‐2‐phenylquinazolin‐4(3 H )‐one,298 4‐chloro‐2‐(4‐bromophenylcarbamoyl)phenyl acetate,299 1,4,5‐triazanaphthalene,300 Martius yellow sodium salt monohydrate,301 1,3‐dibromo‐2,4,5,6‐tetrafluorobenzene and 1,2,3,4,5‐pentafluorobenzene,302 4‐hydroxy‐3[1‐(4‐nitrophenyl)‐3‐oxobutyl]‐2 H ‐1‐benzopyran‐2‐one, acenocoumarol sodium salt,303 N ‐(2′‐furyl)imidazole,304 N ‐hydroxyphthalimide,305 3,3,7,7‐tetrakis(difluoramino)octahydro 1,5‐dinitro‐1,5‐diazocine,306 p ‐bromonitrobenzene,307 4‐chloro‐2‐(3‐chlorophenylcarbamoyl)phenyl acetate,308 alkylamides of thiocyanoacetic acid,309 1,2‐bis(trifluorosilyl)ethane (SiF3CH2CH2SiF3),310 organomolybdenum dithiolene complexes Cp2Mo(dmit),311 methyl trifluoroacetate (CF3C(O)OCH3),312 nitrofurantoin polymorphs,313 methylcyclohexane,314 ethyl‐3‐(3, 4‐dihydroxyphenyl)‐2‐propenoate,315 anilinium sulfate,316 valpromide and some derivatives with antiepileptic activity,…”