Tricapped Trigonal Prismatic Coordination Research Articles

Synthesis, structures, and photoluminescence properties of novel lanthanide tetracyanoplatinates lacking Pt–Pt interactions

The synthesis of a series of lanthanide tetracyanoplatinates all incorporating 2,2′:6′,2″-terpyridine (terpy) have been carried out by reaction of Ln 3+ nitrate salts with terpy and potassium tetracyanoplatinate. The incorporation of different Ln 3+ cations results in the isolation of [ Ln(DMF) 2(C 15H 11N 3)(H 2O) 2(NO 3)]Pt(CN) 4 ( Ln=La–Nd, Sm–Yb) under otherwise identical reaction conditions. These compounds have been isolated as single crystals and X-ray diffraction has been used to investigate their structural features. All of the reported compounds are isostructural. Crystallographic data for the representative Eu 3+ compound ( EuPt) are (Mo Kα, λ=0.71073 Å): monoclinic, space group P2 1/ c, a=10.1234(4) Å, b=18.7060(7) Å, c=17.1642(5) Å, β=97.249(3)°, V=3224.4(2), Z=4, R( F)=2.78% for 426 parameters with 7724 reflections with I>2 σ( I). The structure consists of a zero-dimensional, ionic salt containing complex [Eu(DMF) 2(C 15H 11N 3)(H 2O) 2(NO 3)] 2+ cations and Pt ( CN ) 4 2 − anions. The complex cations contain the Eu 3+ ions in a tri-capped trigonal prismatic coordination environment with one terdentate 2,2′:6′,2″-terpyridine molecule, one bidentate nitrate anion, two O-bound dimethylformamide molecules, and two coordinated water molecules. Photoluminescence data illustrate that EuPt displays intramolecular energy transfer from the coordinated terpy molecule to the Eu 3+ cation. The uncoordinated tetracyanoplatinate anion also exhibits visible emission.

Bis(μ-2-methyl-8-oxidoquinolin-1-ium-κ2O:O)bis[(acetato-κ2O,O′)(2-methyl-8-oxidoquinolin-1-ium-κO)bis(nitrato-κ2O,O′)lanthanum(III)

The N-heterocycles in the centrosymmetric title compound, [La2(C10H9NO)4(CH3COO)2(NO3)4], exist in the zwitterionic form. One heterocycle binds to a metal center whereas the other bridges two metal centers. Each La atom is chelated by an acetate and two nitrate groups and is surrounded by nine O atoms in a distorted tricapped trigonal-prismatic coordination environment. The N—H groups form intra­molecular N—H⋯O hydrogen bonds. One of the nitrate ions is disordered over two positions in a 0.80 (3):0.20 (3) occupancy ratio.

Poly[bis(μ4-benzene-1,2-dicarboxylato)di-μ3-isonicotinato-dilanthanum(III)

In the title compound, [La(2)(C(8)H(4)O(4))(2)(C(6)H(4)NO(2))(2)](n), there are two crystallographically independent La centres, both nine-coordinated in tricapped trigonal prismatic coordination geometries by eight carboxylate O atoms and one pyridyl N atom. The La centres are linked by the carboxylate groups of isonicotinate (IN(-)) and benzene-1,2-dicarboxylate (BDC(2-)) ligands to form La-carboxylate chains, which are further expanded into a three-dimensional framework with nanometre-sized channels by La-N bonds. In the construction of the resultant architecture, in tricapped trigonal prismatic coordination geometries by eight carboxylate O atoms and one pyridyl N atom, while the BDC ligands link to four different cations each, displaying penta- and heptadentate chelating-bridging modes, respectively.

Photoluminescent Porous Modular Lanthanide–Vanadium–Organic Frameworks

AbstractModular mixed metal‐organic frameworks with lanthanide centres,M4[M12V24O24(OH)8(H2hedp)8(Hhedp)16(H2O)64+n]·88+y(H2O) (M3+ = Y3+, Ce3+, Sm3+, Eu3+, Tb3+, Gd3+, Er3+; H5hedp = etidronic acid), have been reported. The compounds have been prepared by (i) slow evaporation of the solvent to afford large single‐crystals of the Y3+, Ce3+ and Er3+compounds and (ii) facile one‐pot synthesis (at ambient conditions) overnight to yield microcrystalline Y3+, Ce3+, Sm3+, Eu3+, Tb3+ and Gd3+ solids. Framework construction has been shown to be modular and based on the self‐assembly of cyclic trinuclear [V3O3(OH)(H2hedp)(Hhedp)2]6– anionic units with cationic {MO8} or {MO9} aqua‐based lanthanide complexes (with dodecahedral, square antiprismatic or tricapped trigonal prismatic coordination geometries), which gives rise to unprecedented trinodal networks (having 2‐ and 4‐connected nodes) with a total Schäfli symbol of {4.83.102}2{42.84}{8}2. The anionic charge of the networks is balanced by highly disordered trivalent lanthanide cations in the channels. The compounds have been studied by single‐crystal and powder X‐ray diffraction, vibrational spectroscopy (FTIR), thermogravimetry, optical and scanning electron microscopy and elemental analysis. The photoluminescence properties of selected compounds have been investigated. Intriguingly, the co‐existence of V4+ and Eu3+ cations in the same material allows the fine tuning of the photoluminescence emission from white to purplish‐blue, by changing the excitation wavelength.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Synthesis, structure, and magnetic properties of a self-assembled salicylaldimine neodymium(III) nitrate coordination polymer

Complex formed by the reaction of neodymium nitrate with Schiff base has been synthesized and characterized by elemental analysis and IR spectroscopy. The crystal structure and magnetic properties of the self-assembled complex, [Nd2(H2salen)3(NO3)6] n (H2salen =N,N′-ethylenebis(salicylideneimine)), are reported. The central Nd(III) ion is nine-coordinate with a typical tricapped trigonal prismatic coordination geometry with an infinite 2-D net structure, in which every Schiff-base ligand links two Nd(III) ions, and Nd(III) ions as nodes make up hexagons with 3 axes passing through the centers. The susceptibility data of the complex are well-fitted to the Curie–Weiss law and anti-ferromagnetic interactions take place between intermolecular adjacent paramagnetic ions.

A 1-D chain praseodymium complex with chelidamic acid: synthesis, structure, and optical properties

The title compound [Pr(C7H3NO5)(C7H4NO5)(H2O)2] n · 1.25nH2O (1) or [Pr(HChel)(H2Chel)(H2O)2] n · 1.25nH2O, where H3Chel is 4-hydroxypyridine-2,6-dicarboxylic (chelidamic) acid, was synthesized by reaction of chelidamic acid, PrCl3 · 6H2O and H2O under hydrothermal conditions, and characterized by X-ray single-crystal diffraction. The crystal structure of 1 reveals that Pr is nine-coordinate with distorted tricapped trigonal prismatic coordination. Coordination polyhedra are interlinked into a 1-D chain, further linked by hydrogen bonds into a 3-D network. Fluorescence spectra exhibit strong green luminescence with maximum emission at 530 nm when excited with λ ex = 475 nm, originating from π–π* of the ligand.

13,27-Dichloro-3,6,9,17,20,23-hexaazatetracyclo[23.3.1.111,15.02,6]triaconta-1(29),9,11,13,15(30),16,23,25,27-nonaene-29,30-diol-κ5N17,N20,N23,O29,O30]bis(nitrato-κ2O,O′)europium(III) nitrate methanol hemisolvate

The title compound, [EuIII(NO3)2(C24H28Cl2N6O2)]NO3·0.5CH3OH, is isostructural with the GdIII and HoIII complexes of the analogous macrocyclic ligand, with both Cl atoms replaced by methyl groups. The Eu atom exhibits a nine-coordinate distorted tricapped trigonal-prismatic coordination geometry. The methanol solvent mol­ecule is disordered about a twofold rotation axis with occupancies of 0.543 (12):0.457 (12).

Poly[tetraaqua-μ3-benzene-1,2-dicarboxylato-μ3-bromido-penta-μ2-bromido-octa-μ3-isonicotinato-heptacopper(I)trilanthanum(III)

A new lanthanum(III)–copper(I) heterometallic coordination polymer, [Cu7La3Br6(C6H4NO2)8(C8H4O4)(H2O)4]n, has been prepared by a hydro­thermal method. Of the three La atoms in the asymmetric unit, two are eight-coordinate with bicapped trigonal–prismatic configurations; the third is nine-coordinated and has a tricapped trigonal–prismatic coordination geometry. Of the seven Cu atoms, two are two-coordinate with CuBrN and CuN2 ligand sets, three have trigonal configurations, viz. CuBrN2, CuBr2N and CuBr3, while the remaining two adopt distorted tetra­hedral CuBr3N geometries. In the crystal structure, adjacent La centers are linked by isonicotinate (IN−) and benzene-1,2-dicarboxyl­ate ligands to form a two-dimensional La–carboxyl­ate layer in the ab plane. These layers are further inter­connected with each other by bridging [Cu(IN)2] motifs, leading to an unusual three-dimensional heterometallic Cu–halide–lanthanide–organic framework, with the inorganic [Cu6Br6]n chains located in the resulting channels. Two Cu atoms are disordered over two positions, both with site occupancy factors of 0.80 and 0.20. O—H⋯O hydrogen bonding between water molecules and carboxylate O atoms helps to consolidate the crystal packing.

Catena-Poly[[[triaqua(nitrato-κ2O,O′)neodymium(III)]-bis(μ2-pyridinium-4-carboxylato-κ2O:O′)] bis(perchlorate) monohydrate

In the title compound, {[Nd(NO3)(C6H5NO2)2(H2O)3](ClO4)2·H2O}n, the NdIII atom is nine-coordinated by four O atoms from four pyridinium-4-carboxyl­ate ligands, two O atoms from a chelating nitrate anion and three water mol­ecules in a distorted tricapped trigonal–prismatic coordination geometry. Adjacent Nd atoms are linked by the bidentate pyridinium-4-carboxyl­ate ligands into a chain running along the b axis. The chains are further connected by O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional network.

Tetra-kis(2,4,6-triamino-1,3,5-triazin-1-ium) tris-(pyridine-2,6-dicarboxyl-ato)calcate(II) hexa-hydrate.

The title compound, (C3H7N6)4[Ca(C7H3NO4)3]·6H2O or (tataH)4[Ca(pydc)3]·6H2O (where tata is 2,4,6-triamino-1,3,5-triazine and pydcH2 is pyridine-2,6-dicarboxylic acid), was obtained by reaction of Ca(NO3)2·4H2O with the proton-transfer compound (tataH)2(pydc) in aqueous solution. The [Ca(pydc)3]4− anion has twofold crystallographic symmetry. It is a nine-coordinate CaII complex with a distorted tricapped trigonal-prismatic coordination geometry. The structure also contains four tataH+ cations and six uncoordinated water mol­ecules. There are extensive O—H⋯O, O—H⋯N, N—H⋯O, N—H⋯N and C—H⋯O hydrogen bonds in the crystal structure.

Catena-Poly[[hexakis(μ-4-methylbenzoato)-κ2O,O′;κ15O,O′:O-trieuropium(III)]-tris(μ-4-methylbenzoato)-κ2O,O′;κ6O,O′:O

The title europium(III) carboxyl­ate, [Eu3(C8H7O2)9]n, has three independent Eu atoms, two of which are eight-coordinate in a square-anti­prismatic coordination geometry, whereas the third is nine-coordinate in a tricapped trigonal-prismatic coordination geometry. The metal atoms are linked by two bidentate and seven tridentate methyl­benzoate groups into a linear chain running along the b-axis direction.

Poly[hexaaquatri-μ-malonato-didysprosium(III)

The title compound, [Dy2(C3H2O4)3(H2O)6]n, forms a coordination polymeric structure comprising hydrated dysprosium ions and malonate ligands. In the asymmetric unit, there are one dysprosium ion, one and a half malonate ligands, and three water mol­ecules. Each DyIII atom is coordinated by six O atoms from four malonate ligands and by three water mol­ecules, and displays a tricapped trigonal–prismatic coordination geometry. The malonate ligands adopt two types of coordination mode, linking dysprosium centres to form a three-dimensional coordination polymer. The extensive network of hydrogen bonds in this polymer enhances the structural stability.

Catena-Poly[bis(μ-4-methylbenzoato-κ2O:O′)heptakis(μ-4-methylbenzoato-κ3O,O′:O)trisamarium(III)

The title samarium coordination polymer, [Sm3(C8H7O2)9]n, was obtained by the hydro­thermal reaction of Sm(NO3)3 with 4-methyl­benzoic acid in alkaline aqueous solution. In the asymmetric unit, there are three crystallographically independent SmIII ions, two of which are eight-coordinate in a distorted square-anti­prismatic environment, while the third is nine-coordinate in a distorted tricapped trigonal-prismatic coordination. The metal centres are coordinated and bridged by four tridentate, three bidentate and two monodentate methyl­benzoate anions, forming polymeric chains running parallel to the b axis.

Syntheses of Alkaline Earth and Lanthanide Cryptates with Pyridine-Based Group

New alkaline earth metal cryptates [ML] (NO 3) 2 · 2H 2O (M = Ca 2+, Sr 2+, Ba 2+; L = 1, 4, 12, 15, 18, 26, 31, 39, 42, 43, 44-undecaazapentacyclo-[13.13.13.1 6, 10.1 20, 24.1 33, 37]-tetratetraconta-4, 6, 8, 10(44), 11, 18, 20, 22, 24(43), 25, 31, 33, 35, 37(42), 38-pentadecaene) were synthesized by [2 + 3] template condensation of tris(2-aminoethyl) amine with 2, 6-diformylpyridine, and then by transmetallation reactions of the calcium cryptate [CaL] (NO 3) 2 · 2H 2O with corresponding lanthanide ions; three lanthanide cryptates [LnL] (NO) 3 · 3H 2O (Ln = Eu, Gd, Tb) were synthesized and characterized by physical methods. The crystal structure of the terbium cryptate [TbL] (NO) 3 · 3H 2O was studied by X-ray analysis. The central atom was coordinated by three pyridyl and six imino nitrogen atoms and exhibited a distorted tricapped trigonal prismatic coordination geometry.

Poly[[diaquatri-μ4-succinato-dineodymium(III)] monohydrate

Carboxyl­ate bridging in the title neodymium(III) coordination polymer, {[Nd2(C4H4O4)3(H2O)2]·H2O}n, leads to a three-dimensional network architecture. One of the two independent succinate groups lies on a centre of inversion whereas the other lies on a general position; both engage in μ4-bridging. The motif is consolidated by hydrogen bonds that involve the coordinated water mol­ecule. The uncoordinated water mol­ecule, which lies on a twofold rotation axis, is only weakly hydrogen bonded to the network. The NdIII atom shows tricapped trigonal prismatic coordination.

Hydrothermal synthesis, structural, Raman, and luminescence studies of Am[ M(CN) 2] 3·3H 2O and Nd[ M(CN) 2] 3·3H 2O ( M=Ag, Au): Bimetallic coordination polymers containing both trans-plutonium and transition metal elements

The polymeric compounds consisting of the man-made element, americium, and gold and silver dicyanides were prepared under mild hydrothermal conditions at 120 °C. It was found that the americium ion and the transition metal ions are interconnected through cyanide bridging in the compounds. Given the similarities in the radii of americium and neodymium, crystals of the latter were also characterized for comparison purposes. The four compounds are isostructural and crystallize in the hexagonal space group, P6 3/ mcm, with only slight differences in their unit cell parameters. Crystallographic data (Mo Kα, λ=0.71073 Å): Am[Ag(CN) 2] 3·3H 2O (1), a=6.7205(10) Å, c=18.577(3) Å, V=726.64(19), Z=2; Am[Au(CN) 2] 3·3H 2O (2), a=6.666(2) Å, c=18.342(3) Å, V=705.9(4), Z=2; Nd[Ag(CN) 2] 3·3H 2O ( 3), a=6.7042(4) Å, c=18.6199(14) Å, V=724.77(8), Z=2; and Nd[Au(CN) 2] 3·3H 2O ( 4), a=6.6573(13) Å, c=18.431(4) Å, V=707.2(2), Z=2. The coordination around the Am and/or Nd consists of six N-bound CN − groups resulting in a trigonal prismatic arrangement. Three capping oxygen atoms of coordinated water molecules complete the tricapped trigonal prismatic coordination environment, providing a total coordination number of nine for the f-elements. Raman spectroscopy, which compliments the structural analyses, reveals that the four compounds display strong signals in the ν CN stretching region. When compared with KAg(CN) 2 or KAu(CN) 2, the ν CN stretching frequencies for these compounds blue-shift due to bridging of the dicyanometallate ions with the f-element ions. There is subsequent reduction in electron density at the cyanide center. Compared with the silver systems, the ν CN frequency appears at higher energy in the gold dicyanide complexes. This shift is consistent with the structural data where the carbon–nitrogen bond distance is found to be shorter in the gold dicyanides.

Poly[[tetraaquabis(5-carboxypyridine-2-carboxylato-κ2N,O)bis(μ4-pyridine-2,5-dicarboxylato-κ5N,O:O:O′:O′′)dilanthanum(III)] dihydrate

The title compound, {[La2(C7H4NO4)2(C7H3NO4)2(H2O)4]·2H2O}n, was prepared by a hydro­thermal reaction at 433 K. The asymmetric unit contains two LaIII ions. Each LaIII ion is nine-coordinated in a slightly distorted tricapped trigonal–prismatic coordination geometry, formed by two N atoms from 5-carboxy­pyridine-2-carboxyl­ate (Hpydc) and pyridine-2,5-dicarboxyl­ate (pydc) ligands, five O atoms from carboxyl­ate groups of one Hpydc and four pydc ligands, and two water mol­ecules. Adjacent LaIII ions are linked together through single bridging carboxyl­ate O atoms and carboxyl­ate groups in a syn–anti mode, forming a two-dimensional layered polymeric structure. Extensive O—H⋯O hydrogen bonding connects adjacent layers into an infinite three-dimensional supra­molecular network structure. The crystal studied was an inversion twin.

Contrasting oxide crystal chemistry of Nb and Ta:: The structures of the hexagonal bronzes BaTa 2O 6 and Ba 0.93Nb 2.03O 6

The high-temperature hexagonal forms of BaTa 2O 6 and Ba 0.93Nb 2.03O 6 have P6 /mmm symmetry with unit-cell parameters a=21.116(1) Å, c=3.9157(2) Å and a=21.0174(3) Å, c=3.9732(1) Å, respectively. Single crystal X-ray structure refinements for both phases are generally consistent with a previously proposed model, except for displacements of some Ba atoms from high-symmetry positions. The structures are based on a framework of corner- and edge-connected Nb/Ta-centred octahedra, with barium atoms occupying sites in four different types of [0 0 1] channels with hexagonal, triangular, rectangular and pentagonal cross-sections. The refinements showed that the non-stoichiometry in the niobate phase is due to barium atom vacancies in the pentagonal channels and to extra niobium atoms occupying interstitial sites with tri-capped trigonal prismatic coordination. The origin of the non-stoichiometry is attributed to minimisation of non-bonded Ba–Ba repulsions. The hexagonal structure is related to the structures of the low-temperature forms of BaNb 2O 6 and BaTa 2O 6, through a 30° rotation of the hexagonal rings of octahedra centred at the origin.

13,27-Dimethyl-3,6,9,17,20,23-hexaazatricyclo[23.3.1.111,15]triaconta-1(29),2,9,11,13,15(30),16,23,25,27-decaene-29,30-diol-κ5N3,N6,N9,O29,O30]bis(nitrato-κ2O,O′)dysprosium(III) nitrate monohydrate

The asymmetric unit of the title complex, [Dy(C26H34N6O2)(NO3)2]NO3·H2O, comprises two cations and two anions, together with two water mol­ecules. The Dy atom exhibits a nine-coordinate distorted tricapped trigonal-prismatic coordination geometry. The water mol­ecules are disordered over five positions, each with a site-occupation factor of 0.4. The crystal structure involves N—H⋯O and N—H⋯N hydrogen bonds.

13,27-Dimethyl-3,6,9,17,20,23-hexaazatricyclo[23.3.1.111,15]triaconta-1(29),2,9,11,13,15(30),16,23,25,27-decaene-29,30-diol-κ5N3,N6,N9,O29,O30]bis(nitrato-κ2O,O′)lutetium(III)–nitrate–water–ethyl acetate (1/1/0.5/0.25)

In the asymmetric unit of the title compound, [LuIII(C26H34N6O2)(NO3)2]NO3·0.5H2O·0.25C4H8O2, there are two cations and two anions of the title complex, together with a water molecule and half a molecule of ethyl acetate. The Lu atom exhibits a nine-coordinate distorted tricapped trigonal-prismatic coordination geometry. The water mol­ecule is disordered, with occupation factors of 0.4 and 0.6.