ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Luminescent lanthanide complexes with phosphoramide and arylphosphonic diamide ligands

Marco Bortoluzzi, Alberto Gobbo, Alberto Palù, Francesco Enrichi, and Alberto Vomiero

Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia, Mestre, Italy

E-mail: alberto.gobbo93@gmail.com

Received: 12 February 2019  Accepted: 23 April 2019

Abstract:

The sensitization of Eu(III) luminescence by the phosphoramide and arylphosphonic diamide ligands OP(NMe₂)₂Ind, OP(NMe₂)₂Cbz, OP(NMe₂)₂Ph, OP(NMe₂)₂(1-Naph) and OP(NMe₂)₂(2-Naph) (Ind = indol-1-yl; Ph = phenyl; Cbz = carbazol-9-yl; 1-Naph = naphtalen-1-yl; 2-Naph = naphtalen-2-yl) was verified by coordination to the [Eu(NO₃)₃] metal fragment. The emission spectra of the corresponding complexes showed only the ⁵D₀ → ⁷F_J transitions of the metal centre, with the exception of the carbazolyl derivative. Some of the ligands were also able to sensitize Tb(III) luminescence, in agreement with the triplet state energies estimated from the phosphorescence spectra of the analogous Gd(III) nitrates. On the basis of the photoluminescence results achieved using nitrate as ancillary ligand, heptacoordinate Eu(III) complexes having general formula [Eu(β-dike)₃L] (β-dike = dibenzoylmethanate, tenoyltrifluoroacetonate; L = phosphoramide or arylphosphomic diamide ligand) were prepared and characterized. All the complexes exhibited bright red emission upon excitation with near-UV and violet-blue light, with intrinsic quantum yields ranging between 18 and 36%.

Keywords: Europium(III); Gadolinium(III); Terbium(III); Photoluminescence; Phosphoramide; Arylphosphonic diamide

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-019-00799-6

Chemical Papers 74 (11) 3693–3704 (2020)