Synthesis and Characterisation of a New Cu(O₂CNAllyl₂)₂ Carbamato Complex and an Unusual Polymeric Cu^I Complex [Cu^I₄Cl₄(NHAllyl₂)₄]_n: New Insights into Metal Carbamato Chemistry

Abstract

Transition‐metal N,N‐dialkylcarbamato complexes represent an interesting class of compounds that can be conveniently used as precursors for the controlled formation of inorganic compounds, typically oxides. They can also be used as convenient precursors for chemical grafting of metal oxides on oxide surfaces as well as for the synthesis of inorganic–organic hybrid materials. In this last case, the presence of double bonds on the complex would enable its covalent embedding into a polymer matrix through reaction with suitable monomers. To this aim, we addressed the synthesis of an allyl‐functionalised copper carbamato complex. During the synthesis of the N,N‐diallylcarbamato complex Cu(O2CNAllyl2)2 (Cu1), the formation of the crystalline and unusual polymeric CuI complex [CuI4Cl4(NHAllyl2)4]n (Cu2) was observed. The new compound was characterised by X‐ray single crystal diffraction and FTIR, 1H and 13C NMR spectroscopic analysis. In an attempt to investigate the redox mechanism and the equilibria leading to the formation of the observed unusual CuI polymeric complex, gas chromatography coupled with mass spectrometry (GC–MS) experiments were carried out, which allowed us to identify 3,4‐dimethylpyrrole as the oxidation product of the reaction, leading to the reduction of CuII to CuI.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Beyond the Simple Copper(II) Coordination Chemistry with Quinaldinate and Secondary Amines

“…It yielded, apart from three metal complexes, a polycyclic piperidine compound 10, which was a product of a complicated electron transfer between amine and Cu 2+ . It is to be noted that copper(II)-assisted transformations of organic substrates often accompany the coordination chemistry of this metal ion [28][29][30][31][32][33][34][35]. Our study provides the basis for the ongoing work on the reduction of copper(II) with piperidine and its homologs.…”

Synthesis and Structure of [Cu(Hapn)]NO3]NO3, [Cu(Hapn)(H2O)2]SiF6, [Cu(Hapn)(H2O)BF4]BF4∙H2O and [Cu(Hapn)(NH2SO3)2] π-complexes (apn = 3-(prop-2-en-1-ylamino)propanenitrile)

“…2 Representatives of this class are wellknown not only as versatile intermediates in organic synthesis and in many other reactions, 3,4 but also as reagents for synthesis of heterocyclic compounds, 5 inhibitors of enzymes, 6 precursors of peptides, 7 amino-acids, 8 which, in turn, exhibit antibiotic, 9 antifungal, 10 and other important biological and pharmacological properties. 11,12 The coordination behaviour of aminonitriles in the complexation reactions with Cu(I) salts can be characterized on the basis of only several related, 13,14 or closely related, 15 compounds, though the matter under discussion is still relevant. It has been noticed that atoms of Cl or Br compete for space in coordination polyhedron with allyl groups and cyano group in the halide complexes of Cu(I) with diallylaminopropanenitrile (the tertiary amine N-atom is protonated).…”