Self-assembly of 3-substituted xanthines in solid phase and at solid-liquid interface

Bényei, Attila; Szolomájer, János [Szolomájer, János (Nukleinsavak), szerző] Orvosi Vegytani Intézet (SZTE / ÁOK); Paragi, Gábor [Paragi, Gábor (molekulafizika, m...), szerző] MTA-SZTE Szupramolekuláris és Nanoszerkezetű An... (SZTE / ÁOK / OVI); Fonseca Guerra, Célia; Bickelhaupt, F Matthias; Kupihár, Zoltán [Kupihár, Zoltán (Szilárd fázisú sz...), szerző] Orvosi Vegytani Intézet (SZTE / ÁOK); Batta, Gyula [Batta, Gyula (NMR spektroszkópia), szerző]; Ciesielski, Artur; Haar, Sebastien; Samori, Paolo; Spada, Gian Piero; Kovács, Lajos [Kovács, Lajos (Nukleinsavak), szerző] Orvosi Vegytani Intézet (SZTE / ÁOK)

Angol nyelvű Tudományos Absztrakt / Kivonat (Egyéb konferenciaközlemény)
    The self-assembly of guanine derivatives into tetrads and their stacks (quadruplex motifs) has long been known.1 In our previous studies, we have demonstrated that 3-methylxanthine with similar hydrogen bonding capacity forms tetrads and octads in gas and liquid phases in the presence of cations.2 As an extension to our findings, we have investigated the structure of 3-methyl- and 3-octadecylxanthines in solid state and at solid-liquid interface. The X-ray structure of 3-methylxanthine shows monomers that are bound by four hydrogen bonds to neighboring molecules resulting overall in a planar arrangement.3 A new X-ray study of a single crystal of 3-methylxanthine revealed, beyond the reported structure, also the presence of a new polymorph with monomers that are bound by only two hydrogen bonds (N1—H1•••N9 and N7—H7•••O2) to the other molecules in a nearly perpendicular arrangement. The need for exploring ordered architectures at the molecular scale has made scanning tunneling microscopy (STM) a widely employed yet extremely powerful tool to investigate supramolecular materials at interfaces with sub-molecular resolution. In the past we have shown the metal-templated reversible assembly/reassembly process of 9-octadecylguanine into highly ordered quartets and ribbons.4 Herein, we present a submolecular-resolution STM visualization of the self-assembly of two alkylated xanthine derivatives, i.e. 3-octadecyl- and 3-methylxanthine at the solid-liquid interface. In order to gain insight into the experimental self-assembly behavior of xanthines forming supramolecular H-bonded ribbons, we have performed computational modelling using high-level quantum chemical methods as well.
    Hivatkozás stílusok: IEEEACMAPAChicagoHarvardCSL
    2019-09-17 04:28