Search results for "Azide"
showing 10 items of 334 documents
Crystal structures and magnetic properties of uniform and alternating azido-bridged (2,2′-bipyridyl)copper(II) chains
1998
Abstract Single crystals of four copper(II) complexes of formula [Cu(bipy)(N3)2]n (1,2), [Cu(bipy)2(N3)(ClO4)] (3) and [Cubipy)2(N3)]ClO4 (4) (bipy=2,2′-bipyridine) were obtained from aqueous solutions containing (2,2′-bipyridyl) copper(II) perchlorate and sodium azide, and their crystal structures were determined by X-ray diffraction methods. The structures of compounds 1 and 4 were already known, but the better accuracy of our structural determination of complex 1 led us to reconsider it here. The structures of compounds 1 and 2 are made up of neutral chains of copper(II) ions bridged by two azide groups exhibiting asymmetrical end-on (1) and alternating asymmetrical end-on and end-to-end…
Azide bridged dicopper(II), dicobalt(II) complexes and a rare double μ-chloride bridged ferromagnetic dicobalt(II) complex of a pyrazolyl-pyrimidine …
2012
Abstract Two new dinuclear copper(II) complexes [Cu2(PymPz)2(N3)2Cl2] (1), [Cu2(PymPz)2(N3)4] (2) and two new dinuclear cobalt(II) complexes [Co2(PymPz)2Cl4] (3), [Co2(PymPz)2(N3)4] (4) [PymPz = 2-(3,5-dimethyl-1H-pyrazol-1-yl)-4,6-dimethylpyrimidine] have been synthesized and characterized crystallographically and spectroscopically. In each of the complexes 1, 2 and 4 the two adjacent metal centers are bridged by a pair of μ-1,1 azide groups whereas in 3 the metal centers are bridged by a pair of chloride ions. In the complexes, all the metal centers are pentacoordinated. In 1 and 2 the copper(II) centers have distorted square pyramidal geometry (τ = 0.18 for 1 and 0.091 for 2) but in 3 an…
Defective dicubane-like tetranuclear nickel(II) cyanate and azide nanoscale magnets.
2010
Four tetrameric nickel(II) pseudohalide complexes have been synthesized and structurally, spectroscopically, and magnetically characterized. Compounds 1-3 are isostructural and exhibit the general formula [Ni(2)(dpk·OH)(dpk·CH(3)O)(L)(H(2)O)](2)A(2)·2H(2)O, where dpk = di-2-pyridylketone; L = N(3)(-), and A = ClO(4)(-) for 1, L = NCO(-) and A = ClO(4)(-) for 2, and L = NCO(-) and A = NO(3)(-) for 3. The formula for 4 is [Ni(4)(dpk·OH)(3) (dpk·CH(3)O)(2)(NCO)](BF(4))(2)·3H(2)O. The ligands dpk·OH(-) and dpk·CH(3)O(-) result from solvolysis and ulterior deprotonation of dpk in water and methanol, respectively. The four tetramers exhibit a dicubane-like core with two missing vertexes where the…
Substrate-dependent fluorinations of highly functionalized cycloalkanes
2016
Abstract Substrate-dependent fluorinations of several highly functionalized cycloalkanes with multiple stereocentres were investigated. The synthetic transformations were based on selective functionalization of the ring C C bonds of the readily available bicyclic β-lactams by epoxidation and regioselective nucleophilic oxirane opening with azide or cyanide, followed by hydroxy–fluorine exchange with Deoxofluor. Depending on the substituents and their relative steric arrangement, the attempted fluorinations produced different types of substituted cycloalkanes. These selective, substrate-directed synthetic procedures and their presumed pathways towards interesting highly functionalized fluori…
Azide Binding Controlled by Steric Interactions in Second Sphere. Synthesis, Crystal Structure, and Magnetic Properties of [Ni II 2 (L)(μ 1,1 -N 3 )]…
2016
International audience; The dinuclear Ni-II complex [Ni-2(L-2)][ClO4](2) (3) supported by the 28-membered hexaaza-dithiophenolate macro-cycle (L-2)(2-) binds the N-3(-) ion specifically end-on yielding [Ni-2(L-2)(mu(1,1)-N-3)] [ClO4] (7) or [Ni-2(L-2)(mu(1,1)-N-3)][BPh4] (8), while the previously reported complex [Ni2L1(mu(1,3)-N-3)][ClO4] (2) of the 24-membered macrocycle (L-1)(2-) coordinates it in the end-to-end fashion. A comparison of the X-ray structures of 2, 3, and 7 reveals the form-selective binding of complex 3 to be a consequence of its preorganized, channel-like binding pocket, which accommodates the azide anion via repulsive CH center dot center dot center dot pi interactions …
Aromatic Nucleophilic Substitution (SNAr) of meso-Nitroporphyrin with Azide and Amines as an Alternative Metal Catalyst Free Synthetic Approach To Ob…
2014
International audience; Aromatic nucleophilic substitution reaction of the nitro group of meso-nitroporphyrins with azide and various amines was achieved and represents an alternative procedure to C-N coupling reactions usually needed to obtain such meso-N-substituted porphyrins in good yields.
Synthesis of the first heterometalic star-shaped oxido-bridged MnCu3 complex and its conversion into trinuclear species modulated by pseudohalides (N…
2011
A tetra-nuclear, star-shaped hetero-metallic copper(II)-manganese(II) complex, [{CuL(H(2)O)}(2)(CuL)Mn](ClO(4))(2) (1) has been synthesized by reacting the "complex as ligand" [CuL] with Mn(ClO(4))(2) where H(2)L is the tetradentate di-Schiff base derived from 1,3-propanediamine and 2-hydroxyacetophenone. Upon treatment with the polyatomic anions azide, cyanate, or thiocyanate in methanol medium, complex 1 transforms into the corresponding trinuclear species [(CuL)(2)Mn(N(3))(2)] (2), [(CuL)(2)Mn(NCO)(2)] (3) and [(CuL)(2)Mn(NCS)(2)] (4). All four complexes have been structurally and magnetically characterized. In complex 1 the central Mn(II) ion is encapsulated by three terminal [CuL] unit…
Pseudohalide derivatives of manganese(II) and copper(II) complexes with mepirizole, a biologically active pyrimidyl-pyrazole ligand
1989
Abstract The synthesis and characterization of thiocyanate and azide derivatives of mepirizole(4-methoxy-2-(5-methoxy-3-methyl-pyrazol-1-yl)-6-methylpyrimidine, hereinafter L) with manganese(II) and copper(II) is reported. The compounds were characterized by IR, electronic and EPR spectra and analytical data. Spectroscopic results suggest the existence of dimeric neutral entities [L2Cu2(μ-X)2(X)2] (X = NCS or N3) with unsymmetrical end-to-end bridges and five-coordination geometry around the copper(II) ion. Magnetic susceptibility data show that in the azide derivative the copper atoms are antiferromagnetically coupled (J = −18 cm−1), but no magnetic exchange interaction could be detected i…
1,2-Methyl shift in the reaction of 4,7-dihydro-4,5-dimethyl-7-phenyl-(1,2,4)-triazolo[1,5-a]pyrimidine with tosyl azide
2000
The reaction of the heterocyclic enamine 1 with tosyl azide (2) leads to the tosylimino derivative 4 of 1,2,4-triazolo[1,5-a]pyrimidine. The extrusion of nitrogen from the primary adduct 3 is followed by a 1,2-shift of a methyl group. The structure determination of 4 is based on 1H and 13C nmr spectra including NOE measurements.
Effect of two antihypertensive combinations on metabolic control in type-2 diabetic hypertensive patients with albuminuria: a randomised, double-blin…
2001
The objective of this study was to compare, at equal blood pressure (BP) reduction, the effect of two different combinations on metabolic control and albuminuria in type 2 diabetic hypertensive patients with albuminuria. This was a prospective, randomised, double-blind, parallel, controlled trial carried out in 11 Spanish hospitals. A total of 103 type 2 diabetic patients with stable albuminuria and BP not controlled on monotherapy were randomised of which 93 finished the study. After a 4-week single-blind placebo period, patients were randomised to verapamil SR/trandolapril 180/2 mg (VT) or to enalapril/hydroclorothiazide 20/12.5 mg (EH). Treatment duration was 6 months. The main outcome m…