Anhydrous mono- and dinuclear tris(quinolinolate) complexes of scandium: the missing structures of rare earth metal 8-quinolinolates

Abstract

The first monomeric anhydrous scandium tris(8-quinolinolate) complex 1 with the 2-amino-8-quinolinolate ligands and the Sc(2)Q(6) dinuclear complex 2 with the unsubstituted 8-quinolinolate ligands have been synthesized and characterized by X-ray analysis and DFT calculations. The intramolecular hydrogen bonds appear to be responsible for the unique monomeric structure of complex 1. The DFT-based analysis of the electron density topology reveals the (3,-1) critical points corresponding to the O···H and N···H bonds. The two scandium atoms in compound 2 are inequivalent due to different ligand surroundings. They are coordinated by seven (5O, 2N) and eight (4O, 4N) ligand atoms. The increase in the coordination number is accompanied by a decrease in the positive charge of the metal atom as evidenced by the DFT calculations.

Synthesis and luminescence of some rare earth metal complexes

“…Most of the products were isolated as mononuclear complexes containing three anionic ligands. The only exception is binuclear derivative 1 containing two bridging and four terminal 8-oxyquinolinolate groups [4]. Upon UV excitation, the complex 1 exhibited a strong green PL peaked at 535 nm that was very similar to that of well-known electroluminophore Alq 3 .…”

“…Due to the poor air stability of 24 and 26, a neutral 1,10-phenantroline ligand was introduced in the coordination sphere of each ion in the dinuclear molecules giving rise to the formation of 25 and 27. 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 phosphinates of samarium 19 and 20 were obtained by reactions of K(S 2 PPh 2 ) or K(Se 2 PPh 2 ) with anhydrous SmCl 3 in THF medium. Under direct excitation at f-f absorption bands, the complexes displayed metalcentered photoluminescence (PL) in the visible and NIR regions corresponding to 4 The compounds of composition Ln 3 I 5 (S 2 N 2 )(S 2 )(THF) 10 were obtained in the reactions of neodymium and dysprosium iodide-nitrides with sulfur. The inorganic core of the molecules contains the cyclic fragments Ln(µ-S2)Ln, LnSNSN and LnSN.…”

“…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].…”

Expanding the Series of [RE2Ca(OQ)8] Structures: New Heterobimetallic Rare Earth/Alkaline Earth 8‐Quinolinolate Complexes

“…The Sc(1)–N(1D) bond is considerably shorter (by about 0.15–0.20 Å), than Sc(1)–N(1A) and Sc(1)–N(1B) (2.460(4) and 2.421(4) Å respectively). Previous crystallographically characterised scandium quinolinolate complexes are [Sc(η 2 ‐MQ) 2 (η 1 ‐MQ)(η 1 ‐HMQ)] · 2H 2 O,15 and the dimeric [Sc(OQ) 3 ] 2 and the discrete [Sc(2NH 2 Q) 3 ] (2NH 2 Q = 2‐amino‐8‐quinolinolate) 16…”