A vibrational spectroscopic study of transition metal tetracyanonickelate complexes of 2-chloropyridine and 2-bromopyridine

The FT-IR and Raman spectra of eight new complexes of formula ML2Ni(CN)(4) (where M = Mn, Fe, Co, Ni, Cu or Cd and L = 2-chloropyridine; M = Ni or Cd and L = 2-bromopyridine) are reported. The spectroscopic results indicate that the complexes have structures consisting of corrugated polymeric layers of [M-Ni(CN)(4)](infinity) with 2-substituted pyridine molecules bound directly to the metal (M). For a given ligand (2-Clpy or 2-Brpy) the effects of metal-ligand bond formation on the ligand modes are examined. Metal-ligand bond strengths of the halo-derivatives of pyridine (L = 2-Clpy or 2-Brpy), inferred by the effects on frequency shifts of certain ligand modes, have also been compared

Theoretical study of the ir spectra of 3-chloropyridine and 3-chloropyridine metal complexes

The vibrational spectrum of 3-chloropyridine was calculated on the basis of normal coordinate analysis. Quantum optimized (MNDO) geometry was used for spectral calculations. The refined force field and electro-optical parameters are found to reproduce well experimental IR spectrum of liquid 3-chloropyridine. The coordination effect on the ligand vibrational modes was also investigated. The calculated results indicate the presence of some alterations on the ring force field of the molecule in complex formation. (C) 1999 Elsevier Science B.V. All rights reserved

Theoretical study of the vibrational spectra of 2-chloropyridine metal complexes. I. Calculation and analysis of the IR spectrum of 2-chloropyridine

The force field and the electrooptical parameters of 2-chloropyridine were determined by the refinement of the corresponding parameters of the pyridine molecule, for further use in the metal complexes study. During the refinement procedure, the results of semiempirical (MNDO) and ab initio (4-31G*) calculations were taken into account. Approximate normal coordinate analysis was performed on the basis of different theoretical calculations. Theoretical results predict significant mixing of the ring and CH modes. Nevertheless, there is qualitative agreement between normal mode assignments made upon quantum chemical calculations, force field refinement results and results based on earlier experimental information. Calculation of the IR intensities serves as an additional check of the force field quality. The interpretation of the IR intensities and contribution of various parts of the molecule to the total IR spectra is given. (C) 1999 Elsevier Science B.V. All rights reserved

Theoretical study of the vibrational spectra of 2-chloropyridine metal complexes II. Calculation and analysis of the IR spectra of Cd- and Ni-2-chloropyridine complexes

The vibrational IR spectra of a Cd complex of 2-chloropyridine, was calculated on the basis of a parameter set determined in our previous study on the 2-chloropyridine molecule. The Cd-N bond strength was determined by the variation of the force field, and the corresponding force constant is found to be (1.064 mdyne/Angstrom). Calculated IR intensities indicate the presence of some changes in electron distribution of the 2Cl-pyridine molecule in a complex formation, with respect to the free molecule. The distortion of the electro-optical parameters occurs around the N atom. The interpretation of the normal vibrations and IR intensities of the Cd-2Cl-pyridine complex is given. Comparison with the corresponding shifts for the case of the Ni complex of 2Cl-pyridine, ensures that the force field of the free 2Cl-pyridine molecule should be altered in a complex formation, in order to represent experimental data. (C) 1999 Elsevier Science B.V. All rights reserved

FT-IR spectroscopic investigation of Hofmann Td-type complexes of 2-, and 3-chloropyridine

Hofmann-type modified clathrate hosts containing 2- or 3-chloropyridine molecules attached to metal (II) tetracyanocadmate frame, with a given formula: M(Clpy)(2)Cd(CN)(4), where M = Mn, Ni or Cd; Clpy = 2- or 3-chloropyridine, have been synthesised for the first time. Their FT-IR spectra are reported in the 400-4000 cm(-1) region. All the vibrational modes of coordinated Clpy are characterised. The spectral features of the compounds studied are found to be similar to each other indicating that they have analogous structures. The coordination effect on the Clpy modes is analyzed

Lymphocyte Subsets and Plasma Il-1-Alpha, Il-2, and Tnf-Alpha Concentrations In Acute Rheumatic-Fever and Chronic Rheumatic Heart-Disease

WOS: A1995TB22800007PubMed ID: 7586724The distribution of CD3(+), CD4(+), CD8(+), CD19(+), CD16(+), and CD25(+) lymphocyte populations in peripheral blood as well as the plasma concentrations of interleukin-1 alpha (IL-1 alpha), and IL-2 and tumor necrosis factor alpha (TNF-alpha) were investigated in 25 children with acute rheumatic fever (ARF) at the time of admission and after 3 months and in 15 children with chronic rheumatic heart disease (CRHD) and in 15 children with streptoccocal pharyngitis (SP) in order to determine changes in lymphocyte subsets and cytokine concentrations occurring during different stages of the disease. The percentages and absolute counts of CD4(+), CD16(+), CD25(+) cells, the ratio of CD4/CD8 and plasma concentrations of IL-1 alpha and IL-2 in patients with ARF were significantly higher at admission than 3 months later. These levels were also significantly higher than in patients with CRHD, SP, or normal controls. Production of IL-2 in ARF and CRHD patients directly correlated with the percentages of CD4(+) and CD25(+) cells. According to our results, the evidences of increased cellular immune response in ARF are increased percentages CD4(+) and CD25(+) cells, CD4/CD8 ratio, and increased plasma concentrations of IL-1 alpha and IL-2. Furthermore, activation of cellular immune response was not present throughout all stages of rheumatic heart disease and also in SP. (C) 1995 Academic Press, Inc

Heat shock protein 70 expression in neonatal rats after hypoxic stress

Objectives: The tissue damage due to hypoxia in newborns is to some-extent age-dependent; organs of premature babies are more vulnerable to hypoxic insult than full-term neonates. The aim of this immunohistochemical study was to investigate the role of heat shock protein 70 (HSP70), a stress-inducible protein, in developing the response to hypoxia in premature newborns. Methods: Postnatal day-7 rats (corresponding to a human fetus of 32-34 weeks' gestation) and day-12 rats (corresponding to a full-term newborn infant) (n = 7) were subjected to mild hypoxia at 33°C. Control rats (n = 7) for each group breathed room air for 4 h. After 4 h of recovery, the animals were killed, and brains, hearts and kidneys were removed for immunohistochemical staining. Results: Immunohistochemically, HSP70 expression was found to be induced in the hippocampus and myocardium after exposure to hypoxia. The level of HSP70 expression in the hippocampus after hypoxic stress was significantly higher in the 12-day rats than in the 7-day rats (p = 0.03). However, HSP70 expression in the myocardium did not show any significant difference between the two groups. In addition, no significant induction of HSP70 expression was apparent in the kidney of rats exposed to hypoxia or in any organ of the control animals. Conclusions: We conclude that diminished HSP70 expression in the hippocampus of premature newborns may play a critical role in developing the response to hypoxic stress. However, HSP70 expression in the heart and the kidney after exposure to hypoxia did not appear to be related to fetal maturity