TY - JOUR
T1 - Observed and predicted hydrogen bond motifs in crystal structures of hydantoins, dihydrouracils and uracils
AU - Cruz-Cabeza, Aurora J.
AU - Schwalbe, Carl H.
PY - 2012/6/1
Y1 - 2012/6/1
N2 - A survey of crystal structures containing hydantoin, dihydrouracil and uracil derivatives in the Cambridge Structural Database revealed four main types of hydrogen bond motifs when derivatives with extra substituents able to interfere with the main motif are excluded. All these molecules contain two hydrogen bond donors and two hydrogen bond acceptors in the sequence of NH, C=O, NH, and C=O groups within a 5-membered ring (hydantoin) and two 6-membered rings (dihydrouracil and uracil). In all cases, both ring NH groups act as donors in the main hydrogen bond motif but there is an excess of hydrogen bond acceptors (two C=O able to accept twice each) and so two possibilities are found: (i) each carbonyl O atom may accept one hydrogen bond or (ii) one carbonyl O atom may accept two hydrogen bonds while the other does not participate in the hydrogen bonding. We observed different preferences in the type and symmetry of the motifs adopted by the different derivatives, and a good agreement is found between motifs observed experimentally and those predicted using computational methods. We identified certain molecular factors such as chirality, substituent size and the possibility of C-H⋯O interactions as important factors influencing the motif observation.
AB - A survey of crystal structures containing hydantoin, dihydrouracil and uracil derivatives in the Cambridge Structural Database revealed four main types of hydrogen bond motifs when derivatives with extra substituents able to interfere with the main motif are excluded. All these molecules contain two hydrogen bond donors and two hydrogen bond acceptors in the sequence of NH, C=O, NH, and C=O groups within a 5-membered ring (hydantoin) and two 6-membered rings (dihydrouracil and uracil). In all cases, both ring NH groups act as donors in the main hydrogen bond motif but there is an excess of hydrogen bond acceptors (two C=O able to accept twice each) and so two possibilities are found: (i) each carbonyl O atom may accept one hydrogen bond or (ii) one carbonyl O atom may accept two hydrogen bonds while the other does not participate in the hydrogen bonding. We observed different preferences in the type and symmetry of the motifs adopted by the different derivatives, and a good agreement is found between motifs observed experimentally and those predicted using computational methods. We identified certain molecular factors such as chirality, substituent size and the possibility of C-H⋯O interactions as important factors influencing the motif observation.
UR - http://www.scopus.com/inward/record.url?scp=84865618895&partnerID=8YFLogxK
UR - http://pubs.rsc.org/en/Content/ArticleLanding/2012/NJ/c2nj21060f#!divAbstract
U2 - 10.1039/c2nj21060f
DO - 10.1039/c2nj21060f
M3 - Article
AN - SCOPUS:84865618895
SN - 1369-9261
VL - 36
SP - 1347
EP - 1354
JO - New Journal of Chemistry
JF - New Journal of Chemistry
IS - 6
ER -