E/Z Isomerization of 3-Hydrazonocamphor Promoted by Coordination to Palladium or Platinum

2007 ◽  
Vol 72 (5-6) ◽  
pp. 649-665 ◽  
Author(s):  
M. Fernanda N. N. Carvalho ◽  
Ana S. D. Ferreira ◽  
João L. Ferreira da Silva ◽  
Luís F. Veiros
Keyword(s):  
Free Ligand ◽  
Intramolecular Hydrogen Bonding ◽  
Planar Geometry ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Square Planar ◽  
Intramolecular Hydrogen ◽  
C Nmr

3-Hydrazonocamphor, 3-(RR1NN)C10H14O (R = Me, R1 = H), undergoes intramolecular hydrogen bridging by coordination to platinum or palladium. This effect is evidenced by considerable decrease in the ν(C=O) frequency (compared to the free ligand) in the IR spectra of the complexes [MCl2L2] (M = Pd, Pt; L = 3-(RR1NN)C10H14O) as well as by the magnetic non- equivalence of the two ligands, as revealed by 13C NMR. DFT calculations indicate that coordination of 3-(Me(H)NN)C10H14O promotes E/Z isomerization of the hydrazono group of the ligand, inducing formation of intramolecular hydrogen bonding and corresponding stabilization of the complex. Characterization of the complexes [MCl2L2] (M = Pt; L: R, R1 = Me (1), R = Me, R1 = H (2) and M = Pd; L: R = Me, R1 = H (3)) was performed by analytical and spectroscopic techniques. Redox properties of the 3-hydazonocamphors and their complexes were studied by cyclic voltammetry. The structure of trans-[PtCl2{3-(Me2NN)C10H14O}2] was determined by single-crystal X-ray diffraction analysis. The complex has square-planar geometry and crystallizes in the tetragonal P43 space group.

scholarly journals Structural, Spectroscopic, and Chemical Bonding Analysis of Zn(II) Complex [Zn(sal)](H2O): Combined Experimental and Theoretical (NBO, QTAIM, and ELF) Investigation

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 259
Author(s):  
Mohammad Usman ◽  
Rais Ahmad Khan ◽  
Ali Alsalme ◽  
Walaa Alharbi ◽  
Khadijah H. Alharbi ◽  
...  
Keyword(s):  
Planar Geometry ◽  
Monoclinic Space Group ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Theoretical Approaches ◽  
Square Planar ◽  
The Difference ◽  
Dft And Tddft Calculations ◽  
Supportive Nature

The Zn(II) complex of salen-like scaffold [Zn(sal)](H2O) was synthesized and characterized by elemental analysis, IR, UV–Vis, and 1H-NMR spectroscopic techniques. The structure of complex was confirmed by single crystal X-ray diffraction studies. In the complex, Zn (II) was placed in the inner N2O2 compartment of the salen scaffold in square planar geometry and crystallized in the monoclinic space group P21/n. DFT and TDDFT calculations were performed to reproduce the experimentally observed structural and spectroscopic (IR and UV–vis) findings. The bonding of the Zn(II) framework in the [Zn(sal)](H2O) complex was explored in depth. The theoretical approaches employed were perturbation theory within the context of the natural bond orbital (NBO) framework, and quantum theory of atoms in molecule (QTAIM) and electron localization function (ELF) analysis. The study begins by delineating the difference between the NBO and QTAIM approaches. This paper thus exhibits the supportive nature of NBO theory and QTAIM in discussion of the bonding in the [Zn(sal)](H2O) complex, when both the methodologies are used in combination.

Design and Characterization of New Dinuclear Macrocyclic Dithiocarbamate Complexes by the Preparation of a Free Ligand Derived from Isopropylamine

2021 ◽  
pp. 1-15
Author(s):  
Noor Al-Huda A.H Al-Mohammadi ◽  
Aeed S.M Al-Fahdawi ◽  
Sattar S.I Al-Janabi
Keyword(s):  
Free Ligand ◽  
13C Nmr Spectroscopy ◽  
Macrocyclic Complexes ◽  
Planar Geometry ◽  
Basic Solution ◽  
Square Planar ◽  
Dithiocarbamate Ligand ◽  
Schiff Base Formation ◽  
Base Formation

The synthesis and structural characterization of new dithiocarbamate (DTC) ligand and some of its dinuclear transition metal complexes are described. The free dithiocarbamate ligand was prepared through several synthetic routes, including Schiff-base formation. The reaction of 2-aminopropane with terephthaldehyde leads to the formation of Schiff_base which is reduced by methanolic NaBH4 to the corresponding secondary diamine. Diamine( N,N'_ (1,4 phenylenebis (methylene)) bis(propan-2 amine))  reacts with (CS2) in a basic solution of (KOH) to provide the corresponding bis(dithiocarbamate) free_ligand, which undergoes complexation with the appropriate metal   (II) chloride to constitute macrocyclic complexes. Characterization of the ligand and its complexes was achieved by FTIR, UV-Vis, melting points, conductance, magnetic susceptibility, and 1H, 13C NMR spectroscopy. The analytical and spectroscopic data were employed to obtain the suggested geometries around metal centres. These studies revealed the formation of dinuclear macrocyclic complexes of the general formula [M(L)]2 (where M= Mn(II) , Fe(II), Co(II), Ni(II), Cu(II)  and Zn(II)), with tetrahedral. geometries for Mn(II) , Fe(II), Co(II) and Zn(II),  and square. planar geometry with Ni(II) and Cu(II) complexes.

scholarly journals Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1498 ◽  
Author(s):  
Abdul Hafeez ◽  
Zareen Akhter ◽  
John F. Gallagher ◽  
Nawazish Ali Khan ◽  
Asghari Gul ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Spectroscopic Characterization ◽  
Spectroscopic Techniques ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
Electrically Conductive ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Ft Ir

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

scholarly journals Metal Complexes of π-Expanded Ligand (7): Syntheses, Structures and Properties of Pt(II) Complexes Containing the Isomeric 1- and 2-Alkyliminomethyl Pyrene Ligands

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 476 ◽  
Author(s):  
Xuan-Dien Luong ◽  
Xuan-Truong Nguyen
Keyword(s):  
Molecular Structure ◽  
Planar Geometry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pt Complex ◽  
Physico Chemical ◽  
Clear Explanation ◽  
Square Planar ◽  
Structures And Properties ◽  
The Relationship

A [O,N] bidentate π-expanded ligand system, (E)-1-(n-octylimino)methylpyren-2-ol (2), was newly synthesized via a six-step synthesis from pyrene. The ligand 2 reacts with [PtCl2(PhCN)2] in chlorobenzene and the presence of a base at reflux for 2 h under the formation of (2(Pt)) complex with a yield of 70%. The molecular structure of (2(Pt)), studied by common spectroscopic methods and X-ray diffraction, shows a square planar geometry with a trans-configuration of the ligands. The molecular structure, absorption spectra, electrochemical properties, and phosphorescence characteristics of the (2(Pt)) complex are discussed, emphasizing the comparison with those of the previously reported Pt complex (1(Pt)) containing the isomeric ligands of 2, (E)-2-(n-octylimino)methylpyren-1-ol. The DFT calculations of the two Pt complexes are carried out and exhibit a clear explanation of the relationship between their physico-chemical characteristics.

Synthesis and characterization of novel poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive

2020 ◽  
Vol 98 (12) ◽  
pp. 755-763
Author(s):  
Hamid Reza Ghayeni ◽  
Reza Razeghi ◽  
Abolfazl Olyaei
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Sodium Acrylate ◽  
Spectroscopic Techniques ◽  
Effective Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cds Nanorods ◽  
Transmission Electron

Cadmium sulfide nanorods with a length of 69 nm have been prepared by using Cd(OAc)2.2H2O and S8 at 125 °C in the presence of triethylenetetramine as the template agent and coordination agent and characterized by using X-ray diffraction, transmission electron microscopy, FTIR, photoluminescence, and UV–vis absorption spectroscopic techniques. Photocopolymerization of glycidyl methacrylate (GMA) and sodium acrylate (SA) was carried out using CdS nanorods as a photocatalyst under UV light exposure at 400 nm in the presence of β-cyclodextrin (β-CD). To optimization of the effective parameters on the synthesis of copolymer nanocomposite, the amounts of initiator, monomers, and β-CD, duration of pre-deoxygenation, and light wavelength were evaluated. Ring opening of poly(GMA-co-SA)/CdS nanocomposite with NaN3 afforded poly(HAzPMA-co-SA)/CdS nanocomposite and subsequent mixing with RDX in DMF led to the formation of poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive. All of the copolymer nanocomposites were characterized using various tools of instrumental analysis.

Structural and Spectral Studies of Palladium (II) Complexes of Pyridil bis{3-Piperidyl-, bis{Hexamethyleneiminyl-, bis{N(4)-Diethyl- and bis{N(4)-Dipropylthiosemicarbazone}

2000 ◽  
Vol 55 (9) ◽  
pp. 863-870 ◽  
Author(s):  
Alfonso Castiñeiras ◽  
Maria Gil ◽  
Elena Bermejo ◽  
Douglas X. West
Keyword(s):  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Intramolecular Hydrogen Bonding ◽  
Isomeric Form ◽  
Spectral Studies ◽  
Imine Nitrogen ◽  
Pyridine Nitrogen ◽  
Square Planar ◽  
Intramolecular Hydrogen ◽  
C Nmr

Pyridil bis{N(4)-substituted thiosemicarbazones}, in which the substituents replacing the NH2 group on the thiosemicarbazone moieties are piperidyl, H2Plpip; hexamethyleneiminyl, H2Plhexim; diethylamino, H2Pl4DE; and dipropylamino, H2PI4 DP, have been synthesized. Representative palladium(II) complexes of these bis (thiosemicarbazones) have been characterized by IR, electronic, mass, and 1H and 13C NMR spectroscopy. Crystal structures have been determined for H2Plhexim and two of its palladium(II) complexes. H2Plhexim is in the Z isomeric form with intramolecular hydrogen bonding from both thiosemicarbazone moieties to pyridine nitrogens. [Pd(Plhexim)] has square-planar N2S2 coordination (i.e., imine nitrogen and thiolato sulfur atoms). [Pd2 (Plhexim)Cl2 · DMSO has two PdNNSCl centers with the pyridine nitrogen, imine nitrogen or hydrazinic nitrogen and thiolato sulfur atoms coordinated

Preparation and Characterization of TiO2 Nanostructures for Catalytic CO2 Photoconversion

2011 ◽  
Vol 183 ◽  
pp. 89-94 ◽  
Author(s):  
Anna Iwulska ◽  
G. Sliwinski
Keyword(s):  
Active Surface ◽  
Laser Pulses ◽  
Point Of View ◽  
Deep Penetration ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
Content Ratio ◽  
Photocatalytic Applications

The titanium dioxide target (99.7%) of 1 cm in dia was ablated in vacuum by laser pulses (6 ns) at 266 nm and at repetition rate of 10 Hz. During deposition the laser fluence between 1 and 3.5 J/cm2 and the O2 pressure from the range of 10-2 – 1 Pa were applied. The thin TiO2 films were deposited on glass substrate (1 × 1 cm2) heated up to 500 °C. The chemical composition of the film and samples produced by annealing were investigated by spectroscopic techniques (μ-Raman, EDX) and the structure, porosity and surface morphology were analysed by means of SEM and x-ray diffraction (XRD). The SEM inspection of the TiO2 thin film samples indicates that the obtained material is mostly crystalline. After annealing in O2 at 500 °C the structure characterized by the presence of both anatase and rutile phases is observed in the Raman spectra and confirmed by the XRD data. The phase content ratio depends on the O2 pressure applied. Results confirm that nanostructures produced in this way represent densely packed columns and promote deep penetration of guest particles such as CO2.The resulting large active surface is advantageous from the point of view of photocatalytic applications.

scholarly journals Synthesis and Characterization of Catecholato Copper(II) Complexes with Sterically Hindered Neutral and Anionic N3 Type Ligands: Tris(3,5-diisopropyl-1-pyrazolyl)methane and Hydrotris(3,5-diisopropyl-1-pyrazolyl)borate

Inorganics ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 37 ◽  
Author(s):  
Kiyoshi Fujisawa ◽  
Tetsuya Ono ◽  
Moemi Okamura
Keyword(s):  
Planar Geometry ◽  
X Ray ◽  
Pyramidal Geometry ◽  
Square Planar ◽  
Ct Transitions ◽  
Sterically Hindered ◽  
Protonated Ligand ◽  
Square Pyramidal Geometry ◽  
Oxidation State Of Copper

Three catecholato copper(II) complexes, [Cu(catCl4)(L1′)], [Cu(catBr4)(L1′)], and [Cu(catCl4)(L1H)], supported by sterically hindered neutral and anionic N3 type ligands: tris(3,5-diisopropyl-1-pyrazolyl)methane (referred to as L1′) and hydrotris(3,5-diisopropyl-1-pyrazolyl)borate (referred to as L1−), are synthesized and characterized in detail. Their X-ray structures reveal that both [Cu(catCl4)(L1′)] and [Cu(catBr4)(L1′)] complexes have a five-coordinate square-pyramidal geometry and [Cu(catCl4)(L1H)] complex has a four-coordinate square-planar geometry. The L1H is unusual protonated ligand that controls its overall charge. For the three catecholato copper(II) complexes, the oxidation state of copper is divalent, and catechol exists in catecholate as two minus anion. This difference in coordination geometry affects their d-d and CT transitions energy and ESR parameters.

Metallation of Ligands with Biological Activity: Synthesis And X-Ray Characterization of [(SDAZ)2Au2(dppe)] (SDAZ = Sulphadiazinide Anion; dppe = 1,2-Bis(diphenylphosphanyl)ethane)

2005 ◽  
Vol 60 (3) ◽  
pp. 318-321 ◽  
Author(s):  
Lenice L. Marques ◽  
Gelson Manzoni Oliveira ◽  
Ernesto Schulz Lang ◽  
Robert A. Burrow
Keyword(s):  
Free Ligand ◽  
Gold Atom ◽  
High Reactivity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ethane Molecule ◽  
Anti Conformation ◽  
Amine Groups ◽  
Novel Complex

Sulphadiazine, [4-amino-N-(2-pyrimidinyl)-benzenesulfonamide], reacts with (dppe)Au2Cl2 and triethylamine in methanol to produce [(SDAZ)2Au2(dppe)]. The structure of this novel complex was analyzed by single crystal X-ray diffraction. In [(SDAZ)2Au2(dppe)] the ligands SDAZ− and dppe have approximately the same bond distances and angles as found for the protonated and free ligand, respectively. The compound is assembled essentially of two gold atoms bonded to the phosphorus centers of one 1,2-bis(diphenylphosphanyl)ethane molecule (in an anti conformation). The coordination sphere is completed with a trans sulphadiazine ligand on each gold atom. Because of their fairly high reactivity, the two aromatic amine groups in the SDAZ ligands represent important sites for the chemical modification of the complex with biological purposes

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