We synthesized and characterized two ligands, 2--(quinolin-8-yl)thiophene (1a) and 3-(quinolin-8-yl)thiophene (1b). The selective C-H activation of the thiophene moieties was achieved by reacting 1a or 1b and [Pt(CH 3 ) 2 (SMe 2 )] 2 . We observed η 2thiophene intermediates during the course of the reactions. The selective C-S bond activation of the thiophene moieties was observed after reacting 1a or 1b and [Pt(dippe)H] 2 . DFT calculations were performed to elucidate the regioselectivity of C-S activations.
We report both the stepwise and one-pot syntheses of Pt(II)-Cu(I) hetero-dinuclear complexes using 4,5-diazafluorenide (L(-)) and 9-(2-(diphenylphosphino)ethyl)-4,5-diazafluorenide (L(p)(-)) as binucleating ligands. In the case of L(p)(-), the tethered phosphine arm helps anchor the Pt(II) centre onto the carbon site of the diazafluorenide and the Cu(I) centre is bound to the N,N-chelate site. In the case of L(-), the Cu(I) centre is bound to the carbon site of diazafluorenide and the Pt(II) centre is coordinated to the N,N-chelate site.
We report the synthesis and characterization of a phosphine-functionalized 4,5-diazafluorene ligand, 9-(2-(diphenylphosphino)ethyl)-4,5-diazafluorene (L p H), and its Cu(IPr) complex (IPr = N,N′-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) [Cu(IPr)L p ] (2a), which exhibits a monomeric structure in solution but dimerizes in the solid state. Compound 2a reacts with Rh(PPh 3 ) 3 Cl, [Rh(COD)-Cl] 2 , Au(SMe 2 )Cl, and Au(IPr)Cl to form the macrocyclic complexes [Rh(PPh 3 )L p ] 2 (2b), [Rh(COD)L p ] 2 (2c), and [AuL p ] 2 (2d) and the mononuclear complex [Au(IPr)L p ] (2f), respectively, via ligand transfer. Although 2b−d,f could also be synthesized from the deprotonated ligand L p − and the corresponding metal starting materials directly, the reactions require longer time and give lower yields. The reaction between L p H and Au(SMe 2 )Cl gives Au(L p H) 2 Cl (2e) exclusively.
Three novel tetradentate ligands with quinoline functionalities, 1,2,4,5-tetrakis(6-ethylquinolin-8yl)benzene, 1,2,4,5-tetrakis(6-tert-butylquinolin-8-yl)benzene, and 1,2,4,5-tetrakis(6-(trifluoromethoxy)quinolin-8-yl)benzene, were synthesized through a three-step protocol and fully characterized by NMR spectroscopic, elemental, and X-ray diffraction analyses. The dinuclear dimethylplatinum(II) complexes of these ligands readily activate C-Cl bonds of CHCl 3 at ambient temperature, leading to the formation of the corresponding dinuclear Pt(IV) complex. In these reactions, the central phenyl rings of the tetradentate ligands are reduced to cyclohexadiene dianions and still retain their planarity.
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