Syntheses, Crystal Structures, and Physico‐Chemical Studies of Sodium and Potassium Alcoholates Bearing Thienyl Substituents and their Derived Luminescent Samarium(III) Alkoxides

Abstract

The synthesis, structural characterisation, electrochemistry, and luminescence properties of a series of alkali metal alcoholates and samarium(III) alkoxides with thiophene-based OR substituents are presented. The alkali metal alcoholates 7-15 were obtained by deprotonation of the carbinol with NaH or KH. Their molecular structures consist of tetranuclear alkali metal alcoholates with a distorted cubane-like M 4 O 4 core (Xray structure analyses). Each alkali metal is surrounded by three carbinolate ligands and (depending on the derivative) by additional tetrahydrofuran molecules. The mononuclear samarium alkoxides {Sm[OC(C 4 H 3 S) 3 ] 3 (thf) 3 }·thf (16) and {Sm[OC(C 16 H 13 S)] 3 (thf) 3 }·thf (17) were synthesised by the salt metathesis reactions between {[KOC(C 4 H 3 S) 3 ] 4 (thf) 2 }·thf (7), [NaOC(C 4 H 3 S) 3 ] 4 (thf) 2 (8) or * Prof. Dr. Dr. h. c. M. Veith E-Mail: Michael.Veith@inm-gmbh.de [a] www.zaac.wiley-vch.de 2263 [NaOC(C 4 H 3 S) 3 ] 4 (thf) 2 (8): All NaH had reacted. The solvent was evaporated; a solid was obtained, from which colorless crystals could be obtained in thf at 5°C. Yield 15 %, 243 mg. 1 H NMR (thf/C 6 D 6 ): δ = 6.9 (dd, 3 J H5-H4 = 4.9 Hz and 4 J H5-H3 = 1.2 Hz, 12H, 5-H), 6.8 (dd, 3 J H3-H4 = 3.4 Hz and 4 J H3-H5 = 1.2 Hz, 12H, 3-H), 6.7 (dd, 3 J H4-H3 = 3.7 Hz and 3 J H4-H5 = 4.9 Hz, 12H, 4-H). C 60 H 52 O 6 S 12 Na 4 : calcd. C 53.50; H 3.86 %; found C 52.24; H 3.56 %. [NaOC(C 14 H 11 S 2 )] 4 (thf) 2 (10): The unreacted NaH was filtered. The solvent was slowly evaporated, a light-brown solid precipitated, which was separated from the liquid residue. The isolated yield is 32 % (529 mg). 1 H NMR (thf/C 6 D 6 ): δ = 7.6 (dd, 3 J H5-H4 = 6.6 Hz and 4 J H5-H3 = 1.3 Hz, 8H, 5-H Th), 7.0 (m, 28 H, 4-H, Ph), 6.7 (dd, 3 J H4-H3 = 4.0 Hz, 8 H, 3-H Th). C 68 H 60 O 6 S 8 Na 4 : calcd. C 61.81; H 4.54 %; found C 60.61; H 4.39 %.[NaOC(C 17 H 15 S)] 4 (thf) 2 (13): The suspension turned into a solution.The solvent was slowly evaporated, a white solid precipitated, which

New Yttrium and Europium(+3) Alkoxides Bearing Thiophene Units: Syntheses, Crystal Structure Determinations and Physico‐Chemical Properties

“…This is because of the paramagnetic character of the europium metal centres. The broadening is similar to previous 1 H NMR spectra recorded for neodymium or samarium alkoxides bearing thiophene moieties 9,17–18. The spectrum shows two signals at δ 7.3 and 6.9 ppm assigned to the protons of the thienyl ligands, and three further broad resonances at δ 3.9, 3.3 and 1.9 ppm.…”

“…The strategy we have employed in our recent studies consists in the preparation of suitable tertiary alcohols with phenyl and/or thienyl substituents (Scheme ) which can be attached to rare earth metal centres through a covalent M–O–R bond, leading to coordination compounds with singular redox and luminescence properties 9,17–18…”

“…In previous papers, we presented the synthesis and X‐ray crystal structure analyses of some rare earth alkoxides (Y 3+ , Nd 3+ , Sm 3+ and Tb 3+ ) bearing thiophene moieties 9,15–17. Moreover, for the lanthanide compounds, their electrochemical and luminescence properties were also investigated 17–18. The studies revealed that the redox properties are dominated solely by the organic ligand (the oxidation values of the metal derivatives are marginally increased in comparison with the carbinols) and the luminescence properties are due to an energy transfer from the ligand to the metal centre and are tunable dependent on the nature of the ligand 17,18.…”

“…Moreover, for the lanthanide compounds, their electrochemical and luminescence properties were also investigated 17–18. The studies revealed that the redox properties are dominated solely by the organic ligand (the oxidation values of the metal derivatives are marginally increased in comparison with the carbinols) and the luminescence properties are due to an energy transfer from the ligand to the metal centre and are tunable dependent on the nature of the ligand 17,18. To further study the possible influence of the ligand on the metal electronic states of metal alkoxides, new yttrium and europium(3+) alkoxides have been synthesized and their electrochemical and photoluminescence properties have been measured.…”

K+···Cπ and K+···F Non-Covalent Interactions in π-Functionalized Potassium Fluoroalkoxides

“…All complexes are soluble in common organic solvents, including aliphatic hydrocarbons. (Figure 1) [6,18,28,29]. Two K 4 O 4 cuboid motifs are associated through bridging K···F interactions to generate a centrosymmetric macromolecular edifice containing eight potassium ions.…”