New Pt→M (M = Ag or Tl) complexes based on anionic cyclometalated Pt(<scp>ii</scp>) complexes

Campillo, David; Belío, Úrsula; Martín, António

doi:10.1039/c9dt00121b

Cited by 12 publications

(20 citation statements)

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“…These spectra indicate that 1- Cl 2 does not undergo a simple activation of the Sb–Cl and Pt–Cl bond as originally anticipated. Instead, the silver activator remains coordinated to the liberated phosphine arm and possibly to the platinum atom . When the same experiment was carried out with [ 2 –Cl][Cl] in CD 2 Cl 2 , a much simpler process was observed, since 31 P{ 1 H} NMR spectroscopy showed the unambiguous formation of a new species characterized by a phosphine resonance at 52.9 ppm ( 1 J Pt–P = 2442 Hz), which is ∼3.2 ppm upfield from that of [ 2 –Cl][Cl] (56.1 ppm), and a phosphine oxide resonance at 30.1 ppm (Figure ).…”

Section: Resultsmentioning

confidence: 99%

“…Instead, the silver activator remains coordinated to the liberated phosphine arm and possibly to the platinum atom. 15 When the same experiment was carried out with [2− Cl][Cl] in CD 2 Cl 2 , a much simpler process was observed, since 31 P{ 1 H} NMR spectroscopy showed the unambiguous formation of a new species characterized by a phosphine resonance at 52.9 ppm ( 1 J Pt−P = 2442 Hz), which is ∼3.2 ppm upfield from that of [2−Cl][Cl] (56.1 ppm), and a phosphine oxide resonance at 30.1 ppm (Figure 4). The spectroscopic features suggest that this new species is the bis(tetrafluoroborate) salt [2][BF 4 ] 2 , stabilized by coordination of the alkyne to the platinum center.…”

Section: ■ Introductionmentioning

confidence: 89%

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An Electrophilic, Intramolecularly Base-Stabilized Platinum–Antimony Complex

2021

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As part of our interest in the chemistry of late transition metal complexes bearing cationic antimony ligands, we have investigated the reaction of ((o-(Ph 2 P)C 6 H 4 ) 3 )SbClPtCl (1) with H 2 O 2 and found that it affords [((o-(Ph 2 P)C 6 H 4 ) 2 (o-Ph 2 PO)C 6 H 4 )SbPtCl] + ([2−Cl] + ), a monocationic complex with the newly installed P=O moiety coordinated intramolecularly to the antimony atom via a P=O → Sb dative bond. The Pt−Cl bond of this complex is readily activated by addition of a ligand such as cyclohexyl isocyanide. When carried out in the presence of AgBF 4 , this reaction affords the dicationic complex [((o-(Ph 2 P)C 6 H 4 ) 2 (o-Ph 2 PO)-C 6 H 4 )SbPt(CNCy)] + ([2−CNCy] 2+). In addition to structurally characterizing [2−Cl] + and [2−CNCy] 2+ as their chloride and tetrafluoroborate salts, respectively, we have also studied the reaction of [2−Cl] + with AgBF 4 in the presence of PhCCH as a substrate surrogate. When monitored by 31 P NMR spectroscopy in CDCl 3 , this reaction shows the formation of a new species tentatively assigned to [((o-(Ph 2 P)C 6 H 4 ) 2 (o-Ph 2 PO)C 6 H 4 )SbPt] 2+ ([2] 2+ ) stabilized by coordination of the alkyne. This formulation is supported by the elevated carbophilic reactivity of [2] 2+ , which readily catalyzes the cyclization of 2-allyl-2-(2propynyl)malonate. Altogether, these results show that the accumulation of charge in such reactive complexes can be facilitated by the intramolecular base-stabilization of the dinuclear core.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 89%

An Electrophilic, Intramolecularly Base-Stabilized Platinum–Antimony Complex

2021

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“…Tridentate CNC bis-cyclometalating Hph(py)phH ligands such as the prototypical 2,6-diphenylpyridine (HPhPyPhH) (Chart ) were introduced to organoplatinum(II) chemistry about 30 years ago. , Neutral or anionic complexes (Chart ) of these dianionic – CNC – ligands have been studied together with derivatives of the monoanionic CNN or NCN ligands (HCNN = derivatives of 6-phenyl-2,2′-bipyridine, Hphbpy; NC(H)N = derivatives of 1,3-bis(2-pyridyl)benzene, py(Hph)py), mainly due to their interesting luminescence properties − and their use as scaffolds with particular chemical reactivity. − …”

Section: Introductionmentioning

confidence: 99%

Cyclometalated Pt Complexes of CNC Pincer Ligands: Luminescence and Cytotoxic Evaluation

et al. 2020

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In the framework of our attempts to develop cyclometalated Pt(II) complexes toward bifunctional targeting inhibitors or agents for photodynamic therapy, diagnostics, and bioimaging, a series of bis-cyclometalated Pt(II) complexes [Pt(CNC)(L)] (L = DMSO, MeCN) containing various (CNC)2– ligands based on 2,6-diphenylpyridine were synthesized and characterized analytically and spectroscopically, focusing on their electrochemical, luminescence, and antiproliferative properties. Electrochemical experiments and UV–vis absorption spectroscopy suggest ligand-centered LUMOs and metal-centered HOMOs in line with DFT calculations. Extension of the ancillary phenyl to naphthyl cores and a central 4-phenylpyridine group instead of pyridine results in bathochromic shifts of the long-wavelength absorption bands ranging from 420 to 440 nm, with the latter shift being more pronounced. The complexes of the fused CNC heterocyclic systems dba (H2dba = dibenzo[c,h]acridine), db(ph)a (H2db(ph)a = 7-phenyldibenzo[c,h]acridine), and bzqph (HbzqphH = 2-phenylbenzo[h]quinoline) absorb far more red-shifted in the range 500–530 nm. All complexes show reversible first electrochemical reductions and irreversible oxidations with an electrochemical gap of about 3 V, roughly in line with the absorption energies. While the 2,6-diphenylpyridine complexes [Pt(CNC)(DMSO)] show no luminescence at ambient temperature in solution, the fused dba, db(ph)a, and bzqph derivatives are efficient triplet emitters at ambient temperature with emission wavelengths in the region 575–600 nm and quantum yields ranging from 7 to 23%. Vibrationally resolved emission spectra calculated in the framework of DFT faithfully reproduce the experimental data. TD-DFT calculations at the excited-state T1 geometry reveal intraligand π–π*/MLCT character of the emission for all three investigated complexes. Antiproliferative tests on selected complexes gave very different toxicities, ranging from lower than 1 μM to virtually nontoxic. The data allowed drawing some structure–activity relationships (SAR), even though variations in solubility could also significantly account for the different toxicities.

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“…It is well-known that Pt II in square-planar complexes with strong field ligands can form metal dative bonds. − When a Hg II ion is an acceptor, dative-type Pt→Hg complexes (type A in Scheme ) are obtained. However, in some cases, covalent-type Pt–Hg complexes (type B) are obtained. − The major differences between the two types of hetero dinuclear complexes are the Pt–Hg distance and the coordination geometry around the Pt.…”

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Coordination Isomers of Trinuclear Pt₂Hg Complex That Differ in Type of Metal–Metal Bond

Yamaguchi

Yoshiya

2019

Inorg. Chem.

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New Pt→M (M = Ag or Tl) complexes based on anionic cyclometalated Pt(ii) complexes

Cited by 12 publications

References 75 publications

An Electrophilic, Intramolecularly Base-Stabilized Platinum–Antimony Complex

An Electrophilic, Intramolecularly Base-Stabilized Platinum–Antimony Complex

Cyclometalated Pt Complexes of CNC Pincer Ligands: Luminescence and Cytotoxic Evaluation

Coordination Isomers of Trinuclear Pt₂Hg Complex That Differ in Type of Metal–Metal Bond

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New Pt→M (M = Ag or Tl) complexes based on anionic cyclometalated Pt(ii) complexes

Cited by 12 publications

References 75 publications

An Electrophilic, Intramolecularly Base-Stabilized Platinum–Antimony Complex

An Electrophilic, Intramolecularly Base-Stabilized Platinum–Antimony Complex

Cyclometalated Pt Complexes of CNC Pincer Ligands: Luminescence and Cytotoxic Evaluation

Coordination Isomers of Trinuclear Pt2Hg Complex That Differ in Type of Metal–Metal Bond

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Coordination Isomers of Trinuclear Pt₂Hg Complex That Differ in Type of Metal–Metal Bond