Structural Arrangement of 4-[4-(Dimethylamino)phenylazo]pyridine Push-Pull Molecules in Acidic Layered Hosts Solved by Experimental and Calculation Methods

KNOTEK, PETR; SVOBODA, JAN; POSPÍ?IL, MIROSLAV; MELÁNOVÁ, KLÁRA; BURE?, FILIP; ZIMA, VÍT?ZSLAV; GAMBA, MARTINA; MIKLÍK, DAVID; BENE?, LUDVÍK; KOVÁ?, PETR

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY

WILEY-V C H VERLAG GMBH

Año: 2017 vol. 2017 p. 115 - 123

1434-1948

4-[4-(N,N-dimethylamino)phenylazo]pyridine(further denoted as G) representing a type of pushpull molecules can beintercalated into α-and γ-modifications of zirconium phosphate (a-ZrP and g-ZrP) and into zirconium 4-sulfophenylphosphonate (ZrSPP).The obtained intercalates form  singlephases with interlayer distances of 12.75, 16.31 and 24.11 Å for a-ZrP·0.2G·1.5H2O, g-ZrP·0.2G·1.5H2Oand ZrSPP·0.5G·1H2O, respectively. The increase of theinterlayer distance on intercalation suggests that the molecules of theintercalated guest lie parallel to the host layers.All intercalates were further characterized byinfrared and UV-Vis spectroscopies.The arrangement of the guests in the interlayer spacewas obtained by molecular simulations methods. The calculations were performedseparately for protonated and unprotonated forms of the guest in the models ofhydrated and dehydrated a-ZrP and γ-ZrP intercalates. In the case of the a-ZrP intercalate, the presence of interlayerwater stabilizes the head-to-tail arrangement of the guest molecules.Dehydration of this intercalate leads to disturbing of their arrangement, mainlyin the case of protonated guest molecules. In the case of dehydrated g-ZrP, the guest molecules are head-to-tailordered and the guest molecules in the hydrated form of g-ZrP are more disordered than in the dehydratedintercalate. The simulations also described a layer shift present in thedehydrated g-ZrP intercalate, which explained why therehydration of this intercalate is not possible.