- Strictly linear trinuclear Dy-Ca/Mg-Dy single-molecule magnets: The impact of long-range f-f ferromagnetic interactions on suppressing quantum tunnelling of magnetization leading to slow magnetic relaxation
-
The synthesis, structural characterization and magnetic properties of four heterometallic complexes with formulas Ln2M(OQ)8 [Ln(iii) = Dy, M(ii) = Ca (1), Mg (2); Ln(iii) = Er, M(ii) = Ca (3), Mg (4); HOQ = 8-hydroxyquinoline] are reported. Complexes display a perfectly linear arrangement of three metal ions involving two terminal Ln(iii) ions and one central alkaline earth M(ii) ion, and they are bridged by three phenolato oxygen atoms from three 8-hydroxyquinoline ligands. Direct-current (dc) magnetic susceptibility studies show that there exists a long-range ferromagnetic (FM) interaction between two f-electronic centers in Dy-based complexes 1 and 2 albeit they are separated by diamagnetic alkaline earth ions, and the FM interaction has been successfully reproduced by ab initio calculations. Alternating current (ac) magnetic susceptibility measurements indicate that complexes 1 and 2 exhibit significant single-molecule magnet (SMM) behaviors. This is mostly attributed to the parallel magnetic axes of individual Dy(iii) sites aligning closely to the Dy-M-Dy direction, and the linearly extending magnetic susceptibility tensors of each ion lead to the FM interaction. The dc and ac susceptibility studies of the intramolecularly diluted complexes reveal that the f-f coupling suppresses the QTMs significantly in the absence of the external magnetic field.
- Zhang, Wan-Ying,Tian, Yong-Mei,Li, Hong-Feng,Chen, Peng,Zhang, Yi-Quan,Yan, Peng-Fei,Sun, Wen-Bin
-
-
Read Online
- Rhodium(I) dimethyl sulfoxide oxyquinolinato carbonyl complex, [Rh(Oxq)(CO)(DMSO)]. NMR and X-ray structure data
-
A new rhodium(I) dimethyl sulfoxide (DMSO) 8-oxyquinolinato (Oxq) complex, [Rh(Oxq)(CO)(DMSO)] (I), has been prepared and characterized by IR, 1H and 13C NMR, and X-ray data. DMSO is S-coordinated in the trans-N position. The values of ν(CO), carbonyl δ13C, as well as δ13C and δ1H of Oxq ligand for three L trans-N complexes, [RhOxq(CO)(L)] (L = NH3, DMSO, and CO), define the intermediate position of DMSO within the ligand L series ranged in their net donating potency. Observed spin-spin couplings of Oxq 13C (C2, C3, C4a, C7, C8a) and 1H (H2) nuclei to 103Rh provide one more tool to study long-range interactions of Oxq rings with metallocenter and remote ligand L.
- Varshavsky,Galding,Khrustalev,Podkorytov,Smirnov,Gindin,Nikolskii
-
-
Read Online
- Expanding the series of [RE2Ca(OQ)8] structures: New heterobimetallic rare earth/alkaline earth 8-quinolinolate complexes
-
A series of heterobimetallic complexes [RE2Ca(OQ) 8]·nHOQ (RE = Sm, Gd, Tb, Ho, Tm, Yb, Lu, Y, Sc) and the isostructural [Gd2Mg(OQ)8] were synthesised and structurally characterised. They were mainly obtained after direct reactions of the elemental rare earth metals with calcium metal in the presence of 8-hydroxyquinoline (HOQ) and a 1,3,5-tri-tert-butyl-benzene (tBuB) flux, and some complexes were synthesised by pseudo solid-state rearrangement reactions between powdered RE(OQ)3 and AE(OQ)2 (AE = Mg, Ca) in a 1,2,4,5-tetramethylbenzene (TMB) flux, at elevated temperatures. The linear trinuclear [RE2Ca(OQ)8] moieties show a six-coordinate central calcium atom flanked by two eight-coordinate rare earth atoms surrounded by six chelating-bridging OQ and two terminal chelating OQ ligands. The structurally novel [Sc2Ca(OQ)8] has a bent Sc-Ca-Sc backbone and exhibits an eight-coordinate central calcium and two seven-coordinate scandium ions.
- Deacon, Glen B.,Junk, Peter C.,Leary, Stuart G.,Urbatsch, Aron
-
-
Read Online
- Synthesis, characterization and liquid crystalline properties of novel benzimidazol-8-hydroxyquinoline complexes
-
The synthesis, characterization and liquid crystalline properties of N4,N4′-bis((1?H-benzo[d]imidazol-2-yl)methyl)-3,3′-dimethyl-[1,1′-biphenyl]-4,4′-diamine and of their corresponding Mn(II), Fe(II), Ni (II), Cu(II), and Zn(II) complexes are described. T
- Al-Noor, Taghreed H.,Karam, Nisreen H.,H. Ghanim, Faeza,Kindeel, Alia S.,Al-Dujaili, Ammar H.
-
-
Read Online
- Hydrazo coupling: The efficient transition-metal-free C-H functionalization of 8-hydroxyquinoline and phenol through base catalysis
-
Azodicarboxylate esters are common reagents in organic synthesis laboratories due to their utility in the Mitsunobu reaction. They can also be regarded as possible starting compounds for C-H functionalization, which up until now has been mainly achieved by transition-metal-catalyzed reactions. We have developed a novel reaction involving the quantitative coupling of 8-hydroxyquinoline or phenol with azodicarboxylate esters. The functionalization proceeds under mild base-catalyzed conditions selectively, and either the ortho-position of 8-hydroxyquinoline or para-position of the phenol/naphthol is involved in the reaction. This type of transformation can be considered as "hydrazo coupling" (by analogy with azo coupling). Herein, we discuss a plausible mechanism for this catalyzed substitution, backing up our findings with deuterium NMR experiments and by varying the starting compounds and bases. Using Boc-NN-Boc as a substrate, we have developed the convenient and efficient synthesis of (8-hydroxyquinolin-7-yl)hydrazines, as well as demonstrating a new stereoselective route for the synthesis of medicinally important 4-hydroxyphenylhydrazine for laboratory use, which almost doubles the yield of the common industrial process and reduces the number of synthetic steps. A new "one-pot" procedure for the synthesis of aromatic 8-hydroxyquinolin-7-yl hydrazones was applied.
- Solyev, Pavel N.,Sherman, Daria K.,Novikov, Roman A.,Levina, Eugenia A.,Kochetkov, Sergey N.
-
p. 6381 - 6389
(2019/12/03)
-
- LITHIUM METAL QUINOLATES AND PROCESS FOR PREPARATION THEREOF AS GOOD EMITTING, INTERFACE MATERIALS AS WELL AS N-TYPE DOPENT FOR ORGANIC ELECTRONIC DEVICES
-
Invention relates to a single step preparation of alkali metal quinolate of general formula 1 wherein M=Lithium, sodium or potassium;R═H, alkyl (C1-C6), alkoxy, aryl, aryloxy, amino, amido or halogen (Cl, F, Br, I) which is substituted or unsubstituted with direct reaction of metal with 8-hydroxyquinoline. Substituted 8-hydroxyquinoline optionally have at least one substituent selected from the group consisting of alkyl, alkoxy, aryl, aryloxy, amino, amido at 2, 5 or 7 position. Halogen substituted 8-hydroxyquinolates are also prepared from this method in the yield of 90-95% from polar solvents like acetonitrile. These complexes are useful as light emitting and electron injecting materials in organic electronic devices. Also the doping of these materials in electron transport materials improves their electron mobility.
- -
-
Paragraph 0091
(2013/03/26)
-