Fluorinated beta-diketonate diglyme lanthanide complexes as new second-order nonlinear optical chromophores: the role of f electrons in the dipolar and octupolar contribution to quadratic hyperpolarizability.
The second-order nonlinear optical (NLO) properties of [Ln(hfac)(3)(diglyme)] (hfac = hexafluoroacetylacetonate; diglyme = bis(2-methoxyethyl)ether; Ln = La, Ce, Pr, Sm, Eu, Gd, Er, Lu) complexes have been investigated by a combination of electric-field second harmonic generation (EFISH) and harmonic light scattering (HLS) techniques, providing evidence for the relevant role of f electrons in tuning the second-order NLO response dominated by the octupolar contribution. These lanthanide NLO chromophores allow a clean valuation of the influence of f electrons on the quadratic hyperpolarizability and on its dipolar and octupolar contributions. Molecular quadratic hyperpolarizability values measured by the EFISH method, beta(EFISH), initially increase rapidly with the number of f electrons, the value for the Gd complex being 11 times that of the La complex, whereas this increase is much lower for the last seven f electrons, the beta(EFISH) value of the Lu complex being only 1.2 times that of the Gd complex. The increase of beta(HLS), which is dominated by an octupolar contribution, is much lower along the Ln series. Remarkably, the good beta(HLS) values of these simple systems, well known for their luminescence properties, are reached at no cost of transparency.
Dipartimento CIMA L. Malatesta dell' Università di Milano, UdR INSTM di Milano, and ISTM del CNR, via Venezian 21, 20133 Milano, Italy.
Adriana
A
Valore
Elena
E
Cariati
Stefania
S
Righetto
Dominique
D
Roberto
Francesca
F
Tessore
Renato
R
Ugo
Ignazio L
IL
Fragalà
Maria Elena
ME
Fragalà
Graziella
G
Malandrino
Filippo
F
De Angelis
Leonardo
L
Belpassi
Isabelle
I
Ledoux-Rak
Khuyen
K
Hoang Thi
Joseph
J
Zyss
D004563:Electrochemistry; D005026:Ethylene Glycols / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008738:Methyl Ethers / Q000737:chemistry*; D008958:Models, Molecular; D055095:Optics and Photonics; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*
D005026:Ethylene Glycols; D007659:Ketones; D028581:Lanthanoid Series Elements; D008738:Methyl Ethers; D009942:Organometallic Compounds; C007391:diglyme