High-Valent Pyrazolate-Bridged Platinum Complexes: A Joint Experimental and Theoretical Study

Arnal Vallés, L. (Universidad de Zaragoza) ; Escudero, D. ; Fuertes Lorda, S. ; Martin, A. ; Sicilia Martínez, V. (Universidad de Zaragoza)

Resumen: Complexes {Pt(C^C*)(µ-pz)}2] (HC^C*A= 1-(4-(ethoxycarbonyl)phenyl)-3-methyl-1H-imidazol-2-ylidene 1a, HC^C*B= 1-phenyl-3-methyl-1H-imidazol-2-ylidene 1b) react with methyl iodide (MeI) at room temperature in the dark to give compounds {PtIV(C^C*)Me(µ-pz)}2(µ-I)]I (C^C*A2a, C^C*B2b). The reaction of 1a with benzyl bromide (BnBr) in the same conditions afforded Br(C^C*A)PtIII(µ-pz)2PtIII(C^C*A)Bn] (5a), which by heating in BnBr(l) became {PtIV(C^C*A)Bn(µ-pz)}2(µ-Br)]Br (6a). Experimental investigations and density functional theory (DFT) calculations on the mechanisms of these reactions from 1a revealed that they follow a SN2 pathway in the two steps of the double oxidative addition (OA). Based on the DFT investigations, species such as (C^C*A)PtIII(µ-pz)2PtIII(C^C*A)R]X (RX = MeI Int-Me, BnBr Int-Bn) and (C^C*A)PtII(µ-pz)2PtIV(C^C*A)(R)X] (RX = MeI Int'-Me, BnBr Int'-Bn) were proposed as intermediates for the first and the second OA reactions, respectively. In order to put the mechanisms on firmer grounds, Int-Me was prepared as (C^C*A)PtIII(µ-pz)2PtIII(C^C*A)Me]BF4(3a') and used to get I(C^C*A)PtIII(µ-pz)2PtIII(C^C*A)Me](4a), (C^C*A)PtII(µ-pz)2PtIV(C^C*A)(Me)I](Int'-Me), and {PtIV(C^C*)Me(µ-pz)}2(µ-I)]BF4(2a'). The single-crystal X-ray structures of 2a, 2b, 3a', and 5a along with the mono- and bi-dimensional 1H and 195Pt{1H} NMR spectra of all the named species allowed us to compare structural and spectroscopic data for high-valent complexes with the same core {Pt(C^C*)(µ-pz)}2] but different oxidation states. © 2022 American Chemical Society. All rights reserved.

Idioma: Inglés

DOI: 10.1021/acs.inorgchem.2c01441

Año: 2022

Publicado en: Inorganic Chemistry 61, 32 (2022), 12559-12569
ISSN: 0020-1669

Factor impacto JCR: 4.6 (2022)

Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 5 / 42 = 0.119 (2022) - Q1 - T1

Factor impacto CITESCORE: 8.0 - Chemistry (Q1)

Factor impacto SCIMAGO: 0.997 - Chemistry (miscellaneous) (Q1) - Physical and Theoretical Chemistry (Q1) - Inorganic Chemistry (Q1)

Financiación: info:eu-repo/grantAgreement/ES/DGA/E17-20R
Financiación: info:eu-repo/grantAgreement/ES/MICIU-FEDER/PGC2018-094749-B-I00

Tipo y forma: Article (Published version)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)