Reactivity of isocyanates with urethanes: Conditions for allophanate formation

International audienceThe reactions between two polyisocyanates, 4,4#-methylenebis(phenyl isocyanate) (MDI) and trimer of isophorone diisocyanate (tIPDI) and a model arylealkyl diurethane were carried out at high temperature (>=170 °C) and several NCO/urethane ratios.A combination of 1H and 13C NMR and MALDI-TOF spectroscopies was used and allows the identification of reaction products.When MDI or tIPDI is reacted with a diurethane at high temperature and after cooled, allophanates are formed but notisocyanurates. 13C NMR was used to quantify the different reaction products obtained under different experimental conditions.Only a few allophanates (%10%) are obtained after 1 h of reaction

Can a highly flexible copper(I) cluster-containing 1D and 2D coordination polymers exhibit MOF-like properties?

International audienceThe reaction of CuI with the highly flexible dithioether ligand p-TolS(CH2)8STol-p affords both in MeCN or in EtCN the 2D coordination polymers [Cu8I8{p-TolS(CH2)8STol-p}3(solvent)2]n (1·MeCN and 1·EtCN) containing octanuclear Cu8I8 clusters as connection nodes. In contrast, treatment of CuI with p-tBuC6H4S(CH2)8SC6H4But-p in EtCN solution leads to the formation of the luminescent 1D CP [Cu4I4{tBuC6H4S(CH2)8SC6H4-tBu}2(EtCN)2]n (2·EtCN) incorporating Cu4(μ3-I)4 clusters of the closed cubane type as secondary building units (SBUs). The 2D coordination polymers 1·MeCN and 1·EtCN demonstrate the ability to lose their solvent crystallisation molecules under vacuum and readsorb the same or a new one using vapor as monitored by powder X-ray diffraction, thermogravimetric, IR, chromaticity, emission spectra and emission lifetime measurements. Conversely, the 1D material 2·EtCN does not readsorb EtCN, likely due to the collapse of the macrocycles formed by the metal cluster nodes and flexible long-chained ArSC8SAr ligands but absorbs a smaller substrate such as CO2

Unexpected Formation of a Doubly Bridged Cyclo-1,2-dithian 1D Coordination Cu2I2-containing Luminescent Polymer

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Copper(I) Halides (X = Br, I) Coordinated to Bis(arylthio)methane Ligands: Aryl Substitution and Halide Effects on the Dimensionality, Cluster Size and Luminescence Properties of the Coordination Polymers

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