scholarly journals Error or exemption to the rule? Development of a diagnostic check for thermochemistry of metal–organic compounds

RSC Advances ◽  
2020 ◽  
Vol 10 (63) ◽  
pp. 38158-38173
Author(s):  
Kseniya V. Zherikova ◽  
Sergey P. Verevkin

A diagnostic tool for checking the consistency of thermochemical data of tris(beta-diketonato)metal complexes is developed.

Author(s):  
Majid Ali ◽  
Syed Majid Bukhari ◽  
Asma Zaidi ◽  
Farhan A. Khan ◽  
Umer Rashid ◽  
...  

Background:: Structurally diverse organic compounds and available drugs were screened against urease and carbonic anhydrase II in a formulation acceptable for high-throughput screening. Objective: The study was conducted to find out potential inhibitors of urease and carbonic anhydrase II. Methods:: Quantification of the possible HITs was carried out by determining their IC50 values. Results and Discussion:: of several screened compounds including derivatives of oxadiazole, coumarins, chromane-2, 4- diones and metal complexes of cysteine-omeprazole showed promising inhibitory activities with IC50 ranging from 47 μM to 412 μM against the urease. The interactions of active compounds with active sites of enzymes were investigated through molecular docking studies which revealed that (R)-1-(4-amino-4-(5-(thiophen-2-yl)-1,3,4-oxadiazol-2-yl) butyl) guanidine possessing IC50 of 47 μM, interacts with one of the nickel metal atom of urease besides further interactions as predictable hydrogen bonds with KCX490, Asp633, His492, His407 and His409 along with Ala440 and 636. Bi-ligand metal complexes of 4-aminoantipyrine based Schiff bases showed activation of urease with AC50 ranging from 68 μM to 112 μM. Almost 21 compounds with varying functional groups including pyrimidines, oxadiazoles, imidazoles, hydrazides and tin based compounds were active carbonic anhydrase II inhibitors presenting 98 μM to 390 μM IC50 values. Several N-substituted sulfonamide derivatives were inactive against carbonic anhydrase II. Conclusion:: Among all the screened compounds, highly active inhibitor of carbonic anhydrase II was (4-(3- hydroxyphenyl)-6-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)phenyl) methanone with IC50 of 98.0 μM. This particular compound showed metallic interaction with Zn ion of carbonic anhydrase II through hydroxyl group of phenyl ring.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1420
Author(s):  
Chenyang He ◽  
Liangliang Liu ◽  
Sergiy Korposh ◽  
Ricardo Correia ◽  
Stephen P. Morgan

A tip-based fibreoptic localised surface plasmon resonance (LSPR) sensor is reported for the sensing of volatile organic compounds (VOCs). The sensor is developed by coating the tip of a multi-mode optical fibre with gold nanoparticles (size: 40 nm) via a chemisorption process and further functionalisation with the HKUST-1 metal–organic framework (MOF) via a layer-by-layer process. Sensors coated with different cycles of MOFs (40, 80 and 120) corresponding to different crystallisation processes are reported. There is no measurable response to all tested volatile organic compounds (acetone, ethanol and methanol) in the sensor with 40 coating cycles. However, sensors with 80 and 120 coating cycles show a significant redshift of resonance wavelength (up to ~9 nm) to all tested volatile organic compounds as a result of an increase in the local refractive index induced by VOC capture into the HKUST-1 thin film. Sensors gradually saturate as VOC concentration increases (up to 3.41%, 4.30% and 6.18% in acetone, ethanol and methanol measurement, respectively) and show a fully reversible response when the concentration decreases. The sensor with the thickest film exhibits slightly higher sensitivity than the sensor with a thinner film. The sensitivity of the 120-cycle-coated MOF sensor is 13.7 nm/% (R2 = 0.951) with a limit of detection (LoD) of 0.005% in the measurement of acetone, 15.5 nm/% (R2 = 0.996) with an LoD of 0.003% in the measurement of ethanol and 6.7 nm/% (R2 = 0.998) with an LoD of 0.011% in the measurement of methanol. The response and recovery times were calculated as 9.35 and 3.85 min for acetone; 5.35 and 2.12 min for ethanol; and 2.39 and 1.44 min for methanol. The humidity and temperature crosstalk of 120-cycle-coated MOF was measured as 0.5 ± 0.2 nm and 0.5 ± 0.1 nm in the humidity range of 50–75% relative humidity (RH) and temperature range of 20–25 °C, respectively.


1962 ◽  
Vol 2 (2) ◽  
pp. 105-106
Author(s):  
D. Braun ◽  
M Herner ◽  
W. Kern

2019 ◽  
Vol 16 (2) ◽  
pp. 143-149
Author(s):  
O. V. Bashta ◽  
L. P. Pasichnyk ◽  
N. M. Voloshchuk ◽  
G. G. Repich ◽  
O. O. Zholob ◽  
...  

The aim of present paper is to study the antifungal activity of the new platinum, palladium and copper chelate complexes with different organic ligands against Fusarium strains and to determine the influence of these compounds on the germination energy and seed germination of investigated grain crops. Methods. In vitro antifungal activities of new chelate complexes were studied by the agar disk diffusion method. New complexes were tested against pathogenic Fusarium strains such as — F. culmorum 3260/4, F. verticillioides and F. sporotrichioides. The toxic effect of new complexes was evaluated according to changes in germination power and seed germination of grain crops — winter wheat, vernal barley and maize. The determination of these characteristics was carried out in accordance with the standard demands. Results. Our results revealed that palladium complex H exhibited fungicidal activity against F. culmorum 3260/4 and fungistatic activity against F. verticillioides with growth inhibition zone diameter 25 mm ad 20 mm respectively. Copper complex 2 showed a moderate fungicidal effect against F. culmorum 3260/4 strain (inhibition zone diameter 12 mm). The treatment of grain crops seeds with the H and 2 complexes demonstrated the less toxicity than standard agent — commercial fungicide tebuconazol. These complexes had also less negative influence on the germination power for all test cultures than tebuconazol. Copper complex 2 showed a noticeable growth promoting effect on studied seeds compared to seeds under conditions without treatment. Conclusions. Thus, the studied complexes can be considered as promising antifungal agents with growth regulating properties. The directional modification of the complexes to obtain the more potent derivatives will be performed.Keywords: metal-organic compounds, antifungal, growths regulation activity.


Author(s):  
Michael T. Huxley ◽  
Campbell J. Coghlan ◽  
Witold M. Bloch ◽  
Alexandre Burgun ◽  
Christian J. Doonan ◽  
...  

Post-synthetic modification of metal–organic frameworks (MOFs) facilitates a strategic transformation of potentially inert frameworks into functionalized materials, tailoring them for specific applications. In particular, the post-synthetic incorporation of transition-metal complexes within MOFs, a process known as ‘metalation’, is a particularly promising avenue towards functionalizing MOFs. Herein, we describe the post-synthetic metalation of a microporous MOF with various transition-metal nitrates. The parent framework, 1 , contains free-nitrogen donor chelation sites, which readily coordinate metal complexes in a single-crystal to single-crystal transformation which, remarkably, can be readily monitored by X-ray crystallography. The presence of an open void surrounding the chelation site in 1 prompted us to investigate the effect of the MOF pore environment on included metal complexes, particularly examining whether void space would induce changes in the coordination sphere of chelated complexes reminiscent of those found in the solution state. To test this hypothesis, we systematically metalated 1 with first-row transition-metal nitrates and elucidated the coordination environment of the respective transition-metal complexes using X-ray crystallography. Comparison of the coordination sphere parameters of coordinated transition-metal complexes in 1 against equivalent solid- and solution-state species suggests that the void space in 1 does not markedly influence the coordination sphere of chelated species but we show notably different post-synthetic metalation outcomes when different solvents are used. This article is part of the themed issue ‘Coordination polymers and metal–organic frameworks: materials by design’.


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