title: Dialkylcyanamides are more reactive substrates toward metal-mediated nucleophilic addition than alkylcyanides.
abstract: The dialkylcyanamide complexes Q[PtCl3(NCNR2)] (Q = Ph3PCH2Ph, R2 = Me21, Et22, C5H103, C4H8O 4; Q = NMe4, R2 = Me25; Q = NEt4, R2 = Me26) were synthesized either by dissolving Q2[Pt2(μ-Cl)2Cl4] in neat NCNR2 (1-4) or by substitution of a NCNR2 ligand with Cl(-) in [PtCl2(NCNR2)2] by its treatment with QCl (5, 6). Nucleophilic addition of dibenzylhydroxylamine, HON(CH2Ph)2, to 1-6 results in the formation of the complexes Q[PtCl3{NHC(NR2)ON(CH2Ph)2}] (Q = Ph3PCH2Ph, R2 = Me2, 7; Et2, 8; C5H10, 9; C4H8O, 10; Q = Me4N, R2 = Me211; Q = Et4N, R2 = Me2, 12) that further convert at room temperature in the solid state (1-24 h) or in a solution (0.5-2 h) to the imine complexes Q[PtCl3{N(CH2Ph)=C(H)Ph}] (Q = Ph3PCH2Ph, 13; Me4N, 14; Et4N, 15) and the corresponding dialkylureas H2NC(=O)NR2. The competitive reactivity study of the nucleophilic addition of HON(CH2Ph)2 to (Ph3PCH2Ph)[PtCl3(NCR')] (R' = Ph, NR2, CH2Ph) indicated that the reactivity of the coordinated NCNR2 is comparable to NCPh, while NCCH2Ph appeared to be much less reactive than the former two ligands. Compounds 1-6 and 13 were fully characterized by elemental analyses (C, H, N), high resolution ESI-MS, IR, and (1)H and (13)C{(1)H} NMR spectroscopy. The structure of 1 was additionally verified by a single-crystal X-ray diffraction.
authors.affiliation: Department of Chemistry, Saint Petersburg State University, Universitetsky Pr. 26, 198504 Stary Petergof, Russian Federation.
authors.forename: Tatyana B
authors.initials: TB
authors.lastname: Anisimova
authors.forename: Nadezhda A
authors.initials: NA
authors.lastname: Bokach
authors.forename: Fedor M
authors.initials: FM
authors.lastname: Dolgushin
authors.forename: Vadim Yu
authors.initials: VY
authors.lastname: Kukushkin