scholarly journals Experimental and Quantum Mechanical Investigation of N-heterocyclic Carbene Palladium Complex: Synthesis and Antibacterial Activity

2021 ◽  
Vol 12 (6) ◽  
pp. 7804-7816

In this study, we report the synthesis, characterization, and biological activity of Pd-NHC-PEPPSI complex 2a. Further confirmations of structural details were provided by a single-crystal X-ray. A single crystal of 2a shows that the coordination geometry around Pd slightly distorted square-planar geometry. Intermolecular interactions have been studied through the NBO analyses. Structural parameters and spectroscopic properties of the complexes are well interpreted by DFT and TD-DFT calculations. Moreover, the complex 2a showed a remarkable antimicrobial effect against Micrococcus luteus LB 14110mm, Listeria monocytogenes ATCC 19117, Salmonella typhimurium ATCC 14028, Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa, and Candida albicans.

2020 ◽  
Vol 98 (4) ◽  
pp. 194-203 ◽  
Author(s):  
Sefia Brahim ◽  
Houari Brahim ◽  
Stéphane Humbel ◽  
Ali Rahmouni

Detailed theoretical studies of Ni(II) complexes in a distorted square planar form and containing dithio and (P, P) chelating ligands were performed. These Ni(II) complexes are investigated for their use in dye-sensitized solar cells (DSSC). Structures and UV–vis spectra are calculated at density functional theory (DFT) and time-dependent density functional theory (TD-DFT) theories using B3LYP and CAM-B3LYP functionals and 6-31G(d,p) and 6-31G+(d) basis sets. Geometry optimizations result in excellent agreement with the experimental results. Moreover, the analysis of the frontier molecular orbitals (FMOs) allowed a detailed assignment and a clear analysis of the electronic transitions. The TD-DFT calculations reproduce the main spectroscopic properties observed and substituent effects. The results reveal that all absorption spectra are characterized by mixed character mainly dominated by metal to ligand and ligand to ligand charge transfers (MLCT and LLCT). We unveil how the substituent variations affect the DSSCs features of the complexes.


1992 ◽  
Vol 47 (4) ◽  
pp. 517-525 ◽  
Author(s):  
Thomas G. Meyer ◽  
Peter G. Jones ◽  
Reinhard Schmutzler

A new synthesis for 2-chloro-1,3,5-trimethyl-4,6-dioxo-1,3,5,2λ3-triazaphosphinane (1) is described. Chlorine-fluorine exchange in 1 by means of sodium fluoride in acetonitrile in the presence of catalytic amounts of a crown ether furnished 2-fluoro-1,3,5-trimethyl-4,6-dioxo-1,3,5,2λ3-triazaphosphinane (2). The synthesis of the bromine and iodine analogues, 3 and 4, by metathesis of 1 with the appropriate trimethylsilyl halides, Me3SiBr and Me3SiI, respectively, is also described. The syntheses of an iron(0)tetracarbonyl complex (5) and of a dichloroplatinum( II) complex (6) are reported. A single crystal X-ray diffraction study was conducted on 6. [P21/c, a = 1161.3(3), b = 1423.2(3), c = 1247.7(3) pm, β = 109.42(2)°, R = 0.028], There are deviations from ideal square planar geometry at platinum. The heterocycles display a flattened boat conformation. A Staudinger reaction of 1 with Me3SiN3 led to the formation of a substituted cyclotriphosphazene.


2020 ◽  
Vol 43 (1) ◽  
pp. 111-116
Author(s):  
Milan Melník ◽  
Peter Mikuš

AbstractIn this review are analyzed and classified crystallographic and structural parameters of P(0)P3, Pt(0) P4 and Pt(II)P4 derivatives – distortion isomers. Some of the isomers are differing not only by degree of distortion but also by crystal class. There are three types of organo-phosphines which build up the respective geometry about the platinum atoms. In Pt(0)P3 a distorted trigonal planar geometry is build up by three monodentate PPh3 ligands. In Pt(0)P4 a tetrahedral geometry with various degree of distortion is build up by a pair of homo-bidentate ligands. In Pt(II)P4 isomers a square-planar geometries with various degree of distortion are build up by bidentate-P,P’donor ligands, (except one example of isomers, where a tetradentate is involved). The bidentate-P,P’-donor ligands form: four-(PNP,PCP), five-(PC2P) and six-(PC3P) metallocyclic rings. The tetradentate forms five-(PC2P). There are some cooperative effects between Pt–P bond distances and the metallocyclic rings, and at the same time a distortion of the respective geometry increases.


2020 ◽  
Vol 44 (1) ◽  
pp. 12-21
Author(s):  
Milan Melník ◽  
Peter Mikuš

Abstract This review covers over fifty Pt (II) complexes of the compositions PtP3X (X = H, OL, NL, BL, Cl, SL, Br, or I). These complexes crystallized in three crystal classes: monoclinic (23 examples) triclinic (17 examples) and orthorhombic (11 examples). The PtP3Cl is most common with 23 examples. There are variable combinations of organophosphines monodentate – P; bidentate- P,P; P,N; P,B; and tridentate – P,P,P; P,O,P; P,N,P; and P,S,P. The structural parameters (Pt–L, L–Pt–L) are analyzed and discussed with an attention to the distortion of a square-planar geometry about the Pt (II) atoms as well as of trans-influence. The sums of Pt–L (x4) bond distances growing with covalent radius of the X-atoms.


Author(s):  
Bhausaheb Dhokale ◽  
Indresh Singh Yadav ◽  
Shaikh M. Mobin ◽  
Rajneesh Misra

Thioether linked meso BODIPY DYEmer 3 was synthesized by two different routes. The reaction of dipyrrothioketone 1 and 8-chloro BODIPY 2 in the presence of triethylamine followed by complexation with [Formula: see text] resulted in thioether linked meso functionalized BODIPY DYEmer 3. Using another route, the reaction of 8-chloro BODIPY 2 with sodium hydrosulphide (NaSH) at room temperature resulted in the thioether linked meso BODIPY DYEmer 3. The DYEmer 3 was characterized by 1H, [Formula: see text]C, [Formula: see text]B, [Formula: see text]F NMR, HRMS, and single crystal X-ray crystallography. The properties of DYEmer 3 was compared with the previously reported thioether linked [Formula: see text] and [Formula: see text] BODIPY DYEmers 4 and 5. The structural parameters indicating the intramolecular arrangements of two BODIPY units of DYEmer were compared and corelated with the observed properties. The time-dependent DFT (TD-DFT) calculations suggested that the thioether group at meso position of BODIPY 3 stabilizes the LUMO energy than 8-chloro BODIPY 2. Compared to 8-chloro BODIPY 2 the HOMO-1 of DYEmer 3 is destabilized whereas the LUMO+1 is stabilized.


Inorganics ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 76 ◽  
Author(s):  
Elia Barchi ◽  
Francesco Musiani

InrS (internal nickel-responsive sensor) is a transcriptional regulator found in cyanobacteria that represses the transcription of the nickel exporter NrsD in the apo form and de-represses expression of the exporter upon Ni(II) binding. Although a crystal structure of apo-InrS from Synechocystis PCC 6803 has been reported, no structure of the protein with metal ions bound is available. Here we report the results of a computational study aimed to reconstruct the metal binding site by taking advantage of recent X-ray absorption spectroscopy (XAS) data and to envisage the structural rearrangements occurring upon Ni(II) binding. The modelled Ni(II) binding site shows a square planar geometry consistent with experimental data. The structural details of the conformational changes occurring upon metal binding are also discussed in the framework of trying to rationalize the different affinity of the apo- and holo-forms of the protein for DNA.


1999 ◽  
Vol 77 (9) ◽  
pp. 1492-1497 ◽  
Author(s):  
Sandra Signorella ◽  
Claudia Palopoli ◽  
Alejandro Frutos ◽  
Graciela Escandar ◽  
Tomoaki Tanase ◽  
...  

The 3-deoxy-D-erythro-hexos-2-ulose bis(thiosemicarbazone) (LH2) acts as a tetradentate ligand with S2N2 donor sites to form a copper(II) chelate (Cu(II)L). The Cu K-edge X-ray absorption spectra analysis of a powdered sample revealed a square-planar S2N2 local coordination geometry with average Cu—N and Cu—S distances of 1.92 and 2.33 Å. The EXAFS and XANES spectra and the structural parameters of a DMF solution sample indicate the retention of the square-planar local structure of the Cu(II)S2N2 chromophore upon dissolution. Semiempirical PM3 calculations indicate that the structure of Cu(II)L with the copper(II) ion bound to the S2N2 donor set disposed in a square-planar geometry is the most favorable one (with the highest |ΔHf |). The formation constant (log Kf = 20.65 ± 0.06) of the neutral [CuL] species was calculated in 30% v/v dioxane-water and the protonation and deprotonation constants determined.Key words: bis(thiosemicarbazone), copper(II), chelate, structure, stability constant.


Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 6
Author(s):  
Mezna Saleh Altowyan ◽  
Saied M. Soliman ◽  
Matti Haukka ◽  
Nora H. Al-Shaalan ◽  
Aminah A. Alkharboush ◽  
...  

Hydrolysis/[3 + 2] cycloaddition/elimination cascades employed for the synthesis of unexpected tricyclic compound derived from isoquinoline. Reaction of ethylene derivative 1 with the isoquinoline ester iminium ion 2 in alkaline medium (MeOH/NEt3) under reflux for 1 h resulted in the formation of the fused pyrrolo[2,1-a]isoquinoline derivative 3. Its structure was elucidated by X-ray single crystal and other spectrophotometric tools. Hirshfeld calculations for 3 and its crystal structure analysis revealed the importance of the short O…H (19.1%) contacts and the relatively long H…C (17.1%), Cl…H (10.6%) and C…C (6.1%) interactions in the molecular packing. DFT calculations were used to compute the electronic and spectroscopic properties of the studied system. The studied compound has polar nature (3.5953 Debye). TD-DFT calculations assigned the shortest wavelength band (220 nm) to the HOMO−1→LUMO+2 (57%), HOMO−1→LUMO+4 (14%) mixed excitations. The calculated NMR chemical shifts correlated very well with the experimental data (R2 = 0.93–0.94).


2016 ◽  
Vol 81 (11) ◽  
pp. 1263-1272 ◽  
Author(s):  
Xin Wang ◽  
Jieqiong Li ◽  
Li Wang ◽  
Wenpeng Wu ◽  
Zheng Du ◽  
...  

The geometries, electronic structures, and spectral properties of three metal complexes Zn(C10H12N3OS)2 (1), Ni(C10H12N3OS)2 (2), and Pd(C10H12N3OS)2 (3) with N-(2-pyridinyl)morpholine-4-carbothioamide as a ligand are investigated by means of DFT (density functional theory) and TD-DFT (time-dependent density functional theory) methods. Complex 1 is a distorted tetrahedral geometry, while complexes 2 and 3 present a distorted square-planar coordination environment. In the simulated range, the spectrum of complex 1 has five obvious absorption peaks and one of them has the strongest intensity. The latter two complexes have one more absorption peak and shoulder peak with the similar intensity. Moreover, the strongest peaks of complexes 2.


2018 ◽  
Vol 73 (10) ◽  
pp. 713-718 ◽  
Author(s):  
Kiran Nakum ◽  
Rajendrasinh N. Jadeja

Abstract1-(2-Chlorophenyl)-3-methyl-4-propionyl-1H-pyrazol-5(4H)-one was synthesized and characterized by Fourier transform infrared (FT-IR) spectroscopy, 1H nuclear magnetic resonance, and single-crystal X-ray analysis. Its Cu(II) complex was prepared and characterized by FT-IR, thermo gravimetric analysis-differential thermal analysis, ultraviolet-visible spectroscopy, cyclic voltammetry, and single-crystal X-ray structure determination. On the basis of analytical and spectroscopic techniques, a distorted square planar geometry of the complex has been found.


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