01592nas a2200181   4500008004100000245010800041210006900149260000800218300001600226490000700242520091900249100002501168700002301193700001901216700002501235700002601260856012401286       2011                        eng d00aAlkynyl and phosphonyl substituted nucleobases: a case of thermally induced conformational polymorphism0 aAlkynyl and phosphonyl substituted nucleobases a case of thermal  cAPR  a2302–23100 v113 a<p>Substituted nucleobases with alkynyl and phosphonyl groups were investigated in the context of supramolecular interactions and possible use toward synthesis of nucleoside phosphonic acids (NPAs). The adeninyl compound (adeninyl-N-9)-CH2CH2CH2CH2C≡CH exhibits conformational polymorphism as revealed by X-ray structures determined at 200 and 298 K. Interestingly, in the compound (adeninyl-N-9)-(CH2)15CH3, the long aliphatic carbon chain does not show disorder. A rather unusual bending of alkyl chain, likely due to C–H···O interactions, is observed in the case of the thymine compound (thyminyl)-CH2CH2CH2C≡CH that possesses a terminal alkyne group. The powerful hydrogen bond acceptor property of the phosphoryl oxygen (P═O) does not perturb (unless assisted by other hydrogen bonding partners) the homo base-pairing in the structures of most of the phosphonyl substituted nucleobases studied.</p>1 aSwamy, K., C. Kumara1 aAllu, Srinivasarao1 aSrinivas, Venu1 aBalaraman, Ekambaram1 aKumar, K., V. P. Pava  uhttps://library.ncl.res.in/content/alkynyl-and-phosphonyl-substituted-nucleobases-case-thermally-induced-conformational