title: Bifunctional reactivity of amidoximes observed upon nucleophilic addition to metal-activated nitriles.
abstract: Treatment of the aromatic nitrile complexes trans-[PtCl2(RC6H4CN)2] (R = p-CF3 NC1, H NC2, o-Cl NC3) with the aryl amidoximes p-R'C6H4C(NH2)=NOH (R' = Me AO1, H AO2, Br AO3, CF3 AO4, NO2 AO5) in all combinations, followed by addition of 1 equiv of AgOTf and then 5 equiv of Et3N, leads to the chelates [PtCl{HN=C(RC6H4)ON=C(C6H4R'-p)NC(RC6H4)═NH}] (1-15; 15 examples; yields 71-88% after column chromatography) derived from the platinum(II)-mediated coupling between metal-activated nitriles and amidoximes. The mechanism of this reaction was studied experimentally by trapping and identification of the reaction intermediates, and it was also investigated theoretically at the DFT level of theory. The combined experimental and theoretical results indicate that the coupling with the nitrile ligands involves both the HON and monodeprotonated NH2 groups of the amidoximes, whereas in the absence of the base, the NH2 functionality is inactive toward the coupling. The observed reaction represents the first example of bifunctional nucleophilic behavior of amidoximes. The complexes 1-16 were characterized by elemental analyses (C, H, N), high-resolution ESI(+)-MS, FTIR, and (1)H NMR techniques, whereas unstable 17 was characterized by HRESI(+)-MS and FTIR. In addition, 8·C4H8O2, 12, and 16·CHCl3 were studied by single-crystal X-ray diffraction.
authors.affiliation: †Institute of Chemistry, Saint Petersburg State University, Universitetsky Pr. 26, 198504 Stary Petergof, Russian Federation.
authors.forename: Dmitrii S
authors.initials: DS
authors.lastname: Bolotin
authors.affiliation: †Institute of Chemistry, Saint Petersburg State University, Universitetsky Pr. 26, 198504 Stary Petergof, Russian Federation.
authors.forename: Marina Ya
authors.initials: MY
authors.lastname: Demakova
authors.affiliation: †Institute of Chemistry, Saint Petersburg State University, Universitetsky Pr. 26, 198504 Stary Petergof, Russian Federation.
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Novikov
authors.affiliation: ‡Institute of Earth Sciences, Saint Petersburg State University, University Emb. 7/9, 199034 Saint Petersburg, Russian Federation.
authors.forename: Margarita S
authors.initials: MS
authors.lastname: Avdontceva
authors.affiliation: §Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon, Portugal.
authors.forename: Maxim L
authors.initials: ML
authors.lastname: Kuznetsov
authors.affiliation: †Institute of Chemistry, Saint Petersburg State University, Universitetsky Pr. 26, 198504 Stary Petergof, Russian Federation.
authors.forename: Nadezhda A
authors.initials: NA
authors.lastname: Bokach
authors.affiliation: †Institute of Chemistry, Saint Petersburg State University, Universitetsky Pr. 26, 198504 Stary Petergof, Russian Federation.|∥Institute of Macromolecular Compounds of Russian Academy of Sciences, V.O. Bolshoii Pr. 31, 199004 Saint Petersburg, Russian Federation.
authors.forename: Vadim Yu
authors.initials: VY
authors.lastname: Kukushkin