51076-46-1Relevant articles and documents
Synthesis of pH-sensitive benzothiazole cyanine dye derivatives containing a pyridine moiety at the meso position
Lovett, Wheeler R.,Al Hamd, Alaa,Casa, Stefanie,Henary, Maged
, (2021/03/18)
Four benzothiazole-derived pentamethine cyanine dyes were synthesized with a pyridine moiety at the meso-position of the methine chain with a reaction yield of 89–93%. These dyes were prepared with high purity in a three-step synthesis as prospective pH-responsive probes. Each compound absorbed and fluoresced between 630 and 670 nm within the far-red range of the visible spectrum with high molar absorptivity values calculated between 134,910 L mol ?1 cm?1 and 163,816 L mol ?1 cm?1 and quantum yields between 9% and 17%. When a 20 μM solution of dye derivatives are exposed to hydrochloric acid in the range of pH 5–6 in ethanol, all the dyes experienced a blueshift in absorbance and emission as well as a decrease in spectral intensity that enables them to operate as pH probes. These properties were further validated via computational studies showing pyridine's influence on each molecules' spectral properties, and pathways for electron delocalization in the presence and absence of acid were proposed.
New cobalt(II) and zinc(II) coordination frameworks incorporating a pyridyl-pyrazole ditopic ligand
Mulyana, Yanyan,Kepert, Cameron J.,Lindoy, Leonard F.,Parkin, Andrew,Turner, Peter
, p. 1598 - 1601 (2007/10/03)
The metal-directed assembly of new molecular frameworks incorporating 4-(4-pyridyl)pyrazole (L), containing non-linear coordination vectors, is presented. Three metallo-arrays of types [Co(LH)2(NO 3)4], [Co(LH)2(H2O) 4][NO3]4-H2O and [Zn 2(L-H)2Cl2]-2EtOH are reported. The cobalt(n) in [Co(LH)2(NO3)4] displays distorted octahedral geometry, with the two protonated pyridyl-pyrazole ligands coordinated through their pyrazole nitrogen atoms in a trans-oricntation; the remaining four coordination sites are occupied by nitrate anions. Two internal hydrogen bonds occur between each pyrazole NH and the oxygens of adjacent coordinated nitrato ligands. Short intermolecular hydrogen bonds also occur between the two pyridinium hydrogens and bound nitrate ligands on different molecules to yield a two-dimensional hydrogen-bonded array. Two of these arrays interpenetrate to form an extended two dimensional layer; such layers stack throughout the crystal structure. A second product of type [Co(LH) 2(H2O)4][NO3]4-H 2O exists as two crystallographically independent, but chemically similar, forms. In each form, the two protonated pyridyl-pyrazole ligands occupy trans positions about the cobalt, with the remaining four coordination sites being filled by water molecules to yield a distorted octahedral coordination geometry. Intramolecular hydrogen-bonding is observed between the two non-coordinated pyrazoyl nitrogen atoms and bound water oxygen atoms. The third complex, [Zn2(L-H)2Cl2]-2EtOH, contains dimer units consisting of two zinc(II) ions bridged by two pyrazoylate groups in which the coordination geometry of each zinc approximates a tetrahedron. Each zinc is bound to two deprotonated pyridine-pyrazole ligands (L-H), one pyridyl group (from a different dimeric unit) and one chloro ligand. Each pyridyl nitrogen thus connects each of these zinc dimers to an adjacent dimer unit, forming a three-dimensional network containing small voids. The latter are occupied by ethanol molecules which form hydrogen bonds to the chloro ligands. The Royal Society of Chemistry 2005.
Studies on the synthesis of 3-amino-5-(4-pyridinyl)-1,2- dihydropyrid-2-one (Cordemcura) from a technical mixture of alkyl pyridines
Niedrich,Heyne,Schrotter,et al.
, p. 173 - 175 (2007/10/02)
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