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Five new complexes Ln(Q(C17))3(H2O)(Solv) (Ln = Y, Solv = H2O, Ln = Tb, Dy, Sm or Eu, Solv = EtOH) were synthesized with the acylpyrazolonato ligand Q(C17) bearing a long aliphatic C17H35 chain in the acyl moiety, and the crystal structure of Y(Q(C17))3(H2O)2 shows the three aliphatic chains from the coordinated ligands positioned in the same direction, affording plane layers built by Y(Q(C17))3(H2O)2 molecules connected through H-bonding interactions. The layers are stitched to each other like in "hook & loop" tapes. Luminescence of complexes was determined and the complex Tb(Q(C17))3(H2O)(EtOH) was immobilized on the surface of silica preprocessed using a C17H35CONH(CH2)3Si(OEt)3 reagent via hydrophobic interactions of long aliphatic chains. Luminescent properties and micromorphology of the obtained hybrid particles and hybrid films were investigated. Intensive green emission of the complex retains after grafting onto the silica surface. Inclusion of the complex on the surface of silica materials occurs as separate molecules, after the disruption of the H-bonding network present in the crystalline phase of the pure terbium sample.

In this paper, well-defined and regular-shaped Na3ScF6 nanocrystals (NCs) have been synthesized in high boiling organic solvents 1-octadecene (ODE) and oleic acid (OA), via the thermal decomposition of rare-earth oleate precursors. It is found that highly uniform monoclinic Na3ScF6 NCs with narrow size distribution have been obtained, which can easily be dispersed in cyclohexane solvent to form transparent colloid solutions. Upon 980 laser diode (LD) excitation, the relative up-conversion (UC) emission intensities of different colors in Yb(3+)/Er(3+), Yb(3+)/Tm(3+) and Yb(3+)/Ho(3+) doped Na3ScF6 can be tuned by altering the Yb(3+) doping concentration, resulting in the tunable multicolor in a wide range. On the basis of the emission spectra and the plot of luminescence intensity to pump power, the UC mechanisms of the co-doped Na3ScF6 NCs were investigated in detail. Moreover, the UC emission intensities can be significantly improved by coating a layer of Na3ScF6:Yb(3+)/Ln(3+) shell on Na3ScF6:Yb(3+)/Ln(3+) cores with respect to that of pure Na3ScF6:Yb(3+)/Ln(3+) core NCs. Furthermore, transparent and UC luminescent NCs/polydimethylsiloxane (PDMS) composites with regular dimensions were also fabricated by an in situ polymerization route. Uniform NCs with a wide variation of luminescence colors will show potential applications in diverse fields.

A new zinc compound, together with a corresponding series of Zn-4f heterometallic coordination polymers, namely, [Zn(H2PBDA)(PBDA)]n (1), {[Ln2(PBDA)2·2H2O] [Zn2(PBDA)2Cl2]}n [H2PBDA = 3-(pyridin-3-yl-oxy) benzene-1,2-dicarboxylic acid, and Ln = Pr(2), Nd(3), Eu(4), Gd(5), Dy(6), Ho(7), Er(8)] have been hydrothermally synthesized and characterized systematically. Polymers 2-8 feature two-dimensional (2D) 4,4 networks, containing the original 1D heterometallic double stranded chains composed of [Ln2Zn2(PBDA)2] entities. The extensive hydrogen bonding and π-π stacking interactions were observed to stabilize the extended architectures. The luminescence emission spectra of the polymers vary depending on the lanthanide(III) ion present. Informative magnetic susceptibility measurements show that the same carboxylate bridging fashion of the PBDA ligand results in the different magnetic properties occurring within the heterometallic coordination polymers. In addition, polymer 6 exhibits an interesting slow magnetic relaxation behavior at lower temperatures.

Two new flexible exo-bidentate ligands were designed and synthesized, incorporating different backbone chain lengths bearing two salicylamide arms, namely 2,2'-(2,2'-oxybis(ethane-2,1-diyl)bis(oxy))bis(N-benzylbenzamide) (L(I)) and 2,2'-(2,2'-(ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl))bis(oxy)bis(N-benzylbenzamide) (L(II)). These two structurally related ligands are used as building blocks for constructing diverse lanthanide polymers with luminescent properties. Among two series of lanthanide nitrate complexes which have been characterized by elemental analysis, TGA analysis, X-ray powder diffraction, and IR spectroscopy, ten new coordination polymers have been determined using X-ray diffraction analysis. All the coordination polymers exhibit the same metal-to-ligand molar ratio of 2 : 3. L(I), as a bridging ligand, reacts with lanthanide nitrates forming two different types of 2D coordination complexes: herringbone framework {[Ln(2)(NO(3))(6)(L(I))(3)·mC(4)H(8)O(2)](∞) (Ln = La (1), and Pr (2), m = 1, 2)} as type I,; and honeycomb framework {[Ln(2)(NO(3))(6)(L(I))(3)·nCH(3)OH](∞) (Ln = Nd (3), Eu (4), Tb (5), and Er (6), n = 0 or 3)} as type II, which change according to the decrease in radius of the lanthanide. For L(II), two distinct structure types of 1D ladder-like coordination complexes were formed with decreasing lanthanide radii: [Ln(2)(NO(3))(6)(L(II))(3)·2C(4)H(8)O(2)](∞) (Ln = La (7), Pr (8), Nd (9)) as type III, [Ln(2)(NO(3))(6)(L(I))(3)·mC(4)H(8)O(2)·nCH(3)OH](∞) (Ln = Eu (10), Tb (11), and Er (12), m, n = 2 or 0) as type IV. The progressive structural variation from the 2D supramolecular framework to 1D ladder-like frameworks is attributed to the varying chain length of the backbone group in the flexible ligands. The photophysical properties of trivalent Sm, Eu, Tb, and Dy complexes at room temperature were also investigated in detail.

Three novel equations were proposed to perform graphical model-free analysis of lanthanide-induced shifts in NMR spectra of axially symmetrical complexes within Bleaney's T(-2) expansion. Application and efficiency of these newly developed approaches were demonstrated on the example of heteroleptic triple-decker crown-phthalocyaninates (Pc)M[(15C5)(4)Pc]M(Pc), where (15C5)--15-crown-5, (Pc(2-))--phthalocyaninato-dianion, M = Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Y as diamagnetic reference. By construction of these equations, the proposed analytical techniques are more sensitive to variations of hyperfine coupling terms throughout lanthanide series, in comparison with previously developed approaches, becoming a valuable tool for the investigation of structural and electronic characteristics of lanthanide complexes., (This journal is © The Royal Society of Chemistry 2011)

Three new lanthanide complexes with dihalo-substituted 8-quinolinol: [Gd(BrQ)(3)(H(2)O)(2)]·1.33EtOH·0.33H(2)O (1), [Dy(ClQ)(3)(H(2)O)(2)]·1.33EtOH·0.33H(2)O (2), [Er(ClQ)(3)(H(2)O)(2)]·1.33EtOH·0.33H(2)O (3) (H-BrQ = 5,7-dibromo-8-quinolinol, H-ClQ = 5,7-dichloro-8-quinolinol) have been synthesized and characterized by elemental analysis, IR, ESI-MS, single-crystal X-ray diffraction and TGA. The single-crystal X-ray diffraction analyses reveal that complexes 1-3 are mononuclear and isostructural. Each metal centre is coordinated by three dihalo-substituted 8-quinolinol and two aqua ligands. The in vitro cytotoxicity of dihalo-substituted 8-quinolinol and complexes 1-3 against liver cancer BEL7404 was evaluated. The IC(50) values of 1-3 to BEL7404 were 47.2 ± 2.6, 18.3 ± 1.0 and 31.5 ± 1.2 nM, respectively. The lanthanide complexes 1-3 exhibited significantly enhanced cytotoxicity vs. free substituted 8-quinolinol. The binding properties of dihalo-substituted 8-quinolinol and complexes 1 and 2 to DNA were investigated by UV-vis, fluorescence, CD spectroscopy and viscosity measurements, as well as agarose gel electrophoresis experiments. Both complexes 1 and 2 interact more strongly with DNA than the free quinolinol ligand. Intercalation is the most probable binding mode for both the complexes and the quinolinol ligands.

High-quality Y(6)O(5)F(8)/YF(3) microcrystals have been synthesised by using a hydrothermal and subsequent calcination route. Upon changing the initial solution pH value, the as-prepared microcrystal can be well tuned from YF(3) octahedron microcrystals to YF(3) hollow spheres and finally to Y(6)O(5)F(8) microtubes. The as-obtained microcrystals have been characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence (PL) spectra. When the Y(6)O(5)F(8):Ln(3+) microtubes are excited by a 980 nm continual wave laser diode, bright red, green, and blue room temperature upconversion PL emissions have been observed. A series of white light emissions have been obtained by precisely adjusting dopants concentration in Y(6)O(5)F(8) microtubes.

Eight DO3A-based lanthanide(III) complexes bearing ester protected and unprotected phosphonate groups at variable distances from the macrocyclic moiety have been synthesized and analyzed. The ligands were made by straightforward four-step synthetic procedures and purified with preparative RP-HPLC, after which they were used to prepare gadolinium(III) and europium(III) complexes. Relaxometric experiments were performed on the Gd(III) complexes at 300 MHz, varying the pH of the solutions or the concentration of human serum albumin (HSA). It was found that when the pH of the medium was changed from neutral to pH 4 the longitudinal relaxivity of GdDO3A-ethylphosphonate and GdDO3A-propylphosphonate complexes increased by 50% and 60%, respectively. Diethyl esters of these complexes did not change longitudinal relaxivity in the same pH range but their transverse relaxivity increased upon binding to HSA. 31P NMR experiments on Eu(III) complexes showed a change in the chemical shift of both acid complexes in the same region where the highest relaxivity changes were observed and proved the stability of the complexes in the investigated pH range, while no shift was observed for the diester complexes. Luminescence studies on europium(III) complexes additionally supported observations obtained by NMR methods. The change in the form of the luminescence emission spectra, and the reduction in the q value upon addition of HSA proved the ternary adduct formation between the charge neutral diester complexes and HSA. Similarly, the change in the emission spectra showing a phosphonate bound structure at pH 7 to a species where the phosphonate oxygen is not coordinated at pH 4 in parallel with the increase of q value is supporting the hypothesis that the deprotonation of phosphonates is the main reason for the distinct relaxivity change from slightly acidic to the neutral solution media.

The synthesis and characterisation of two new cyclen-based near IR-emitting lanthanide complexes is reported; the lanthanides are sensitised by rhodamine, which in turn is excited by energy transfer from a coumarin 2 moiety. The three lumophores function as an energy transfer cascade spanning the UV-visible-near IR region of the spectrum, resulting in large Stokes shifts. Double stranded DNA selectively switches one of the two energy transfer processes off, enabling luminescent DNA-sensing in the near IR region. The regioselective di-alkylation of the cyclen scaffold is explained with the help of DFT calculations.

The enantiopure amine macrocycle H(3)L, as well as the parent macrocyclic Schiff base H(3)L1, the 3 + 3 condensation product of (1R,2R)-1,2-diaminocyclohexane and 2,6-diformyl-4-methylphenol, are able to form mononuclear complexes with lanthanide(III) ions. The lanthanide(III) complexes of H(3)L have been studied in solution using NMR spectroscopy and electrospray mass spectrometry. The NMR spectra indicate the presence of complexes of low C(1) and C(2) symmetry. The (1)H and (13)C NMR signals of the Lu(III) complex obtained from H(3)L have been assigned on the basis of COSY, TOCSY, NOESY, ROESY and HMQC spectra. The NMR data reveal unsymmetrical binding of lanthanide(III) ion and the presence of a dynamic process corresponding to rotation of Lu(III) within the macrocycle. The [Ln(H(4)L)(NO(3))(2)](NO(3))(2)(Ln = Sm(III), Eu(III), Dy(III), Yb(III) and Lu(III)) complexes of the cationic ligand H(4)L(+) have been isolated in pure form. The X-ray analysis of the [Eu(H(4)L)(NO(3))(2)](NO(3))(2) complex confirms the coordination mode of the macrocycle determined on the basis of NMR results. In this complex the europium(III) ion is bound to three phenolate oxygen atoms and two amine nitrogen atoms of the monoprotonated macrocycle H(4)L(+), as well as to two axial bidendate nitrate anions. In the presence of a base, mononuclear La(III), Ce(III) and Pr(III) complexes of the deprotonated form of the ligand L(3-) can be obtained. When 2 equivalents of Pr(III) are used in this synthesis Na(3)[Pr(2)L(NO(3))(2)(OH)(2)](2)NO(3).5H(2)O is obtained. The NMR, ES MS and an X-ray crystal model of this complex show coordination of two Pr(III) ions by the macrocycle L. The X-ray crystal structure of the free macrocycle H(3)L1 has also been determined. In contrast to macrocyclic amine H(3)L, the Schiff base H(3)L1 adopts a cone-type conformation resembling calixarenes.

Reaction of 1-hydrazinophthalazine with chloroacetyl chloride yields 3-chloromethyl-1,2,4-triazolo-phthalazine. Reaction of this product with the tris tert-butyl ester of DO3A yields a triazolophthalazine appended macrocycle. Hydrolysis and complexation with lanthanide ions gives access to a series of lanthanide complexes (Ln = Nd, Eu, Yb, Er); these are all luminescent and exhibit sensitisation of the lanthanide centre by the chromophore.