Diverse Coordination Numbers and Geometries in Pyridyl Adducts of Lanthanide(III) Complexes Based on β-Diketonate

Ten mononuclear rare earth complexes of formula [La(btfa)(3)(H2O)(2)] (1), [La(btfa)(3)(4,4 '-Mt(2)bipy)] (2), [La(btfa)(3)(4,4 '-Me(2)bipy)(2)] (3), [La(btfa)(3)(5,5 '-Me(2)bipy)(2)] (4), [La(btfa)(3)(terpy)] (5), [La(btfa)(3)(phen)(EtOH)] (6), [La(btfa)(3)(4,4 '-Me(2)bipy)(EtOH)] (7), [La(btfa)(3)(2-benzpy)(MeOH)] (8), [Tb(btfa)(3)(4,4 '-Me(2)bipy)] (9) and (Hpy)[Eu(btfa)(4)] (10), where btfa = 4,4,4-trifuoro-1-phenylbutane-1,3-dionato anion, 4,4 '-Mt(2)bipy = 4,4 '-dimethoxy-2,2 '-bipyridine, 4,4 '-Me(2)bipy = 4,4 '-dimethyl-2,2 '-bipyridine, 5,5 '-Me(2)bipy = 5,5 '-dimethyl-2,2 '-bipyridine, terpy = 2,2 ':6 ',2 '-terpyridine, phen = 1,10-phenathroline, 2-benzpy = 2-(2-pyridyl)benzimidazole, Hpy = pyridiniumH(+) cation) have been synthesized and structurally characterized. The complexes display coordination numbers (CN) eight for 1, 2, 9, 10, nine for 5, 6, 7, 8 and ten for 3 and 4. The solid-state luminescence spectra of Tb-9 and Eu-10 complexes showed the same characteristic bands predicted from the Tb(III) and Eu(III) ions. The Overall Quantum Yield measured (Phi(TOT)) at the excitation wavelength of 371 nm for both compounds yielded 1.04% for 9 and up to 34.56% for 10.

Automated summary

These complexes exhibit different coordination numbers, with Tb-9 and Eu-10 complexes showing characteristic bands predicted from Tb(III) and Eu(III) ions in the solid-state luminescence spectra. The Overall Quantum Yield measured at the excitation wavelength of 371 nm yielded 1.04% for 9 and up to 34.56% for 10.