Solid State Analysis and Theoretical Explorations on Polymorphic and Hydrate Forms of p-Hydroxybenzaldehyde Isonicotinichydrazone: Effect of Additives on Polymorphic Crystallization

Author(s):  
Lincy Tom ◽  
Victoria A. Smolenski ◽  
Jerry P. Jasinski ◽  
M.R. Prathapachandra Kurup

The reaction of p-hydroxybenzaldehyde with an equimolar amount of isonicotinic hydrazide afforded two polymorphic and hydrate forms of p-hydroxybenzaldehyde isonicotinichydrazone (HBIH) by varying the experimental reaction conditions. The compounds are fully characterized by means of single crystal and powder diffraction methods, vibrational spectroscopy (FT-IR and Raman), thermal and elemental analysis. The compound crystallizes in three different forms in two different space groups, P21/c (form PA and PB) and Pbca (PC). The Hirshfeld surface analysis shows the differences in the relative contributions of intermolecular interactions to the total Hirshfeld surface area for the HBIH molecules. The calculated pairwise interaction energies (104-116 kJ/mol) can be related to the stability of the crystals. Energy framework analysis identifies the interaction hierarchy and their topology. The geometry and conformation of the three forms are essentially similar which differ only by packing arrangement.

2018 ◽  
Author(s):  
Lincy Tom ◽  
Victoria A. Smolenski ◽  
Jerry P. Jasinski ◽  
M.R. Prathapachandra Kurup

The reaction of p-hydroxybenzaldehyde with an equimolar amount of isonicotinic hydrazide afforded two polymorphic and hydrate forms of p-hydroxybenzaldehyde isonicotinichydrazone (HBIH) by varying the experimental reaction conditions. The compounds are fully characterized by means of single crystal and powder diffraction methods, vibrational spectroscopy (FT-IR and Raman), thermal and elemental analysis. The compound crystallizes in three different forms in two different space groups, P21/c (form PA and PB) and Pbca (PC). The Hirshfeld surface analysis shows the differences in the relative contributions of intermolecular interactions to the total Hirshfeld surface area for the HBIH molecules. The calculated pairwise interaction energies (104-116 kJ/mol) can be related to the stability of the crystals. Energy framework analysis identifies the interaction hierarchy and their topology. The geometry and conformation of the three forms are essentially similar which differ only by packing arrangement.


2019 ◽  
Vol 10 (4) ◽  
pp. 386-402
Author(s):  
Aysegul Suzan Polat ◽  
Ilkay Gumus ◽  
Hakan Arslan

The title molecule, N,N'-(azanediylbis(2,1-phenylene))bis(2-chloropropanamide) (LNNN) was synthesized and characterized by means of Hirshfeld surface analysis and vibrational (FT-IR and RAMAN) studies. Ab-initio Hartree-Fock (HF) and density functional theory (DFT; BLYP, B3LYP, B3PW91 and mPW1PW91) calculations were accomplished using 6-31G(d,p) and 6-311G(d,p) basis sets. The comparison of calculated bond lengths and angles with X-ray crystal structure shows sufficient agreement. The solid phase FT-IR and FT-RAMAN spectra of LNNN have been recorded in the regions 4000-525 cm-1 and 4000-50 cm-1, respectively. A comparative analysis between the calculated and experimental vibrational frequencies was carried out and significant bands were assigned. The results indicated a good correlation between experimental and theoretical IR and RAMAN frequencies. A detailed analysis of the intermolecular interactions via Hirshfeld surface analysis and fingerprint plots revealed that supramolecular structure of the LNNN is stabilized mainly by the formation of H···H, C···H, Cl···H ve O···H  intermolecular interactions.


Author(s):  
Fatiha Mahdi ◽  
Assia Sid ◽  
Rafika Bouchene ◽  
Paul Mosset ◽  
Thierry Roisnel

The title compound, (E,E)-3-methyl-2,5-bis(4-methylbenzylidene)cyclopentanone (MBMCP), C22H22O, was obtained by Claisen–Schmidt condensation of 4-methylbenzaldehyde with 3-methylcyclopentanone in good yield. The structure of MBMCP was studied using UV, FT–IR and Raman spectroscopy, single-crystal X-ray diffraction (XRD) measurements, and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The molecular structure of MBMCP is fully extended in the E,E configuration. C—H...π stacking interactions play a significant role in the stabilization of the molecular packing. Hirshfeld surface analysis was used to quantify the non-covalent interactions in the crystal lattice. Microbiological studies were performed to investigate the antimicrobial activity of this new product.


Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 963
Author(s):  
Nemanja Vucetic ◽  
Pasi Virtanen ◽  
Ayat Nuri ◽  
Andrey Shchukarev ◽  
Jyri-Pekka Mikkola ◽  
...  

A thorough experimental optimization of supported ionic liquid catalyst (SILCA) was performed in order to obtain a stable and efficient catalyst for the Heck reaction. Out of fifteen proposed structures, propyl imidazolium bromide-tetramethylguanidinium pentanoate modified SiO2 loaded with PdCl2 appeared to be the most stable and to have a good activity in the reaction between butylacrylate and iodobezene, resulting in a complete conversion in 40 min at 100 °C, in four consecutive experiments. This study elucidated on the stability of the catalytic system with an ionic liquid layer during the catalyst synthesis but also under reaction conditions. In the bis-layered catalyst, the imidazolium moiety as a part of internal layer, brought rigidity to the structure, while in external layer pentanoic acid gave sufficiently acidic carboxylic group capable to coordinate 1,1,3,3-tetramethylguanidine (TMG) and thus, allow good dispersion of Pd nanoparticles. The catalyst was characterized by means of XPS, FT-IR, TEM, ICP-OES, ζ-potential, EDX, TGA, and 13C NMR. The release and catch mechanism was observed, whereas Pd re-deposition can be hindered by catalyst poisoning and eventual loss of palladium.


Molbank ◽  
10.3390/m1179 ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. M1179
Author(s):  
Eleftherios Halevas ◽  
Antonios Hatzidimitriou ◽  
Barbara Mavroidi ◽  
Marina Sagnou ◽  
Maria Pelecanou ◽  
...  

A novel Cu(II) complex based on the Schiff base obtained by the condensation of ortho-vanillin with gamma-aminobutyric acid was synthesized. The compounds are physico-chemically characterized by elemental analysis, HR-ESI-MS, FT-IR, and UV-Vis. The complex and the Schiff base ligand are further structurally identified by single crystal X-ray diffraction and 1H and 13C-NMR, respectively. The results suggest that the Schiff base are synthesized in excellent yield under mild reaction conditions in the presence of glacial acetic acid and the crystal structure of its Cu(II) complex reflects an one-dimensional polymeric compound. The molecular structure of the complex consists of a Cu(II) ion bound to two singly deprotonated Schiff base bridging ligands that form a CuN2O4 chelation environment, and a coordination sphere with a disordered octahedral geometry.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
I Mamarelis ◽  
V Mamareli ◽  
M Kyriakidou ◽  
O Tanis ◽  
C Mamareli ◽  
...  

Abstract Background The atherosclerotic ascending aorta could represent a potential source of emboli or could be an indicator of atherosclerosis in general with high mortality. The mechanism of aneurysm formation and atherosclerosis of the ascending aorta at the molecular level has not yet been clarified. To approach the mechanism of ascending aortic lesions and mineralization at a molecular level, we used the non-destructive FT-IR, Raman spectroscopy, SEM and Hypermicroscope. Methods Six ascending aorta biopsies were obtained from patients who underwent aortic valve replacement (AVR) cardiac surgery. CytoViva (einst inc) hyperspectral microscope was used to obtain the images of ascending aorta. The samples were dissolved in hexane on a microscope glass plate. The FT-IR and Raman spectra were recorded with Nicolet 6700 thermoshintific and micro-Raman Reinshaw (785nm, 145 mwatt), respectively. The architecture of ascending aorta biopsies was obtained by using scanning electron microscope (SEM of Fei Co) without any coating. Results FT-IR and Raman spectra showed changes arising from the increasing of lipophilic environment and aggregate formation (Fig. 1). The band at 1744 cm–1 is attributed to aldehyde CHO mode due to oxidation of lipids. The shifts of the bands of the amide I and amide II bands to lower are associated with protein damage, in agreement with SEM data. The bands at about 1170–1000 cm–1 resulted from the C-O-C of advanced glycation products as result of connecting tissues fragmentations and polymerization. The spectroscopic data were analogous with the lesions observed with SEM and hypermicroscopic images. Conclusions The present innovate molecular structure analysis showed that upon ascending aorta aneurysm development an excess of lipophilic aggregate formation and protein lesions, changing the elasticity of the aorta's wall. The released Ca2+ interacted mostly with carbonate-terminal of cellular protein chains accelerated the ascending aorta calcifications. Figure 1. FT-IR and Raman spectra Funding Acknowledgement Type of funding source: None


Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajinkya More ◽  
Thomas Elder ◽  
Zhihua Jiang

Abstract This review discusses the main factors that govern the oxidation processes of lignins into aromatic aldehydes and acids using hydrogen peroxide. Aromatic aldehydes and acids are produced in the oxidative degradation of lignin whereas mono and dicarboxylic acids are the main products. The stability of hydrogen peroxide under the reaction conditions is an important factor that needs to be addressed for selectively improving the yield of aromatic aldehydes. Hydrogen peroxide in the presence of heavy metal ions readily decomposes, leading to minor degradation of lignin. This degradation results in quinones which are highly reactive towards peroxide. Under these reaction conditions, the pH of the reaction medium defines the reaction mechanism and the product distribution. Under acidic conditions, hydrogen peroxide reacts electrophilically with electron rich aromatic and olefinic structures at comparatively higher temperatures. In contrast, under alkaline conditions it reacts nucleophilically with electron deficient carbonyl and conjugated carbonyl structures in lignin. The reaction pattern in the oxidation of lignin usually involves cleavage of the aromatic ring, the aliphatic side chain or other linkages which will be discussed in this review.


Biopolymers ◽  
1984 ◽  
Vol 23 (4) ◽  
pp. 623-627 ◽  
Author(s):  
V. Renugopalakrishnan ◽  
P. H. B. Kloumann ◽  
Rajendra S. Bhatnagar

2012 ◽  
Vol 506 ◽  
pp. 158-161 ◽  
Author(s):  
A. Jaidee ◽  
Pornchai Rachtanapun ◽  
S. Luangkamin

N,O-Carboxymethyl chitosans were synthesized by the reaction between shrimp, crab and squid chitosans with monochloroacetic acid under basic conditions at 50°C. The mole ratio of reactants was obtained from various reaction conditions of shrimp chitosan polymer and oligomer types. The mole ratio 1:12:6 of chitosan:sodium hydroxide:monochloroacetic acid was used for preparing carboxymethyl of chitosan polymer types while carboxymethyl of chitosan oligomer types were used the mole ratio 1:6:3 of chitosan:sodium hydroxide:monochloroacetic acid. The chemical structure was analyzed by fourier transformed infrared spectroscopy (FT-IR) and proton nuclear magnatic resonance spectroscopy (1H-NMR). The FT-IR was used for confirm the insertion of carboxymethyl group on chitosan molecules. The 1H-NMR was used for determining the degree of substitution (DS) of carboxymethylation at hydroxyl and amino sites of chitosans. Carboxymethyl chitosan samples had the total DS of carboxymethylation ranging from 1.0-2.2. The highest of DS of carboxymethylation was from shrimp chitosan oligomer type.


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