title: Reactions of platinum(IV)-bound nitriles with isomeric nitroanilines: addition vs. substitution.
abstract: The platinum(IV) complex trans-[PtCl(4)(EtCN)(2)] reacts smoothly and under mild conditions with isomeric o-, m- and p-nitroanilines (NAs) yielding two different types of products depending on the NA isomer, viz. the nitroaniline complexes cis/trans-[PtCl(4)(NA)(2)] (cis/trans-1-3) and the amidine species trans-[PtCl(4){NH=C(Et)NHC(6)H(4)NO(2)-m}(EtCN)] (4), trans-[PtCl(4){NH=C(Et)NHC(6)H(4)NO(2)-m}(2)] (5) and trans-[PtCl(4){NH=C(Et)NHC(6)H(4)NO(2)-p}(EtCN)] (6). Complexes 4 and 5 undergo cyclometalation, furnishing mer-[PtCl(3){NH=C(Et)NHC(6)H(3)NO(2)-m}(EtCN)] (7) and mer-[PtCl(3){NH=C(Et)NHC(6)H(4)NO(2)-m}{NH=C(Et)NHC(6)H(3)NO(2)-m}] (8), respectively. Moreover, 8 both in the solid state and in solution undergoes the second step of the cyclometalation, generating [PtCl(2){NH=C(Et)NHC(6)H(3)NO(2)-m}(2)] (9). In 4, the nitrile ligand is highly reactive toward nucleophilic addition and it undergoes facile hydration accompanied by the elimination of the nitrile, thus producing cis-[PtCl(4)(NH(2)C(6)H(4)NO(2)-m){NH=C(OH)Et}] (10), or methanol addition providing trans-[PtCl(4){NH=C(Et)NHC(6)H(4)NO(2)-m}{NH=C(Et)OMe}] (11). All compounds, besides 9, were characterized by C, H, and N elemental analyses, high-resolution ESI-MS, IR, (1)H and (13)C{(1)H} NMR spectroscopic techniques. Complex 9, which was not isolated as a pure compound, was identified in the reaction mixture by ESI-MS and (1)H and (13)C{(1)H} NMR spectroscopies. Complexes trans-1, trans-2, 4, 5, 6, 8, 10, and 11 were additionally studied by X-ray diffraction.
authors.affiliation: Department of Chemistry, St. Petersburg State University, Universitetsky Pr. 26, 198504 Stary Petergof, Russian Federation.
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Chernyshev
authors.forename: Nadezhda A
authors.initials: NA
authors.lastname: Bokach
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Gushchin
authors.forename: Matti
authors.initials: M
authors.lastname: Haukka
authors.forename: Vadim Yu
authors.initials: VY
authors.lastname: Kukushkin
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D007536:Isomerism; D009570:Nitriles / Q000737:chemistry*; D009944:Organoplatinum Compounds / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D009570:Nitriles; D009944:Organoplatinum Compounds; D010984:Platinum