On the Stability and Spectroscopic Properties of 5-Hydroxyoxazole-4-carboxylic Acid Derivatives

2021 ◽  
Author(s):  
Alina Tirla ◽  
Kevin M. Wernke ◽  
Seth B. Herzon
Keyword(s):  
Carboxylic Acid ◽  
Spectroscopic Properties ◽  
The Stability

scholarly journals Photoluminescent Coordination Polymers Based on Group 12 Metals and 1H-Indazole-6-Carboxylic Acid

Inorganics ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 20
Author(s):  
Antonio A. García-Valdivia ◽  
Estitxu Echenique-Errandonea ◽  
Gloria B. Ramírez-Rodríguez ◽  
José M. Delgado-López ◽  
Belén Fernández ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Coordination Polymers ◽  
Density Functional ◽  
Free Ligand ◽  
Emission Spectra ◽  
Point Of View ◽  
Theoretical Point ◽  
Fourier Transformed Infrared Spectroscopy ◽  
3D Network ◽  
The Stability

Two new coordination polymers (CPs) based on Zn(II) and Cd(II) and 1H-indazole-6-carboxylic acid (H2L) of general formulae [Zn(L)(H2O)]n (1) and [Cd2(HL)4]n (2) have been synthesized and fully characterized by elemental analyses, Fourier transformed infrared spectroscopy and single crystal X-ray diffraction. The results indicate that compound 1 possesses double chains in its structure whereas 2 exhibits a 3D network. The intermolecular interactions, including hydrogen bonds, C–H···π and π···π stacking interactions, stabilize both crystal structures. Photoluminescence (PL) properties have shown that compounds 1 and 2 present similar emission spectra compared to the free-ligand. The emission spectra are also studied from the theoretical point of view by means of time-dependent density-functional theory (TD-DFT) calculations to confirm that ligand-centred π-π* electronic transitions govern emission of compound 1 and 2. Finally, the PL properties are also studied in aqueous solution to explore the stability and emission capacity of the compounds.

Lanthanide coordination compounds with 1H-benzimidazole-2-carboxylic acid: syntheses, structures and spectroscopic properties

CrystEngComm ◽  
2013 ◽  
Vol 15 (1) ◽  
pp. 86-99 ◽  
Author(s):  
Zhengqiang Xia ◽  
Qing Wei ◽  
Qi Yang ◽  
Chengfang Qiao ◽  
Sanping Chen ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Coordination Compounds ◽  
Spectroscopic Properties

scholarly journals Concomitant polymorphs of aryl-ether amine via catemer and dimer carboxylic acid supramolecular interactions and their effect on optical properties

2021 ◽  
Author(s):  
Mehboobali Pannipara ◽  
Abdullah G Al-Sehemi
Keyword(s):  
Optical Properties ◽  
Carboxylic Acid ◽  
Crystal Lattice ◽  
Functional Groups ◽  
Molecular Orbital ◽  
Acid Group ◽  
Supramolecular Interactions ◽  
Aryl Ether ◽  
Stability Calculation ◽  
The Stability

Abstract Carboxylic acid supramolecular synthon exhibited dimer or catemer motifs in the crystal lattice depend on the substituent and other functional groups present in the structure. In general, presence of other competing functional groups produced catemer motifs whereas unsubstituted acids showed dimer. In this manuscript, we have synthesized a new aryl ether amine-based Schiff base with carboxylic acid functionality ( 1 ) and demonstrated polymorphic structure via catemer ( 1a ) and dimer ( 1b ) motifs in the solid state. In both the structure, carboxylic acid group adopted different orientation in the crystal lattice. The different H-bonding lead to modulation of optical properties that was further supported highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) calculation. Further the stability calculation indicates that catemer structure was more stable by 8.54 kcal/mole relative to dimer motifs. In contrast, naphthyl group attached carboxylic acid structure did not show neither dimer nor catemer motifs in the crystal lattice as compared to diethylaminophenyl group, which confirm the presence of other substituent or competing functional groups strongly influence on the motifs of supramolecular interactions.

scholarly journals Foliar application of sodium selenate induces regulation in yield formation, grain quality characters and 2-acetyl-1-pyrroline biosynthesis in fragrant rice

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Haowen Luo ◽  
Bin Du ◽  
Longxin He ◽  
Axiang Zheng ◽  
Shenggang Pan ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Grain Yield ◽  
Grain Quality ◽  
Foliar Application ◽  
Higher Plants ◽  
Sodium Selenate ◽  
Rice Varieties ◽  
Fragrant Rice ◽  
The Stability ◽  
Heading Stage

Abstract Background Selenium (Se) is a beneficial element for higher plants and essential for mammals. To study the effect of the foliar application of sodium selenate on fragrant rice performance, a pot experiment was conducted in Guangdong, China. At the initial heading stage, one-time foliar application of sodium selenate with concentrations of 0, 10, 20, 30, 40 and 50 μmol·L− 1 (named CK, Se1, Se2, Se3, Se4 and Se5, respectively) were foliar applied on two fragrant rice varieties, ‘Meixiangzhan-2’ and ‘Xiangyaxiangzhan’. Results Selenate application at the initial heading stage not only improved the grain yield of fragrant rice by increasing the seed-setting rate and grain weight, but also promoted the grain quality by increasing crude protein contents and lowering the chalky rice rate. Furthermore, Se applications enhanced the biosynthesis of 2-acetyl-1- pyrroline (2-AP), the main aromatic compound, by increasing the contents of precursors (△1- pyrroline, proline and pyrroline-5-carboxylic acid (P5C)) and the activities of enzymes (proline dehydrogenase (PRODH), △1-pyrroline-5-carboxylic acid synthetase (P5CS), and ornithine aminotransferase (OAT)) in fragrant rice. The results also showed that foliar application of sodium selenate enhanced the antioxidant system of both varieties by promoting the activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and reducing the contents of malondialdehyde (MDA). Furthermore, the real-time PCR analyses depicted that foliar application of selenate up-regulated the GPX1, GPX4 and CATC transcripts. The higher antioxidative enzymatic activities might strength the stress resistant to ensure the stability of yield in fragrant rice form abiotic stress. Conclusions Foliar applications of sodium selenate at the initial heading stage increased the grain 2-AP content by enhancing the biosynthesis-related enzymes and precursors. The grain yield and quality of fragrant rice also increased due to selenate application. Furthermore, foliar application of selenate promoted the activities of enzymes such as POD, SOD and CAT and up-regulated the expression of gene GPX4, GPX1 and CATC.

Theoretical study of the stability and NMR spectroscopic properties of vanadium(V) complexes

2019 ◽  
Vol 138 (11) ◽  
Author(s):  
Lisset Noriega ◽  
María Eugenia Castro ◽  
Jose Manuel Perez-Aguilar ◽  
Norma A. Caballero ◽  
Thomas Scior ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Spectroscopic Properties ◽  
The Stability

Synthesis, Spectroscopic Properties, and Crystal Structure of the Oxonium Acid [H(OEt2)2]+[Ti2Cl9]–

2003 ◽  
Vol 58 (8) ◽  
pp. 745-750 ◽  
Author(s):  
Stefan Rannabauer ◽  
Tassilo Habereder ◽  
Heinrich Nöth ◽  
Wolfgang Schnick
Keyword(s):  
Crystal Structure ◽  
Ir Spectroscopy ◽  
Single Crystals ◽  
Nmr Spectra ◽  
Spectroscopic Properties ◽  
Partial Hydrolysis ◽  
Distorted Tetrahedron ◽  
Methyl Carbon ◽  
H Nmr ◽  
The Stability

The oxonium acid [H(OEt2)2]+[Ti2Cl9]− (1) was obtained by the reaction of TiCl4 with Et2O in n-pentane and subsequent partial hydrolysis. Suitable single crystals of 1 were obtained by sublimation at 5° C ([H(OEt2)2]+[Ti2Cl9]−, P212121 (no. 19), Z = 4, a = 1101.08(8), b = 1328.4(2), c = 1525.0(2) pm, T = 193(2) K, 4489 independent reflections, 197 parameters, R1 = 0.049). The cation is made up from two independent Et2O molecules and one disordered proton on two split positions. Both ether molecules exhibit a W form, and their molecular planes include an angle of 74.1(7)°. Thus a distorted tetrahedron is formed by the four methyl carbon atoms of the two ether molecules. The distance O···O amounts to 237.7(1) pm. The proton of the cation was characterized both by 1H NMR (CDCl3, T = 23 °C: δ = 11.7 ppm, w1/2 = 100 Hz) and IR spectroscopy (3120 cm−1, ν vbr). The [Ti2Cl9]− ion consists of two face sharing octahedra. 47Ti and 49Ti NMR spectra were recorded in solution (CH2Cl2, T = 23 °C: δ 49Ti = 137 ppm, w1/2 = 175 Hz; δ 47Ti = −124 ppm, w1/2 = 250 Hz). The absence of a signal for TiCl4 at δ 49Ti = 0 ppm indicates the stability of the dinuclear anion in solution.

Consideration of end effects of DNA hybridization in selection of fluorescent dyes for development of optical biosensors

1999 ◽  
Vol 77 (12) ◽  
pp. 2083-2087 ◽  
Author(s):  
S C Jakeway ◽  
U J Krull
Keyword(s):  
Quantum Efficiency ◽  
Dna Hybridization ◽  
Fluorescent Dyes ◽  
Hydrocarbon Chain ◽  
Spectroscopic Properties ◽  
Excitation Wavelength ◽  
End Effects ◽  
High Quantum Efficiency ◽  
The Stability ◽  
Selection Of

Intercalating fluorescent dyes are in widespread use to detect the presence of double-stranded DNA. Applications include the development of biosensors that rely on the attachment ("tethering") of a dye molecule by a short hydrocarbon chain to the terminus of a strand of DNA so that dye is continuously available and the biosensor is fully reversible. Double strands of DNA have end effects that limit the stability of hybridization and dye intercalation near the termini of the duplexes. Therefore, the selection of the dye must be based on consideration of spectroscopic properties and also issues associated with tether length and the stoichiometry of the binding of the dye with double- and single-stranded DNA. Ethidium bromide (EB) has been used extensively to detect hybridization of DNA in applications such as electrophoresis, gene chips, and biosensors. A number of dyes with greater quantum efficiency than EB for detection of hybridization have been reported. Furthermore, other practical spectroscopic advantages can be gained in terms of improved S/N by use of dyes that have excitation that is red shifted relative to EB. Pyrilium iodide has been disclosed as an intercalator of high quantum efficiency and long excitation wavelength. This work investigates pyrilium iodide in comparison to EB as a candidate for preparation of a tethered dye for detection of hybridization of DNA 20-mers.Key words: biosensors, DNA, hybridization, fluorescence, end effects.

The detrimental effect of orotic acid substitution in the peptide nucleic acid strand on the stability of PNA2:NA triple helices

2005 ◽  
Vol 83 (10) ◽  
pp. 1731-1740 ◽  
Author(s):  
Robert HE Hudson ◽  
Filip Wojciechowski
Keyword(s):  
Nucleic Acid ◽  
Carboxylic Acid ◽  
Peptide Nucleic Acid ◽  
Triple Helix ◽  
Orotic Acid ◽  
Uv Spectroscopy ◽  
Triplex Formation ◽  
Helix Formation ◽  
Triple Helix Formation ◽  
The Stability

We have investigated the incorporation of C6 derivatives of uracil into polypyrimidine peptide nucleic acid oligomers. Starting with uracil-6-carboxylic acid (orotic acid), a peptide nucleic acid monomer compatible with Fmoc-based synthesis was prepared. This monomer then served as a convertible nucleobase whereupon treatment of the resin-bound methyl orotate containing hexamers with hydroxide or amines cleanly converted the ester to an orotic acid or orotamide-containing peptide nucleic acid. Peptide nucleic acid hexamers containing the C6-modified nucleobase hybridized to both poly(riboadenylic acid) and poly(deoxyriboadenylic acid) via triplex formation. Complexes formed with poly(riboadenylic acid) were more stable than those formed with poly(dexoyriboadenylic acid), as measured by temperature-dependent UV spectroscopy. However, both of these complexes were destabilized relative to the complexes formed by an unmodified peptide nucleic acid oligomers. Internal or doubly substituted hexamers are destabilized more strongly than a terminally substituted one, and the type of substitution (carboxamide, ester, carboxylic acid) affects the overall triplex stability. These results clearly show that incorporation of a C6-substituted uracil into polypyrimidine PNA is detrimental to triplex formation. We have also extended this chemistry to incorporate uracil-5-methylcarboxylate into a peptide nucleic acid hexamer. After on-resin conversion of the C5 ester to the 3-(N,N-dimethylamino)propylamide, significant stabilization of the triplex formed with poly(riboadenylic acid) was observed, which illustrates the compatibility of C5 substitution with peptide nucleic acid directed triple helix formation. Key words: peptide nucleic acid, triple helix, orotic acid, orotamide, PNA.

Sign in / Sign up

Export Citation Format

Share Document