González Herrero, Pablo

Person:
González Herrero, Pablo

Name

González Herrero, Pablo

publication.page.department

Universidad de Murcia. Departamento de Química Inorgánica

Full item page

Search Results

Now showing 1 - 10 of 27

Open Access
Data for compounds included in the article "Luminescent Platinum(II) Complexes with Terdentate N∧C∧C Ligands".
(2023) Poveda Otazo, Dionisio; Vivancos Ureña, Ángela; Bautista, Delia; González Herrero, Pablo; Química Inorgánica; Facultades de la UMU::Facultad de Química
Open Access
Reductive Elimination Reactions in Gold(III) Complexes Leading to C(sp3)–X (X = C, N, P, O, Halogen) Bond Formation: Inner-Sphere vs SN2 Pathways
(American Chemical Society, 2023-01-19) Portugués Rodríguez, Alejandro; Martínez-Nortes, Miguel Ángel; Bautista, Delia; González Herrero, Pablo; Gil Rubio, Juan; Química Inorgánica
The reactions leading to the formation of C–heteroatom bonds in the coordination sphere of Au(III) complexes are uncommon, and their mechanisms are not well known. This work reports on the synthesis and reductive elimination reactions of a series of Au(III) methyl complexes containing different Au–heteroatom bonds. Complexes [Au(CF3)(Me)(X)(PR3)] (R = Ph, X = OTf, OClO3, ONO2, OC(O)CF3, F, Cl, Br; R = Cy, X = Me, OTf, Br) were obtained by the reaction of trans-[Au(CF3)(Me)2(PR3)] (R = Ph, Cy) with HX. The cationic complex cis-[Au(CF3)(Me)(PPh3)2]OTf was obtained by the reaction of [Au(CF3)(Me)(OTf)(PPh3)] with PPh3. Heating these complexes led to the reductive elimination of MeX (X = Me, Ph3P+, OTf, OClO3, ONO2, OC(O)CF3, F, Cl, Br). Mechanistic studies indicate that these reductive elimination reactions occur either through (a) the formation of tricoordinate intermediates by phosphine dissociation, followed by reductive elimination of MeX, or (b) the attack of weakly coordinating anionic (TfO– or ClO4–) or neutral nucleophiles (PPh3 or NEt3) to the Au-bound methyl carbon. The obtained results show for the first time that the nucleophilic substitution should be considered as a likely reductive elimination pathway in Au(III) alkyl complexes.
Open Access
Data for compounds included in the article "Bimetallic platinum(ii) complexes with bridging di-NHC and N^C^C ligands: synthesis and photophysical properties"
(2026-05-22) Mariano Paredes; Vivancos Ureña, Ángela; Poveda Otazo, Dionisio; González Herrero, Pablo; Química Inorgánica; Facultades de la UMU::Facultad de Química
Open Access
Synthesis, Luminescence, and Electrochemistry of Tris-Chelate Platinum(IV) Complexes with Cyclometalated N-Heterocyclic Carbene Ligands and Aromatic Diimines
(ACS Publications, 2024-12-19) Serrano Guarinos, José; Jiménez García, Adrián; Bautista, Delia; González Herrero, Pablo; Vivancos Ureña, Ángela; Química Inorgánica; Facultades de la UMU::Facultad de Química
Dicationic, C2-symmetrical, tris-chelate Pt(IV) com plexes of general formula [Pt(trz)2(N∧N)](OTf)2, bearing two cyclometalated 4-butyl-3-methyl-1-phenyl-1H-1,2,3-triazol-5-yli- dene (trz) ligands and one aromatic diimine [N∧N = 2,2′- bipyridine (bpy, 2), 4,4′-di-tert-butyl-2,2′-bipyridine (dbbpy, 3), 4,4′-dimethoxi-2,2′-bipyridine (dMeO-bpy, 4), 1,10-phenanthro- line (phen, 5), 4,7-diphenyl-1,10-phenanthroline (bphen, 6), dipyrido[3,2-a:2′,3′-c]phenazine (dppz, 7), or 2,3- diphenylpyrazino[2,3-f ][1,10]phenanthroline (dpprzphen, 8)] are obtained through chloride abstraction from [PtCl2(trz)2] (1) using AgOTf in the presence of the corresponding diimine. Complexes 2−4 show long-lived phosphorescence from 3LC excited states involving the diimine ligand, with quantum yields that reach 0.18 in solution and 0.58 in the solid matrix at room temperature for 3. Derivatives with more extended aromatic systems show dual phosphorescent/fluorescent emissions (5, 6) or mainly fluorescence (7, 8) in solution. Comparisons with similar complexes bearing cyclometalated 2-arylpyridines instead of aryl-N-heterocyclic carbenes indicate that the {Pt(trz)2} subunit is crucial to enable efficient emissions from diimine-centered excited states. It is also shown that the introduction of protective bulky substituents on the diimine, such as the tert-butyl groups in 3, is a key strategy to reach higher emission efficiencies. The new compounds represent rare examples of luminescent Pt(IV) complexes that show quasi-reversible one-electron reductions, indicating an unusually high redox stability.
Open Access
Selective synthesis, reactivity and luminescence of unsymmetrical bis-cyclometalated Pt(IV) complexes
(Royal Society of Chemistry, 2019-09-18) Vivancos Ureña, Ángela; Poveda Otazo, Dionisio; Muñoz, Alonso; Moreno, Julia; Bautista, Delia; González Herrero, Pablo; Química Inorgánica
Pt(II) complexes cis-N,N-[PtCl(C^N)(N′^C′H)], where C^N represents a monocyclometalated 2,6-diaryl- or 2-arylpyridine ligand and N′^C′H is an N-coordinated 2-arylpyridine, are selectively obtained from bridge-cleavage reactions of dimers [Pt2(μ-Cl)2(C^N)2] with excess N′^C′H at room temperature; isolation and characterization of derivatives of this kind is reported for the first time. Oxidation with PhICl2 affords Pt(IV) complexes [PtCl2(C^N)(C′^N′)], bearing two cyclometalated ligands in an unsymmetrical arrangement. The abstraction of the two chlorides using AgOTf at 120 °C in the presence of an additional 2-arylpyridine ligand leads to mer isomers of tris-cyclometalated Pt(IV) complexes if C^N derives from a 2-arylpyridine, whereas it results in a reductive C–C coupling if C^N is a monocyclometalated 2,6-diarylpyridine. Complexes [PtCl2(C^N)(C′^N′)] show phosphorescence in frozen PrCN glasses arising from essentially 3LC excited states localized on the cyclometalated ligand with the lowest π–π* transition energy. The combined photophysical data and computational results substantiate a variable degree of MLCT admixture into the emitting state depending on the atom trans to the metalated carbon of the chromophoric ligand (Cl or N), which has an appreciable effect on the characteristics of the observed luminescence.
Open Access
Luminescent halido(aryl) Pt(IV) complexes obtained via oxidative addition of iodobenzene or diaryliodonium salts to bis-cyclometalated Pt(II) precursors.
(2021-09-09) López López, Juan Carlos; Bautista, Delia; González Herrero, Pablo; Química Inorgánica
The synthesis of bis-cyclometalated halido(aryl) Pt(IV) complexes [PtX(Ar)(C^N)2], with C^N = cyclometalated 4-(tert-butyl)-2-phenylpyridine (bppy), 2-(p-tolyl)pyridine (tpy), 2-(2-thienyl)pyridine (thpy), or 1-phenylisoquinoline (piq), X = I, Cl, or F, and Ar = Ph (for all C^N ligands) or t-BuPh (for C^N = tpy), and the photophysical properties of the chlorido and fluorido series is reported. The oxidative addition of iodobenzene to cis-[Pt(C^N)2] precursors is demonstrated to occur in MeCN under irradiation with visible light to give complexes [PtI(Ph)(C^N)2], presumably involving radical species that also produce the activation of the solvent to give cyanomethyl complexes [PtI(CH2CN)(C^N)2]. The introduction of an aryl ligand can also be achieved by reacting cis-[Pt(C^N)2] with (Ar2I)PF6 (Ar = Ph, t-BuPh), which affords cationic intermediates of the type [Pt(Ar)(C^N)2(NCMe)]+. The subsequent addition of an iodide or chloride salt gives the corresponding iodido- or chlorido(aryl) complexes. The fluorido(aryl) derivatives can be obtained from the iodido complexes by halide exchange using AgF. The chlorido- and fluorido(aryl) complexes display intense phosphorescence in deaerated CH2Cl2 solution and poly(methyl methacrylate) (PMMA) films at 298 K from triplet excited states primarily localized on the cyclometalated ligands (3LC) with a small MLCT admixture. Compared with the chlorido complexes, the fluorido derivatives consistently present significantly shorter emission lifetimes and higher radiative and nonradiative rate constants due to a greater MLCT contribution to the emissive state. In contrast, the introduction of the t-BuPh group did not induce significant changes in radiative rates with respect to the phenyl complexes.
Open Access
Luminescent platinum (II) Complexes with Terdentate N∧C∧C Ligands
(2023-12-05) Poveda Otazo, Dionisio; Vivancos Ureña, Ángela; Bautista, Delia; González Herrero, Pablo; Química Inorgánica
The synthesis, structure, and luminescence of Pt(II) complexes of the type [Pt(N∧C∧C)(L)] are reported, where N∧C∧C is a terdentate ligand resulting from the cycloplatination of 2-(3,5-diphenoxyphenyl)pyridine or 2-(4,4″-dimethyl-[1,1′:3′,1″-terphenyl]-5′-yl)pyridine, and L represents a monodentate ancillary ligand, which can be γ-picoline, 4-pyridinecarboxaldehyde, PPh3, n-butyl or 2,6-dimethylphenyl isocyanide, CO, or the N-heterocyclic carbenes 1-butyl-3-methylimidazol-2-ylidene or 4-butyl-3-methyl-1-phenyl-1H-1,2,3-triazol-5-ylidene. Derivatives bearing CO, isocyanides, or carbenes showed the highest stabilities in solution, whereas the pyridine and PPh3 derivatives establish ligand-exchange equilibria in acetonitrile. Different supramolecular structures are observed in the solid state, which largely depend on the nature of the ancillary ligand. Isocyanides and CO favor π interactions between the aromatic rings, metallophilic Pt···Pt contacts, or a combination of both. In contrast, pyridine ligands may lead to bimolecular assemblies driven by C–H···O, C–H···Pt, or C–H/π hydrogen bonds. Luminescence was examined in fluid solution, poly(methyl methacrylate) matrices, and the solid state at 298 K, and in 2-methyltetrahydrofuran glasses at 77 K. The majority of derivatives show highly efficient emissions from 3ILCT/MLCT or 3ILCT/MLCT/LLCT excited states of monomeric species. The formation of excimers and different types of emissive aggregates are demonstrated, which lead to red-shifted emissions of different origins and characteristics depending on the
Open Access
Bimetallic platinum(II) complexes with bridging di-NHC and N^C^C ligands: synthesis and photophysical properties
(Royal Society of Chemistry, 2025-10-02) Mariano Paredes; Vivancos Ureña, Ángela; Poveda Otazo, Dionisio; González Herrero, Pablo; Química Inorgánica; Facultades de la UMU::Facultad de Química
Three new bimetallic Pt(II) compounds of the type [{Pt(dmtppy)}2{μ-(ImMe)2(CH2)n}] [n = 1 (1), 3 (2), 6 (3)], where dmtppy is the dimetalated tridentate N^C^C ligand 2-(4,4’’-dimethyl-[1,1’:3’,1’’-terphenyl]-5’-yl) pyridine and ImMe is N-methylimidazol-N-yl-2-ylidene, have been synthesized in order to explore their ability to form molecular assemblies that affect their luminescence. Restricted rotation around the Pt–carbene bond leads to mixtures of atropisomers, which hinder the growth of single crystals. The com- plexes show efficient emissions with high phosphorescence quantum yields in 2 wt% doped PMMA films at 298 K (PLQY: 73–77%). Significant modifications of their photophysical properties in fluid solution are observed upon variation of the solvent, with the highest efficiencies found in 2-methyltetrahydrofurane (up to 63% quantum yield for complex 3). In the case of complex 1, which contains the shortest linkage, the formation of excimers in MeCN and MeOH causes a significant quenching of the emission, with a substantial decrease in the quantum yield.
Open Access
Developing strongly luminescent platinum(IV) complexes: facile synthesis of bis- cyclometalated neutral emitters
(2016) Juliá Hernández, Fabio; Bautista, Delia; González Herrero, Pablo; Química Inorgánica
A straightforward, one-pot procedure has been developed for the synthesis of bis-cyclometalated chloro(methyl)platinum(IV) complexes with a wide variety of heteroaromatic ligands of the 2-arylpyridine type. The new compounds exhibit phosphorescent emissions in the blue to orange colour range and represent the most efficient Pt(IV) emitters reported to date, with quantum yields up to 0.81 in fluid solutions at room temperature.
Open Access
Exploring Excited-State Tunability in Luminescent Tris-cyclometalated Platinum(IV) Complexes: Synthesis of Heteroleptic Derivatives and Computational Calculations
(2014-10-29) Aullón, Gabriel; Bautista, Delia; Juliá Hernández, Fabio; González Herrero, Pablo; Química Inorgánica
The synthesis, structure, electrochemistry, and photophysical properties of a series of heteroleptic tris-cyclometalated Pt(IV) complexes are reported. The complexes mer-[Pt(C^N)2(C'^N')]OTf, with C^N = C-deprotonated 2-(2,4-difluorophenyl)pyridine (dfppy) or 2-phenylpyridine (ppy), and C'^N' = C-deprotonated 2-(2-thienyl)pyridine (thpy) or 1-phenylisoquinoline (piq), were obtained by reacting bis-cyclometalated precursors [Pt(C^N)2Cl2] with 2 equiv of AgOTf and an excess of the N'^C'H pro-ligand. The complex mer-[Pt(dfppy)2(ppy)]OTf was obtained analogously and photoisomerized to its fac counterpart. The new complexes display long-lived luminescence at room temperature in the blue to orange color range. The emitting states involve electronic transitions almost exclusively localized on the ligand with the lowest π-π* energy gap and have very little metal character. DFT and TD-DFT calculations on mer-[Pt(ppy)2(C'^N')]+ (C'^N' = thpy, piq) and mer/fac-[Pt(ppy)3]+ support this assignment and provide a basis for the understanding of the luminescence of tris-cyclometalated Pt(IV) complexes. Excited states of LMCT character may become thermally accessible from the emitting state in the mer isomers containing dfppy or ppy as chromophoric ligands, leading to strong nonradiative deactivation. This effect does not operate in the fac isomers or the mer complexes containing thpy or piq, for which nonradiative deactivation originates mainly from vibrational coupling to the ground state.