Bis(2,6-dinitroaryl)platinum(II) Complexes. Cis/Trans Isomerization

Vicente, José; Arcas, Aurelia; Gálvez-López, María-Dolores; Jones, Peter G.

doi:10.1021/om060398t

Cited by 41 publications

(31 citation statements)

References 43 publications

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“…As inferred from these NMR data, cleavage of the bridging system rendered compounds trans -(C*,PPh 3 )[PtCl(R-C^C*)(PPh 3 )] (R-C = Naph, 1A ; R = CO 2 Et, 1B ) as unique isomers and the subsequent replacement of Cl by py in the coordination environment of platinum proceeds with stereoretention, giving compounds trans -(C*,PPh 3 )[Pt(R-C^C*)(py)(PPh 3 )]PF 6 (R-C= Naph, 2A ; R = CO 2 Et, 2B ). These results were expected considering the degree of transphobia (T) of pairs of ligands in trans positions. − In our previous work, we concluded that T[C Ar /L] > T[C*/L] and T[C Ar /PPh 3 ] > T[C Ar /py] > T[C Ar /Cl], in such a way that T[C Ar /PPh 3 ] should be the greatest one. The current experimental results indicated that, as was observed in the case of compounds 1C – 4C , the difference between T[C Ar /PPh 3 ] and T[C*/PPh 3 ] is big enough to direct the selective formation of trans -(C*,PPh 3 ) complexes 1A , 1B , 2A , and 2B as pure compounds.…”

Section: Resultsmentioning

confidence: 60%

Heteroleptic Cycloplatinated N-Heterocyclic Carbene Complexes: A New Approach to Highly Efficient Blue-Light Emitters

et al. 2017

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New heteroleptic compounds of platinum(II)-containing cyclometalated N-heterocyclic carbenes, [PtCl(R-C^C*)(PPh)] [R-CH^C*-κC* = 3-methyl-1-(naphthalen-2-yl)-1H-imidazol-2-ylidene (R-C = Naph; 1A), 1-[4-(ethoxycarbonyl)phenyl]-3-methyl-1H-imidazol-2-ylidene (R = COEt; 1B), and [Pt(R-C^C*)(py)(PPh)]PF (py = pyridine; R-C = Naph, 2A; R = COEt, 2B], have been prepared and fully characterized. All of them were obtained as the trans-(C*,PPh) isomer in high yields. The selectivity of their synthesis has been explained in terms of the degree of transphobia (T) of pairs of ligands in trans positions. X-ray diffraction studies on both 2A and 2B revealed that only in 2A, containing a C^C* with a more extended π system, do the molecules assemble themselves into head-to-tail pairs through intermolecular π···π contacts. The photophysical properties of 2A and 2B and those of the related compounds [Pt(NC-C^C*)(PPh)L]PF [NC-CH^C*-κC* = 1-(4-cyanophenyl)-3-methyl-1H-imidazol-2-ylidene; L = pyridine (py; 2C), 2,6-dimethylphenylisocyanide (CNXyl; 3C), and 2-mercapto-1-methylimidazole (MMI; 4C)] have been examined to analyze the influence of the R substituent on R-C^C* (R-C = Naph; R = COEt, CN) and that of the ancillary ligands (L) on them. Experimental data and time-dependent density functional theory calculations showed the similarity of the electronic features associated with R-C^C* (R = CN, COEt) and their difference with respect to R-C^C* (R-C = Naph). All of the compounds are very efficient blue emitters in poly(methyl methacrylate) films under an argon atmosphere, with QY values ranging from 68% (2B) to 93% (2C). In the solid state, the color of the emission changes to yellowish-orange for compounds 2A (λ = 600 nm) and 3C (λ = 590 nm) because of the formation of aggregates through intermolecular π···π interactions. 2C and 3C were chosen to fabricate fully solution-processed electroluminescent devices with blue-light (2C), yellow-orange-light (3C), and white-light (mixtures of 2C and 3C) emission from neat films of the compounds as emitting layers.

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Section: Resultsmentioning

confidence: 60%

Heteroleptic Cycloplatinated N-Heterocyclic Carbene Complexes: A New Approach to Highly Efficient Blue-Light Emitters

et al. 2017

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“…Investigations of the cis to trans isomerization of square-planar Pt II complexes have been carried out since the 1950s. [9,38,39] The mechanisms of isomerization in this class of complexes can be divided into two major categories. The first involves consecutive displacement, consisting of ligand dissociation resulting in the formation of a three-coordinate intermediate, whereas the second involves pseudorotation, consisting of an intramolecular rearrangement accompanied by formation of a five-coordinate intermediate.…”

Section: Mechanistic Investigationsmentioning

confidence: 99%

Highly Efficient Deep‐Blue Emitters Based on cis and trans N‐Heterocyclic Carbene Pt^II Acetylide Complexes: Synthesis, Photophysical Properties, and Mechanistic Studies

Zhang

Blacque

Venkatesan

2013

Chemistry A European J

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We have synthesized cis and trans N-heterocyclic carbene (NHC) platinum(II) complexes bearing σ-alkynyl ancillary ligands, namely [Pt(dbim)2 (CCR)2 ] [DBIM=N,N'-didodecylbenzimidazoline-2-ylidene; R=C6 H4 F (4), C6 H5 (5), C6 H2 (OMe)3 (6), C4 H3 S (7), and C6 H4 CCC6 H5 (8)] and [Pt(ibim)2 (CCC6 H5 )2 ] (9) (ibim=N,N'-diisopropylbenzimidazoline-2-ylidene), starting from [Pt(cod)(CCR)2 ] (COD=cyclooctadiene) and 2 equivalents of [dbimH]Br ([ibimH]Br for complexes 9) in the presence of tBuOK and THF. Mechanistic investigations aimed at uncovering the cis to trans isomerization reaction have been performed on the representative cis complex 5 a [Pt(dbim)2 (CCC6 H5 )2 ] and revealed the isomerization to progress smoothly in good yield when 5 a was treated with catalytic amounts of [Pt(cod)(CCR)2 ] at 75 °C in THF or when 5 a was heated at 200 °C in the solid state under an inert atmosphere. Detailed examination of the reactions points to the possible involvement, in a catalytic fashion, of a solvent-stabilized Pt(II) dialkyne complex in the former case and a Pt(0) NHC complex in the latter case, for the transformation of the cis isomer to the corresponding trans complex. Thermal stability and the isomerization process in the solid state have been further investigated on the basis of TGA and DSC measurements. X-ray diffraction studies have been carried out to confirm the solid-state structures of 4 b, 5 a, 5 b, and 9 b. All of the synthesized dialkyne complexes 4-9 exhibit phosphorescence in solution, in the solid state at room temperature (RT), and also in frozen solvent glasses at 77 K. The emission wavelengths and quantum yields have been found to be highly tunable as a function of the alkynyl ligand. In particular, the trans isomer of complex 9 in a spin-coated film (10 wt % in poly(methyl methacrylate), PMMA) exhibits a high phosphorescence quantum yield of 80 %, which is the highest reported for Pt(II) -based deep-blue emitters. Experimental observations and time-dependent density functional theory (TD-DFT) calculations are strongly indicative of the emission being mainly governed by metal-perturbed interligand ((3) IL) charge transfer.

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“…However, the bond lengths at Pd vary over a very wide range (e.g. PdÐN = 2.09±2.32 A Ê ), making generalization dif®cult, and the iodo ligand may be trans to C or P. There are no examples with P trans to C for this donor atom set; consistent with the great extent of P/C`transphobia' (Vicente et al, 1997(Vicente et al, , 2002(Vicente et al, , 2006, the P-and C-atom donors are mutually cis in (I) and in the other literature examples.…”

Section: Figurementioning

confidence: 61%

An organometallic compound withZ′ = 4: {2-[2-(benzylideneamino)phenyl]-1,2-bis(methoxycarbonyl)ethenyl-κ²C¹,N}iodo(triphenylphosphine-κP)palladium(II)

Jones

López‐Serrano

2006

Acta Crystallogr C

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The title compound, [Pd(C19H17NO4)I(C18H15P)], crystallizes with four independent molecules in the asymmetric unit. The main difference between the molecules is the disposition of the PPh3 ligand, for which in each molecule one ring is perpendicular to the ligand plane, but may be directed in either direction away from the plane; of the four molecules, two represent each possible direction. The independent molecules are arranged to form a chain parallel to [101] with an approximate translation of (a+c)/4 between successive molecules, excluding the PPh3 rings. This leads to a systematic weakness of the reflections with h + l not equal 4n.

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Bis(2,6-dinitroaryl)platinum(II) Complexes. Cis/Trans Isomerization

Cited by 41 publications

References 43 publications

Heteroleptic Cycloplatinated N-Heterocyclic Carbene Complexes: A New Approach to Highly Efficient Blue-Light Emitters

Heteroleptic Cycloplatinated N-Heterocyclic Carbene Complexes: A New Approach to Highly Efficient Blue-Light Emitters

Highly Efficient Deep‐Blue Emitters Based on cis and trans N‐Heterocyclic Carbene Pt^II Acetylide Complexes: Synthesis, Photophysical Properties, and Mechanistic Studies

An organometallic compound withZ′ = 4: {2-[2-(benzylideneamino)phenyl]-1,2-bis(methoxycarbonyl)ethenyl-κ²C¹,N}iodo(triphenylphosphine-κP)palladium(II)

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Bis(2,6-dinitroaryl)platinum(II) Complexes. Cis/Trans Isomerization

Cited by 41 publications

References 43 publications

Heteroleptic Cycloplatinated N-Heterocyclic Carbene Complexes: A New Approach to Highly Efficient Blue-Light Emitters

Heteroleptic Cycloplatinated N-Heterocyclic Carbene Complexes: A New Approach to Highly Efficient Blue-Light Emitters

Highly Efficient Deep‐Blue Emitters Based on cis and trans N‐Heterocyclic Carbene PtII Acetylide Complexes: Synthesis, Photophysical Properties, and Mechanistic Studies

An organometallic compound withZ′ = 4: {2-[2-(benzylideneamino)phenyl]-1,2-bis(methoxycarbonyl)ethenyl-κ2C1,N}iodo(triphenylphosphine-κP)palladium(II)

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Highly Efficient Deep‐Blue Emitters Based on cis and trans N‐Heterocyclic Carbene Pt^II Acetylide Complexes: Synthesis, Photophysical Properties, and Mechanistic Studies

An organometallic compound withZ′ = 4: {2-[2-(benzylideneamino)phenyl]-1,2-bis(methoxycarbonyl)ethenyl-κ²C¹,N}iodo(triphenylphosphine-κP)palladium(II)