Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.21/5093
Título: Acylated cyanoimido-complexes trans-[Mo(NCN){NCN(O)R}(DPPE)(2)]Cl and their reactons with electrophiles: Chemical, electrochemical and theoretical study
Autor: Alegria, Elisabete Clara Bastos do Amaral
Silva, Maria de Fátima Costa Guedes da
Kuznetsov, Maxim L.
Cunha, S. M. P. R. M.
Martins, Luísa Margarida D. R. S.
Pombeiro, Armando J. L.
Palavras-chave: Crystal-structures
Coordination Chemistry
Structural-Characterization
Cyanoguanidine Complexes
Cyanamide Complexes
Metal-Complexes
Bond Formation
Nitrile
Organonitriles
Isomerization
Data: 2012
Editora: Royal Soc Chemistry
Citação: Alegria, E. C. B. A.; [et al] – Acylated cyanoimido-complexes trans-[Mo(NCN){NCN(O)R}(DPPE)(2)]Cl and their reactons with electrophiles: Chemical, electrochemical and theoretical study. Dalton Transactions. ISSN: 1477-9226. Vol. 41, nr. 45 (2012), pp. 13876-13890
Resumo: Treatment of a dichloromethane solution of trans-[Mo(NCN){NCNC(O)R}(dppe)(2)]Cl [R = Me (1a), Et (1b)] (dppe = Ph2PCH2CH2PPh2) with HBF4, [Et3O][BF4] or EtC(O)Cl gives trans-[Mo(NCN)Cl-(dppe)(2)]X [X = BF4 (2a) or Cl (2b)] and the corresponding acylcyanamides NCN(R')C(O)Et (R' = H, Et or C(O)Et). X-ray diffraction analysis of 2a (X = BF4) reveals a multiple-bond coordination of the cyanoimide ligand. Compounds 1 convert to the bis(cyanoimide) trans-[Mo(NCN)(2)(dppe)(2)] complex upon reaction with an excess of NaOMe (with formation of the respective ester). In an aprotic medium and at a Pt electrode, compounds 1 (R = Me, Et or Ph) undergo a cathodically induced isomerization. Full quantitative kinetic analysis of the voltammetric behaviour is presented and allows the determination of the first-order rate constants and the equilibrium constant of the trans to cis isomerization reaction. The mechanisms of electrophilic addition (protonation) to complexes 1 and the precursor trans[Mo(NCN)(2)(dppe)(2)], as well as the electronic structures, nature of the coordination bonds and electrochemical behaviour of these species are investigated in detail by theoretical methods which indicate that the most probable sites of the proton attack are the oxygen atom of the acyl group and the terminal nitrogen atom, respectively.
Peer review: yes
URI: http://hdl.handle.net/10400.21/5093
DOI: 10.1039/c2dt30867c
ISSN: 1477-9226
Aparece nas colecções:ISEL - Eng. Quim. Biol. - Artigos



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