Showing papers on "Isostructural published in 2009"
TL;DR: A series of isostructural metal-organic framework polymers of composition [Cu2(L)(H2O)2] (L= tetracarboxylate ligands), denoted NOTT-nnn, has been synthesized and characterized and it is suggested that introducing methyl groups or using kinked ligands to create smaller pores can enhance the isosteric heat of adsorption and improve H2 adsorptive capacity.
Abstract: A series of isostructural metal−organic framework polymers of composition [Cu2(L)(H2O)2] (L= tetracarboxylate ligands), denoted NOTT-nnn, has been synthesized and characterized. Single crystal X-ray structures confirm the complexes to contain binuclear Cu(II) paddlewheel nodes each bridged by four carboxylate centers to give a NbO-type network of 64·82 topology. These complexes are activated by solvent exchange with acetone coupled to heating cycles under vacuum to afford the desolvated porous materials NOTT-100 to NOTT-109. These incorporate a vacant coordination site at each Cu(II) center and have large pore volumes that contribute to the observed high H2 adsorption. Indeed, NOTT-103 at 77 K and 60 bar shows a very high total H2 adsorption of 77.8 mg g−1 equivalent to 7.78 wt% [wt% = (weight of adsorbed H2)/(weight of host material)] or 7.22 wt% [wt% = 100(weight of adsorbed H2)/(weight of host material + weight of adsorbed H2)]. Neutron powder diffraction studies on NOTT-101 reveal three adsorption sit...
707 citations
TL;DR: These materials show higher thermal stability than other metal-organic perovskite series of [AmineH][M(HCOO)(3)] templated by the organic monoammonium cations as a result of the stronger hydrogen bonding between guanidinium and the formate of the framework.
Abstract: We report the synthesis, crystal structures, and spectral, thermal, and magnetic properties of a family of metal-organic perovskite ABX(3), [C(NH(2))(3)][M(II)(HCOO)(3)], in which A = C(NH(2))(3) is guanidinium, B = M is a divalent metal ion (Mn, Fe, Co, Ni, Cu, or Zn), and X is the formate HCOO(-). The compounds could be synthesized by either diffusion or hydrothermal methods from water or water-rich solutions depending on the metal. The five members (Mn, Fe, Co, Ni, and Zn) are isostructural and crystallize in the orthorhombic space group Pnna, while the Cu member in Pna2(1). In the perovskite structures, the octahedrally coordinated metal ions are connected by the anti-anti formate bridges, thus forming the anionic NaCl-type [M(HCOO)(3)](-) frameworks, with the guanidinium in the nearly cubic cavities of the frameworks. The Jahn-Teller effect of Cu(2+) results in a distorted anionic Cu-formate framework that can be regarded as Cu-formate chains through short basal Cu-O bonds linked by the long axial Cu-O bonds. These materials show higher thermal stability than other metal-organic perovskite series of [AmineH][M(HCOO)(3)] templated by the organic monoammonium cations (AmineH(+)) as a result of the stronger hydrogen bonding between guanidinium and the formate of the framework. A magnetic study revealed that the five magnetic members (except Zn) display spin-canted antiferromagnetism, with a Neel temperature of 8.8 (Mn), 10.0 (Fe), 14.2 (Co), 34.2 (Ni), and 4.6 K (Cu). In addition to the general spin-canted antiferromagnetism, the Fe compound shows two isothermal transformations (a spin-flop and a spin-flip to the paramagnetic phase) within 50 kOe. The Co member possesses quite a large canting angle. The Cu member is a magnetic system with low dimensional character and shows slow magnetic relaxation that probably results from the domain dynamics.
227 citations
TL;DR: In this paper, six metal−organic coordination polymers, [Cu(bdc)(bimb)]n (H2bdc = 1,4-benzenedicarboxylate; bimb = 4,4′-bis(1-imidazolyl)biphenyl) was obtained under hydrothermal conditions and characterized structurally.
Abstract: Six metal−organic coordination polymers, [Cu(bdc)(bimb)]n (H2bdc = 1,4-benzenedicarboxylate; bimb = 4,4′-bis(1-imidazolyl)biphenyl) (1), [Cu3(btc)2(bimb)2·(H2O)3]n (H3btc = 1,3,5-benzenetricarboxylate) (2), [M3(btc)2(bimb)2·(H2O)4]n (M = Mn for 3, Co for 4, Cd for 5), and [Cd(btcH)(bimb)]n (6) were obtained under hydrothermal conditions and characterized structurally. The networks exhibit a variety of topologies: compound 1 exhibits a triply interpenetrating three-dimensional (3D) framework with a distorted primitive cubic (α-Po) single net; compounds 2−5 are isomorphic, which possess a trinodal 4-connected 3D framework; compound 6 has a two-dimensional (3,4)-connected framework. In addition, the thermal stabilities for 1−6 and the photoluminescence properties for 5 and 6 were examined. An anionic organic dye X3B was selected as a model pollutant in aqueous media to evaluate the photocatalytic effectiveness of isostructural compounds 3 and 4, and the results indicated compounds 3 and 4 represent rare exam...
196 citations
TL;DR: Dynamic measurements reveal that 2-4 display a single-molecule magnet behavior, while the Co2Eu (1) analogue does not show any out-of-phase ac susceptibility, and trinuclear heterobimetalllic compounds 1-4 retain their integrity in solution as determined by electrospray ionization mass spectrometry studies.
Abstract: Sequential reaction of LH3 (LH3 = (S)P[N(Me)N═CH−C6H3-2-OH-3-OMe]3) with Co(OAc)2·4H2O followed by reaction with lanthanide salts afforded trinuclear heterobimetalllic compounds {[L2Co2Ln][X]} [Ln = Eu (1), X = Cl; Ln = Tb (2), Dy (3), Ho (4), X = NO3] in excellent yields. These compounds retain their integrity in solution as determined by electrospray ionization mass spectrometry studies. The molecular structures of 1−4 were confirmed by a single-crystal X-ray structural study and reveal that these are isostructural. In all of the compounds, the three metal ions are arranged in a perfectly linear manner and are held together by two trianionic ligands, L3−. The two terminal CoII ions contain a facial coordination environment (3N, 3O) comprising three imino nitrogen atoms and three phenolate oxygen atoms. The coordination geometry about the cobalt atom is severely distorted. An all-oxygen coordination environment (12O) is present around the central lanthanide ion, which is present in a distorted icosahedra...
171 citations
TL;DR: The random character of the spatial distribution of the metallic ions is demonstrated and the solid-state luminescent properties of compounds belonging to the ternary system are studied and compared to those of the corresponding mixtures.
Abstract: Reactions in water between mixtures of rare earth ions (Ln =Y, La−Tm, except Pm) and the sodium salt of terephthalic acid lead to an infinite family of isostructural heteropolynuclear coordination polymers. The monophasic character of the synthesized powders as well as the isostructurality of the heteropolynuclear compounds with the previously described mononuclear [Tb2(C8H4O4)3(H2O)4]∞ are ascertained on the basis of the X-ray powder diffraction diagrams. One family of heterodinuclear compounds has been studied in detail, that is, [(La2−xYx)(C8H4O4)3(H2O)4]∞ with 0 ≤ x ≤ 2. This study demonstrates the random character of the spatial distribution of the metallic ions. In order to demonstrate the high modularity of the physical properties, the solid-state luminescent properties of the compounds of general formula [(Eu2−xTbx)(C8H4O4)3(H2O)4]∞ with 0 ≤ x ≤ 2 have been studied and compared to those of the corresponding mixtures of [(Eu2)(C8H4O4)3(H2O)4]∞ and [(Tb2)(C8H4O4)3(H2O)4]∞. In order to confirm the ge...
125 citations
TL;DR: In this paper, two 2:2 types of monolanthanide substituted polyoxometalates are constructed from monovacant Keggin-type polyoxoanions and trivalent lanthanide cations.
Abstract: Two 2:2 types of monolanthanide substituted polyoxometalates [{(α-PW11O39H)Ln(H2O)3}2]6− (Ln = NdIII for 1 and GdIII for 2) and [{(α-PW11O39)Ln(H2O)(η2,μ-1,1)-CH3COO}2]10− (Ln = SmIII for 3, EuIII for 4, GdIII for 5, TbIII for 6, HoIII for 7 and ErIII for 8) have been synthesized in aqueous solution and characterized by elemental analyses, IR spectra, UV−vis−NIR spectra, thermogravimatric analyses and single-crystal X-ray diffraction. The common structural features are that they are constructed from monovacant Keggin-type polyoxoanions [α-PW11O39]7− and trivalent lanthanide cations. Both 1 and 2 are essentially isomorphous, and the molecular structure is built by two symmetrically related monolanthanide substituted Keggin units [α-PW11O39Ln(H2O)3]4− linked via two Ln−O−W bridges, representing the first monovacant Keggin polyoxotungstate dimers constituted by two [α-PW11O39]7− polyoxoanions and two lanthanide cations in polyoxometalate chemistry. 3−8 are also isostructural and display another dimeric struc...
120 citations
TL;DR: Six compounds prepared under hydrothermal conditions and characterized by single crystal X-ray diffraction analyses, elemental analyses, IR, and thermal gravimetric analyses display strong photoluminescent properties in the solid state at room temperature.
Abstract: A family of organic−inorganic hybrid frameworks, {[Ln(H2O)4(pdc)]4} [XMo12O40]·2H2O (Ln = La, Ce, and Nd; X = Si and Ge; H2pdc = pyridine-2,6-dicarboxylate), have been prepared under hydrothermal conditions and characterized by single crystal X-ray diffraction analyses, elemental analyses, IR, and thermal gravimetric analyses. Single crystal X-ray diffraction reveals that all six compounds are isostructural, and each consists of a zeolite-like four-connected three-dimensional cationic framework {[Ln(H2O)4(pdc)]4}4+ and ball-shaped Keggin type [XMo12O40]4− as templates. Interesting channels exist in the cationic framework with the gismondine topology, and these channels intersect each other to form large cavities, which array in a zigzag fashion and are occupied by nanosized [XMo12O40]4− counterions. Moreover, these compounds display strong photoluminescent properties in the solid state at room temperature.
118 citations
TL;DR: In this paper, a low temperature solvothermal method has been used for preparation of two semiconductor compounds CuSbQ{sub 2} (Q=S(1), Se(2)) by the reactions of Cu, Sb and S(or Se) powders in 1,2-diaminopropane at 160 deg. C for 10 days.
114 citations
TL;DR: Four new 5-aminoisophthalates of cobalt and nickel have been prepared employing hydro/solvothermal methods, and magnetic studies indicate antiferromagnetic behavior in I and II, a field-induced magnetism in III, and a canted antiferroelectric behavior in IV.
Abstract: Four new 5-aminoisophthalates of cobalt and nickel have been prepared employing hydro/solvothermal methods: [Co2(C8H5NO4)2(C4H4N2)(H2O)2]·3H2O (I), [Ni2(C8H5NO4)2(C4H4N2)(H2O)2]·3H2O (II), [Co2(H2O)(μ3-OH)2(C8H5NO4)] (III), and [Ni2(H2O)(μ3-OH)2(C8H5NO4)] (IV). Compounds I and II are isostructural, having anion-deficient CdCl2 related layers bridged by a pyrazine ligand, giving rise to a bilayer arrangement. Compounds III and IV have one-dimensional M−O(H)−M chains connected by the 5-aminoisophthalate units forming a three-dimensional structure. The coordinated as well as the lattice water molecules of I and II could be removed and inserted by simple heating−cooling cycles under the atmospheric conditions. The removal of the coordinated water molecule is accompanied by changes in the coordination environment around the M2+ (M = Co, Ni) and color of the samples (purple to blue, Co; green to dark yellow, Ni). This change has been examined by a variety of techniques that include in situ single crystal to sin...
114 citations
TL;DR: In this article, a two-dimensional hexagonal tungsten oxide (HTO) type topology with layers of corner-shared VO6 octahedra was characterized by singlecrystal X-ray diffraction.
Abstract: Two new polar noncentrosymmetric oxides, RbSe2V3O12 and TlSe2V3O12, have been synthesized and characterized. The oxides are isostructural, as Tl+ exhibits an inert rather than a stereoactive lone pair. The reported materials were structurally characterized by single-crystal X-ray diffraction. The materials exhibit a two-dimensional hexagonal tungsten oxide (HTO) type topology with layers of corner-shared VO6 octahedra. The layers are capped, above and below, by SeO3 polyhedra. The Rb+ and Tl+ cations are found between the layers. The V5+ and Se4+ cations are in asymmetric coordination environments attributable to second-order Jahn−Teller (SOJT) effects. In addition to structural characterization, second-harmonic generation (SHG), piezoelectric, and polarization measurements were performed. SHG measurements using 1064 nm radiation revealed doubling efficiencies ranging from ∼40−50 × α-SiO2. Piezoelectric experiments revealed d33 values of ∼6−12 pm V−1. Polarization measurements indicate the materials are n...
114 citations
TL;DR: A family of four isostructural complexes with a V-shaped pentanuclear core of general formula [Zn(2)Ln(3)(m-salen)(3)(N(3))(5)(OH)(2)] were isolated and structurally characterized.
Abstract: A family of four isostructural complexes with a V-shaped pentanuclear [Zn2Ln3] core of general formula [Zn2Ln3(m-salen)3(N3)5(OH)2] [LnIII = TbIII (1), EuIII (2), HoIII (3), DyIII (4); m-salen = N,N′-ethylenebis(3-methoxysalicylideneamine)] were isolated and structurally characterized. The fluorescence and magnetic measurements of the four compounds were investigated. Complex 1 exhibits strong fluorescence properties, while single-molecule-magnet behavior is seen in complex 4.
TL;DR: In this paper, four zinc(II) metal-organic frameworks have been determined by single-crystal X-ray diffraction analyses and further characterized by Xray powder diffraction, elemental analyses, IR spectra, and TG analyses.
Abstract: Four novel zinc(II) metal-organic frameworks, {[Zn7(trz)6(1,3-bdc)4(H2O)2]·2H2O}n (1), {[Zn7(trz)6(hip)4(H2O)2]·8H2O}n (2), [Zn4(trz)4(Hnip)2(nip)]n (3), and [Zn5(trz)2(Hbtc)4(H2O)4]n (4) (Htrz = 1,2,4-triazole, 1,3-H2bdc = 1,3-benzenedicarboxylic acid, H2hip = 5-hydroxyisophthalic acid, H2nip = 5-nitroisophthalic acid, and H3btc = 1,3,5-benzenetricarboxylic acid), have been hydrothermally synthesized by reaction of Zn salt and Htrz with four different aromatic acids, respectively. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by X-ray powder diffraction, elemental analyses, IR spectra, and TG analyses. The structures of compounds 1 and 2 are isostructural and feature the 3D structure containing multidimensional intersecting ring channels formed by the interconnection of 2D layers {[Zn7(trz)6]8+}n with 1,3-bdc (1) or hip (2). Compound 3 consists of {[Zn4(trz)4]4+}n layers with (4, 82) topology arranged in the −ABAB− stacking sequence, which are con...
TL;DR: It was found that complexes 1-6 are efficient initiators for the ring-opening polymerization of l-lactide, and the ionic radii of the central metals have a significant effect on the catalytic activity.
Abstract: A series of neutral rare-earth metal amides supported by an imidazolidine-bridged bis(phenolato) ligand were synthesized, and their catalytic activity for the polymerization of l-lactide was explored. The amine elimination reactions of Ln[N(TMS)2]3(μ-Cl)Li(THF)3 with H2[ONNO] {H2[ONNO] = 1,4-bis(2-hydroxy-3,5-di-tert-butyl-benzyl)-imidazolidine} in a 1:1 molar ratio in tetrahydrofuran (THF) gave the neutral rare-earth metal amides [ONNO]Ln[N(TMS)2](THF) [Ln = La (1), Pr (2), Nd (3), Sm (4), Yb (5), and Y (6)] in high isolated yields. All of these complexes are fully characterized. X-ray structural determination revealed that complexes 1−6 are isostructural and have a solvated monomeric structure. The coordination geometry around each of the rare-earth metal atoms can be best described as a distorted trigonal bipyramid. It was found that complexes 1−6 are efficient initiators for the ring-opening polymerization of l-lactide, and the ionic radii of the central metals have a significant effect on the catalyt...
TL;DR: The calculated band structure of 1 implies that the optical absorptions of BLn(6)M(2)Q(14) and ALn(3)MQ(7) family compounds are mainly ascribed to the charge transitions from Q-p to Ln-4f (4d for Y) states.
Abstract: Four new quaternary isostructural rare-earth thiosilicates, ZnY6Si2S14 (1), Al0.50Dy3(Si0.50Al0.50)S7 (2), Al0.38Dy3(Si0.85Al0.15)S7 (3), and Al0.33Sm3SiS7 (4), crystallized in the chiral and polar space group P63, have been prepared by a facile synthetic routine. Compounds 1−3 show strong second harmonic generation effects at 2.1 um with the intensities of 1, 2, and 3 being about 2, 2, and 1 times that of KTP (KTiOPO4), respectively. The calculated band structure of 1 implies that the optical absorptions of BLn6M2Q14 and ALn3MQ7 family compounds are mainly ascribed to the charge transitions from Q−p to Ln−4f (4d for Y) states. Compounds 2−4 exhibit antiferromagnetic-like interactions.
TL;DR: Five isostructural dicyanometallate coordination polymers containing metallophilic interactions were synthesized and investigated by variable-temperature powder X-ray diffraction to probe their thermal expansion properties.
Abstract: Five isostructural dicyanometallate coordination polymers containing metallophilic interactions (In[M(CN)2]3 (M = Ag, Au), KCd[M(CN)2]3, and KNi[Au(CN)2]3) were synthesized and investigated by variable-temperature powder X-ray diffraction to probe their thermal expansion properties. The compounds have a trigonal unit cell and show positive thermal expansion (PTE) in the ab plane, where Kagome sheets of M atoms reside, and negative thermal expansion (NTE) along the trigonal c axis, perpendicular to these sheets. The magnitude of thermal expansion is unusually large in all cases (40 × 10−6 K−1 < |α| < 110 × 10−6 K−1). The system with the weakest metallophilic interactions, In[Ag(CN)2]3, shows the most “colossal” thermal expansion of the series (αa = 105(2) × 10−6 K−1, αc = −84(2) × 10−6 K−1 at 295 K), while systems containing stronger Au−Au interactions show relatively reduced thermal expansion. Thus, it appears that strong metallophilic interactions hinder colossal thermal expansion behavior. Additionally,...
TL;DR: Calculations on this P6(3)/mmc (hP4) structure as a function of pressure show three isostructural transitions and three distinctive types of chemical bonding: free electron, ionic, and metallic.
Abstract: Experimentally, we have found that among the ``complicated'' phases of potassium at intermediate pressures is one which has the same space group as the double hexagonal-close-packed structure, although its atomic coordination is completely different. Calculations on this $P{6}_{3}/mmc$ ($hP4$) structure as a function of pressure show three isostructural transitions and three distinctive types of chemical bonding: free electron, ionic, and metallic. Interestingly, relationships between localized metallic structures and ionic compounds are found.
TL;DR: A series of 3d−4f heterometallic coordination polymers has been synthesized and structurally characterized in this article, and the magnetic properties of compounds 2, 4−6 have been investigated through the magnetic measurements over the temperature range of 1.8−300 K.
Abstract: A series of 3d−4f heterometallic coordination polymers {[CuLn2(pdc)2(SO4)(H2O)6]·H2O}n (Ln = Tb (1), Dy (2); H3pdc = 3,5-pyrazoledicarboxylic acid), {[CuLn2(pdc)2(SO4)(H2O)4]·H2O}n (Ln = Sm (3), Eu (4), Gd (5), Tb (6), Dy (7)) have been hydrothermally synthesized and structurally characterized. The sulfate anions were in situ obtained from oxidation of CuSCN during the reaction. Complexes 1−7 are all constructed from pyrazole-bridged CuIILnIII dinuclear units and sulfate anions. Complexes 1 and 2 are isostructural and possess an infinite double-stranded tapelike 1D coordination framework. However, complexes 3−7 are interesting 3d−4f heterometallic coordination polymers with similar 3D framework structures. The magnetic properties of compounds 2, 4−6 have been investigated through the magnetic measurements over the temperature range of 1.8−300 K.
TL;DR: Investigation of the magnetic properties has revealed that the Mn compound 1 is an isotropic Heisenberg chain with unusual antiferromagnetic coupling between the Mn(2+) ions linked by double end-on azide anions, and the Co compound 2 shows a strong anisotropic Ising-type ferromagnetic chain within the material.
Abstract: Contrasting magnetic properties: Two isostructural metal-azido magnetic chains embedded in 3D threefold interpenetrated H-bonded frameworks and separated by a long bpeado spacer have been assembled (see figure). Incorporation of Mn2+ displays a rarely observed antiferromagnetic Heisenberg chain, while incorporation of Co2+ displays a ferromagnetic Ising chain.
We present here the structures and magnetism of two isostructural magnetic metal-azido chain compounds of the type [M(N3)2(H2O)2]⋅(bpeado) (1, M=Mn; 2, M=Co; bpeado=1,2-bis(4-pyridyl)ethane-N,N′-dioxide), prepared by utilizing the long spacer bpeado. The structure is composed of [M(N3)2(H2O)2]n metal-azido chains, in which metal ions are bridged by two end-on azido ligands, and the chains are further supported by H-bonding interactions between the coordination water of the chain and the lattice bpeado in a three-dimensional (3D) threefold interpenetrated H-bonded framework. Within the structure, the metal-azido chains are separated quite well. Investigation of the magnetic properties has revealed that the Mn compound 1 is an isotropic Heisenberg chain with unusual antiferromagnetic coupling between the Mn2+ ions linked by double end-on azide anions. The Co compound 2 shows a strong anisotropic Ising-type ferromagnetic chain within the material. Detailed magnetic studies on both polycrystalline and single-crystal samples of 2 have revealed a large coercivity of up to 37.5 kOe (along the crystallographic b-axis), multi-magnetic transitions, and single-chain-magnet-like magnetic relaxation behavior.
TL;DR: Structural analysis indicates that the title complexes 1-3 are isostructural compounds, which possess metal-formate 2D layers perpendicularly pillared by the ligand L to afford a 3D open framework, an interesting example of a Kagome lattice based on the formate mediator.
Abstract: Sparked by the strategy of pillared-layer MOFs, three formate coordination polymers, {[Ni(2)(HCO(2))(3)(L)(2)](NO(3)).2H(2)O}(infinity) (1), {[Co(2)(HCO(2))(3)(L)(2)](HCO(2)).2H(2)O}(infinity) (2), and {[Cu(2)(HCO(2))(3)(L)(2)](HCO(2)).2H(2)O}(infinity) (3), have been synthesized by employing the rodlike ligand 4,4'-bis(imidazol-1-yl)biphenyl (L) as the pillar. Structural analysis indicates that the title complexes 1-3 are isostructural compounds, which possess metal-formate 2D layers perpendicularly pillared by the ligand L to afford a 3D open framework. This is an interesting example of a Kagome lattice based on the formate mediator. Moreover, the formate anion of this 2D Kagome layer exhibits various bridging modes: anti-anti, syn-anti, and 3.21 modes. Their magnetic measurements reveals that only complex 1 presents the spin canting phenomenon, while its isostructural Co(II) and Cu(II) complexes are simply paramagnets with antiferromagnetic coupling.
TL;DR: Two metal- organic frameworks (MOFs) based on metal-organic cuboctahedra were prepared using a rigid C3 symmetric ligand, where Zn polyhedron-based MOF (PMOF-2(Zn)) did not show any significant gas sorption behavior, whereas the isostructural Cu polyhedrons-basedMOF ( PMOF- 2(Cu)) showed a large surface area, high hydrothermal stability, and very promising H2
TL;DR: In this article, the authors have discovered arsenide oxides (Fe2As2)(Sr4M2O6) (M = Sc, Cr: M-22426).
Abstract: We have discovered new arsenide oxides (Fe2As2)(Sr4M2O6) (M = Sc, Cr: M-22426). These materials are isostructural with (Fe2P2)(Sr4Sc2O6), which was found in our previous study. The new compounds are tetragonal with a space group of P4/nmm and consist of the anti-fluorite-type FeAs layer and a perovskite-type blocking layer. These compounds have long interlayer Fe–Fe distances corresponding to the c-axis length; the 15.8 A in Sc-22426 is the longest in the iron-based pnictide oxide systems. Chemical flexibility of the perovskite block in this system was probed by chromium-containing (Fe2As2)(Sr4Cr2O6). Different trends were found in bond angle and bond length of the new pnictide oxides compared to the reported systems, such as REFePnO. The absence of superconductivity in these compounds is considered to be due to insufficient carrier concentration as in the case of undoped REFeAsO.
TL;DR: The effect of nicotinic/isonicotinic acid ligands on the structures and the photoluminescence properties, as well as the relationship between the photobombing properties and the structures, was investigated based on IR, UV-vis absorption spectra, low temperature phosphorescent specta, excitation, and emission spectra.
Abstract: Two structural series, including two isomorphous homodinuclear complexes Ln2(H2O)4(C6NO2H4)6 (Ln = Tb (1) and Er (2)) and four isostructural one-dimensional (1-D) chain-like assemblies [Ln(H2O)4(C6NO2H4)2]n·nCl (Ln = Sm (3), Eu (4), Tb (5), and Dy (6)), have been rationally prepared through a facile ultrasonic synthesis and have been characterized by X-ray diffraction and photophysical measurements. Both complexes, 1 and 2, feature a homodinuclear structure, based on two 8-fold coordination lanthanide atoms bridged by four nicotinic acid ligands. Complexes 3−6 are characterized by a 1-D polycationic chain-like structure, containing eight-coordinated lanthanide ions and bridging isonicotinic acid ligands. The 1-D polycationic chains and the isolated chloride anions are interconnected via hydrogen bonds and π-π interactions to form a three-dimensional supramolecular network. The effect of nicotinic/isonicotinic acid ligands on the structures and the photoluminescence properties, as well as the relationship ...
TL;DR: Magnetic susceptibility data, structural data, variable temperature NMR spectroscopy, and density functional theory calculations lend support to this proposal.
Abstract: Cobalt coordination complexes featuring the redox-active alpha-iminopyridine ligand are described. The quite reducing bis(ligand)cobalt monoanion (1(red)) was isolated and characterized by X-ray crystallography. The complex forms a three-membered electron-transfer series along with its neutral and monocationic counterparts, which were previously reported. The electronic structures in this series are all consistent with divalent cobalt and the redox events being ligand-centered. The reactivity profile of 1(red) was briefly explored, and two new compounds were isolated, bis(ligand)methylcobalt (2) and bis(ligand)iodocobalt (3). Though 2 and 3 are isostructural, they are characterized by different electronic structures. The methylcobalt complex is best described by a Co(III) center with two ligand radicals, whereas the iodocobalt species is more aptly assigned as a Co(II) center with only one ligand radical. Further evidence of their different electronic structures is that a low-lying excited state is populated at room temperature in the case of the iodocobalt compound, whereas the methylcobalt complex is an energetically well-isolated spin singlet. Magnetic susceptibility data, structural data, variable temperature NMR spectroscopy, and density functional theory calculations lend support to this proposal.
TL;DR: L Luminescence measurements indicate that Ln(3)Pb(3)(IO(3))(13)(mu(3)-O) (Ln = Ce, Pr, Nd) exhibit strong emission bands in the visible or near IR region.
Abstract: Hydrothermal reactions of lanthanide oxide, lead chloride, I2O5, and H2O at 200 °C led to four novel quaternary compounds, namely, Ln3Pb3(IO3)13(μ3−O) (Ln = La−Nd). They are isostructural, and thei...
TL;DR: In this article, a set of isostructural dicarboxylic acid salts of lamotrigine have been obtained from succinic acid, fumaric acid, dl-tartaric acid and saccharin.
Abstract: Salt formation is an approach to improve the physicochemical properties of the solid forms of an active pharmaceutical ingredient. As the anticonvulsant drug Lamotrigine presents low water solubility, a set of its salts with four different counterions has been obtained, and the influence of the counterion on the salt properties has been investigated. Lamotrigine salts have been obtained from succinic acid, fumaric acid, dl-tartaric acid, and saccharin. Powder samples of each salt have been characterized by infrared spectroscopy, powder X-ray diffraction, and thermal methods. Single crystal structures of four of these salts have been solved from single crystal X-ray diffraction data. The salts crystallized in P21/c and P21/n space groups, being isostructural dicarboxylic acid salts of lamotrigine. Crystal structures of these salts are built up by hydrogen bond interactions of type N(+)−H···O(−), N−H···O(−), O−H···N, and N−H···O. The water solubility of these salts has been determined and appears directly r...
TL;DR: The results of X-ray crystallographic analysis revealed that compounds {[Cd5(atz)8(μ2-Cl)2]n·3nH2O (2) contains three different kinds of bridging modes of the atz− anion and is an intricate 3D polymer.
Abstract: Five Cd(II) coordination polymers with the in situ generated ligand 5-amino-tetrazolate (atz−) were prepared from the hydrothermal reactions of the corresponding Cd(II) salts, and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA) and single crystal X-ray diffraction. The results of X-ray crystallographic analysis revealed that compounds {[Cd5(atz)9]Cl}n·2nH2O (1) and {[Cd5(atz)9](SO4)0.5}n·2nH2O (3) are isostructural with the perfect Kagome layers bridged by [Cd2(μ4-atz)3] clusters to generate a three-dimensional (3D) rare lon (topological type symbol) topological network with a vertex symbol of 66. Its hexagonal channels are filled by Cl− or SO42− anions and water molecules. Compound [Cd5(atz)8(μ2-Cl)2]n·3nH2O (2) contains three different kinds of bridging modes of the atz− anion and is an intricate 3D polymer. It possesses a 5,6-connected btv topology with a vertex symbol of (47·62·8)2(410·65), which is rarely observed but only predicted by O’Keeffe in theory in coor...
TL;DR: The results indicate that the mode of action of the coordination compounds is different, and the isostructural cobalt(II) complexes showed not significant activity.
TL;DR: In this paper, a 3D Cd(II) coordination polymers with flexible tetradentate ligand 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (L) was synthesized by reactions of corresponding CdII salts with flexible ligand.
Abstract: Six new three-dimensional (3D) Cd(II) coordination polymers, {[Cd2(L)3](NO3)4·6H2O}n (1), {[Cd2(L)3](ClO4)4·2H2O}n (2), {[Cd2(L)3](BF4)4·2H2O}n (3), {[Cd(L)Cl2]·2H2O}n (4), {[Cd2(L)2(SO4)2(H2O)]·2H2O}n (5) and {[Cd2(L)(SO4)2(H2O)3]·4H2O}n (6), have been solvothermally synthesized by reactions of the corresponding Cd(II) salts with flexible tetradentate ligand 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (L), respectively. The X-ray diffraction analysis revealed that the isostructural 1, 2 and 3 have 3D framework structures with (46·66·83)2(42·63·8)3 topology. Complex 4 has a different 3D framework structure with (65·8) topology, while 5 and 6 possess pillared-layer and plywood-like 3D framework structures, respectively. The distinct structures of 1 (2, 3), 4 and 5 indicate that the counter anions with different coordination abilities play an important role in the formation of coordination polymers. Complexes 5 and 6, synthesized by the same reactants in the same solvent, have different structures due to the different metal/ligand ratio. In addition, the results also demonstrated that the flexible tetradentate ligand L can adopt varied conformations and coordination modes to form complexes with different structures. L adopts up,up,down,down-conformation in 1–3, while in 4, it has a up,down-conformation. It is interesting that two different conformations of up,down,down,up- and H-type of L coexist in 5. In the case of 6, L has H-type conformation. Furthermore, the reversible anion exchange property of 1 was studied.
TL;DR: In this paper, four isostructural heterometallic Mn-Ln tetranuclear complexes of formula [Mn 2 III Ln 2 ( bdea ) 2 (bdeaH 2 ( piv ) 6 ] · 2 MeCN (Ln = La (1), Ce (2), Pr (3) and Nd (4)), where bdeaaH2 is N-butyldiethanolamine and (piv)− is pivalate, are reported.
TL;DR: An A-site-ordered double perovskite BiCu(3)Fe(4)O(12) was synthesized at high-pressure and high-temperature conditions and appears to enhance the charge-transfer temperature by stabilizing the square-planar coordinated Cu(3+).
Abstract: An A-site-ordered double perovskite BiCu3Fe4O12 was synthesized at high-pressure and high-temperature conditions. Similar to the isostructural LaCu3Fe4O12, the temperature-induced intermetallic charge transfer between the A′-site Cu and the B-site Fe ions occurs but at higher temperature (428 K) than LaCu3Fe4O12 (393 K) does. This charge transfer causes an isostructural phase transition with volume contraction by 0.6% as well as semiconductor-to-metal and antiferromagnetism-to-paramagnetism transitions. Although the Bi cation at the A site does not take part in the charge transfer, it appears to enhance the charge-transfer temperature by stabilizing the square-planar coordinated Cu3+.