Search results for "405"
showing 10 items of 3208 documents
Synthesis, Crystal Structure and Magnetic Properties of Heteropolynuclear Re IV M II Complexes Based on the Robust [ReCl 5 (pyzCOO)] 2– Unit (pyzCOO …
2016
The syntheses, crystal structures and magnetic properties of four rhenium(IV) compounds of formulae NBu4[ReCl5(pyzCOOH)]·H2O (1), [ReCl5(µ-pyzCOO)M(dmphen)2]·2CH3CN [M = Ni (2) and Co (3)] and {[ReCl5(µ3-pyzCOO)]2Mn2(dmphen)3}n (4) (NBu4 = tetra-n-butylammonium cation, pyzCOOH = 2-pyrazinecarboxylic acid, dmphen = 2,9-dimethyl-1,10-phenanthroline) are reported herein. Compound 1 was obtained by the reaction of NBu4[ReCl5(dmf)] (dmf = dimethylformamide) with pyzCOOH in acetone, whereas the other complexes were obtained by the reaction of 1 with M(ClO4)2·6H2O [M = Ni (2), Co (3), Mn (4)] and dmphen in acetonitrile. Complex 1 is a mononuclear compound, 2 and 3 are neutral heterodinuclear compl…
Linking PO43− and HAsO42− anions with a dinuclear [ZnII2] complex: Formation and stabilization of novel decanuclear metallomacrocyclic [ZnII10] and t…
2017
The linkage of PO43- and HAsO42--anions with a newly synthesized five-coordinate dinuclear zinc complex, Zn-2(cpdp)(H2O)(2)]Cl (1) H(3)cpdp =N,N'-bis2-carboxybenzomethyl]-N,N'-bis2-pyridylmethyl]-1,3diamino propan-2-ol], has been explored. In methanol-water, the reaction of 1 with Na2HPO4 center dot 2H(2)O and Na2HAsO4 center dot 7H(2)O/NaBr separately, at ambient temperature, yielded the novel phosphate-bridged decanuclear zinc cluster, (H3O)(4)Zn-10(cPdP)(4)(mu(5)-PO4)(2)(H2O)(6)](6 center dot Cl)center dot 53H(2)O (2) and hydrogen arsenate bridged tetranuclear zinc cluster, Na-2Zn-4(cpdp)(2)(mu(4)-HAsO4)]ClBr center dot 13H(2)O (3), respectively. Analysis of the single crystal X-ray stru…
Insights into the crystal packing of phosphorylporphyrins based on the topology of their intermolecular interaction energies
2014
Four metal complexes of 5,15-bis(diethoxyphosphoryl)-10,20-diphenylporphyrin 1M (M = Cd(II), Ni(II), Pd(II), and Pt(II)) were synthesized and crystallographically characterized. The crystal organization patterns were analyzed using DFT (B97-D3/def2-SVP) calculations of the intermolecular interaction energies between complexes in the crystals. For the systematic analysis of crystal packing, the calculations were extended to previously reported compounds 1M (M = H2, Cu(II), and Zn(II)). Quantitative analysis of the interaction energies shows the essential role of weak intermolecular interactions, such as C-H⋯O, C-H⋯π and M⋯π, in the formation of basic structural motifs and their organization …
Regio-, Diastereo-, and Enantioselective Organocatalytic Addition of 4-Substituted Pyrazolones to Isatin-Derived Nitroalkenes
2019
"This is the peer reviewed version of the following article: [FULL CITE], which has been published in final form at [Link to final article using the DOI]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."
Hybrid GMP–polyamine hydrogels as new biocompatible materials for drug encapsulation
2020
Here we present the preparation and characterization of new biocompatible materials for drug encapsulation. These new gels are based on positively charged [1+1] 1H-pyrazole-based azamacrocycles which minimise the electrostatic repulsions between the negatively charged GMP molecules. Rheological measurements confirm the electroneutral hydrogel structure as the most stable for all the GMP-polyamine systems. Nuclear magnetic resonance (NMR) was employed to investigate the kinetics of the hydrogel formation and cryo-scanning electron microscopy (cryo-SEM) was used to obtain information about the hydrogel morphology, which exhibited a non-homogeneous structure with a high degree of cross-linking…
Acylchalcogenourea Complexes of Silver(I)
2016
Acylthio- or acylselenoureas react with silver(I) oxide to form tetranuclear silver(I) complexes containing the deprotonated acylchalcogenourea ligands bound to the silver atoms through the chalcogen and oxygen atoms. These tetrasilver(I) species react with either 4 or 8 equiv. of a phosphine to afford either dinuclear silver(I) phosphine complexes or tetrahedral silver diphosphine complexes. In these compounds, the acylchalcogenourea ligands form six-membered rings by coordinating to the metal atom through the chalcogen and oxygen atoms. In one case, we observed a very rare example of an acylthiourea ligand coordinated through the nitrogen and sulfur atoms to form a four-membered ring. A s…
Synthesis and structural characterization of well-defined bis(oxamato)palladate(II) precatalysts for Suzuki and Heck reactions
2018
Abstract A family of tetra-n-butylammonium salts of bis(oxamato)palladate(II) complexes of formula (n-Bu4N)2[Pd(Lm)2]·pH2O [m = 1–9; L1 = N-phenyloxamate (pma) and p = 2 (1), L2 = N-2-methylphenyloxamate (2-Mepma) and p = 4 (2), L3 = N-4-methylphenyloxamate (4-Mepma) and p = 2 (3), L4 = N-2,3-dimethylphenyloxamate (2,3-Me2pma) and p = 3 (4), L5 = N-2,4-dimethylphenyloxamate (Me2pma) and p = 4 (5), L6 = N-2,5-dimethylphenyloxamate (2,5-Me2pma) and p = 7 (6), L7 = N-3,4-dimethylphenyloxamate (3,4-Me2pma) and p = 6 (7), L8 = N-3,5-dimethylphenyloxamate (3,5-Me2pma) and p = 5 (8)] have been prepared and characterized by spectroscopic methods. The crystal structure of 1 that has been solved by s…
Scalable and Selective Preparation of 3,3′,5,5′-Tetramethyl-2,2′-biphenol
2016
Biphenols are indispensable building blocks in ligand systems for organic catalysis. 3,3′5,5′-Tetramethyl-2,2′-biphenol is a particular versatile motif in different catalytic systems. We developed an easy to perform and scalable process to give access to large quantities of this important building block by the use of selenium dioxide, a common and readily available oxidizer.
Rational Synthesis of Chiral Metal-Organic Frameworks from Preformed Rodlike Secondary Building Units.
2017
The lack of rational design methodologies to obtain chiral rod-based MOFs is a current synthetic limitation that hampers further expansion of MOF chemistry. Here we report a metalloligand design strategy consisting of the use, for the first time, of preformed 1D rodlike SBUs (1) for the rational preparation of a chiral 3D MOF (2) exhibiting a rare eta net topology. The encoded chiral information on the enantiopure ligand is efficiently transmitted first to the preformed helical 1D building block and, in a second stage, to the resulting chiral 3D MOF. These results open new routes for the rational design of chiral rod-based MOFs, expanding the scope of these unique porous materials.
From six-coordinate to eight-coordinate iron(ii) complexes with pyridyltriazolo-pyridine frameworks
2016
A new octacoordinated Fe(II) compound, [FeII(LN4)2](BPh4)2·3CH2Cl2, as an example of the scarce FeN8 systems, has been isolated with a tetradentate triazolopyridine-based ligand from a solution containing the related hexacoordinated [FeII(LN3)2]2+ complex, with LN3 = pyridyltriazolo-pyridyl-bromopyrimidine and LN4 = bis(pyridyltriazolo-pyridine).