Solvent induced shifts in the UV spectrum of amides
Nuwan De Silva1, Soohaeng Y Willow, Mark S Gordon
1Department of Chemistry, Iowa State University , Ames, Iowa 50011, United States.
Abstract:
Solvent effects on the electronic spectra of formamide and trans-N-methylacetamide are studied using four different levels of theory: singly excited configuration interaction (CIS), equations of motion coupled-cluster theory with singles and doubles (EOM-CCSD), completely renormalized coupled-cluster theory with singles and doubles with perturbative triple excitations (CR-EOM-CCSD(T)), and time-dependent density functional theory (TDDFT), employing small clusters of water molecules. The simulated electronic spectrum is obtained via molecular dynamics simulations with 100 waters modeled with the effective fragment potential method and exhibits a blue-shift and red-shift, respectively, for the n → π* and πnb → π* vertical excitation energies, in good agreement with the experimental electronic spectra of amides.
Related Concept Videos
NMR Spectroscopy Of Amines
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
IR and UV–Vis Spectroscopy of Aldehydes and Ketones
Inductive Effects on Chemical Shift: Overview
Chemical Shift: Internal References and Solvent Effects
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
NMR Spectroscopy: Chemical Shift Overview
For instance, the proton...


