PMID- 32490447
OWN - NLM
STAT- MEDLINE
DCOM- 20201123
LR  - 20201123
IS  - 1463-9084 (Electronic)
IS  - 1463-9076 (Linking)
VI  - 22
IP  - 23
DP  - 2020 Jun 21
TI  - Microhydration of protonated biomolecular building blocks: protonated pyrimidine.
PG  - 13092-13107
LID - 10.1039/d0cp02110e [doi]
AB  - Protonation and hydration of biomolecules govern their structure, conformation, 
      and function. Herein, we explore the microhydration structure in mass-selected 
      protonated pyrimidine-water clusters (H(+)Pym-W(n), n = 1-4) by a combination of 
      infrared photodissociation spectroscopy (IRPD) between 2450 and 3900 cm(-1) and 
      density functional theory (DFT) calculations at the dispersion-corrected 
      B3LYP-D3/aug-cc-pVTZ level. We further present the IR spectrum of H(+)Pym-N(2) to 
      evaluate the effect of solvent polarity on the intrinsic molecular parameters of 
      H(+)Pym. Our combined spectroscopic and computational approach unequivocally 
      shows that protonation of Pym occurs at one of the two equivalent basic ring N 
      atoms and that the ligands in H(+)Pym-L (L = N(2) or W) preferentially form 
      linear H-bonds to the resulting acidic NH group. Successive addition of water 
      ligands results in the formation of a H-bonded solvent network which increasingly 
      weakens the NH group. Despite substantial activation of the N-H bond upon 
      microhydration, no intracluster proton transfer occurs up to n = 4 because of the 
      balance of relative proton affinities of Pym and W(n) and the involved solvation 
      energies. Comparison to neutral Pym-W(n) clusters reveals the drastic effects of 
      protonation on microhydration with respect to both structure and interaction 
      strength.
FAU - Chatterjee, Kuntal
AU  - Chatterjee K
AD  - Institut fur Optik und Atomare Physik, TU Berlin, Hardenbergstr. 36, 10623 
      Berlin, Germany. dopfer@physik.tu-berlin.de.
FAU - Dopfer, Otto
AU  - Dopfer O
LA  - eng
PT  - Journal Article
DEP - 20200603
PL  - England
TA  - Phys Chem Chem Phys
JT  - Physical chemistry chemical physics : PCCP
JID - 100888160
RN  - 0 (Ligands)
RN  - 0 (Protons)
RN  - 0 (Pyrimidines)
RN  - 059QF0KO0R (Water)
RN  - K8CXK5Q32L (pyrimidine)
RN  - N762921K75 (Nitrogen)
SB  - IM
MH  - Density Functional Theory
MH  - Ligands
MH  - Nitrogen/chemistry
MH  - Protons
MH  - Pyrimidines/*chemistry
MH  - Spectrophotometry, Infrared
MH  - Water/chemistry
EDAT- 2020/06/04 06:00
MHDA- 2020/11/24 06:00
CRDT- 2020/06/04 06:00
PHST- 2020/06/04 06:00 [pubmed]
PHST- 2020/11/24 06:00 [medline]
PHST- 2020/06/04 06:00 [entrez]
AID - 10.1039/d0cp02110e [doi]
PST - ppublish
SO  - Phys Chem Chem Phys. 2020 Jun 21;22(23):13092-13107. doi: 10.1039/d0cp02110e. 
      Epub 2020 Jun 3.