Microhydrated clusters of a pharmaceutical drug: infrared spectra and structures of amantadineH⁺(H₂O)_n

Abstract

Solvation of pharmaceutical drugs has an important effect on their structure and function. Analysis of infrared photodissociation spectra of amantadineH+(H2O)n=1-4 clusters in the sensitive OH, NH, and CH stretch range...

Microhydration of the adamantane cation: intracluster proton transfer to solvent in [Ad(H2O)n=1–5]+ for n ≥ 3

“…As shown for Ad + (H 2 O) and related clusters such as amantadine + (H 2 O) n and amantadineH + (H 2 O) n , this computational level reproduces the experimental IR spectra and binding energies with satisfactory accuracy and represents an efficient compromise between accuracy and calculation time. 29,30,59 All structures shown in this work are confirmed as minima by harmonic frequency analysis. Relative energies (E e ) and binding energies (D e ) are corrected for harmonic zero-point vibrational energies to derive E 0 and D 0 values, respectively.…”

“…87 These studies will extend our previous work on microhydrated (protonated) amantadine clusters, in which H 2 O ligands bind to the less acidic NH 2 + (NH 3 + ) groups via NHÁ Á ÁO H-bonds without exhibiting ICPT. 29,59 Further directions include variations of the solvent molecules (e.g., methanol and acetonitrile) and probing the ICPT by electronic spectroscopy. 86,88,89…”