2026-04-17T03:29:17Zhttps://recercat.cat/oai/request

oai:recercat.cat:2072/3766822024-12-20T16:16:06Zcom_2072_300912com_2072_4427col_2072_301309

Luminescent Rhenium(I)tricarbonyl Complexes Containing Different Pyrazoles and Their Successive Deprotonation Products: CO2 Reduction Electrocatalysts Merillas, Beatriz Cuellar, Elena Diez-Varga, Alberto Torroba, Tomas García-Herbosa, Gabriel Fernańdez, Sergio Lloret-Fillol, Julio Martín-Alvarez, Jose M. Miguel, Daniel Villafañe, Fernando Cationic fac-[Re(CO)3(pz*H)(pypzH)]OTf (pz*H = pyrazole, pzH; 3,5-dimethylpyrazole, dmpzH; indazole, indzH; 3-(2-pyridyl)pyrazole, pypzH) were obtained from fac- [ReBr(CO)3(pypzH)] by halide abstraction with AgOTf and subsequent addition of the corresponding pyrazole. Successive deprotonation with Na2CO3 and NaOH gave neutral fac- [Re(CO)3(pz*H)(pypz)] and anionic Na{fac-[Re(CO)3(pz*)- (pypz)]} complexes, respectively. Cationic fac-[Re(CO)3(pz*H)- (pypzH)]OTf, neutral complexes fac-[Re(CO)3(pz*H)(pypz)], and fac-[Re(CO)3(pypz)2Na] were subjected to photophysical and electrochemical studies. They exhibit phosphorescent decays from a prevalently 3MLCT excited state with quantum yields (Φ) in the range between 0.03 and 0.58 and long lifetimes (τ from 220 to 869 ns). The electrochemical behavior in Ar atmosphere of cationic and neutral complexes indicates that the oxidation processes assigned to ReI → ReII occurs at lower potentials for the neutral complex compared to cationic complex. The reduction processes occur at the ligands and do not depend on the charge of the complexes. The electrochemical behavior in CO2 saturated media is consistent with CO2 electrocatalyzed reduction, where the values of the catalytic activity [icat(CO2)/icat(Ar)] ranged from 2.7 to 11.5 (compared to 8.1 for fac-[Re(CO)3Cl(bipy)] studied as a reference). Controlled potential electrolysis for the pyrazole cationic (3a) and neutral (4a) complexes after 1 h affords CO in faraday yields of 61 and 89%, respectively. These values are higher for indazole complexes and may be related to the acidity of the coordinated pyrazole. 2021-07-24T02:45:06Z 2024-04-23T10:38:20Z 2021-07-24T02:45:06Z 2024-04-23T10:38:20Z 2021-07-24T02:45:06Z 2024-04-23T10:38:20Z 2020-07-24 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion http://hdl.handle.net/2072/376682 https://doi.org/10.1021/acs.inorgchem.0c01654 eng PGC2018- 099470−B-I00 VA130618 Project BU263P18 AGAUR 2017-SGR-1647 CTQ2016-80038-R info:eu-repo/semantics/openAccess L'accés als continguts d'aquest document queda condicionat a l'acceptació de les condicions d'ús establertes per la següent llicència Creative Commons:http://creativecommons.org/licenses/by-nc-nd/4.0/ RECERCAT (Dipòsit de la Recerca de Catalunya)