Metal-mediated and solvent dependent chlorination of the nitrosonaphtholato ligandThe authors are very much obliged to Prof. Yuri N. Kukushkin (deceased Nov. 31st, 1998) for stimulating ideas and discussions relevant to this work.

Abstract

Reaction of K[PtCl 3 (Me 2 SO)] and 1,2-naphthoquinone-1-monoxime in water-dimethyl sulfoxide medium led to cis-(S,N)-[PtCl{2-(O)C 10 H 6 NO}(Me 2 SO)] 1. Chlorination of the latter in methanol readily generates, under mild conditions, the platinum() compound cis-(S,N)-[PtCl 3 {2-(O)C 10 H 5 Cl 2 (OMe)NO}(Me 2 SO)] 2 with a chelating nitrosonaphtholato ligand bearing a new chiral atom due to concomitant chlorination and nucleophilic addition of a MeOH solvent molecule. The newly formed ligand was liberated from 2 by reaction with excess thiourea. The chlorination course is strongly dependent on the nature of solvent employed and in CHCl 3 also at room temparature the chlorination with either Cl 2 or NOCl brings about only oxidation of the metal center to achieve cis-(S,N)-[PtCl 3 {2-(O)C 10 H 6 NO}(Me 2 SO)] 3. All complexes were characterized by C, H, N, Cl and Pt elemental analyses, FAB ϩ mass-spectrometry, IR and 1 H, 13 C{ 1 H} and 195 Pt NMR spectroscopies, and 2 and 3 by X-ray crystallography which indicates the chelating bidentate ligand adopts the nitroso form.

First Example of the Solid-State Thermal Cyclometalation of Ligated Benzophenone Imine Giving Novel Luminescent Platinum(II) Species

“…In addition, 2-6 displayed very strong ν(SdO) [1113-1134 cm -1 ] bands shifted vs ν(SdO) of the free sulfoxides due to S coordination. 49 The structures of 1, trans-[PtCl 2 (Ph 2 CdNH)(Me 2 SO)] (2), and trans-[PtCl 2 (Ph 2 CdNH){(CH 2 ) 4 SO}] (4) were determined by X-ray single-crystal diffraction (Table 1 and Figures 1-3). The coordination geometries of the three complexes are slightly distorted square-planar.…”

Novel platinum(ii) compounds with O,S bidentate ligands: synthesis, characterization, antiproliferative properties and biomolecular interactions

“…Once coordinated to the Pt(II) center, DMSO as a ligand can be kept in the complex 32,50-52 or be substituted against a more stable ligand during the progression of the reaction. 35,53,54 A new synthesis towards target compounds 7-12 was developed (Scheme 1). Potassium tetrachloroplatinate (K 2 PtCl 4 ) was reacted with excess DMSO in a minimal amount of water.…”

Unexpected Formation of Ferrocenyl(vinyl)benzoquinoline Ligands by Oxidation of an Alkyne Benzoquinolate Platinum(II) Complex

“…hypervalent iodine reagents, electrophilic halogenating reagents, ...). − In these processes, reductive elimination from a high oxidation state (mononuclear M IV , dinuclear Pd III ) has been proposed as a key step of the carbon–carbon and carbon–halide bond-forming reactions. − Thus, in Pt II chemistry the general mechanism for the formation of new bonds under oxidative conditions usually involves the initial oxidation of the Pt center giving rise to a Pt IV intermediate, which undergoes subsequent reductive elimination to produce C–C or C–halide bonds. − En route, diplatinum(III) complexes and even paramagnetic mononuclear Pt III species have been rarely found as short-lived precursors of the Pt IV intermediates. Direct attack of the electrophilic reagent at the ligand is very rare, although some examples of fluorination, chlorination, and bromination have been reported when the axial site at Pt is sterically protected . Here we report the synthesis of unusual ( Z )-10-[1-X,1-ferrocenyl(vinyl)]benzoquinoline ligands (X = Cl, I) generated by simple reaction of the alkyne complex [Pt(bzq-κ N ,κ C 10 )(C 6 F 5 )(η 2 -HCCFc)] ( 1 ), containing the redox-active ferrocenyl group, with oxidants (PhICl 2 and I 2 ).…”