Rhodium and palladium complexes of a pyridyl-centred polyphenylene derivative

Ollagnier, Cecile M. A.; Perera, Sarath D.; Fitchett, Christopher M.; Draper, Sylvia M.

doi:10.1039/b709818a

Cited by 14 publications

(9 citation statements)

References 22 publications

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“…Instrumentation. 1 H, 13 C, and 19 F NMR spectra were recorded on a Bruker Avance II 300 MHz ( 1 H, 300 MHz; 13 C, 75 MHz; 19 F, 282 MHz) double-resonance (BBFO) 5 mm observation probehead with a z-gradient coil spectrometer. Chemical shifts were relative to TMS.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…Cyclometalated complexes for the noble transition metals Ru, Rh, Ir, Pd, Pt, and Au carrying the anionic tridentate (Phbpy – ) ligand have been synthesized and investigated since the early 1990s. − Most of them were accessed through a chelate-assisted C–H activation reaction, presumably after N ∧ N precoordination. Corresponding complexes of the base metal nickel were first reported in 2014. − Initially, the parent [Ni(Phbpy)Br] complex (Chart , top) was generated in high yields by introduction of a bromo substituent to the 2-position of the phenyl unit and follow-up treatment with [Ni(COD) 2 ] (COD = 1,5-cyclooctadiene), affording the desired complex by a chelation-mediated oxidative addition .…”

Section: Introductionmentioning

confidence: 99%

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Role of the X Coligands in Cyclometalated [Ni(Phbpy)X] Complexes (HPhbpy = 6-Phenyl-2,2′-bipyridine)

et al. 2021

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The coligand X was varied in the organonickel complexes [Ni(Phbpy)X] (X = F, Cl, Br, I, C 6 F 5 ) carrying the anionic tridentate C ∧ N ∧ N ligand 6-(phen-2-ide)-2,2′-bipyridine (Phbpy − ) to study its effect on electronic structures of these complexes and their activity in Negishi-like C−C cross-coupling catalysis. The complexes were synthesized from the precursor [Ni(COD) 2 ] (COD = 1,5-cyclooctadiene) by chelate-assisted oxidative addition into the phenyl C−X bond of the protoligand 6-(2-halidophenyl)-2,2′-bipyridine) and were obtained as red powders. Protoligands X−Phbpy carrying the halide surrogates X = OMe, OTf (triflate) failed in this reaction. Single-crystal XRD allowed us to add the structures of [Ni(Phbpy)Cl] and [Ni(Phbpy)I] to the previously reported Br derivative. Cyclic voltammetry showed reversible reductions for X = C 6 F 5 , F, Cl, while for Br and I the reversibility is reduced through rapid splitting of X − after reduction (EC mechanism). UV−vis spectroelectrochemistry confirmed the decreasing degree of reversibility along the series C 6 F 5 > F > Cl ≫ Br > I, which parallels the "leaving group character" of the X coligands. This method also revealed mainly bpy centered reduction and essentially Ni(II)/Ni(III) oxidations, as corroborated by DFT calculations. The rather X-invariant long-wavelength UV−vis absorptions and excited states were analyzed in detail using TD-DFT and were consistent with predominant metal to ligand charge transfer (MLCT) character. Initial catalytic tests under Negishi-like conditions showed the complexes to be active as catalysts in C−C cross-coupling reactions but did not display marked differences along the series from Ni−F to Ni−I.

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Section: ■ Experimental Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Role of the X Coligands in Cyclometalated [Ni(Phbpy)X] Complexes (HPhbpy = 6-Phenyl-2,2′-bipyridine)

et al. 2021

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“…Figures 3 and 4 feature the images obtained by using Mercury software. 3,4,5,6-Tetraphenyl-2,2′-bipyridine ( 7) was prepared according to a procedure recorded in relevant literature (Ollangnier, et al, 2008).…”

Section: Methodsmentioning

confidence: 99%

“…Synthesis of the pyridyl-centred polyphenylene (7) (see Scheme 1) and its coordination chemistry particularly with rhodium and palladium have been reported (Ollangnier, et al, 2008;Perera & Draper, 2009;Perera, 2018). It is of interest to explore the chemistry of this pyridyl-centred polyphenylene ligand (7) with platinum centres in order to prepare possible photoactive luminescent complexes of the type [(C^N^N)PtX] (X = halide, trifluoroacetate, acetylides), [(C^N^N)Pt(L′)]PF6 (L′ = pyridine or phosphine) and a binuclear complex containing bridging ligands.…”

Section: Figure 2 Molecular Structures Of Cyclometallated Pt(ii) Complexesmentioning

confidence: 99%

Synthesis of Cyclometallated Pt(II) Complexes of a Bulky Bipyridine Ligand

Perera

2021

OUSL Jnl

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Treatment of 3,4,5,6-tetraphenyl-2,2′-bipyridine (LH) ( 7) with [PtCl2(dmso)2] (dmso = dimethyl sulfoxide) in chloroform afforded the cyclometallated square-planar platinum(II) complex [PtCl(L)] ( 8) and the octahedral Pt(IV) complex mer-[PtCl3(L)] (9) containing an anionic tridentate (C^N^N) ligand. The chloride of ( 8) can be easily replaced by trifluoroacetate to yield [(L)PtO2CCF3] (10). Reaction of (8) with the alkyne HC≡CC6H4Bu t -4 resulted in the formation of [(L)PtC≡CC6H4Bu t -4] (11). Treatment of ( 8) with 4-dimetylaminopyridine (DMAP) and PPh3 in dichloromethane, and the subsequent addition of NH4PF6 in methanol produced the salts [Pt(DMAP)(L)]PF6 ( 12) and [Pt(PPh3)(L)]PF6 (13), respectively. In a similar manner, reaction of (8) with 0.5 equiv. of bis(diphenyl-phosphino)methane (dppm) formed the dppm-bridged binuclear dicationic salt [(L)Pt(dppm)Pt(L)][PF6]2 (14).

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“…In this context, bipyridyl or phenanthroline-based ligands have been used. Other aromatic diimines have seen application with photoresponsive metal centers [130,131] and there is scope to rethink and redesign ligand systems that might be appropriate to extending luminescence lifetimes and quantum yields in Cu(I) systems. A synthetic protocol that can be extended to multiple systems is very attractive and new aromatic ligands generated by Diels-Alder cycloaddition have come to the fore in Ru(II) chemistry [132][133][134].…”

Section: Old Systems For New Challengesmentioning

confidence: 99%