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1.
《Liquid crystals》2001,28(2):279-285
Rare-earth complexes of mesomorphic Schiff 's bases, 4-[(alkylimino)methyl]-3-hydroxyphenyl 4-alkyloxybenzoates, were synthesized. Whereas the ligands LH display a nematic and/or a smectic C phase, the metal complexes show a viscous smectic A phase and decompose at the clearing point. The mesophase was investigated by hot-stage polarizing optical microscopy, by differential scanning calorimetry and by high temperature X-ray diffraction. Two types of complex were found, [Ln(LH)3 (NO3)3] and [Ln(LH)2L(NO3)2], depending on the ligand or the central metal ion. The first coordination sphere of the rare-earth ion in these metallomesogens is comparable to that in the structure of complexes with 4-alkoxy-N-alkyl2-hydroxybenzaldimine ligands. 相似文献
2.
O. A. Kharitonova A. V. Prosvirin Yu. G. Galyametdinov I. V. Ovchinnikov 《Russian Chemical Bulletin》1996,45(9):2213-2215
Complexes of the composition L(LH)2Ln(NO3)2 (Ln = La, Dy, Gd, Er, Eu, or Tb) were obtained by the reaction of -aminovinyl ketone (LH) with rare earth metal nitrates. All the compounds synthesized are thermotropic liquid crystals having the smectic SA phase. The values of magnetic anisotropy of these complexes measured by magnetic birefringence are fairly high.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2331–2333, September, 1996. 相似文献
3.
The synthesis and liquid crystalline properties of lanthanide complexes with different but structurally related Schiff's base ligands are described. The complexes all contain nitrate counterions and have the stoichiometry [Ln(LH)3 (NO3)3], where Ln is a trivalent rare-earth ion (La, Nd, Gd or Ho) and LH is a Schiff's base ligand. None of the Schiff's base ligands exhibits mesomorphism, but some of the complexes do (SmA phase). It is shown that the presence or absence and the position of substituents on the ligand determine whether or not the complexes show mesomorphism. The thermal behaviour of these compounds has been investigated by hot stage polarizing microscopy and differential scanning calorimetry. 相似文献
4.
Nine novel heteronuclear complexes of Ln(III)-Cu(II) with salicylidene tetraethylene glycol diamine (SALTTA) have been synthesized and characterized. They have the general formulae [LnCu2(SALTTA)2(NO3)3](NO3)4·3H2O (Ln=La, Pr, Nd, Sm) and [LnCu3(SALTTA)3(NO3)5]-(NO3)4·4H2O (Ln=Gd, Tb, Er, Yb, Y). The IR spectra show that vC=N in the Ln(III)-Cu(II) heteronuclear complexes are splitted up into two peaks with a far distance. It has been confirmed that oxygen atoms in oxyethylene of the ligand are not all coordinated to the central metal ions by both IR and NMR methods. 相似文献
5.
Gaël Zucchi Dr. Olivier Maury Dr. Pierre Thuéry Dr. Frédéric Gumy Jean‐Claude G. Bünzli Prof. Dr. Michel Ephritikhine Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(38):9686-9696
Treatment of Ln(NO3)3?nH2O with 1 or 2 equiv 2,2′‐bipyrimidine (BPM) in dry THF readily afforded the monometallic complexes [Ln(NO3)3(bpm)2] (Ln=Eu, Gd, Dy, Tm) or [Ln(NO3)3(bpm)2]?THF (Ln=Eu, Tb, Er, Yb) after recrystallization from MeOH or THF, respectively. Reactions with nitrate salts of the larger lanthanide ions (Ln=Ce, Nd, Sm) yielded one of two distinct monometallic complexes, depending on the recrystallization solvent: [Ln(NO3)3(bpm)2]?THF (Ln=Nd, Sm) from THF, or [Ln(NO3)3(bpm)(MeOH)2]?MeOH (Ln=Ce, Nd, Sm) from MeOH. Treatment of UO2(NO3)2?6H2O with 1 equiv BPM in THF afforded the monoadduct [UO2(NO3)2(bpm)] after recrystallization from MeOH. The complexes were characterized by their crystal structure. Solid‐state luminescence measurements on these monometallic complexes showed that BPM is an efficient sensitizer of the luminescence of both the lanthanide and the uranyl ions emitting visible light, as well as of the YbIII ion emitting in the near‐IR. For Tb, Dy, Eu, and Yb complexes, energy transfer was quite efficient, resulting in quantum yields of 80.0, 5.1, 70.0, and 0.8 %, respectively. All these complexes in the solid state were stable in air. 相似文献
6.
《Journal of Coordination Chemistry》2012,65(8):693-703
A new planar aromatic tridentate terpyridine-like ligand, 2,4-bis(3,5-dimethylpyrazol-1-yl)-6-diethylamino-1,3,5-triazine (L), has been synthesized and the structures of its complexes [YL(NO3)3] (1) and [LnL(NO3)3(H2O)]L [Ln?=?La (2), Ce (3), Pr (4), Nd (5), Eu (6)] have been determined by X-ray crystal structural analysis. The structures of the five lanthanoid complexes are isomorphous and isostructural but different from the crystal structure of the yttrium complex [YL(NO3)3]. The latter shows a nine-coordinate metal center whereas the crystal structure of the lanthanoid complexes [LnL(NO3)3(H2O)]L show a 10-coordinate metal center. The?π–π?stacking and hydrogen bonding between the coordinated and uncoordinated L molecules sensitized the Ln luminescence. The thermal behavior of the ligand and its complexes is discussed. 相似文献
7.
Until now, although there are many examples of studying the magnetic properties of Schiff base binuclear lanthanide complexes, the relationship between the structure and magnetic properties of the complexes still is worth further investigation in order to improve the magnetic properties of Schiff base lanthanide complexes. In this work, we successfully obtained two series of binuclear Ln complexes by in situ reaction of 4-diethylaminosalicylaldehyde, benzoic hydrazide and different lanthanide salts at 80°C under solvothermal conditions, namely, [Ln2(L)3(NO3)3]·CH3CN·CH3OH·H2O [Ln = Dy ( 1 ), Ho ( 2 ), Gd ( 3 ) L = deprotonated 4-diethylamino salicylaldehyde benzoylhydrazine], [Ln2(L)4(CH3COO)]CH3COO·CH3CN [Ln = Dy ( 4 ), Ho ( 5 ), Gd ( 6 )]. The complex 1 contains three Schiff base ligands L, two Dy (III) ions, and three NO3−. The ligand H1L is formed by in situ Schiff base reaction with 4-diethylaminosalicylaldehyde and benzoic hydrazide with the participation of Ln (NO3)3. When replacing Ln (NO3)3 with Ln (OAc)3, obtained three μ2-OAc bridged binuclear Ln (III) complexes. The magnetic study showed that complex 4 exhibits field-induced single-molecule magnet (SMM) behavior while complex 1 does not show any SMMs behavior. In addition, we have studied the magnetocaloric effect of complexes 3 and 6 , their maximum −ΔSm values are 21.37 J kg−1 K−1 and 15.32 J kg−1 K−1, respectively, under ΔH = 7 T and T = 2 K. 相似文献
8.
Maria Lalia-Kantouri 《Transition Metal Chemistry》1996,21(6):491-493
Summary Reaction of Cu(OAc)2, 4-(1H)-pyridone (LH) and Dy or Gd nitrate in MeOH resulted in the formation of the heterometallic complexes [Cu2LnL2(LH)2(NO3)(OH)4· xH2O], Ln = Dy (1) or Gd (2). Reaction of Cu(OH)2 with 4-(1H)-pyridone and Dy(NO3)3 in DMF resulted in the formation of the heterometallic compound [Cu2DyL2(LH)2(NO3)2(OH)3·DMF] (3). The Cu complexes [Cu(OAc)L]2 and [CuL2·DMF]
x
have also been prepared from the reaction of 4-(1H)-pyridone with Cu2+ in MeOH and DMF, respectively. All the complexes were characterized by elemental analyses, and i.r. and X-band e.s.r. spectroscopies. 相似文献
9.
Two series of new lanthanide(III) complexes of the type [Ln(HSAT)2(H2O)3Cl3] and [Ln(HSAT)2(NO3)3], where Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Tm, Yb, or Lu, and HSAT = 2-(N-salicylideneamino)-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene,
are synthesized by the reaction of LnCl3 or Ln(NO3)3 with the title ligand in ethanol. The complexes are characterized by elemental analysis, magnetic moment values, molar conductivity,
IR, UV-Vis, and 1H NMR spectral data. Two selected complexes are subject to thermogravimetric analysis, and their kinetic parameters are estimated
using Coats-Redfern equation. The complex [La(HSAT)2(NO3)3] underwent facile transesterification when refluxed in methanol. The ligand and some selected complexes are screened for
their antimicrobial properties. Antimicrobial activities of the ligand increase on coordination with the metal ion.
The text was submitted by the authors in English. 相似文献
10.
Newly designed hetero-dinuclear 3d–4f complex [Cu(L)La (NO3)2(μ-NO3)(H2O)]·EtOH ( 1 ), hetero-tetranuclear 3d–4f complex [Cu(L)Ce (NO3)2(μ-NO3)(OAc)2]2·MeOH ( 2 ) and hetero-multinuclear 3d–4f complexes [{Cu(L)Ln (NO3)3}2][Cu(L)Ln (NO3)3]2 (Ln = Pr ( 3 ) and Nd = ( 4 )) have been self-assembled from the reaction of Cu (OAc)2·H2O, Ln (NO3)3·6H2O (Ln = La, Ce, Pr and Nd) with an unsymmetric salamo-like bisoxime ligand H2L (6-Methoxy-6′-ethoxy-2,2′-[ethylenedioxybis (nitrilomethylidyne)]diphenol) based on a Schiff base condensation of 2-[O-(1-ethoxyamide)]oxime-6-methoxyphenol and 3-ethoxysalicylaldehyde. The structures of complexes 1 – 4 were characterized by elemental analyses, PXRD analyses, IR, UV–Vis spectra, and single-crystal X-ray analyses. In addition, the supramolecular interactions and fluorescence properties of complexes 1 – 4 are discussed in detail. Moreover, the antioxidant activities of the complexes 1 – 4 were determined by superoxide radical-scavenging method in vitro, which indicates that the complexes 1 – 4 all show potential antioxidant properties. 相似文献
11.
Lanthanide(III) (Eu,Gd, Tb,Dy) Complexes Derived from 4‐(Pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole: Crystal Structure,Magnetic Properties,and Photoluminescence
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Dr. Evgeniya S. Bazhina Anna A. Bovkunova Dr. Alexey V. Medved'ko Evgeniya A. Varaksina Dr. Ilya V. Taidakov Dr. Nikolay N. Efimov Prof. Dr. Mikhail A. Kiskin Prof. Dr. Igor L. Eremenko 《化学:亚洲杂志》2018,13(16):2060-2068
The reaction of lanthanide(III) nitrates with 4‐(pyridin‐2‐yl)methyleneamino‐1,2,4‐triazole (L) was studied. The compounds [Ln(NO3)3(H2O)3] ? 2 L, in which Ln=Eu ( 1 ), Gd ( 2 ), Tb ( 3 ), or Dy ( 4 ), obtained in a mixture of MeCN/EtOH have the same structure, as shown by XRD. In the crystals of these compounds, the mononuclear complex units [Ln(NO3)3(H2O)3] are linked to L molecules through intermolecular hydrogen‐bonding interactions to form a 2D polymeric supramolecular architecture. An investigation into the optical characteristics of the Eu3+‐, Tb3+‐, and Dy3+‐containing compounds ( 1 , 3 , and 4 ) showed that these complexes displayed metal‐centered luminescence. According to magnetic measurements, compound 4 exhibits single‐ion magnet behavior, with ΔEeff/kB=86 K in a field of 1500 Oe. 相似文献
12.
Liquid crystalline complexes of the formula [Ln(LH)3(DOS)3] have been synthesized, where Ln is a trivalent rare earth-ion (Y, La-Lu, except Pm), LH is the ligand N-octadecyl-4-tetradecyloxysalicylaldimine and DOS is the dodecyl sulphate counterion. Although the Schiff 's base ligands do not exhibit mesomorphism, the complexes do (SmA phase). The mesophase behaviour of these compounds has been investigated by polarizing optical microscopy, differential scanning calorimetry, high temperature X-ray diffraction and thermogravimetric analysis. The stoichiometry of the complexes remains constant throughout the lanthanide series. 相似文献
13.
《Polyhedron》2001,20(15-16):2055-2062
The reaction of Ln(NO3)3·6H2O (Ln=lanthanide except Pm) with Ph2MePO in a 1:3 or 1:4 ratio in acetone or ethanol produces [Ln(Ph2MePO)3(NO3)3] which have been characterised by analysis, IR, 1H and 31P{1H} NMR spectroscopy and conductance measurements. The [Ln′(Ph2MePO)3(NO3)3] (Ln′=Pr–Tb) exist only as tris complexes in solution and are unaffected by the presence of excess Ph2MePO. In contrast the [Ln″(Ph2MePO)3(NO3)3] (Ln″=Ho–Lu) partially decompose in CH2Cl2 solution into [Ln″(Ph2MePO)4(NO3)2]+, and [Ln″(Ph2MePO)4(NO3)2]PF6 are readily isolated from Ln″(NO3)3, Ph2MePO and NH4PF6 in acetone. For lanthanum only, a neutral 1:4 complex [La(Ph2MePO)4(NO3)3] was isolated. X-ray crystal structures show that [La(Ph2MePO)3(NO3)3] contains nine-coordinate La, whilst [La(Ph2MePO)4(NO3)3]·xMe2CO contains a ten-coordinate metal centre. The structure of [Yb(Ph2MePO)4(NO3)2]PF6 reveals an eight-coordinate cation and all complexes contain bidentate nitrato-groups. 相似文献
14.
Recrystallization of Ln(NO3)3 (Ln = Sm, Eu, Yb) in the presence of 18‐crown‐6 under aqueous conditions yielded [Ln(NO3)3(H2O)3] · 18‐crown‐6. X‐ray crystallography revealed isomorphous structures for each of the lanthanide complexes where [Ln(NO3)3(H2O)3] is involved in hydrogen bonding interactions with 18‐crown‐6. The transition point where the structural motif changes from [Ln(18‐crown‐6)(NO3)3] (with the metal residing in the crown cavity) to [Ln(NO3)3(H2O)3] · 18‐crown‐6 has been identified as at the Nd/Sm interface. A similar investigation involving [Ln(tos)3(H2O)6] (tos = p‐toluenesulfonate) and 18‐crown‐6 were resistant to crown incorporation. X‐ray studies show extensive intra‐ and intermolecular hydrogen bonding is present. 相似文献
15.
E. A. Mainicheva O. A. Gerasko L. A. Sheludyakova D. Yu. Naumov I. I. Karsanova R. R. Amirov V. P. Fedin 《Russian Chemical Bulletin》2006,55(11):1956-1965
The tetranuclear lanthanide complexes {[Ln4(μ3-OH)4(μ2-OH)2(C5NH4COO)2 (H2O)4-(C36H36N24O12)2][Ln(H2O)8]1.5[Ln(H2O)6(NO3)2]0.5} (NO3)9·nH2O (Ln = Ho, Gd, or Er) were prepared by heating (130 °C) aqueous solutions of lanthanide nitrates, cucurbit[6]uril (C36H36N24O12), and 4-cyanopyridine. The tetradentate coordination of the macrocyclic cucurbit[6]uril ligands through the portals leads
to the formation of sandwich compounds, in which the tetranuclear hydroxo complex is located between two macrocyclic molecules.
The polynuclear complexes are additionally stabilized by the chelating effect of the isonicotinate ligands generated by hydrolysis
of 4-cyanopyridine. In the complexes, the aromatic moiety of the isonicotinate ion is encapsulated into the hydrophobic inner
cavity of cucurbit[6]uril. In the absence of cucurbit[6]uril, the reaction with 4-cyanopyridine produces only the polymeric
complexes [Nd(C5NH4COO)3(H2O)2] and [Ln(C5NH4COO)2(H2O)4]NO3 (Ln = Pr, Sm, or Gd), whose structures were established by X-ray diffraction. In water and aqueous solutions of nonionic
and cationic surfactants, irreversible changes of the tetranuclear fragment of the complex (Ln = Gd) were observed after storage
for two days, whereas the anionic surfactant stabilizes the complexes.
Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1885–1894, November, 2006. 相似文献
16.
Channabasaveshwar V. Yelamaggad Rashmi Prabhu Govindaswamy Shanker 《Liquid crystals》2013,40(3):247-255
The synthesis, molecular structural characterisation and mesomorphic behaviour of lanthanidomesogens with the formula [LnL(LH)2 ][X]2 are reported. These mesogens were derived from ligands (LH- n ) formed by covalently linking the pro-mesogenic cholesterol segment with the N-(n-decyl)salicylaldimine core through either an even-parity (4-oxybutanoyloxy/6-oxyhexanoyloxy/8-oxyoctanoyloxy) or an odd-parity (5-oxypentano-yloxy) spacer. These ligands were designed based on the recently conceived concept of decoupling the anisometric segment from the metal-coordinating site by a flexible spacer to account for the stabilisation of nematic and/or smectic phases at lower temperatures. The even parity spacer ligands are polymesomorphic whereas the odd parity analogue exhibits only the chiral nematic phase. In contrast, the complexes display solely the smectic A phase indicating that the variation in the nature of lanthanide has no influence on the general phase behaviour of the complexes. The clearing temperatures of both the ligands and the complexes display an odd-even effect; the even members show relatively higher transition temperatures. 相似文献
17.
Complexes between the heavier lanthanoid nitrates Ln(NO3)3 and 15-crown-5 ( 1 ) and 18-crown-6 ( 2 ) ethers were isolated and characterized. Both 1:1 and 4:3 complexes are formed with each Ln(III) ion, except in the case of Gd and 2 . The thermal transformation of the 1:1 complexes into the corresponding 4:3 complexes was studied by thermogravimetry and by DSC, X-ray and vibrational data provide information about the structure of these complexes. The interaction between Ln(III) ions and ligands 1 and 2 in non-aqueous solutions is discussed on the basis of conductometric, fluorescence, UV./VIS. and 1H-NMR. data. Only 1:1 complexes of 2 formed in solution and their formation constants range from logKf = 4.4 (Ln = La) to 2.4 (Ln = Yb); for Eu, Kf of the 15-crown-5 and 18-crown-6 ether complexes are of the same order of magnitude. For La, Pr, Nd, Eu, Yb, a variable temperature NMR. study gave some indications about the chemical exchanges in solution. The factors which determine the stoichiometry of the complexes are discussed. 相似文献
18.
Zdenek Spichal Blanka Hegrova Zdenek Moravec Jiri Pinkas Marek Necas 《Polyhedron》2011,30(9):225-1627
Three large-bite diphosphine dioxide ligands were reacted with lanthanide salts to yield either molecular or polymeric complexes. The two flexible ligands gave bischelate complexes of general formulae [Ln(dppfO2)2Clx(NO3)2−x][FeCl4] and [Ln(dppdO2)2(NO3)2]NO3, where dppfO2 and dppdO2 are bis(diphenylphosphoryl)ferrocene and bis(diphenylphosphoryl)diphenyl ether, respectively. Reactions of the rigid bis(diphenylphosphoryl)benzene (dppbO2) with lanthanide salts yielded linear coordination polymers of a 1:1.5 metal-to-ligand stoichiometry. The compounds were studied by single crystal X-ray diffraction, IR spectroscopy, mass spectrometry, and TG/DSC techniques. 相似文献
19.
Synthesis and characterization of Pr(III), Nd(III) and Er(III) complexes with 2,6-pyridinedimethanol
The reactions of Ln(NO3)3?6H2O (Ln=Pr, Nd or Er) with the potentially tridentate O,N,O chelating ligand 2,6-pyridinedimethanol (H2pydm) in a 1:2 M ratio were investigated, and complexes with the formula [Ln(H2pydm)2(NO3)2](NO3) (Ln=Pr or Nd) (1 and 2) and [Er(H2pydm)3](NO3)3 (3) were isolated. The compounds contain 10-coordinate Pr(III) and Nd(III) ions that crystallize in the triclinic space group P-1 while the 9-coordinate Er(III) complex crystallizes in the monoclinic system (P21/n). A new lanthanide complex, [Pr(H2pydm)3](Cl)3?DMF (4), has been synthesized by reaction of PrCl3?6H2O and H2pydm. The nine-coordinate Pr(III) is bound to three H2pydm ligands. X-ray crystal structures of 1–4 reveal that the ligand coordinates tridentate via the pyridyl nitrogen and the two hydroxyl oxygens. The electronic absorption spectra of 1–4 show 4f–4f transitions. 相似文献
20.
Dr. Dmitry M. Lyubov Tatyana V. Mahrova Anton V. Cherkasov Prof. Georgy K. Fukin Prof. Yury V. Fedorov Prof. Alexander A. Trifonov 《欧洲无机化学杂志》2023,26(25):e202300292
We report the synthesis of Ln3+ nitrate [Ln(Tpm)(NO3)3] ⋅ MeCN (Ln=Yb ( 1Yb ), Eu ( 1Eu )) and chloride [Yb(Tpm)Cl3] ⋅ 2MeCN ( 2Yb ), [Eu(Tpm)Cl2(μ-Cl)]2 ( 2Eu ) complexes coordinated by neutral tripodal tris(3,5-dimethylpyrazolyl)methane (Tpm). The crystal structures of 1Ln and 2Ln were established by single crystal X-ray diffraction, while for 1Yb high resolution experiment was performed. Nitrate complexes 1Ln are isomorphous and both adopt mononuclear structure. Chloride 2Yb is monomeric, while Eu3+ analogue 2Eu adopts a binuclear structure due to two μ2-bridging chloride ligands. The typical lanthanide luminescence was observed for europium complexes ( 1Eu and 2Eu ) as well as for terbium and dysprosium analogues ([Ln(Tpm)(NO3)3] ⋅ MeCN, Ln=Tb ( 1Tb ), Dy ( 1Dy ); [Ln(Tpm)Cl3] ⋅ 2MeCN, Ln=Tb ( 2Tb ), Dy ( 2Dy )). 相似文献