Ni(II)/H(2)O(2) reactivity in bis[(pyridin-2-yl)methyl]amine tridentate ligand system. aromatic hydroxylation reaction by bis(mu-oxo)dinickel(III) complex.

The nickel(II) complexes 1(X) supported by bis[(pyridin-2-yl)methyl]benzylamine tridentate ligands carrying m-substituted phenyl groups (X = OMe, Me, H, Cl, NO(2)) at the 6-position of pyridine donor groups (L(X), N,N-bis[(6-m-substituted-phenylpyridin-2-yl)methyl]benzylamine) have been synthesized and characterized. The X-ray crystallographic analyses have revealed that [Ni(II)(L(H))(CH(3)CN)(H(2)O)](ClO(4))(2) (1(H)), [Ni(II)(L(OMe))(CH(3)CN)(MeOH)](ClO(4))(2) (1(OMe)), [Ni(II)(L(Me))(CH(3)CN)(H(2)O)](ClO(4))(2) (1(Me)), and [Ni(II)(L(Cl))(CH(3)CN)(H(2)O)](ClO(4))(2) (1(Cl)) have a five-coordinate square pyramidal geometry, whereas [Ni(II)(L(NO(2)))(CH(3)CN)(2)(H(2)O)](ClO(4))(2) (1(NO(2))) exhibits a six-coordinate octahedral geometry having an additional CH(3)CN co-ligand. (1)H NMR spectra of the nickel(II) complexes 1(X) in CD(3)CN have indicated that all the complexes have a high spin ground state. The nickel(II) complexes 1(X) react with hydrogen peroxide (H(2)O(2)) in acetone to give bis(mu-oxo)dinickel(III) complexes 2(X) exhibiting a characteristic UV-vis absorption band at approximately 420 nm. In the case of 2(H), a resonance Raman band ascribable to a Ni(2)O(2) core vibration was observed at 611 cm(-1) that shifted to 586 cm(-1) upon H(2)(18)O(2). The bis(mu-oxo)dinickel(III) intermediates 2(X) undergo an efficient aromatic ligand hydroxylation reaction, producing a mononuclear nickel(II)-phenolate complexes 4(X) via a putative intermediate (mu-phenoxo)(mu-hydroxo)dinickel(II) (3(X)). The kinetic studies on the aromatic ligand hydroxylation process including m-substituent effects (Hammett analysis) and kinetic deuterium isotope effects (KIE) have indicated that the reaction of 2(X) to 3(X) involves an electrophilic aromatic substitution mechanism, where C-O bond formation and C-H bond cleavage occur in a concerted manner. Intermediate 3(H) was detected by ESI-MS during the course of the reaction, and the final product 4(H) was characterized by elemental analysis, ESI-MS, and X-ray crystallographic analysis.

Role of prehypertension in the development of coronary atherosclerosis in Japan.

BACKGROUND: Hypertension is an important risk factor of coronary heart disease. A new guidelines for hypertension prevention and management in The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure in the United States recommended lifestyle modification or medical treatment for subjects with prehypertension. However, whether prehypertension increases the risk of coronary atherosclerosis in the Japanese population is still unknown. METHODS: A cross-sectional study in a clinical setting was conducted. The subjects were 705 patients (417 males and 288 females) aged 30 years and older who underwent a first-time coronary angiography for suspected or known coronary heart disease at 5 major cardiology departments in the Fukuoka metropolitan area between September 1996 and August 1997. RESULTS: Compared to subjects with normal blood pressure, those with prehypertension had an increased risk of coronary atherosclerosis even after adjusting for other factors. CONCLUSION: Prehypertension may be an important clinical entity which requires treatment in the Japanese population.

Relation between type A behavior pattern and the extent of coronary atherosclerosis in Japanese women.

This study examined the relation of Type A behavior pattern and its components to angiographically documented coronary atherosclerosis in 198 Japanese women. A questionnaire-based interview elicited psychosocial and other factors. Type A behavior pattern was measured by 12 questions. Significant coronary stenosis was defined when a 75% or greater luminal narrowing occurred at one or more major coronary arteries or 50% or greater narrowing occurred at the left main artery. Gensini's score also was calculated. Logistic regression analysis was used to calculate odds ratios and 95% confidence intervals with adjustment for traditional coronary risk factors and the presence of a job. Global Type A behavior pattern showed no material association with the severity of coronary atherosclerosis assessed by both Gensini's score and the presence of significant coronary stenosis. However, its subcomponents, enthusiasm and competitiveness, were positively related to the severity of coronary atherosclerosis, whereas self-confidence and perfectionism were negatively related. These findings suggest overall a null association between global Type A and coronary atherosclerosis as well as the presence of toxic or beneficial components of Type A behaviors in Japanese women.