Europium(III) Complex-Functionalized SiO2@mTiO2 Nanospheres for Al3+-Modulated Multicolor Emission.

A europium(III) hybrid material Eu(tta)3bpdc-SiO2@mTiO2 (Htta = 2-thenoyltrifluoroacetone, H2bpdc = 2,2'-bipyridine-3,3'-dicarboxylic acid) was successfully designed and synthesized by the covalent grafting complex Eu(tta)3bpdc to SiO2@mTiO2 core-shell nanosphere. The FT-IR, PXRD, XPS, TEM, HRTEM, SAED, TGA and PL were performed to characterize these materials. The results indicate that core-shell nanosphere structure and anatase crystallites of SiO2@mTiO2 are retained well after grafting the europium complex. Hybrid material Eu(tta)3bpdc-SiO2@mTiO2 displays uniform nanosphere structure, bright red color and long lifetime, which can serve as a multicolor emission material modulated by using Al3+ ions via the cation exchange approach under a single-wavelength excitation. To the best of our knowledge, this work is the first multicolor emissive sensor for Al3+ ions based on the lanthanide hybrid material.

Structural investigation of one- and three-dimensional lanthanide(III) coordination polymers based on functionalized terpyridine carboxylate and aromatic dicarboxylate ligands.

Three series of lanthanide coordination polymers, namely catena-poly[[lanthanide(III)-µ2-(benzene-1,2-dicarboxylato)-µ2-[2-(2,2':6',2''-terpyridin-4'-yl)benzoato]] monohydrate], {[Ln(C8H4O4)(C22H14N3O2)]·H2O}n or {[Ln(1,2-bdc)(L)]·H2O}n, with lanthanide (Ln) = dysprosium (Dy, 1), holmium (Ho, 2) and erbium (Er, 3), poly[bis(µ2-benzene-1,3-dicarboxylato)bis[µ2-2-(2,2':6',2''-terpyridin-4'-yl)benzoato]dilanthanide(III)], [Ln2(C8H4O4)2(C22H14N3O2)2]n or [Ln2(1,3-bdc)2(L)2]n, with Ln = gadolinium (Gd, 4), Ho (5) and Er (6), and poly[(µ2-benzene-1,4-dicarboxylato)[µ2-2-(2,2':6',2''-terpyridin-4'-yl)benzoato]lanthanide(III)], [Ln(C8H4O4)(C22H14N3O2)]n or [Ln(1,4-bdc)(L)]n, with Ln = Dy (7), Ho (8), Er (9) and ytterbium (Yb, 10), were synthesized under hydrothermal conditions and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Compounds 1-3 possess one-dimensional loop chains with Ln2(COO)2 units, which are extended into three-dimensional (3D) supramolecular structures by π-π interactions. Isostructural compounds 5 and 6 show 6-connected 3D networks, with pcu topology consisting of Ln2(COO)2 units. Compounds 7-10 display 8-connected 3D frameworks with the topological type rob, consisting of Ln2(COO)2 units. The influence of the coordination orientations of the aromatic dicarboxylate groups on the crystal structures is discussed.

Lanthanide coordination polymers based on designed bifunctional 2-(2,2':6',2″-terpyridin-4'-yl)benzenesulfonate ligand: syntheses, structural diversity and highly tunable emission.

Seven novel lanthanide coordination polymers, [Eu(STP)(glu)]n (1), [Ln4(STP)2(glu)5]n·4nH2O [Ln = Er (2), Yb (3)], [Ln(STP)(1,3-bdc)]n·0.5nH2O [Ln = Tb (4), Yb (5)], and [Ln(STP)(1,2-bdc)]n [Ln = Eu (6), Tb (7)] [NaSTP = sodium 2-(2,2':6',2″-terpyridin-4'-yl)benzenesulfonate, H2glu = glutaric acid, H2(1,3-bdc) = benzene-1,3-dicarboxylic acid, H2(1,2-bdc) = benzene-1,2-dicarboxylic acid], have been prepared under hydrothermal conditions and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Compound (1) possesses a 2D layered structure based on 1D chains with STP- and glu2- anions acting as bridges. Compounds (2) and (3) are isomorphous and show a rare 3D tcj/hc net with a tetranuclear Ln3+ unit regarded as a seven-connected node and a glu2- anion serving as a three-connected node. Compounds (4) and (5) are isomorphous and exhibit six-connected pcu nets by denoting binuclear units to six-connected nodes. Compounds (6) and (7) display 3D 3,5T1 nets with (1,2-bdc)2- anions and dimetallic units serving as three- and five-connected nodes, respectively. The Eu compounds (1) and (6) demonstrate typically red emission, while the Tb compounds (4) and (7) exhibit characteristic green emission. The emission spectra of heteronuclear compounds [EuxTb1-x(STP)(1,2-bdc)]n (0 ≤ x ≤ 1) as efficient luminescent tags were investigated. The intermetallic energy transfer of Tb to Eu was also evaluated.

Dy(iii) zig-zag chains assembled in a 3D framework with single-molecule magnet behaviour.

A new lanthanide-based framework, [Dy(STP)(1,2-bdc)]n (1), was constructed. It represents dysprosium(iii) 1D zigzag chains in a 3D framework and displays single-molecule magnet (SMM) behaviour with an energy barrier of 55.76 K under zero dc field.

Lanthanide coordination frameworks constructed from 3,3',4,4'-diphenylsulfonetetracarboxylic and 1,10-phenanthroline: synthesis, crystal structures and luminescence properties.

Two series of lanthanide coordination polymers, [Ln(Hdpstc)(H2O)2]n·nH2O (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7), Yb (8)) and [Ln(Hdpstc)(phen)(H2O)]n·1.5nH2O (Ln = Pr (9), Nd (10), Eu (11), Tb (12)) (H4dpstc = 3,3',4,4'-diphenylsulfonetetracarboxylic acid and phen = 1,10-phenanthroline), have been hydrothermally synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. Isostructural compounds 1-8 and 9-12 exhibit (3,6)-connected 2D layered structures with Hdpstc3- anions as bridges. The Eu3+ and Tb3+ compounds exhibit bright red and green emissions with absolute quantum yields of 11.19% for 2-Eu, 26.05% for 4-Tb, 35.74% for 11-Eu, and 48.05% for 12-Tb. With a rational design strategy, we have constructed a series of Tb3+-doped Eu3+ materials emitting tunable three primary colors towards efficient white light emission with compounds 2-Eu and 4-Tb, and the absolute quantum yield of white light emission is 13.58%. Meanwhile, 4-Tb displays a highly sensitive response toward Fe3+ ions through significant fluorescence quenching of Tb3+.

Synthesis, Structure, White-Light Emission, and Temperature Recognition Properties of Eu/Tb Mixed Coordination Polymers.

Two series of Eu(III)/Tb(III) coordination polymers, [LnL(glu)]n·2nH2O (Ln = Eu (1), Tb (2)) and [LnL(glu)(H2O)]n (Ln = Eu (3), Tb (4)) [HL = (2-(2-sulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline, H2glu = glutaric acid] have been hydrothermally synthesized by controlling the pH values and characterized by elemental analysis, infrared spectra, and single-crystal X-ray diffraction. Isomorphic compounds 1 and 2 exhibit 6-connected 3D network with the pcu topological net, containing left- and right-handed helical chains. Isomorphic compounds 3 and 4 show 3,4-connected 2D new topology with the point symbol of (4(2)·6(3)·8)(4(2)·6). Multicolor luminescence can be tailored from red to green regions by singly varying the mixing molar ratio of Eu(III)/Tb(III) cations. The mixing component of 1Eu/2Tb = 4:6 not only achieves white-light emission with the CIE coordinate of (0.323, 0.339) upon excitation at 405 nm but also presents a temperature recognition property with the significantly high sensitivity of 0.68% per K in the 50-225 K temperature range upon excitation at 370 nm.

Diruthenium(III,III) diphosphonate with a spin ground state S = 2.

Complexes containing a Ru(2)(n+) core (n = 4, 5 or 6) have been of great interest because of their variety of electronic configurations and magnetic properties. Herein, we report a novel homovalent Ru(2)(6+)-based complex, (H(2)pip)(2)[Ru(2)(hedp)(2)Cl(2)]·6H(2)O (pip = piperazine) (1), isolated by the direct reaction of the mixed-valent Ru(2)(5+)-based anion Ru(2)(hedp)(2)(3-) [hedp = 1-hydroxyethylidenediphosphonate, CH(3)C(OH)(PO(3))(2)] with oxidant peracetic acid under room temperature conditions. Magnetic measurements unambiguously confirm that this complex contains four unpaired electrons with a spin ground state of S = 2.

A diruthenium soft ferromagnet showing T(c) = 3.0 K: Mn4(H2O)16H[Ru2(CO3)4]2[Ru2(CO3)4(H2O)2]·11H2O.

A three-dimensional CO(3)(2-)-bridged Mn(II)-Ru(2)(II,III) complex, Mn(4)(H(2)O)(16)H[Ru(2)(CO(3))(4)](2)[Ru(2)(CO(3))(4)(H(2)O)(2)]·11H(2)O (1), was synthesized by self-assembling Ru(2)(CO(3))(4)(3-) paddle-wheel precursors and Mn(2+) cations. It contains an unprecedented layer [Ru(2)(CO(3))(4)](n)(3n-) with (4,4) network. The ferromagnetic coupling between spin centers results in ordering below 3.0 K.

Auxiliary ligand-directed structural variation from 2D→3D polythreaded net to 3-fold interpenetrating 3D pillar-layered framework: syntheses, crystal structures and magnetic properties.

By auxiliary N-donor ligand-directed assembled, two entangled Co(II)-coordination nets have been constructed from 3,3',5,5'-azobenzenetetracarboxylic acid (H(4)abtc), which present a rare 2D→3D polythreading motif constructed from 2-fold (6,3) polymeric layers with thickness being 10.2 Šand a 3-fold interpenetrating pillar-layered framework based on linear trinuclear Co(II)-SBUs. In addition, two Co(II)-complexes both show an antiferromagnetic coupling by long organic spacers and H(2)O bridges, respectively.

Pyridinium [2,6-bis-(5-phenyl-1H-pyrazol-3-yl-κN)pyridine-κN]tetra-nitrato-κO,O';κO-samarium(III) pyridine monosolvate.

In the title compound, (C(5)H(6)N)[Sm(NO(3))(4)(C(23)H(17)N(5))]·C(5)H(5)N, the Sm(III) atom is ten-coordinated by the N,N',N''-tridentate bis-(pyrazole) ligand and seven O atoms from four nitrate anions (three bidentate and one monodentate). The dihedral angles between the central pyridine ring and adjacent pyrazole rings in the ligand are 1.3 (2) and 3.2 (2)°; the dihedral angles between the pyrazole rings and their pendant phenyl rings are 42.0 (3) and 16.1 (2)°. The conformation of the anionic complex ion is supported by an intra-molecular N-H⋯O hydrogen bond. In the crystal, inversion dimers linked by pairs of N-H⋯O hydrogen bonds occur. The pyridinium cation forms an N-H⋯N hydrogen bond.

Diaqua-(2,2'-bipyridine-6,6'-dicarboxyl-ato)nickel(II).

In the title compound, [Ni(C(12)H(6)N(2)O(4))(H(2)O)(2)], the Ni(II) atom (site symmetry 2) displays a distorted cis-NiN(2)O(4) octa-hedral coordination geometry with two N atoms and two O atoms of the tetra-dentate 2,2'-bipyridine-6,6'-dicarboxyl-ate ligand in the equatorial plane and two water mol-ecules in axial positions. The complete dianionic ligand is generated by crystallographic twofold symmetry. In the crystal, a two-dimensional supra-molecular structure parallel to (001) is formed through O-H⋯O hydrogen-bond inter-actions between the coordinated water mol-ecules and the O atoms of nearby carboxyl-ate groups.

An investigation of the self-assembly of neutral, interlaced, triple-stranded molecular braids.

The synthesis and structures of six compounds prepared in two different systems have been explored with the purpose of isolating coordination polymers with interlaced triple-stranded molecular braid architectures. The dinuclear paddle-wheel units of [Cu(2)(maa)(4)2 H(2)O] can be rationally tuned to form three classes of isomorphous compounds, namely [Cu(2)(maa)(4)(bpp)] (1) (bpp=1,3-bis(4-pyridyl)propane, Hmaa=2-methylacrylic acid), [Cu(3)(maa)(6)(bpp)(2)] (2), and[Cu(4)(maa)(8)(bpp)(4)(H(2)O)(2)]2 H(2)O (3), with a bridging bpp ligand, at controlled ligand-to-metal molar ratios, and lead to three coordination polymers having similar one-dimensional characteristics but different mono- and dinuclear nodes. Compound 1, with a bpp:[Cu(2)(maa)(4)2 H(2)O] stoichiometry of 1:1, contains a zigzag chain containing dinuclear nodes, whereas polymer 2, with a bpp:[Cu(2)(maa)(4)2 H(2)O] stoichiometry of 1.5:1, also adopts the topology of a zigzag chain but with both mono- and dinuclear nodes. Compound 3, with a bpp:[Cu(2)(maa)(4)2 H(2)O] stoichiometry of 2:1, contains a neutral, interlaced, triple-stranded molecular braid, which is interwoven by three single-stranded meso-helical chains that contain only a mononuclear node. With the three aromatic chelating terminal ligands 2,2':6',2''-terpyridine (tpy), 1,10-phenanthroline (phen), and di(2-pyridyl)amine (dpa) we have also prepared three neutral complexes containing the linear, rigid bridging ligand biphenyl-4,4'-dicarboxylate (bpdc), namely [Cd(bpdc)(tpy)]H(2)O (4), [Cu(bpdc)(phen)(2)]4.25 H(2)O (5), and [Cu(bpdc)(dpa)] (6). An infinite meso-helix is formed initially in 4, and then three of these chains assemble into a triple-stranded braid similar to that of 3. Complexes 5 and 6 have a mononuclear and a looped dinuclear structure, respectively. Compounds 3 and 4 are unusual examples of triple-stranded molecular braid coordination frameworks based on different types of co-ligands.

catena-Poly[europium(III)-tri-micro-2,3-dimethoxybenzoato].

The title compound, [Eu(C(9)H(9)O(4))(3)](n) or [Eu(2,3-DMOBA)(3)](n), where 2,3-DMOBA is 2,3-dimethoxybenzoate, is an infinite one-dimensional non-centrosymmetric coordination polymer. The unique Eu(III) atom is bridged by six carboxylate ligands; it is ennea-coordinated and has a distorted tricapped trigonal prism geometry. The Eu-O distances are in the range 2.315 (3)-2.959 (5) A.