32 research outputs found

    A diamagnetic iron complex and its twisted sister:structural evidence on partial spin state change in a crystalline iron complex

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    Abstract We report here the syntheses of a diamagnetic Fe complex [Fe(HL)₂] (1), prepared by reacting a redox non-innocent ligand precursor N,N′-bis(3,5-di-tert-butyl-2-hydroxy-phenyl)-1,2-phenylenediamine (H₄L) with FeCl₃, and its phenoxazine derivative [Fe(L′)₂] (2), which was obtained via intra-ligand cyclisation of the parent complex. Magnetic measurements, accompanied by spectroscopic, structural and computational analyses show that 1 can be viewed as a rather unusual Fe(III) complex with a diamagnetic ground state in the studied temperature range due to a strong antiferromagnetic coupling between the low-spin Fe(III) ion and a radical ligand. For a paramagnetic high-spin Fe(II) complex 2 it was found that, when crystalline, it undergoes a thermally induced process where 25% of the molecules in the material change to a diamagnetic low-spin ground state below 100 K. Single crystal X-ray studies conducted at 95 K afforded detailed structural evidence for this partial change of spin state of 2 showing the existence of crystallographically distinct molecules in a 3 : 1 ratio which exist in high- and low-spin states, respectively. Also, the magnetic behaviour of 2 was found to be related with the crystallinity of the material as demonstrated by near-IR radiation to unpaired electrons conversion ability of amorphous sample of 2

    Monotherapy and Dual Combination Therapies Based on Olmesartan: A Comprehensive Strategy to Improve Blood Pressure Control

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    Olmesartan medoxomil is an antihypertensive drug of the class of angiotensin II type 1 (AT1) receptor antagonists (or blockers), characterized by tight and prolonged binding to AT1 receptor compared to other molecules within the same class. These characteristics produce effective and sustained blood pressure reductions in hypertensive patients at different cardiovascular risk profile with a good tolerability profile. After a brief description of the pharmacological characteristics of olmesartan, we will provide a thorough overview of the clinical studies that investigated its efficacy and safety in the clinical management of hypertensive patients both in monotherapy and in dual combination therapies with either thiazide diuretics or calcium channel blockers. These studies demonstrated that olmesartan-based antihypertensive strategy may indeed provide sustained BP control over the 24-h period in a wide proportion of hypertensive patients, thus contributing to a substantial progress in hypertension management. Finally, since growing evidence suggest that olmesartan may also exert potential favourable effects at vascular level, thereby antagonizing the vascular inflammatory process involved in the development and progression of atherosclerosis, the main clinical studies addressing this issue will be also discussed
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