Vibrational spectroscopy and DFT calculations of di‐amino acid peptides: α‐ and β‐N‐acetyl‐L‐Asp‐L‐Glu in the solid state

Abstract

Experimental vibrational spectroscopic studies and density functional theory (DFT) calculations of the di-amino acid peptide derivatives α-and β-N-acetyl-L-Asp-L-Glu have been undertaken. Raman and infrared spectra have been recorded for samples in the solid state. DFT simulations were conducted using the B3-LYP correlation functional and the cc-pVDZ basis set to determine energy minimized/geometry optimized structures (based on a single isolated molecule in the gaseous state). Normal coordinate calculations have provided vibrational assignments for fundamental modes, including their potential energy distributions. Significant differences are observed between α-and β-N-acetyl-L-Asp-L-Glu both in the computed structures and in the vibrational spectra. The combination of experimental and calculated spectra provide an insight into the structural and vibrational spectroscopic properties of di-amino acid peptide derivatives.

Seven 3-methylidene-1H-indol-2(3H)-ones related to the multiple-receptor tyrosine kinase inhibitor sunitinib

“…Our investigation of compounds (2)-(4) by Raman and FT-IR spectroscopy (Spencer et al, 2010), supported by theoretical calculations (Kausar et al, 2009;Bell et al, 2007), has been facilitated by structure determinations from single-crystal X-ray diffraction analysis, reported here. The molecules selected for this study can be subdivided into several categories:…”

“…This offers the potential for synthesizing oxindoles with extended molecular architectures and biological properties (Spencer et al, 2009) and will be of continuing invaluable assistance to theoretical calculations (Kausar et al, 2009). …”

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,…”