39642-60-9Relevant academic research and scientific papers
Anchoring Drugs to a Zinc(II) Coordination Polymer Network: Exploiting Structural Rationale toward the Design of Metallogels for Drug-Delivery Applications
Biswas, Protap,Dastidar, Parthasarathi
supporting information, p. 3218 - 3231 (2021/03/01)
A new series of coordination polymers (CPs) were synthesized and crystallographically characterized by single-crystal X-ray diffraction with the aim of developing drug-delivery systems via metallogel formation. Structural rationale was employed to design such coordination-polymer-based metallogels. As many as nine CPs were obtained by reacting two bis(pyridyl)urea ligands, namely, 1,3-dipyridin-3-ylurea (3U) and 1,3-dipyridin-4-ylurea (4U), and the sodium salt of various nonsteroidal antiinflammatory drugs, namely, ibuprofen (IBU), naproxen (NAP), fenoprofen (FEN), diclofenac (DIC), meclofenamic acid (MEC), mefenamic acid (MEF), and Zn(NO3)2. All of the CPs displayed 1D polymeric chains that were self-assembled through various hydrogen-bonding interactions involving the urea N-H and carboxylate O atoms and, in a few cases, lattice-occluded water molecules. The reacting components of the CPs produced five metallogels in dimethyl sulfoxide/water. The gels were characterized by rheology and transmission electron microscopy. Three selected metallogelators, namely, 3UMEFg, 3UNAPg, and 3UMECg, showed in vitro anticancer, cell imaging, and multidrug delivery for antibacterial applications, respectively. The shear-thinning properties of 3UMECg (rheoreversibility and injectability) make it a potential candidate for plausible topical application.
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.
Consequence of presence and absence of π-clouds at strategic locations of designed binuclear Pd(II) complexes on packing: Self-assembly of self-assembly by intermolecular locking and packing
Naranthatta, Mili C.,Das, Deepika,Tripathy, Debakanta,Sahoo, Himansu S.,Ramkumar, Venkatachalam,Chand, Dillip K.
, p. 6012 - 6022 (2013/03/13)
Self-assembled binuclear coordination cages of general formula [Pd 2(N-N)2(L)2](X)4, 1a/b-4a/b are prepared by the combination of N,N′-bis(m-pyridyl)urea, L, with a variety of cis-protected palladium(II) components, Pd(N-N)(X)2. The cis-protecting units "N-N" employed for the synthesis of 1-4 are ethylenediamine (en), tetramethylethylenediamine (tmeda), 2,2′-bipyridine (bpy), and 1,10-phenanthroline (phen), respectively. The term "X" stands for nitrate and perchlorate for a and b, respectively. The assemblies are characterized by NMR and electrospray ionization mass spectrometry (ESI-MS) techniques, and in some cases (i.e., 1a, 2b, 3b, 4a, and 4b) the structures are confirmed by single crystal X-ray diffraction. The conformations of bound L in the crystal structures of all the Pd(II) complexes are found to be syn-syn. The influence of the presence and absence of π cloud at the cis-protecting units on the crystal packing has been studied in detail. In the packing of [Pd 2(phen)2L2](NO3)4, 4a, one unit of [Pd2(phen)2L2]4+ is associated with two other units by π-π stacking interactions thus giving a one-dimensional growth as envisioned on the basis of a design principle. In the case of [Pd2(en)2(L)2](NO3) 4, 1a, and [Pd2(tmeda)2(L)2] (ClO4)4, 2b, such packing is not observed due to the absence of π-cloud at the strategic locations, instead notable H-bonding interactions are seen. However, [Pd2(bpy)2(L) 2](ClO4)4, 3b, displays a π-π interactions using only two units of [Pd2(bpy)2(L) 2]4+(ClO4)-.
HAMMICK CYCLIZATIONS STUDIES ON THE MECHANISM OF THE HAMMICK REACTION
Bohn, Bernhard,Heinrich, Nicolaus,Vorbrueggen, Helmut
, p. 1731 - 1746 (2007/10/02)
Heating of 3-hydroxypicolinic acid with the acetylketene precursor 2,2,4-trimethyldioxin-4-one, ethyl acetoacetate or ethyl 2-cyclopentaneonecarboxylate leads via the 3-O-acylated 3-hydroxypicolinic acids, which cannot be isolated, and subsequent decarboxylation to the corresponding Hammick cyclization products in up to 25 percent yields besides 3-hydroxypyridine.In the case of 3-aminopicolinic acid the 3-(3-oxobutyrylamido)picolinic acid can be isolated but gives on heating only 3-aminopyridine and 3-(3-oxobutyrylamido)pyridine albeit none of the anticipated Hammick cyclization products.The Hammick cyclization reactions, side reactions and reaction mechanisms are discussed.
