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

Abstract

Oxidation of [Pt(bzq-κN,κC 10 )(C 6 F 5 )(η 2 -HCCFc)] (1) with PhICl 2 and I 2 affords the unusual halideferrocenyl(vinyl)benzoquinoline Pt II derivatives [Pt{bzq-κN-η 2 -CHC(X)Fc}(C 6 F 5 )X] (X = Cl (4a), I (4b)), arising from C−X and C−C coupling processes, together with small amounts of the corresponding Pt IV products [{Pt(bzq-κN,κC 10 )(C 6 F 5 )X(μ-X)} 2 ] (X = Cl (5a), I (5b)), respectively. Complexes 4 are very stable but they undergo easy displacement reactions with PPh 3 , yielding trans-[Pt(C 6 F 5 )X(PPh 3 ) 2 ] and the corresponding new functionalized (vinyl)benzoquinoline ligands [(Z)-bzq-CHC(X)Fc] (X = Cl (6a), I (6b)). The dinuclear Pt IV derivatives 5 are alternatively obtained in high yield by oxidation of the solvate [Pt(bzq-κN,κC 10 )(C 6 F 5 )(CH 3 COCH 3 )] (2). Treatment of 5 with dmso or direct oxidation of [Pt(bzq-κN,κC 10 )(C 6 F 5 )(tht)] (3) provides mononuclear [Pt(bzq-κN,κC 10 )(C 6 F 5 )X 2 (L)] (L = dmso (7a−c), tht (8a−c)) as a mixture of cis and trans isomers.

Luminescent pentafluorophenyl-cycloplatinated complexes: synthesis, characterization, photophysics, cytotoxicity and cellular imaging

“…2, 3 and 4 show views of the corresponding complexes and Table 1 lists a selection of relevant bond lengths. The structural data are similar to those found for [Pt(bzq) (13) 3b] slightly larger than the average of this distance in related structures. The HC^N ligands adopt a transoidal (or anti) disposition in relation to the platinum square planar, with dihedral angles between the pyridine groups and the Pt coordination planes of ~55º.…”

“…Calcd for C 24 H 13 F 5 N 2 PtS 2 : C,42.17;H,1.92;N,4.10;S,9.38. 13 C{ 1 H} NMR (100.6 MHz, CDCl 3 , ): 32-7.28 (m, 2H, H 9',3' ), 7.00 (t, J = 4.0, 1H, H 10 ), 6.80 (t, J = 6.3, 1H, H 3 ), 6.46 (d, J = 4.7, 3 J Pt-H = 26, 1H, H 10' ).…”

“…Unfortunately, we found that by dissolving 2a-c in DMSO, the N  CH ligand is easily substituted by a molecule of DMSO, giving rise the corresponding DMSO solvate [Pt(C^N) (C 6 F 5 )(DMSO)] (C  N = thpy 3a, bt 3b). All experiments were recorded in CDCl 3 and the signals were assigned on the basis on 1 H-1 H and 1 H- 13 C correlation experiments (see Experimental Section and Fig. In the case of 2c, a complex mixture of species was formed, in which the expected 3c is also present.…”

Facile Approaches to Phosphorescent Bis(cyclometalated) Pentafluorophenyl PtIV Complexes: Photophysics and Computational Studies

“…It is worth noting that the closeness of the ortho ‐fluorine atoms of C 6 F 5 to the two protons adjacent to the C ‐metalated rings (H11, 11′, 3 a , c , d ; H9, 9 ′ 3 b ; H12, 12′ 3 e ; H10, 10′ 3 f ) and to H2 ( 3 a , b , f ) or H7 ( 3 c , d )/H8 ( 3 e ) (see labelling in the Experimental Section and Figures S6–S10 in the Supporting Information) is reflected in the additional coupling in the corresponding signals ( 1 H, 13 C, 19 F resonances) and confirmed by decoupling and NOE experiments (see Figures S6–S8 for 3 c ). The coordination of the C 6 F 5 ring to Pt IV is reflected in the observed 4 J Pt‐F values (88–151 Hz), which show an important decrease with respect to the values found in 2 a – f (465–505 Hz) due to the change from Pt II to Pt IV …”

“…Among the organyl ligands, the C 6 F 5 group has proven to be able to stabilize many organometallic complexes in high oxidation states mainly due to its high electronegativity and reluctance to undergo reductive/elimination processes . Following our continuing interest in the chemistry and properties of heteroleptic cyclometalated pentafluorophenyl Pt II complexes, previously we reported the easy access to mono(cyclometalated) pentafluorophenyl Pt IV derivatives [Pt(bzq)(C 6 F 5 )X 2 L] [bzq=benzoquinolinyl; X=Cl, Br, I; L=dmso, tetrahydrothiophene (tht)] as a mixture of cis and trans isomers by the direct halogenation of the corresponding Pt II [Pt(bzq)(C 6 F 5 )L] complexes . Unfortunately, these complexes were not emissive, which presumably might be due to the presence of only one benzoquinolinyl group.…”