Search results for "405"
showing 10 items of 3208 documents
Sn<sup>IV</sup> and Zr<sup>IV</sup> Compounds of a <i>C</i>&l…
2017
This contribution describes the synthesis and structural characterization of a triaminoguanidinium (TAG)-based ligand [H6(OMe)3Limin]BF4 (1) containing imine bonds (Limin) and its reduction with a dimethylamino borane complex to the corresponding amine compound (Lamin)[H9(OMe)3Lamin]OTs (2). In solution, both ligands are C3-symmetric but crystal structures show the great influence of the reduction on the molecular structure. We show that the planar imine ligand is converted to a highly flexible compound which has nine potential coordination sites, three phenoxy and six amine donors, for binding metal ions. First solid state structures of 1:1 (metal:ligand) coordination compounds with SnIV a…
Direct Visualization of Pyrrole Reactivity upon Confinement within a Cyclodextrin Metal–Organic Framework
2019
Metal–organic frameworks can be used as porous templates to exert control over polymerization reactions. Shown here are the possibilities offered by these crystalline, porous nanoreactors to capture highly-reactive intermediates for a better understanding of the mechanism of polymerization reactions. By using a cyclodextrin framework the polymerization of pyrrole is restricted, capturing the formation of terpyrrole cationic intermediates. Single-crystal X-ray diffraction is used to provide definite information on the supramolecular interactions that induce the formation and stabilization of a conductive array of cationic complexes.
Ring opening polymerization of $\varepsilon$-caprolactone in the presence of wet $\beta$-cyclodextrin: Effect of the operative pressure and of water …
2016
International audience; The ring opening polymerization (ROP) of $\varepsilon$-caprolactone (CL) in the presence of $\beta$-cyclodextrin ($\beta$-CD) wasperformed in batch reactors both at room pressure and with the reaction system pressurized with CO$_2$, N$_2$ orAr. Significant enhancements of the polymerization rate was observed when the ROP was carried out withwet $\beta$-CD under pressure. For example, after 24 hours at 120° C with a $\beta$-CD/CL molar ratio of about1/100, the monomer conversion increased from 4 to 98–99% when the pressure was changed from 0.1to 12.5–13.0 MPa independent of the nature of the compressing gas. MALDI-TOF analyses indicated thata major fraction of polymer…
Host–guest inclusion complexes between peracetylated β-cyclodextrin and diphenyl(4-phenylphenyl)phosphine : computational studies
2006
PM3 and molecular dynamic calculations were performed upon the inclusion complexation of peracetylated β-cyclodextrin (Per-Ac-β-CD) with diphenyl(4-phenylphenyl)phosphine (DBP). Results show that the 4-phenylphenyl part of the DBP phosphine fits tightly in the cavity of the Per-Ac-β-CD, leading to the formation of stable inclusion complexes. Complexation energies indicate that the complex formed via the primary side of the Per-Ac-β-CD is more stable than that formed via the secondary side. Electrostatic potential mapping and frontier orbital analysis suggest that van der Waals interaction constitute a major driving force in the complexation of the DBP and Per-Ac-β-CD.
2,2′:6′,2″-Terpyridine Trimethylplatinum(IV) Iodide Complexes as Bifunctional Halogen Bond Acceptors
2016
Three new organometallic trimethylplatinum(IV) iodide complexes of 2,2′:6′,2″-terpyridines have been synthesized and characterized by 1H NMR spectroscopy, mass spectrometry, elemental analysis, and single crystal X-ray diffraction analysis. The X-ray crystal structures of PtMe3I(L) complexes 1–3 {L for 1 = 4′-chloro-2,2′:6′,2″-terpyridine, 2 = 4′-(4-cyanophenyl)-2,2′:6′,2″-terpyridine, and 3 = 4′-(4-tolyl)-2,2′:6′,2″-terpyridine} reveal distorted octahedral coordination geometry of the platinum(IV) metal centers with bidentate coordination of the terpyridine ligands. Complexation of 1–3 with iodopentafluorobenzene (IPFB) afforded single-crystal structures of halogen bond (XB) complexes 1a–3…
Selective Guest Inclusion in Oxalate-Based Iron(III) Magnetic Coordination Polymers
2016
The preparation and structural characterization of four novel oxalate-based iron(III) compounds of formulas {(MeNH3)2[Fe2(ox)2Cl4]·2.5H2O}n (1), K(MeNH3)[Fe(ox)Cl3(H2O)] (2), {MeNH3[Fe2(OH)(ox)2Cl2]·2H2O}n (3), and {(H3O)(MeNH3)[Fe2O(ox)2Cl2]·3H2O}n (4) (MeNH3+ = methylammonium cation and H2ox = oxalic acid) are reported here. 1 is an anionic waving chain of oxalato-bridged iron(III) ions with peripheral chloro ligands, the charge balance being ensured by methylammonium cations. 2 is a mononuclear complex with a bidentate oxalate, three terminal chloro ligands, and a coordinated water molecule achieving the six-coordination around each iron(III) ion. Its negative charge is balanced by potas…
New dinuclear copper complexes incorporating bis(imidazolyl) based ligands and bidentate–monodentate oxalate bridges. Crystal structure and magnetic …
2016
Abstract This paper reports the synthesis, X-ray crystal structure and magnetic characterization of two novel copper(II) dinuclear compounds including bis(imidazolyl) ligands and oxalate anions, [Cu2(BIM)2(C2O4)2]·4H2O (1) (BIM = bis(2-imidazolyl)methane) and [Cu2(BIK)2(C2O4)2] (2) (BIK = bis(2-imidazolyl)ketone). The oxalate anion acts as bidentate–monodentate in both cases, although it exhibits different coordination bridging modes: whereas in compound 1 a μ1,1,2-oxalato is observed, a μ1,2,3-oxalato is found in compound 2. In both cases, the 3D framework is held together by a combination of H-bonding and aromatic-aromatic interactions provided by the convenient structural features of BIM…
Insertion of FeII complexes with Schiff base ligands derived from imidazole or pyridine into 3D bimetallic oxalate-based ferromagnets
2013
Abstract The syntheses, structures and magnetic properties of the compounds [FeII(imid2-trien)][MnII(CH3OH)CrIII(ox)3]2·(CH3OH)4(CH3CN)(H2O) (1), [FeII(tren(6-Me-py)3)][MnIICrIII(ox)3][MnII(CH3OH)0.58(H2O)0.42CrIII(ox)3]·(CH3OH)2(CH3CN)0.5(H2O)0.42 (2) and [FeII(tren(imid)3)]2[Mn2.5(CH3OH)3Cr3(ox)9]·(CH3OH)4.75·(H2O)4.25 (3) are reported. They are prepared by the insertion of FeII-Schiff base complexes derived from imidazole and pyridine into bimetallic oxalate networks. Different types of 3D oxalate networks are obtained for each templating cation. Thus, [FeII(imid2-trien)]2+ and [FeII(tren(6-Me-py)3)]2+ give rise to unusual 3D achiral bimetallic oxalate networks with heptacoordinated MnII…
In vitro evaluation of leishmanicidal properties of a new family of monodimensional coordination polymers based on diclofenac ligand
2020
Some series of isostructural chains with general formula [M(diclof)(HO)]·(EtOH) have been obtained from reaction between diclofenac ligand (diclof) and first row transition salts (M = Mn (1),Ni (2) and Co (3)). These monodimensional coordination polymers have been characterized and their crystal structures have been solved by X-ray diffraction methods, elucidating isostructural compounds that are chains with water molecules acting as bridge between different metallic centers, while diclofenac ligands are coordinated to the octahedral coordination environment of the same. Magnetic studies of these complexes have revealed the existence of moderate ferromagnetic interactions among manganese, n…
Stable 17-electron Mo(III) complexes containing alkyl ligands
1999
Abstract The alkylation of the half-sandwich complex CpMoCl 2 ( η 4 -diene) (diene=C 4 H 6 , 2,3-Me 2 C 4 H 4 ) affords the first thermally stable 17-electron compounds containing Mo(III)–alkyl bonds.