Selectivity in metal–carbon bond protonolysis in p-tolyl- (or methyl)-cycloplatinated(ii) complexes: kinetics and mechanism of the uncatalyzed isomerization of the resulting Pt(ii) products

Haghighi, Mohsen Golbon; Nabavizadeh, S. Masoud; Rashidi, Mehdi; Kubicki, Maciej

doi:10.1039/c3dt51339d

Cited by 42 publications

(42 citation statements)

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“…This is the opposite of what has been observed for platinum(II). 135,136 For the platinum complex Pt(N-N)MePh 78, Bercaw et al observed mainly protolytic cleavage of the sp 3 -C of the methyl group, rather than the sp 2 -C of the phenyl (Scheme 3.3). If the gold(III) complex 77-BF 4 in dichloromethane-d 2 was allowed to warm to room temperature, it decomposed to ethane and metallic gold as well as 2-(ptolyl)pyridinium (Scheme 3.2).…”

Section: Reactivity Towards Acidsmentioning

confidence: 99%

Versatile Methods for Preparation of New Cyclometalated Gold(III) Complexes

et al. 2012

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The interest in organogold compounds continues to grow. Gold(III) complexes are being investigated as catalysts for organic transformations as well as tested as potential anti-cancer drugs. Despite this wide-ranging interest in the properties of such complexes, the synthetic methods for preparing them are underdeveloped. Thus, Chapter 2 discusses the synthesis of cyclometalated gold(III) complexes bearing the C-N chelating ligand 2-(p-tolyl)pyridine (tpy). Monoalkylation andarylation were possible by use of Grignard reagents, whereas alkyl and aryl lithium reagents gave the dialkylated and diarylated gold(III) complexes. By a combination of the two alkylation procedures, mixed alkyl/aryl complexes of the type AuMePh(tpy) were obtained and both isomers were available. Chapter 3 discusses the reactivity of the cyclometalated gold(III) complexes towards different gases such as carbon monoxide and oxygen. Most of the cyclometalated gold(III) complexes prepared react with acids. The monoalkylated and-arylated complexes of the type AuBrR(tpy) (R = Me, Et, CHCH 2 , CCH, Ph) react with silver(I) salts to give a potential open coordination site at gold(III). Ethylene formally inserts into the Au-O bond trans to nitrogen in the chelating C-N ligand of the complex Au(OCOCF 3) 2 (tpy) (62) in trifluoroacetic acid or dichloromethane, to yield Au(CH 2 CH 2 OCOCF 3)(OCOCF 3)(tpy) (94). In trifluoroethanol, a slightly different complex resulted due to nucleophilic attack by trifluoroethanol rather than trifluoroacetate, Au(CH 2 CH 2 OCH 2 CF 3)(OCOCF 3)(tpy) (95). The mechanism of the insertion was investigated experimentally as well as computationally and the results are discussed in Chapter 4. The formal insertion takes place with alkenes other than ethylene, and alkynes react too. A key step in the catalytic reactions involving gold(III) is assumed to be the coordination of a CC multiple bond to the gold centre. Various catalytic cycles involving a gold(III) π-complex have been proposed. However, gold(III) alkene, alkyne, allene, or arene complexes have until recently not been conclusively detected and characterised. Chapter 5 discusses the first, and thus far only, crystallographically characterised gold(III) alkene complex, Au(cod)Me 2 BArF (133-BArF, BArF = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, cod = 1,5-cyclooctadiene).

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Section: Reactivity Towards Acidsmentioning

confidence: 99%

Versatile Methods for Preparation of New Cyclometalated Gold(III) Complexes

et al. 2012

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“…The synthesis routes for these complexes are shown in Scheme . Complexes [Pt (bhq)(Me)(SMe 2 )], 1 , and [Pt (bhq)(CF 3 COO)(SMe 2 )], 2 , where bhq = deprotonated 7,8‐benzo[h]quinoline, were prepared as reported in the literature. All the new complexes have shown to be stable powders at ambient temperature.…”

Section: Resultsmentioning

confidence: 99%

“…The reagents SMe 2 , trifluoroacetic acid (CF 3 COOH), and NaN 3 and the ligands PPh 3 , PPh 2 Me, dppm, dppe, and dppa were purchased from commercial resources. Complexes [Pt (bhq)(Me)(SMe 2 )], 1 , and [Pt (bhq)(CF 3 COO)(SMe 2 )], 2 , were prepared as reported in the literature. The 1 H NMR labeling for the cyclometalated moiety has been embedded in Scheme .…”

Section: Discussionmentioning

confidence: 99%

Luminescent mononuclear and dinuclear cycloplatinated (II) complexes comprising azide and phosphine ancillary ligands

Nikahd

Aghakhanpour

Nabavizadeh

et al. 2019

Applied Organom Chemis

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A new series of cycloplatinated (II) complexes with general formulas of [Pt (bhq)(N 3 )(P)] [bhq = deprotonated 7,8-benzo[h]quinoline, P = triphenyl phosphine (PPh 3 ) and methyldiphenyl phosphine], [Pt (bhq)(P^P)]N 3 [P^P = 1,1-bis (diphenylphosphino)methane (dppm) and 1,2-bis (diphenylphosphino)ethane] and [Pt 2 (bhq) 2 (μ-P^P)(N 3 ) 2 ] [P^P = dppm and 1,2-bis (diphenylphosphino) acetylene] is reported in this investigation. A combination of azide (N 3 − ) and phosphine (monodentate and bidentate) was used as ancillary ligands to study their influences on the chromophoric cyclometalated ligand. All complexes were characterized by nuclear magnetic resonance spectroscopy. To confirm the presence of the N 3 − ligand directly connected to the platinum center, complex [Pt (bhq)(N 3 )(PPh 3 )] was further characterized by single-crystal X-ray crystallography. The photophysical properties of the new products were studied by UV-Vis spectroscopy in CH 2 Cl 2 and photoluminescence spectroscopy in solid state (298 or 77 K) and in solution (77 K). Using density functional theory calculations, it was proved that, in addition to intraligand chargetransfer (ILCT) and metal-to-ligand charge-transfer (MLCT) transitions, the L ′LCT (L′ = N 3 , L = C^N) electronic transition has a remarkable contribution in low energy bands of the absorption spectra (for complexes [Pt (bhq)(N 3 ) (P)] and [Pt 2 (bhq) 2 (μ-P^P)(N 3 ) 2 ]). It is indicative of the determining role of the N 3 − ligand in electronic transitions of these complexes, specifically in the low energy region. In this regard, the photoluminescence studies indicated that the emissions in such complexes originate from a mixed 3 ILCT/ 3 MLCT (intramolecular) and also from aggregations (intermolecular). /journal/aoc 1 of 12 3 J PtH ≈ 50 Hz, 2 J PH = 21 Hz, 2H, CH 2 of dppm]; aromatic protons: 8.55 [d, 3 J HH = 8.0 Hz, 1H, H 9 of bhq]; 8.67 [t, 3 J HH ≈ 4 J PH = 3.7 Hz, 3 J PtH ≈ 23 Hz, 1 H, H 2 of bhq]; other aromatic protons: 6.8-8.4 ppm; δ ( 31 P) = 35.59 [d, 2 J PP = 42 Hz, 1 J PtP = 3364 Hz, P of dppm]; 21.78 [d, 2 J PP = 42 Hz, 3 J PtP = 1446 Hz, P of dppm].[Pt (bhq)(dppe)]N 3 , 5bDppe (40 mg, 0.1 mmol) was added to a solution of 3 (48 mg, 0.1 mmol) in acetone (20 mL). The mixture was NIKAHD ET AL. 9 of 12

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“…In this complex the dppf ligand adopts an ''open bridge'' conformation. 2,[5][6][7][8][9][10] However, when complex A was treated with one equivalent of the dppf ligand the PtNbipyO-H bond easily dissociated, and the mononuclear complex [PtMe(κ 1 C-bipyO-H)(dppf)], 2, was formed. This bond breaking is related to the potent chelating ability of dppf ligand due to its large P^P bite angle.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

“…1,2,4 The dppf is a biphosphine ligand and can adopts numerous coordination modes in complexes of a range of transition metals. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] These dppf complexes have been utilized in several area such as catalysis, materials science, electrochemistry, and biology. 1,2,7,9,10,[19][20][21] On the other hand, the chemistry of cyclometalated complexes is of great interest because of their use in a wide range of applications.…”

Section: Introductionmentioning

confidence: 99%

Cyclometalated platinum(ii) complexes of 2,2′-bipyridine N-oxide containing a 1,1′-bis(diphenylphosphino)ferrocene ligand: structural, computational and electrochemical studies

et al. 2017

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The preparation and characterization of new heteronuclear-platinum(ii) complexes containing a 1,1'-bis(diphenylphosphino)ferrocene (dppf) ligand are described. The reaction of the known starting complex [PtMe(κN,C-bipyO-H)(SMe)], A, in which bipyO-H is a cyclometalated rollover 2,2'-bipyridine N-oxide, with the dppf ligand in a 2 : 1 ratio or an equimolar ratio led to the formation of the corresponding binuclear complex [PtMe(κN,C-bipyO-H)(μ-dppf)], 1, or the mononuclear complex [PtMe(κC-bipyO-H)(dppf)], 2, respectively. According to the reaction conditions, the dppf ligand in 1 and 2 behaves as either a bridging or chelating ligand. All complexes were characterized by NMR spectroscopy. The solid-state structure of 2 was determined by the single-crystal X-ray diffraction method and it was shown that the chelating dppf ligand in this complex was arranged in a "synclinal-staggered" conformation. Also, the occurrence of intermolecular C-HO interactions in the solid-state gave rise to an extended 1-D network. The electronic absorption spectra and the electrochemical behavior of these complexes are discussed. Density functional theory (DFT) was used for geometry optimization of the singlet states in solution and for electronic structure calculations. The analysis of the molecular orbital (MO) compositions in terms of occupied and unoccupied fragment orbitals in 2 was performed.

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Selectivity in metal–carbon bond protonolysis in p-tolyl- (or methyl)-cycloplatinated(ii) complexes: kinetics and mechanism of the uncatalyzed isomerization of the resulting Pt(ii) products

Cited by 42 publications

References 58 publications

Versatile Methods for Preparation of New Cyclometalated Gold(III) Complexes

Versatile Methods for Preparation of New Cyclometalated Gold(III) Complexes

Luminescent mononuclear and dinuclear cycloplatinated (II) complexes comprising azide and phosphine ancillary ligands

Cyclometalated platinum(ii) complexes of 2,2′-bipyridine N-oxide containing a 1,1′-bis(diphenylphosphino)ferrocene ligand: structural, computational and electrochemical studies

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