Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.21/7148
Título: Mono-alkylation of cyanoimide at a molybdenum(IV) diphosphinic center by alkyl halides: synthesis, cathodically induced isomerization and theoretical studies
Autor: Alegria, Elisabete C. B. A.
da Silva M. Fatima, Guedes
Kuznetsov, Maxim L.
Martins, Luísa Margarida D. R. S.
Pombeiro, Armando J. L.
Palavras-chave: Cyanoimido complexes
Alkylated cyanoimido
Digital simulation of cyclic voltammetry
Electron-transfer induced reactions
Double square ECEC-type mechanism
Data: Nov-2016
Editora: Elsevier
Citação: ALEGRIA, Elisabete C. B. A. [et al] - Mono-alkylation of cyanoimide at a molybdenum(IV) diphosphinic center by alkyl halides: synthesis, cathodically induced isomerization and theoretical studies. Electrochimica Acta. ISSN: 0013-4686. Vol. 218, (novembro2016), pp. 252-262.
Resumo: Treatment of trans-[Mo(NCN)(2)(dppe)(2)] with alkyl halides (RX) affords the alkylated cyanoimidocomplexes trans-[Mo(NCN)(NCNR)(dppe)(2)]X [R = Me, X = I (1); R = Et, X = I (2); R = Pr, X = I (3); R = Pr-i, X = I (4); R = CH2Ph, X = Br (5); R = CH2C6H4NO2-4, X = Br (6)], while its reaction with the trimethyloxonium salt [Me3O][BF4] affords trans-[Mo(NCN)(NCNMe)(dppe)(2)][BF4] (7). The reactions are accelerated by microwave irradiation. Complexes 1-7 were fully characterized by elemental analyses, IR and NMR spectroscopies, FAB-MS spectrometry, cyclic voltammetry and controlled potential electrolysis. The electrophilic addition to the exo-N atom of one of the cyanoimide ligands was confirmed by single crystal X-ray crystal analysis of 1. In aprotic medium and at a Pt electrode, compounds 1-7 undergo, apart from two consecutive single-electron reversible oxidations, also two successive single-electron reductions at different potentials, involving a cathodically induced trans-to-cis isomerization, following a double square ECEC-type mechanism which was studied in detail by digital simulation of the cyclic voltammograms. Quantum-chemical calculations indicate that the oxidations and reductions are mainly metal centered (although the latter with some involvement of the cyanoimide moieties), and that the reduction leads to a decrease of the relative stability of the trans isomer vs. the cis one.
Peer review: yes
URI: http://hdl.handle.net/10400.21/7148
DOI: 10.1016/j.electacta.2016.09.120
ISSN: 0013-4686
Versão do Editor: http://ac.els-cdn.com/S0013468616320382/1-s2.0-S0013468616320382-main.pdf?_tid=acb5819a-452b-11e7-ac32-00000aab0f27&acdnat=1496144134_1226d420a2e999fbc69f72bd157e54dd
Aparece nas colecções:ISEL - Eng. Quim. Biol. - Artigos

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