scholarly journals Ligand Effects on Structural, Protophilic and Reductive Features of Stannylated Dinuclear Iron Dithiolato Complexes

2020 ◽  
Author(s):  
Hassan Abul-Futouh ◽  
Laith R. Almazahreh ◽  
Sara J. Abaalkhail ◽  
Helmar Görls ◽  
Sven T. Stripp ◽  
...  
Keyword(s):  
Solution Nmr ◽  
Donor Ligands ◽  
Boat Conformation ◽  
Spectroscopic Techniques ◽  
Cyclic Voltammetric ◽  
X Ray Crystallography ◽  
Ligand Effects ◽  
Dinuclear Iron ◽  
Site Exchange

The synthesis and characterization of Fe2(CO)5(L){μ-(SCH2)2}SnMe2 (L = PPh3 (2) and P(OMe)3 (3) derived from the parent hexacarbonyl complex Fe2(CO)6{μ-(SCH2)2}SnMe2 (1) is reported. Whereas 1 exhibits a unique planar structure, X-ray crystallography showed that the apical orientation of L in complexes 2 and 3 results in a chair/boat conformation of the Fe2S2C2Sn fused six-membered rings, which is typical for diiron dithiolato complexes. In solution, NMR and FTIR spectroscopic techniques provide evidence for a dynamic process of apical-basal site exchange of the ligand L in 2 and 3. Protonation experiments on 2 and 3 in MeCN using CF3CO2H, HCl or HBF4·Et2O suggest enhanced protophilicity of the Fe-Fe bond due to the presence of the electron donor ligands L as well as the stannylation effect. While the carbonyl ligands in 2 stretch at lower wavenumbers ν(CO) than those in 3, the cyclic voltammetric reduction of 2 unpredictably occurs at less negative potential than that of 3. In contrast to 1, the presence of PPh3 and P(OMe)3 in 2 and 3, respectively, allows protonation prior to reduction as shown by FTIR spectroscopy and cyclic voltammetry.

scholarly journals Ligand Effects on Structural, Protophilic and Reductive Features of Stannylated Dinuclear Iron Dithiolato Complexes

2020 ◽  
Author(s):  
Hassan Abul-Futouh ◽  
Laith R. Almazahreh ◽  
Sara J. Abaalkhail ◽  
Helmar Görls ◽  
Sven T. Stripp ◽  
...  
Keyword(s):  
Solution Nmr ◽  
Donor Ligands ◽  
Boat Conformation ◽  
Spectroscopic Techniques ◽  
Cyclic Voltammetric ◽  
X Ray Crystallography ◽  
Ligand Effects ◽  
Dinuclear Iron ◽  
Site Exchange

The synthesis and characterization of Fe2(CO)5(L){μ-(SCH2)2}SnMe2 (L = PPh3 (2) and P(OMe)3 (3) derived from the parent hexacarbonyl complex Fe2(CO)6{μ-(SCH2)2}SnMe2 (1) is reported. Whereas 1 exhibits a unique planar structure, X-ray crystallography showed that the apical orientation of L in complexes 2 and 3 results in a chair/boat conformation of the Fe2S2C2Sn fused six-membered rings, which is typical for diiron dithiolato complexes. In solution, NMR and FTIR spectroscopic techniques provide evidence for a dynamic process of apical-basal site exchange of the ligand L in 2 and 3. Protonation experiments on 2 and 3 in MeCN using CF3CO2H, HCl or HBF4·Et2O suggest enhanced protophilicity of the Fe-Fe bond due to the presence of the electron donor ligands L as well as the stannylation effect. While the carbonyl ligands in 2 stretch at lower wavenumbers ν(CO) than those in 3, the cyclic voltammetric reduction of 2 unpredictably occurs at less negative potential than that of 3. In contrast to 1, the presence of PPh3 and P(OMe)3 in 2 and 3, respectively, allows protonation prior to reduction as shown by FTIR spectroscopy and cyclic voltammetry.

X-ray crystallography and solution NMR spectroscopy characterization of heptakis(2,3-di-O-acetyl-6-bromo-6-deoxy)cyclomaltoheptaose

2004 ◽  
Vol 339 (6) ◽  
pp. 1189-1194 ◽  
Author(s):  
Petros Giastas ◽  
Kyriaki Eliadou ◽  
Zoi F. Plyta ◽  
Konstantina Yannakopoulou ◽  
Irene M. Mavridis
Keyword(s):  
Nmr Spectroscopy ◽  
Solution Nmr ◽  
X Ray ◽  
X Ray Crystallography ◽  
Solution Nmr Spectroscopy

scholarly journals Ligand effects on structural, protophilic and reductive features of stannylated dinuclear iron dithiolato complexes

2021 ◽  
Vol 45 (1) ◽  
pp. 36-44
Author(s):  
Hassan Abul-Futouh ◽  
Laith R. Almazahreh ◽  
Sara J. Abaalkhail ◽  
Helmar Görls ◽  
Sven T. Stripp ◽  
...  
Keyword(s):  
Synthesis And Characterization ◽  
Ligand Effects ◽  
Dinuclear Iron

The synthesis and characterization of Fe2(CO)5(L){μ-(SCH2)2SnMe2} (L = PPh3 (2) and P(OMe)3 (3)) derived from the parent hexacarbonyl complex Fe2(CO)6{μ-(SCH2)2}SnMe2 (1) are reported.

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

NMR Studies of the Inclusion Complexes Between Ezetimibe and Cyclodextrins

2018 ◽  
Vol 69 (7) ◽  
pp. 1838-1841
Author(s):  
Hajnal Kelemen ◽  
Angella Csillag ◽  
Bela Noszal ◽  
Gabor Orgovan
Keyword(s):  
Inclusion Complex ◽  
Inclusion Complexes ◽  
Water Solubility ◽  
Solution Nmr ◽  
Spectroscopic Techniques ◽  
Nmr Studies ◽  
The Poor ◽  
Poor Water Solubility

Ezetimibe, the antihyperlipidemic drug of poor bioavailability was complexed with native and derivatized cyclodextrins.The complexes were characterized in terms stability, stoichiometry and structure using various 1D and 2D solution NMR spectroscopic techniques. The complexes were found to be of moderate stability (logK[3). The least stable inclusion complex is formed with b-cyclodextrin, while the ezetimibe-methylated-b--cyclodextrin has a 7-fold higher stability. The results can be useful to improve the poor water-solubility and the concomitant bioavailability of ezetimibe.

Synthesis and Characterization of Potential and Degraded Impurities of Regadenoson

2020 ◽  
Vol 16 (8) ◽  
pp. 1130-1139
Author(s):  
Singaram Sathiyanarayanan ◽  
Chidambaram Subramanian Venkatesan ◽  
Senthamaraikannan Kabilan
Keyword(s):  
Mass Spectra ◽  
Degradation Products ◽  
Hplc Method ◽  
Forced Degradation ◽  
Spectroscopic Techniques ◽  
A2a Adenosine Receptor ◽  
Degradation Study ◽  
Related Substances ◽  
Adenosine Receptor Agonist

Background: Regadenoson is an A2A adenosine receptor agonist that is a coronary vasodilator and commonly used as a pharmacologic cardiac stressing agents. Methods: HPLC method was used for the analysis of related substances. The degraded impurities during the process were isolated and characterized by IR, Mass and NMR spectral analysis. Results: Forced degradation study of regadenoson under conditions of hydrolysis (neutral, acidic and alkaline) and oxidations suggested in the ICH Q1A(R2) was accomplished. The drug showed significant degradation under all the above conditions. On the whole, five novel degradation products were found under diverse conditions along with process related impurities which were not reported earlier. Conclusion: All the degradation products were well characterized by using advanced spectroscopic techniques like IR, 1H NMR, 13C NMR and Mass spectra. The identification of these impurities will be productive for the quality control during the production and stability behavior of the regadenoson drug substance.

Synthesis of sandwich type acyclic tetra-nuclear silver(I)-N-heterocyclic carbene complexes for wound healing applications

2020 ◽  
Vol 75 (9-10) ◽  
pp. 369-376
Author(s):  
Ayesha Riaz ◽  
Muhammad Adnan Iqbal ◽  
Haq Nawaz Bhatti ◽  
Muhammad Shahid
Keyword(s):  
Alkyl Halides ◽  
Wound Contraction ◽  
Spectroscopic Techniques ◽  
Open Chain ◽  
Standard Drug ◽  
Sandwich Type ◽  
Benzimidazolium Salts ◽  
Multistep Reaction

AbstractTwo meta-xylyl linked tetrakis-benzimidazolium salts (L1-L2) as multidentate ligands and two respective silver complexes (C1 and C2) were synthesized. A multistep reaction was done at room temperature, starting with simple benzimidazole and alkyl halides, going through precursors and salt formation by reflux and finally in situ deprotonation of tetrabenzimidazolium salts with Ag2O to yield respective tetra-nuclear Ag(I)-N-heterocyclic Carbene (NHC) complexes. Propyl and butyl groups were bonded at the terminal positions of tetra-azolium open chain salts. Characterization of compounds was done by analytical and spectroscopic techniques. On the basis of spectroscopic data, a chemical structure with open chains having four Ag(I) ions sandwiched between NHC layers was established. Potential of synthesized complexes (C1 & C2) for wound contraction was evaluated and compared with standard wound contraction gel. Percentage wound contraction of both complexes was found very close to that of standard drug used in parallel.

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