Orthopalladated imidazolones and thiazolones: synthesis, photophysical properties and photochemical reactivity

Dumitras, Darius ; Dalmau, David ; García-Orduña, Pilar ; Pop, Alexandra ; Silvestru, Anca ; Urriolabeitia, Esteban P.

Resumen: The reaction of Pd(OAc)2 with (Z)-5-arylidene-4-(4H)-imidazolones (2a–e) and (Z)-4-arylidene-5(4H)-thiazolones (3a–e) in trifluoroacetic acid results in the corresponding orthopalladated dinuclear complexes (4a–e, imidazolones; 11a–d, thiazolones) with trifluoroacetate bridges through regioselective C–H activation at the ortho position of the 4-arylidene group. Compound 4e, which contains an imidazolone substituted at 2- and 4-positions of the arylidene ring with methoxide groups and exhibits strong push–pull charge transfer, is an excellent precursor for the synthesis of fluorescent complexes with green yellowish emission and remarkable quantum yields. Breaking the bridging system with pyridine yields the mononuclear complex 5e (ΦF = 5%), while metathesis of trifluoroacetate ligands with chloride leads to the dinuclear complex 6e, also a precursor of fluorescent complexes by breaking the chloride bridging system with pyridine (7e, ΦF = 7%), or by substitution of chloride ligands with pyridine (8e, ΦF = 15%) or acetylacetonate (9e, ΦF = 2%). In addition to notable photophysical properties, dinuclear complexes 4 and 11 also exhibit significant photochemical reactivity. Thus, irradiation of orthopalladates 4a–c and 11a–c in CH2Cl2 with blue light (465 nm) proceeds via [2 + 2] photocycloaddition of the C[double bond, length as m-dash]C double bonds of imidazolone and thiazolone ligands, yielding the corresponding cyclobutane-bridging diaminotruxillic derivatives 10a–c and 12a–c, respectively.

Idioma: Inglés

DOI: 10.1039/d4dt00730a

Año: 2024

Publicado en: Dalton Transactions 53, 21 (2024), 8948-8957
ISSN: 1477-9226

Factor impacto JCR: 3.3 (2024)

Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 10 / 43 = 0.233 (2024) - Q1 - T1

Factor impacto CITESCORE: 6.0 - Inorganic Chemistry (Q2)

Factor impacto SCIMAGO: 0.653 - Inorganic Chemistry (Q2)

Financiación: info:eu-repo/grantAgreement/ES/AEI/PID2019-106394GB-I00
Financiación: info:eu-repo/grantAgreement/ES/DGA/E17-23R

Tipo y forma: Article (Published version)