Search results for "MOI"
showing 10 items of 2109 documents
Towards the synthesis of substituted porphyrins by a pyridyl group bearing a reactive functionality
2010
Pyridyl-substituted porphyrins bearing a reactive functionality were prepared via Suzuki cross-coupling reactions and resulted in very good yields. These compounds are precursors of new porphyrin architectures able to coordinate two metals: one in the porphyrin core and the second around the pyridyl moiety. During the coupling reactions, a higher reactivity of a chloro picolyl group was evidenced compared to a bromo function on the same reacting molecule.
Versatile behavior of conjugated diynes with zirconocene reactive species
2008
Thermal decomposition of Cp2ZrPh2 in the presence of the buta-1,3-diynes RC≡CC≡CR (R = Ph, SiMe3) can lead to seven- or five-membered metallacycles. In both cases a stable benzo-fused seven-membered zirconacyclocumulene arising from a 2-fold insertion of the triple bonds of the dialkyne in the in situ generated zirconocene benzyne is formed. In the case of Me3SiC≡CC≡CSiMe3 a second minor complex is isolated: a 3-alkynyl-substituted zirconaindene arising from a β monoinsertion of one acetylenic function of the conjugated diyne in the zirconocene benzyne. No stable 2-alkynyl-substituted zirconacycle was isolated. This α monoinsertion complex is an intermediate in the exchange of the metalated…
Fluorescence Quenching in BODIPYs Having Ir‐ and Rh‐Tethered Complexes
2016
The effect of Rh- and Ir-centers on the optical properties of the BODIPY core has been studied. To this end, novel metal complexes tethered to BODIPY have been prepared through an easy and versatile procedure using N-directed C–H activation reactions. The organometallic moiety has a tremendous influence on the emissive properties of the BODIPY fragment. A photoinduced electron transfer (PET) mechanism is suggested to be the main mechanism responsible for the suppression of the BODIPY fluorescence emission in the newly formed dyads. The efficiency of the PET depends on both the distance between the chromophores in the dyad and the nature of the transition metal (Rh vs. Ir).
Water-Soluble Squaramide Dihydrates: N-Methylation Modulates the Occurrence of One- and Two-Dimensional Water Clusters through Hydrogen Bonding and D…
2018
Water confined in molecular size domains is distinct to bulk water. The altered interactions between adjacent water molecules, and between water molecules and molecular wall components of the confinement system, determine aspects of important phenomena in material science, biology, and nanotechnology. The structural determination of confined water, however, has proven to be challenging. Here, we describe the crystal structures of three related squaramides 1–3 whose molecular structures are modulated by the gradual incorporation of N-methyl groups to the squaramide moiety. The three squaramides differ in their hydrogen bonding capabilities due to the different degree of N-methylation of each…
Subphthalocyanine basicity: reversible protonation at the azomethine bridge
2017
International audience; Subphthalocyanine (SubPc) could be reversibly protonated at the azomethine bridge. This phenomenon was examined by addressing the pKa of the acid (TFA, MSA, TMSA) and the SubPc electron-withdrawing properties of the peripheral isoindolic substituents (F12 vs. H12 and NO2), which tunes the basic character of the azomethine moiety. The protonation of up to three azomethines was suggested and monitored spectrophotometrically with the appearance of new absorption bands at 610, 630 nm and 660 nm, together with marked colour changes from purple to blue to green. Evidence of such a protonation was also shown by significant changes in the 1H-NMR spectrum and new bands in the…
The separation of cis- and trans-1,3-cyclohexanediol isomers by copper complexation. Crystal structures of cis-1,3-cyclohexanediol and copper(II) chl…
2002
Abstract A 1:1 complex between copper(II) chloride and cis-1,3-cyclohexanediol has been synthesized and its crystal structure determined. The structure is composed of two different dinuclear [CuCl2(c-13chd)]2 units in which the copper(II) ions are surrounded by the two oxygen atoms of the diol and the two halide ions in a distorted cis-square planar arrangement in both cases. A fifth coordination site is occupied by a halide ion in one dinuclear unit for both copper ions and an O atom belonging to the adjacent CuCl2(c-13chd) moiety in the other dinuclear unit for both copper ions, thus forming a distorted square pyramidal geometry for the metals in all cases. The ability of CuCl2 to prefere…
Metal- and Reagent-Free Anodic C−C Cross-Coupling of Phenols with Benzofurans leading to a Furan Metathesis
2018
Heterobiaryls consisting of a phenol and a benzofuran motif are of significant importance for pharmaceutical applications. An attractive sustainable, metal- and reagent-free, electrosynthetic, and highly efficient method, that allows access to (2-hydroxyphenyl)benzofurans is presented. Upon the electrochemical dehydrogenative C-C cross-coupling reaction, a metathesis of the benzo moiety at the benzofuran occurs. This gives rise to a substitution pattern at the hydroxyphenyl moiety which would not be compatible by a direct coupling process. The single-step protocol is easy to conduct in an undivided electrolysis cell, therefore scalable, and inherently safe.
Alkali Blues: Blue‐Emissive Alkali Metal Pyrrolates
2019
2-Iminopyrroles [HtBu L, 4-tert-butyl phenyl(pyrrol-2-ylmethylene)amine] are non-fluorescent π systems. However, they display blue fluorescence after deprotonation with alkali metal bases in the solid state and in solution at room temperature. In the solid state, the alkali metal 2-imino pyrrolates, M(tBu L), aggregate to dimers, [M(tBu L)(NCR)]2 (M=Li, R=CH3 , CH(CH3 )CNH2 ), or polymers, [M(tBu L)]n (M=Na, K). In solution (solv=CH3 CN, DMSO, THF, and toluene), solvated, uncharged monomeric species M(tBu L)(solv)m with N,N'-chelated alkali metal ions are present. Due to the electron-rich pyrrolate and the electron-poor arylimino moiety, the M(tBu L) chromophore possesses a low-energy intra…
Magnetostructural correlations in CuII−NC−WV linkage: the case of [CuII(diimine)]2+−[WV(CN)8]3− 0D assemblies
2009
International audience; We report on the syntheses, crystal structures, and magnetic properties of two cyano-bridged molecular assemblies: [CuII(phen)3]2{[CuII(phen)2]2[WV(CN)8]2}(ClO4)2·10H2O (phen = 1,10-phenanthroline) (1) and {[CuII(bpy)2]2[WV(CN)8]} {[CuII(bpy)2][WV(CN)8]}·4H2O (bpy = 2,2′-bipyridyl) (2). Compound 1 consists of cyano-bridged [CuII2WV2]2− molecular rectangles and isolated [CuII(phen)3]2+ complexes. The molecular structure of 2 reveals cyano-bridged trinuclear [CuII2WV]+ and dinuclear [CuIIWV]− ions. Magnetic interactions in 1 are interpreted in terms of the model of a tetranuclear moiety consisting of two ferromagnetic CuII−NC−WV units (J1 = +39(4) cm−1) interacting ant…
Supramolecular Assembly of Organophosphonate Diesters Using Paddle-Wheel Complexes: First Examples in Porphyrin Series
2014
The reactions of dicopper tetrapivalate complex Cu2(μ-OOC-t-Bu)4(NCMe)2 (1) with triphenylphosphine oxide and diethyl phosphite allow paddle-wheel (PW) copper(II) complexes with phosphorus-containing axial ligands (2, 3) to be obtained. When meso-bis(diethoxyphosphoryl)porphyrins 4M were employed in this ligand exchange reaction, a series of one-dimensional (1D) homo- and heterometallic coordination polymers 5M composed of PW subunits and organophosphonate diesters were prepared and characterized by means of single crystal X-ray analysis. Planar porphyrinate 4Pd and nonplanar metalloporphyrinates 4Cu and 4Ni proved to be appropriate molecular structural blocks for assembly of coordination p…