Intramolecular hydrogen bonds in 1,4-dihydropyridine derivatives

Петрова, М. В.; Muhamadejev, Ruslan; Vı̄gante, Brigita; Дубурс, Г.; Лиепиньш, Э. Э.

doi:10.1098/rsos.180088

Cited by 13 publications

(15 citation statements)

References 31 publications

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“…In CH 2 Cl 2 , when the NH group is not involved in the intramolecular hydrogen bonding, the stretching frequency is 3450–3460 cm –1 which shifts to 3300–3350 cm –1 in the presence of hydrogen bonding. , In the present studies, both the molecules, UB and SB, have an absorption band at ∼3320 cm –1 for NH stretching and remain constant with the change in FP concentration from 0.04 to 1.60 mM. Additionally, it confirms that NH is also taking part in intramolecular hydrogen bonding.…”

Section: Resultssupporting

confidence: 77%

Stercobilin and Urobilin in Aqueous Media: Existence of Specific H-Aggregates and Nonspecific Higher Aggregates at Different Concentrations

Prakash

Mishra

2020

J. Phys. Chem. A

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Fecal matter is considered to be one of the primary sources of water pollution. Understanding the aggregation behavior of the fecal pigments (FPs) could play a critical role in their detection and analysis. This work shows that in aqueous media, the fluorescence of FPs indicates the presence of multiple emitting species, which have been assigned to monomers, lower-order Haggregates (dimers), and higher-order H-aggregates. Steady-state absorbance, fluorescence and time-resolved fluorescence decay studies conclude that the emission of FPs in aqueous medium indicates H-type of aggregation, even up to nanomolar and subnanomolar concentrations. Four sets of independent experiments involving the variation of (i) concentration of FPs, (ii) temperature, (iii) pH, and (iv) ethanol/water composition as solvent media suggest the presence of monomer (540 nm), dimer (516 nm), and higher-order aggregates (500 nm) of FPs in aqueous solutions. The dimeric FP species appear to be present in the entire concentration range of 1 pM to 1 μM. Fluorescence lifetimes of H-aggregates are relatively longer as compared to the corresponding monomers. Hydrogen bonding appears to play an important role in forming H-aggregates in the aqueous phase of FPs as observed in the IR spectra of the FPs in dichloromethane. Density functional theory (DFT) calculations using the B3LYP functional and the LANL2DZ basis set show the contributions of π−π stacking and hydrogen-bonding interactions toward the formation of H-aggregated dimer of FPs in aqueous media.

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Section: Resultssupporting

confidence: 77%

Stercobilin and Urobilin in Aqueous Media: Existence of Specific H-Aggregates and Nonspecific Higher Aggregates at Different Concentrations

Prakash

Mishra

2020

J. Phys. Chem. A

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“…For a range of 293-313 K, the temperature coefficient of the amide proton (H7) was determined to be −8.9 ppb/K. It is generally accepted that temperature coefficients with values higher than −4.5 ppm/K are strongly indicative of intramolecular H-bonds, whereas lower values suggest strong interactions with solvent [23][24][25]. Moreover, ∆δ/∆T values in at about −7.5 ppb/K indicate weakly hydrogen bonded amide protons [26].…”

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confidence: 99%

Conjugation of Penicillin-G with Silver(I) Ions Expands Its Antimicrobial Activity against Gram Negative Bacteria

et al. 2020

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Conjugation of penicillin G (PenH) with silver(I) ions forms a new CoMeD (conjugate of metal with a drug) with formula [Ag(pen)(CH3OH)]2 (PenAg). PenAg was characterized by a plethora of physical and spectroscopic techniques, which include in the solid state m.p.; elemental analysis; X-ray fluorescence (XRF) spectroscopy; scanning electron microscopy (SEM); energy-dispersive X-ray spectroscopy (EDX); FT-IR; and in solution: attenuated total reflection spectroscopy (FT-IR-ATR), UV–Vis, 1H NMR, and atomic absorption (AA). The structure of PenAg was determined by NMR spectroscopy. Silver(I) ions coordinate to the carboxylic group of PenH, while secondary intra-molecular interactions are developed through (i) the nitrogen atom of the amide group in MeOD-d4 or (ii) the sulfur atom in the thietane ring in deuterated dimethyl sulfoxide DMSO-d6. The antibacterial activities of PenAg and the sodium salt of penicillin (PenNa) (the formulation which is clinically used) against Gram positive (Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus)) and Gram negative (Pseudomonas aeruginosa (P. aeuroginosa PAO1)) bacteria were evaluated by the means of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and inhibition zone (IZ). PenAg inhibits the growth of the Gram negative bacterial strain P. aeuroginosa with a MIC value of 23.00 ± 2.29 μM, in contrast to PenNa, which shows no such activity (>2 mM). The corresponding antimicrobial activities of PenAg against the Gram positive bacteria S. epidermidis and S. aureus are even better than those of PenNa. Moreover, PenAg exhibits no in vivo toxicity against Artemia salina at concentration up to 300 μΜ. The wide therapeutic window and the low toxicity, make PenAg a possible candidate for the development of a new antibiotic.

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“…52 The 0.17 ppm downshift of the peak-related NH 3 group in MAPbBr 3 /N-rGO compared to MAPbBr 3 indicates the shortening of the hydrogen bonding as well as the stronger hydrogen binding interaction in the MAPbBr 3 /N-rGO. 53 This is a direct evidence for the interfacial conjugation between rGO and perovskite via strong hydrogen bonding.…”

Section: ■ Results and Discussionmentioning

confidence: 81%

“…However, in MAPbBr 3 /N-rGO, those peaks appeared to have shift to the low field at 5.93 and 2.83 ppm [some narrow 1 H peaks adding to the board band are due to the dried N-rGO (Figure S18b) and γ-butyrolactone] . The 0.17 ppm downshift of the peak-related NH 3 group in MAPbBr 3 /N-rGO compared to MAPbBr 3 indicates the shortening of the hydrogen bonding as well as the stronger hydrogen binding interaction in the MAPbBr 3 /N-rGO . This is a direct evidence for the interfacial conjugation between rGO and perovskite via strong hydrogen bonding.…”

Section: Resultsmentioning

confidence: 90%

Photodetector Based on Spontaneously Grown Strongly Coupled MAPbBr₃/N-rGO Hybrids Showing Enhanced Performance

Tang

Liang

Zhang

et al. 2019

ACS Appl. Mater. Interfaces

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Recently, metal-halide perovskites have emerged as a candidate for optoelectronic applications such as photodetectors. However, the poor device performance and instability have limited their future commercialization. Herein, we report the spontaneous growth of perovskite/N-rGO hybrid structures using a facile solution method and their applications for photodetectors. In the hybrid structures, perovskites were homogeneously wrapped by N-rGO sheets through strong hydrogen bonding. The strongly coupled N-rGOs facilitate the charge carrier transportation across the perovskite crystals but also distort the surface lattice of the perovskite creating a potential barrier for charge transfer. We optimize the addition of N-rGO in the hybrid structures to balance interfacial structural distortion and the intercrystal conductivity. High-performance photodetection up to 3 × 104 A/W, external quantum efficiency exceeding 105%, and detectivity up to 1012 Jones were achieved in the optimal device with the weight ratio between perovskites and N-rGO to be 8:1.5. The underlying mechanism behind the optimal N-rGO addition ratio in the hybrids has also been rationalized via time-resolved spectroscopic studies as a reference for future applications.

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Intramolecular hydrogen bonds in 1,4-dihydropyridine derivatives

Cited by 13 publications

References 31 publications

Stercobilin and Urobilin in Aqueous Media: Existence of Specific H-Aggregates and Nonspecific Higher Aggregates at Different Concentrations

Stercobilin and Urobilin in Aqueous Media: Existence of Specific H-Aggregates and Nonspecific Higher Aggregates at Different Concentrations

Conjugation of Penicillin-G with Silver(I) Ions Expands Its Antimicrobial Activity against Gram Negative Bacteria

Photodetector Based on Spontaneously Grown Strongly Coupled MAPbBr₃/N-rGO Hybrids Showing Enhanced Performance

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Intramolecular hydrogen bonds in 1,4-dihydropyridine derivatives

Cited by 13 publications

References 31 publications

Stercobilin and Urobilin in Aqueous Media: Existence of Specific H-Aggregates and Nonspecific Higher Aggregates at Different Concentrations

Stercobilin and Urobilin in Aqueous Media: Existence of Specific H-Aggregates and Nonspecific Higher Aggregates at Different Concentrations

Conjugation of Penicillin-G with Silver(I) Ions Expands Its Antimicrobial Activity against Gram Negative Bacteria

Photodetector Based on Spontaneously Grown Strongly Coupled MAPbBr3/N-rGO Hybrids Showing Enhanced Performance

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Product

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Photodetector Based on Spontaneously Grown Strongly Coupled MAPbBr₃/N-rGO Hybrids Showing Enhanced Performance