4013-73-4Relevant articles and documents
SYNTHESIS AND PHARMACOLOGICAL PROPERTIES OF THE HYDROCHLORIDE OF d,l-&α-TOCOPHEROL-&γ-AMINOBUTYRATE
Zakharova, E. I.,Lukinova, M. M.,Sarycheva, I. K.,Evstigneeva, R. P.,Shmuilovich, L. M.,et al.
, p. 614 - 616 (1985)
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Sulfate binding with a tripodal tris(4-pyridylurea) receptor
Zhang, Rui,Zhang, Yanlei,Wang, Jiamin,Ji, Liguo,Huang, Xiaojuan,Wu, Biao
, p. 679 - 683 (2013)
The tris(2-aminoethyl)amine (tren)-based tris(4-pyridylurea) receptor L has been synthesized and its anion binding properties were studied. The ligand forms a 2:1 (host/guest) complex with MgSO4, [SO4 2-aSL2], in which a sulfate ion is encapsulated by six urea groups from the two ligands through multiple hydrogen bonds. The metal ions do not coordinate to the pyridyl groups but exist as the hydrate [Mg(H2O)6]2+ and interact with the [SO4aSL2] capsules in the outer coordination sphere to form a three dimensional extended structure. The anion binding behavior of ligand L in solution was studied. The tripodal tris(4-pyridylurea) receptor (L) was synthesized and its anion binding properties studied. The ligand forms a 2:1 (H/G) complex with MgSO4, [SO4 2-aSL2], in which a sulfate ion is encapsulated by six urea groups as in the analogous complex of the 3-pyridyl-substituted ligand. The anion binding behavior of ligand L in solution was studied. Copyright
Spectroscopic Characterization of Nicotinoyl and Isonicotinoyl Nitrenes and the Photointerconversion of 4-Pyridylnitrene with Diazacycloheptatetraene
Liu, Qian,Qin, Yuanyuan,Lu, Yan,Wentrup, Curt,Zeng, Xiaoqing
, p. 3793 - 3801 (2019/05/10)
Recently, nicotinoyl nitrene (2) has been generated from the photodecomposition of nicotinoyl azide (1) and used as the key intermediate in probing nucleobase solvent accessibility inside cells. Following the 266 nm laser photolysis of nicotinoyl azide (1) and isonicotinoyl azide (5) in solid N2 matrices at 15 K, nicotinoyl nitrene (2) and isonicotinoyl nitrene (6) have now been identified by matrix-isolation infrared (IR) spectroscopy. Both aroyl nitrenes 2 and 6 adopt closed-shell singlet ground states stabilized by significant Nnitrene···O interactions, which is consistent with the spectroscopic analysis and calculations at the CBS-QB3 level of theory. Upon subsequent visible light irradiations, 2 (400 ± 20 nm) and 6 (532 nm) undergo rearrangement to pyridyl isocyanates 3 and 7. Further dissociation of 3 and 7 under 193 nm laser irradiation results in CO elimination and formation of ketenimines 12 and 13 via the ring opening of elusive pyridyl nitrenes 4 and 8, respectively. In addition to the IR spectroscopic identification of 8 in the triplet ground state, its reversible photointerconversion with ring expansion to diazacycloheptatetraene 9 has been observed directly. The spectroscopic identification of the nitrene intermediates was aided by calculations at the B3LYP/6-311++G(3df,3pd) level, and the mechanism for their generation in stepwise decompositions of the azides is discussed in the light of CBS-QB3 calculations.
Photolysis and thermolysis of pyridyl carbonyl azide monolayers on single-crystal platinum
Adkinson, Dana K.,Magri, David C.,Pitters, Jason L.,Griffiths, Keith,Norton, Peter R.,Workentin, Mark S.
, p. 1020 - 1028 (2013/09/24)
The photochemical and thermal reactivity of a number of acyl azide-substituted pyridine compounds, namely nicotinyl azide, isonicotinyl azide, picolinyl azide and dinicotinyl azide with investigated as saturated monolayers on a single-crystal Pt(111) surface in an ultrahigh vacuum chamber. Multilayers of the substrates exhibited a maximum rate of desorption at 270 K, above which, stable saturated monolayers formed as characterized by reflection-absorption infrared spectroscopy by observation of C=O and N 3 bands at 1700 cm-1, and 2100 and 1300 cm-1 respectively. The monolayers were stable up to 400 K. Photolysis of the monolayer (or heating above 400 K) results in the formation of the respective isocyanate intermediate after loss of nitrogen as evidenced by the appearance of a new infrared band at 2260 cm-1 with concomitant loss of the azide bands. The resulting isocyanate saturated monolayer is stable in absence of nucleophiles, but can be quenched with appropriate nucleophiles. Saturated monolayers of a number of acyl azide-substituted pyridine compounds, namely nicotinyl azide, isonicotinyl azide, picolinyl azide and dinicotinyl azide, were formed on single-crystal Pt(111) surfaces in a UHV chamber. These monolayers were characterized by RAIR and thermal programmed desorption. Photolysis or thermolysis of these saturated monolayers leads to the corresponding isocyanate via a Curtius rearrangement.
