A spectroscopic study of sulphide, selenide, and telluride complexes of palladium(II) and mercury(II)

1973 ◽  
Vol 26 (12) ◽  
pp. 2615 ◽  
Author(s):  
JE Fergusson ◽  
KS Loh
Keyword(s):  
Low Temperature ◽  
Low Frequency ◽  
Temperature Inversion ◽  
Spectroscopic Techniques ◽  
Electronic Effects ◽  
Sulphur Atom ◽  
Spectral Bands ◽  
Bonding System ◽  
Square Planar ◽  
Square Planar Complexes

trans-Square planar complexes of the type PdX2L2 (X = Cl, Br, I, NO3, NO2 and L = R2S, Et2Se, Et2Te, PhRS, PhEtSe) have been prepared and studied using low-frequency i.r., 1H N.M.R., and u.v.-visible spectroscopic techniques. The i.r. and u.v.-visible spectral bands have been assigned. The 1H N.M.R. spectra have proved informative in separating out the different electronic effects transmitted through both the bonding system as well as through space. Evidence for low temperature inversion about the pyramidal sulphur atom has been obtained for a number of complexes. The dimeric, halogen-bridged mercury(II) complexes [HgX2L]2 (X = Cl, Br; L = R2S Et2S, Et2Te and X = I; L = Et2Se) have been isolated and studied in a similar manner.

π-BONDING IN INORGANIC COMPOUNDS: II. THE TRANSMISSION OF ELECTRONIC EFFECTS THROUGH SQUARE-PLANAR COMPLEXES

1961 ◽  
Vol 39 (2) ◽  
pp. 324-330 ◽  
Author(s):  
A. D. Westland ◽  
L. Westland
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Central Atom ◽  
Inorganic Compounds ◽  
Electron Drift ◽  
Electronic Effects ◽  
Trans Effect ◽  
Pyridine Ligands ◽  
Square Planar ◽  
In Trans ◽  
Square Planar Complexes

Measurement of the transmission of electronic effects through square-planar complexes of platinum has provided evidence of double bonding to halogen and nitro ligands. The nuclear magnetic resonance chemical shift of the β-protons in pyridine ligands serves as an indicator of electron drift in the complexes. Justification is thus provided for the assumed mechanism of the trans effect involving π-bonding. The observations are in accord with the assumption that the increase in trans-directing powers with atomic number of the halogen is due to an increasing tendency to accept d-electrons from the central atom.

scholarly journals Synthesis, Characterization, and Non-Covalent Interactions of Palladium(II)-Amino Acid Complexes

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4331
Author(s):  
David B. Hobart ◽  
Michael A. G. Berg ◽  
Hannah M. Rogers ◽  
Joseph S. Merola
Keyword(s):  
Amino Acid ◽  
High Resolution Mass Spectrometry ◽  
Resonance Spectroscopy ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
Amino Acid Complexes ◽  
Acetone Water ◽  
Square Planar ◽  
Non Covalent Interactions ◽  
Covalent Interactions

The reaction of palladium(II) acetate with acyclic amino acids in acetone/water yields square planar bis-chelated palladium amino acid complexes that exhibit interesting non-covalent interactions. In all cases, complexes were examined by multiple spectroscopic techniques, especially HRMS (high resolution mass spectrometry), IR (infrared spectroscopy), and 1H NMR (nuclear magnetic resonance) spectroscopy. In some cases, suitable crystals for single crystal X-ray diffraction were able to be grown and the molecular structure was obtained. The molecular geometries of the products are discussed. Except for the alanine complex, all complexes incorporate water molecules into the extended lattice and exhibit N-H···O and/or O···(HOH)···O hydrogen bonding interactions. The non-covalent interactions are discussed in terms of the extended lattice structures exhibited by the structures.

Chlorine nuclear quadrupole resonance in some chloro complexes of divalent copper

1971 ◽  
Vol 24 (10) ◽  
pp. 1993 ◽  
Author(s):  
DE Scaife
Keyword(s):  
Nuclear Quadrupole Resonance ◽  
Covalent Bonding ◽  
Divalent Copper ◽  
Chloro Complexes ◽  
35Cl Nucleus ◽  
Square Planar ◽  
Bonding Interaction ◽  
Quadrupole Resonance ◽  
Square Planar Complexes ◽  
Nuclear Quadrupole

Nuclear quadrupole resonance for the 35Cl nucleus has been observed in some chloro complexes of divalent copper. Square-planar complexes each show two resonance lines, with the following frequencies (at 77�K): (CH3NH3)2CuCl4, 10.780, 12.157 MHz; (C2H5NH3)2CuCl4, 10.817, 12.074 MHz; (enH2)CuCl4, 10.271, 11.901 MHz; and (C3H7NH3)2CuCl4 at 223�K, 11.290 and 11.781 MHz. NH4CuCl3, containing dimeric Cu2Cl62- units, has resonances, at 77�K, at 11.907, 11.993, and 12.448 MHz. The trigonal pyramidal anion in Co(NH3)6CuCl5 has two resonances at 9.642 and 10.352 MHz at 77�K. ��� These results are compared with previous results for copper chloro complexes, and the implications of covalent bonding are discussed. In particular, it is suggested that the long-bond interaction between units in square-planar complexes amounts to 7-16% of the bonding interaction within the units.

Extended X-ray absorption fine structure and multiple-scattering simulation of nickel dithiolene complexes Ni[S2C2(CF3)2]2n(n= −2, −1, 0) and an olefin adduct Ni[S2C2(CF3)2]2(1-hexene)

2015 ◽  
Vol 22 (1) ◽  
pp. 124-129 ◽  
Author(s):  
Weiwei Gu ◽  
Hongxin Wang ◽  
Kun Wang
Keyword(s):  
Fine Structure ◽  
Multiple Scattering ◽  
Edge Structure ◽  
X Ray ◽  
Absorption Fine ◽  
Square Planar ◽  
Square Planar Complexes ◽  
Uv Visible ◽  
Edge Features ◽  
X Ray Absorption

A series of Ni dithiolene complexes Ni[S2C2(CF3)]2n(n= −2, −1, 0) (1,2,3) and a 1-hexene adduct Ni[S2C2(CF3)2]2(C6H12) (4) have been examined by NiK-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine-structure (EXAFS) spectroscopies. Ni XANES for1–3reveals clear pre-edge features and approximately +0.7 eV shift in the NiK-edge position for `one-electron' oxidation. EXAFS simulation shows that the Ni—S bond distances for1,2and3(2.11–2.16 Å) are within the typical values for square planar complexes and decrease by ∼0.022 Å for each `one-electron' oxidation. The changes in NiK-edge energy positions and Ni—S distances are consistent with the `non-innocent' character of the dithiolene ligand. The Ni—C interactions at ∼3.0 Å are analyzed and the multiple-scattering parameters are also determined, leading to a better simulation for the overall EXAFS spectra. The 1-hexene adduct4presents no pre-edge feature, and its NiK-edge position shifts by −0.8 eV in comparison with its starting dithiolene complex3. Consistently, EXAFS also showed that the Ni—S distances in4elongate by ∼0.046 Å in comparison with3. The evidence confirms that the neutral complex is `reduced' upon addition of olefin, presumably by olefin donating the π-electron density to the LUMO of3as suggested by UV/visible spectroscopy in the literature.

Low-frequency single-crystal Raman, far-infrared, and inelastic neutron scattering studies of acetanilide at low temperature

1991 ◽  
Vol 95 (13) ◽  
pp. 5281-5286 ◽  
Author(s):  
Clifford T. Johnston ◽  
Stephen F. Agnew ◽  
Juergen Eckert ◽  
Llewellyn H. Jones ◽  
Basil I. Swanson ◽  
...  
Keyword(s):  
Low Temperature ◽  
Neutron Scattering ◽  
Single Crystal ◽  
Inelastic Neutron Scattering ◽  
Low Frequency ◽  
Far Infrared ◽  
Inelastic Neutron

scholarly journals Investigation of the Effect of Sodium Selenate on Acetylcholinesterase Activity under Extremely Low Frequency Electromagnetic Field

2012 ◽  
Vol 4 (1) ◽  
Author(s):  
Ezzatollah Fathi ◽  
Raheleh Farahzadi
Keyword(s):  
Electromagnetic Field ◽  
Structural Changes ◽  
Tertiary Structure ◽  
Low Frequency ◽  
Acetylcholinesterase Activity ◽  
The Elderly ◽  
Skin Aging ◽  
Sodium Selenate ◽  
Spectroscopic Techniques ◽  
Extremely Low Frequency

Acetylcholinestrase (AChE EC 3.1.1.7) is one of the most important enzymes in nervous system, which plays a role in Alzheimer’s disease. Selenium is a vital micronutrient and many investigations have been performed about the physiological, biochemical and behavioral effects of this element, such as postponing the Alzheimer's symptoms in the elderly and delaying the initiation signs of skin aging. Recent studies have shown that this element protects various enzymes against the toxicity caused by heavy metals such as; Pb, Al, Cu and Cd. AChE activity is altered under the influence of extremely low frequency electromagnetic field (ELF-EMF). In this study, the effects of ELF-EMF, with 0.3 mT field intensity and 50, 100, 217 Hz frequencies, were investigated on the AChE, in the presence of different concentrations of sodium selenate, using UV-Visible, fluorescence and circular dichroism spectroscopic techniques. The results demonstrated that the enzyme activity declined by increasing the frequency and the amount of sodium selenate. Also, significant structural changes occurred in the secondary and tertiary structures of AChE. Our results showed that with increasing the concentration of sodium selenate transition from α-helix to β-structure was appeared in the presence of ELF-EMF. In conclusion, according to changes observed in the secondary and tertiary structure of enzyme, it is proposed that these fields are able to affect the structure and dynamics of the active site gorge of AChE.

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