Synthesis, structure and luminescent properties of lanthanide fluoroalkoxides

Abstract

Alkoxides [Ln(OR)3(DME)]2 (R = CH(CF3)2, Ln = Sm (1), Yb (2)), [Ce(OR)3(Phen)]2 (3) (Phen = 1,10-phenanthroline), [Ce(OR′)3(DME)2]2 (R′ = C(CF3)3) (4), {Gd(OR′)3(DME)2} (5), {Ln2[O(CF3)2C–C(CF3)2O]3} (Ln = Ce (6), Gd (7)), {Ce2[O(CF3)2C–C(CF3)2O]3(Phen)2} (8), and {Ce[O(CF3)2C–C(CF3)2O][O(CF3)2–C(CF3)2OH](Phen)2} (9) were synthesized by the reactions of silylamides Ln[N(SiMe3)2]3 with respective fluorinated alcohols. The heterovalent trinuclear complex {Sm2(μ2-OR)3(μ3-OR)2Sm(OR)2(THF)2.5(Et2O)0.5} (10) was obtained by treatment of SmI2(THF)2 with ROK. The reaction of europium(II) and yttrium(III) silylamides with ROH afforded the heterobimetallic alkoxide {Eu2(μ2-OR)3(μ3-OR)2Y(OR)2(DME)2} (11) containing divalent europium. The molecular structures of 1, 2, 3, 9, 10 and 11 were determined by X-ray analysis. All the prepared cerium derivatives as well as the europium–yttrium isopropoxide upon UV excitation exhibited photoluminescence in the regions of 370–425 (for Ce3+) and 485 nm (for Eu2+) which was assigned to 4d→5f transitions.

Synthesis, X-ray structures, and characterization of hexafluoro-iso-propoxide group 3 and lanthanide precursors

“…A separate larger scale and higher concentration synthesis with the remnants of an H-hfip reagent bottle that had been stored for an extended amount of time ('aged') led to the isolation of Sc-OH ( Figure 4 For these systems, a direct comparison of the metrical data to the respective metal hfip compounds was made, when possible. For Y, the reported distances were slightly longer than the representative models; whereas, the remainder of the metals appeared to have distances [11,12,[27][28][29][31][32][33] [12,13] that were in agreement with the species isolated in this work. The metrical data noted for the DME derivatives proved to be consistent for the Ln-hfip distances; however, Ln-ODME distances were consistently shorter than the Ln-OH2O distance.…”

“…Fluorinated alkoxide ligands can overcome some of these issues, since they yield decreased M---O interaction through the electron withdrawing nature of the pendant CFx groups and M---F interactions that can occur, which leads to lower nuclearity compounds with higher volatility and increased stability to hydrolysis. [6,[10][11][12][13] Unfortunately for ceramic oxide production, upon conversion, fluoride retention is often observed; however, this 'detrimental' Fretention has been successfully exploited for the production of fluoride based materials. [10] In particular, lanthanum fluoride (LaF3), has shown some laboratory success as a Fion detector.…”

Synthesis and luminescence of some rare earth metal complexes

“…Insertion of the phenanthroline ligand in the Ce 2 (OR) 6 (DME) 4 caused a red shift of the emission maximum from 370 to 425 nm, whereas the same procedure conducted with butanediolate initiated a slight blue shift (from 410 to 405 nm) and a decrease in PL intensity. Meanwhile the monomer 28 containing two butanediolate and two phenantroline units emitted at a shorter wavelength in comparison with 26 and 27 [9]. The observed spectral changes confirm the high sensitivity of the frontal molecular orbitals of lanthanide complexes (containing the essential contribution of 5d orbitals) to the nature of the coordination environment.…”

“…Aspiring to fill this gap, we synthesized some scandium derivatives and studied their photoluminescent (PL) and electroluminescent (EL) properties. To design the compounds of Sc and other rare earth metals well-known 8-hydroxyquinoline H(q), 2-amino-8-hydroxyquinoline H(q NH2 ) [3,4], 2-mercaptobenzothiazole H(mbt) [5], 2-(2-pyridyl)phenol H(pp) [6], 2-(2-benzimidazol-2-yl)phenol H(NON), 2-(2-benzoxyazol-2-yl)phenol (HOON), 2-(2-benzothiazol-2-yl)phenol H(SON) [7], pentafluorophenol (C 6 F 5 OH) [8], fluorinated iso-propanol (HOCH(CF 3 ) 2 ), tert-butanol (HOC(CF 3 ) 3 ) and 2,3-butanediol (HO(CF 3 ) 2 C-C(CF 3 ) 2 OH) [9]) and new (1-(2-pyridyl)naphth-2-ol H(pn) [6], 3-(5-methylbenzoxazol-2-yl)naphthol H(OON 5Me ), 3-(6-methylbenzoxazol-2-yl)naphthol H(OON 6Me ) [10], 3-(2-benzoxazol-2-yl)-2-naphthol H(NpOON), 3-(2-benzothiazol-2-yl)-2-naphthol H(NpSON) [11]) alcohols as well as potassium salts K(S 2 PPh 2 ) and K(Se 2 PPh 2 ) [12]) were synthesized. Quite unusual complexes of Nd and Dy were synthesized by direct reactions of lanthanide meals, iodine, nitrogen and sulfur [13].…”

Cerium(iii) complexes with azolyl-substituted thiophenolate ligands: synthesis, structure and red luminescence

“…The energies of 5d states, in contradistinction to 4f states, are extremely sensitive to ligand environment. It is known that some cerium complexes with silylamide, 21 guanidinate, aryloxide, 15 alkoxide, 22 cyclopentadienyl, [23][24][25] tripodal, 26,27 carboxylate, 28,29 bipyridyl, 30 Schiff-base 31 and crown-ether 32 ligands exhibit the PL in the range from near ultraviolet (UV) to yellow colour. To the best of our knowledge the red luminescent Ce(III) complexes are still unknown.…”