Showing papers on "Isostructural published in 2014"
TL;DR: Four uncommon isostructural nanocage-based 3D Ln-MOFs, 1-Ln (Ln = Eu, Tb, Gd and Dy), were constructed using a new diisophthalate ligand with active pyridyl sites, which exhibits highly efficient luminescent sensing for Cu(2+) ions and selective CO2 capture.
234 citations
TL;DR: Two isostructural chiral metal-organic frameworks decorated with chiral dihydroxy or -methoxy auxiliares from enantiopure tetracarboxylates-bridging ligands of 1,1'-biphenol and a manganese carboxylate chain are reported.
Abstract: The separation of racemic molecules is of substantial significance not only for basic science but also for technical applications, such as fine chemicals and drug development. Here we report two isostructural chiral metal-organic frameworks decorated with chiral dihydroxy or -methoxy auxiliares from enantiopure tetracarboxylate-bridging ligands of 1,1'-biphenol and a manganese carboxylate chain. The framework bearing dihydroxy groups functions as a solid-state host capable of adsorbing and separating mixtures of a range of chiral aromatic and aliphatic amines, with high enantioselectivity. The host material can be readily recycled and reused without any apparent loss of performance. The utility of the present adsorption separation is demonstrated in the large-scale resolution of racemic 1-phenylethylamine. Control experiments and molecular simulations suggest that the chiral recognition and separation are attributed to the different orientations and specific binding energies of the enantiomers in the microenvironment of the framework.
204 citations
TL;DR: The crystal structures of the two new compounds 2 and 3 were determined and it was shown that at T1 (433 K) the infinite nickel oxide chains built of the repeating structural unit [Ni3(μ3-OH)2](4+) in 1 collapse and lead to infinite porous layers, forming compound 2.
Abstract: Dehydration of the hybrid compound [Ni3(OH)2(tp)2(H2O)4] (1) upon heating led to the sequential removal of coordinated water molecules to give [Ni3(OH)2(tp)2(H2O)2] (2) at T1 = 433 K and thereafter anhydrous [Ni2(OH)2(tp)] (3) at T2 = 483 K. These two successive structural transformations were thoroughly characterized by powder X-ray diffraction assisted by density functional theory calculations. The crystal structures of the two new compounds 2 and 3 were determined. It was shown that at T1 (433 K) the infinite nickel oxide chains built of the repeating structural unit [Ni3(μ3-OH)2](4+) in 1 collapse and lead to infinite porous layers, forming compound 2. The second transformation at T2 (483 K) gave the expected anhydrous compound 3, which is isostructural with Co2(OH)2(tp). These irreversible transitions directly affect the magnetic behavior of each phase. Hence, 1 was found to be antiferromagnetic at TN = 4.11 K, with metamagnetic behavior with a threshold field Hc of ca. 0.6 T. Compound 2 exhibits canted antiferromagnetism below TN = 3.19 K, and 3 is ferromagnetic below TC = 4.5 K.
186 citations
TL;DR: Two isostructural lanthanide-based 3D coordination networks with densely packed distorted cuboid nanoscopic cages with significant cryogenic magnetocaloric effect are reported for the first time.
Abstract: Two isostructural lanthanide-based 3D coordination networks [Ln = Gd3+ (1), Dy3+(2)] with densely packed distorted cuboid nanoscopic cages are reported for the first time. Magnetic characterization reveals that complex 1 shows a significant cryogenic magnetocaloric effect (−ΔSm = 44 J kg–1 K–1), whereas 2 shows slow relaxation of magnetization.
105 citations
TL;DR: It is shown that an organic directing solvent, 1,4-dioxane, has a dominant effect on the lattice energy for a series of organic cage molecules, and hence, a noncovalent auxiliary interaction assumes the role of directional coordination bonding or covalent bonding in extended crystalline frameworks.
Abstract: Small structural changes in organic molecules can have a large influence on solid-state crystal packing, and this often thwarts attempts to produce isostructural series of crystalline solids. For metal–organic frameworks and covalent organic frameworks, this has been addressed by using strong, directional intermolecular bonding to create families of isoreticular solids. Here, we show that an organic directing solvent, 1,4-dioxane, has a dominant effect on the lattice energy for a series of organic cage molecules. Inclusion of dioxane directs the crystal packing for these cages away from their lowest-energy polymorphs to form isostructural, 3-dimensional diamondoid pore channels. This is a unique function of the size, chemical function, and geometry of 1,4-dioxane, and hence, a noncovalent auxiliary interaction assumes the role of directional coordination bonding or covalent bonding in extended crystalline frameworks. For a new cage, CC13, a dual, interpenetrating pore structure is formed that doubles the ...
104 citations
TL;DR: In this article, two novel isostructural lanthanide-based three-dimensional (3D) metal organic frameworks (MOFs), [Ln2(pam)3(DMF)2(H2O)2]n·nDMF {Ln = Gd(1), Dy(2); H2pam = 4,4′-methylenebis[3-hydroxy-2-naphthalenecarboxylic acid]} using the pharmaceutical agent "pamoic acid (H2Pam)
Abstract: Two novel isostructural lanthanide- based three-dimensional (3D) metal organic frameworks (MOFs), [Ln2(pam)3(DMF)2(H2O)2]n·nDMF {Ln = Gd(1), Dy(2); H2pam = 4,4′-methylenebis[3-hydroxy-2-naphthalenecarboxylic acid]} using the pharmaceutical agent “pamoic acid (H2pam)” are synthesized for the first time. Single crystal structure analysis shows that the 3D framework originates from the self-assembly of lanthanide metallomacrocycles made of dumble-shaped basic secondary building units and having channels of sizes 17.427 × 15.163 A (for 1) and 14.58 × 17.23 A (for 2), respectively. In both the complexes, two eight-coordinated lanthanide centers are connected with six pamoate groups to give a paddle-wheel type building block. The arrangement of pamoates and lanthanides in the framework provokes both right- (P) and left-hand (M) helicity around the 21 screw axis. The magnetic measurements show that complex 1 acts as a cryogenic magnetic refrigerant having magnetic entropy change, −ΔSm, of 17.25 J kg–1 K–1(ΔH = 7...
93 citations
TL;DR: Five M(II)-malonate complexes having a common formula have been synthesized and their crystal structures have been determined and the lone pair-π and π-π noncovalent interactions have been analyzed by means of DFT calculations, mainly focusing on the influence of the coordinating metal on the strength of the interactions and the interplay between hydrogen bonding and ρ-interactions.
Abstract: Five M(II)–malonate complexes having a common formula (C6H9N2)4[MII(C3H2O4)2(H2O)2](PF6)2.(H2O)2 (1–5) [where C6H9N2 = protonated 3-picoline, M(II) = Ni/Co/Mn/Mg/Zn, C3H4O4 = malonic acid, and PF6– = hexafluorophospahte], have been synthesized and their crystal structures have been determined. Complexes 1–5 were found to be isostructural and protonated 3-picoline has primarily mediated the self-assembly process. Role of a discrete water dimer in complexes 1–5 was also studied. Weaker π–interactions have also played crucial role in stabilizing 1D chain constructed by discrete [MII(C3H2O4)2(H2O)2] units. An additional copper complex namely, (C6H9N2)4[Cu(C3H2O4)2](PF6)2 (6) has been synthesized from the same reagents and was found to have a completely different structure from the others. Structures of all the complexes are fully described and compared here. Moreover, the lone pair−π and π–π noncovalent interactions have been analyzed by means of DFT calculations, mainly focusing our attention to the influenc...
83 citations
TL;DR: A new porous metal-organic framework (MOF) with three types of preserved polyhedral molecular building units, all of which have been observed in a series of isostructural MOFs, was formed even from a pre-designed related tetracarboxylic ligand with drastically reduced symmetry.
78 citations
TL;DR: The quantum yield and lifetime measurements prove that energy transfer from Tb( III) to Eu(III) is being achieved, namely, that the Tb (III) center is also acting to sensitize the Eu(-III) and enhancing Eu’s emission in 4.
Abstract: A novel amide type ligand benzyl-N,N-bis[(2′-furfurylaminoformyl)phenoxyl)ethyl]-amine (L) has been designed and applied for the self-assembly generation of homodinuclear lanthanide coordination compounds [Ln2(μ2-L)2(NO3)6(EtOH)2] [Ln = Eu (1), Tb (2), and Gd (3)] and a heterodinuclear derivative [EuTb(μ2-L)2(NO3)6(EtOH)2] (4). All the complexes have been characterized by the X-ray single-crystal diffraction analyses. They are isostructural, crystallize in a monoclinic space group P21/c, and form [2 + 2] rectangular macrocycle structures. Compound 4 is the first example of a [2 + 2] rectangular macrocycle heterodinuclear EuTb complex assembled from an amide type ligand. In 4, the discrete 0D dimeric [EuTb(μ2-L)2(NO3)6(EtOH)2] units are extended, via the multiple N–H···O hydrogen bonds, into a 2D supramolecular network that has been topologically classified as a uninodal 4-connected underlying net with the sql [Shubnikov tetragonal plane net] topology. The triplet state (3ππ*) of L studied by the Gd(III) c...
75 citations
TL;DR: In this article, a linear partially fluorinated ligand 2,2′-bis-trifluoromethyl-biphenyl-4,4′-dicarboxylic acid (H2L) was synthesized and used to construct five metal organic frameworks with Pb(II) through hydro-and solvothermal techniques.
Abstract: Rigid, linear partially fluorinated ligand 2,2′-bis-trifluoromethyl-biphenyl-4,4′-dicarboxylic acid (H2L) was synthesized and used to construct five metal organic frameworks with Pb(II) through hydro- and solvothermal techniques. Depending on the nature of the solvent or solvent mixture, five different coordination polymers, {[Pb6(L)5(OH)2]·2H2O}n (1), {[Pb3(L)2(O)(EtOH)]·(EtOH)}n (2), {[Pb3(L)2(O)(PrOH)]·(PrOH)}n (3), {[Pb3(L)2(O)(i-PrOH)]·(i-PrOH)}n (4), and {[Pb6(L)4(O)2]·(benzylalcohol)2(H2O)2}n (5), were synthesized. All of these compounds were characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, elemental analysis, and powder X-ray diffraction measurements. Complex 1, which is a 3D MOF, can be synthesized hydrothermally. However, isostructural complexes 2–4 can be obtained solvothermally using ethanol, propanol, and isopropanol, respectively, with water. The alcohols (ethanol, propanol, and isopropanol) are incorporated in the final 3D structures. Com...
74 citations
TL;DR: In this article, a series of fluorinated porphyrins, 5,10,15,20-tetrakis(2′,6′-difluorophenyl)porphyrin, MT(2.6, 6′-DFP)P and Zn(II)·(THF) 3, 5 have been structurally characterized by single crystal X-ray diffraction analysis.
TL;DR: The magnetic susceptibility and magnetization data confirm a paramagnetic behavior, and no remnant magnetization exists in any of these compounds at vanishing magnetic field.
Abstract: A new family of 3d–4f heterometal 2 × 2 complexes [CoII2(L)2(PhCOO)2LnIII2(hfac)4] (1–5) (Ln = Gd (compound 1), Tb (compound 2), Dy (compound 3), Ho (compound 4), and La (compound 5)) have been synthesized in moderate yields (48–63%) following a single-pot protocol using stoichiometric amounts (1:1 mol ratio) of [CoII(H2L)(PhCOO)2] (H2L = N,N′-dimethyl-N,N′-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine) as a metalloligand and [LnIII(hfac)3(H2O)2] (Hhfac = hexafluoroacetylacetone) as a lanthanide precursor compound. Also reported with this series is the Zn–Dy analog [ZnII2(L)2(PhCOO)2DyIII2(hfac)4] 6 to help us in understanding the magnetic properties of these compounds. The compounds 1–6 are isostructural. Both hexafluoroacetylacetonate and benzoate play crucial roles in these structures as coligands in generating a tetranuclear core of high thermodynamic stability through a self-assembly process. The metal centers are arranged alternately at the four corners of this rhombic core, and the carboxylato o...
TL;DR: A general solvothermal method is proposed for preparing carboxylate complexes in DMF solution without any basic additive.
Abstract: Seven coordination polymers, namely [Mn(4-cptpy)2]n (1), [Co(4-cptpy)2]n (2), [Mn3(4-cptpy)6(H2O)]n·2nH2O (3), [Co(4-cptpy)(HCOO)(H2O)]n·nDMF (4), [Zn2(4-Hcptpy)2Cl4]n·2nC2H5OH·nH2O (5), [Co4(3-cptpy)4(HCOO)4(H2O)2]n (6), and [Mn(3-cptpy)2]n (7) (4-Hcptpy = 4-(4-carboxyphenyl)-4,2′:6′,4′′-terpyridine; 3-Hcptpy = 4-(4-carboxyphenyl)-3,2′:6′,3′′-terpyridine), have been synthesized under hydro(solvo)thermal conditions and structurally characterized. A general solvothermal method is proposed for preparing carboxylate complexes in DMF solution without any basic additive. 1 and 2 possess isostructural 3D metal–organic frameworks containing nanosized cavities. 3 is a beautiful 2D coordination polymer assembled by flower-like Mn3(4-cptpy)6(H2O) subunits. 4 and 6 both display 2D polymeric networks constructed from 4/3-cptpy− ligands, in which the formate ligands originate from the hydrolysis of DMF. 5 is a 1D 21 helical chain polymer. 7 shows a 2D network with a (3.6) two-nodal kgd topology. 4/3-Hcptpy ligands display seven types of coordination modes. The zinc complex 5 emits strong violet luminescence. 1 and 2 are both thermally stable below 440 °C and exhibit antiferromagnetic interactions.
TL;DR: Both n-butylmagnesium complexes showed remarkable stability in air, both in the solid state and in solution, and single crystals of the highly sensitive magnesium hydride underwent partial hydrolysis by solid-state water diffusion to the isostructural hydroxide compound [(Ar)LMgOH].
Abstract: The highly sterically encumbered chelating β-diketiminate ligand, [HC{C(Me)N(2,6-CHPh2-4-MeC6H2)}2]−, ArL–, has been used to prepare a series of heteroleptic three-coordinate magnesium complexes. Both the bis(imine) and imine-enamine tautomers of the ligand precursor, ArLH, as well as the diethyl ether adduct of the bromide complex [ArLMgBr(OEt2)], the monomeric methyl complex [ArLMgMe], the THF-solvated and unsolvated n-butylmagnesium complexes [ArLMgnBu(THF)] and [ArLMgnBu], and the 1-hexynyl analogue [ArLMgC≡CnBu] have been crystallographically characterized. Both n-butylmagnesium complexes showed remarkable stability in air, both in the solid state and in solution. Single crystals of the highly sensitive magnesium hydride, [ArLMgH], underwent partial hydrolysis by solid-state water diffusion to the isostructural hydroxide compound [ArLMgOH].
TL;DR: This approach of utilizing a variety of both semirigid ligands and metals is the first general methodology to prepare this class of 1D nanomaterial.
Abstract: Employment of semirigid double-hinged di-1,2,4-triazoles has led to the synthesis of an isostructural series of metal–organic nanotubes (MONTs). The ditriazole ligands adopt a syn conformation between rigid metal chains while an appropriate anion choice provides a “capping” of the metal ions, leading to MONT formation. This approach of utilizing a variety of both semirigid ligands and metals is the first general methodology to prepare this class of 1D nanomaterial. The local geometry at the metal center depends on the metal ion employed, with Cu(I) centers adopting a tetrahedral geometry, Ag(I) centers adopting a seesaw geometry, and Cu(II) centers adopting a square-pyramidal geometry upon MONT synthesis. The pore size of the MONTs is adjusted by changing the central portion of the double-hinged ligand, allowing for a predictable method to control the pore width of the MONT. The adsorption properties of MONTs as a function of pore size revealed selective uptake of CO2 and CH4, with copper MONTs exhibiting...
TL;DR: A theoretical study of the structure of β-NiOOH, one of the active components of NiOx, identifies two groups of favorable structures: layered structures with alternate Ni(OH)2 and NiO2 layers, consistent with the doubling of the c axis observed in high resolution transmission electron microscopy measurements, and tunnel structures isostructural with MnO2 polymorphs, which can provide a rationale for the mosaic textures observed in TEM.
Abstract: Fe-doped NiOx has recently emerged as a promising anode material for the oxygen evolution reaction, but the origin of the high activity is still unclear, due largely to the structural uncertainty of the active phase of NiOx. Here, we report a theoretical study of the structure of β-NiOOH, one of the active components of NiOx. Using a genetic algorithm search of crystal structures combined with dispersion-corrected hybrid density functional theory calculations, we identify two groups of favorable structures: (i) layered structures with alternate Ni(OH)2 and NiO2 layers, consistent with the doubling of the c axis observed in high resolution transmission electron microscopy (TEM) measurements, and (ii) tunnel structures isostructural with MnO2 polymorphs, which can provide a rationale for the mosaic textures observed in TEM. Analysis of the Ni ions oxidation state further indicates a disproportionation of half of the Ni(3+) cations to Ni(2+)/Ni(4+) pairs. Hybrid density functionals are found essential for a correct description of the electronic structure of β-NiOOH.
TL;DR: A polymorph screen on a new 1:1 co-crystal of caffeine, C8H10N4O2, with anthranilic acid, has revealed a rich diversity of crystal forms (two polymorphs, two hydrates and seven solvates, including two sets of isostructural solvate).
Abstract: A polymorph screen on a new 1:1 co-crystal of caffeine, C8H10N4O2, with anthranilic acid, C7H7NO2, has revealed a rich diversity of crystal forms (two polymorphs, two hydrates and seven solvates, including two sets of isostructural solvates). These forms were prepared by liquid-assisted grinding and solution crystallization, and the crystal structures of nine of these forms have been solved using either single-crystal or powder X-ray data. The structures contain O—H⋯N and N—H⋯O hydrogen bonds through which caffeine and anthranilic acid molecules assemble to form zigzag-type chains. These chains can interact in an anti-parallel and offset manner to form cage- or channel-type skeletons within which solvent molecules can be located, giving rise to the diversity of forms observed for this co-crystal. In contrast, an equivalent series of liquid-assisted grinding and solution crystallization experiments with the closely related system of theobromine, C7H8N4O2, and anthranilic acid resulted in the formation of only one 1:1 co-crystal form.
TL;DR: This study demonstrates that these different optical behaviors can be attributed to the presence of a PET (photoinduced electron transfer) mechanism that is only present in the amino-isophthalate-containing coordination polymers.
Abstract: The luminescent properties of two families of heteronuclear lanthanide-containing coordination polymers are compared. These families have general chemical formulas [Ln2–2xLn′2x(ip)3(H2O)9·6H2O]∞ and [Ln2–2xLn′2x(aip)2(H2O)10·(aip)·4H2O]∞ where H2ip and H2aip stand for isophthalic acid and 5-amino-isophthalic acid, respectively, and where Ln and Ln′ are one of the lanthanide ions between Sm3+ and Dy3+. Heteronuclear compounds that belong to each family are isostructural to the already reported homonuclear compounds [Gd2(ip)3(H2O)9·6H2O]∞ and [Eu2(aip)2(H2O)10·(aip)·4H2O]∞, respectively. These two crystal structures are very similar. However, despite similar chemical formulas, similar crystal structures, and similar hydration rates, these two families of compounds present very different luminescent properties that have thus been deeply investigated. This study demonstrates that these different optical behaviors can be attributed to the presence of a PET (photoinduced electron transfer) mechanism that is onl...
TL;DR: A series of isostructural M-MOF-74 materials with proper pore sizes and highly dense unsaturated metal sites have been examined for the selective adsorption of SF6 over nitrogen as discussed by the authors.
TL;DR: Measurements of the magnetization as a function of applied magnetic field at 2 K for Na4MnU6F30 confirmed that the U(4+) magnetic cation exhibits a nonmagnetic singlet ground state at low temperature.
Abstract: A family of rare U(IV)-containing quaternary fluorides, Na4MU6F30 (M = Mn2+, Co2+, Ni2+, Cu2+, and Zn2+), was synthesized in single crystal form via a mild hydrothermal technique utilizing an in situ U(VI) to U(IV) reduction step. The modified hydrothermal route is described, and the conditions to obtain single crystals in high yield are detailed. The crystal structures were determined by single crystal X-ray diffraction. The isostructural fluorides crystallize in a new structure type in the trigonal space group P3c1. They exhibit a complex three-dimensional crystal structure consisting of corner- and edge-shared UF9 and MF6 polyhedra. The main building block, a U6F306– group, is arranged to create two distinct hexagonal channels, inside which MF6 octahedra and Na+ cations are located. The copper-containing member of the series, Na4CuU6F30, is unusual in that the Cu2+ cation exhibits a rare symmetrical coordination environment consisting of six identical Cu–F bond distances, indicating the lack of the ex...
TL;DR: In this article, three metal-II-organic frameworks (MOFs) formulated as M2L4·3H2O [M = Co (1), Cu (2), and Zn (3)] were synthesized and characterized by single-crystal X-ray diffraction.
Abstract: Using a rigid ligand, 4-(5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl) benzoic acid (HL), three metal(II)–organic frameworks (MOFs) formulated as M2L4·3H2O [M = Co (1), Cu (2), and Zn (3)] were synthesized and characterized by single-crystal X-ray diffraction. The three MOFs are isostructural except for different unsaturated coordinated metal(II) ions in the structures, and they display a uninodal two-dimensional layer with 44-sql topology. Among the three complexes, the Co and Cu complexes can act as electrocatalysts for water splitting, and the Co complex shows better electrocatalytic activity. The present work shows that the species of metal(II) ions plays an important role in the electrocatalytic activity for water splitting. The three complexes show different thermal stabilities, UV–vis absorption characteristics, and photoluminescence properties.
TL;DR: In this article, two new alkali metal bismuth iodates, K2BiI5O15 and Rb2BI5Os15, have been synthesized by a hydrothermal method.
Abstract: Two new alkali metal bismuth iodates, K2BiI5O15 and Rb2BiI5O15, have been synthesized by a hydrothermal method. They are isostructural with the same noncentrosymmetric (NCS) orthorhombic space group Abm2 and contain a unique [I3O9]3− bridging anionic group. Their powders showed phase-matchable second-harmonic generation (SHG) effects 3 times that of KH2PO4 (KDP) and the laser-induced damage threshold values of 84 and 72 MW cm−2, respectively. They also exhibit a wide transparent range (up to 12 μm) and good thermal stability (450 °C).
TL;DR: In this article, the structural and vibrational properties of sphaerobismoite (β-Bi2O3) at high pressures in which room-temperature angle-dispersive angles were obtained were investigated.
Abstract: We report a joint experimental and theoretical study of the structural and vibrational properties of synthetic sphaerobismoite (β-Bi2O3) at high pressures in which room-temperature angle-dispersive...
TL;DR: Structural investigation by X-ray crystallography reveals similar structural features for complexes 1 and 2 and they exhibit butterfly like shapes of the molecules and magnetization changes for both dysprosium analogues 2 and 4 are revealed.
Abstract: The synthesis, crystal structure and magnetic properties of four polynuclear lanthanide coordination complexes having molecular formulae, [Gd3L12(H2O)8(Cl)](Cl)4·10H2O (1), [Dy3L12(H2O)9](Cl)5·6H2O (2) [Gd6L22(HCO2)4(μ3-OH)4(DMF)6(H2O)2](Cl)2·4H2O (3) and [Dy6L22(HCO2)4(μ3-OH)4(DMF)6(H2O)2](Cl)2·4H2O (4) (where H2L1 = bis[(2-pyridyl)methylene]pyridine-2,6-dicarbohydrazide and H4L2 = bis[2-hydroxy-benzylidene]pyridine-2,6-dicarbohydrazide) are reported. Structural investigation by X-ray crystallography reveals similar structural features for complexes 1 and 2 and they exhibit butterfly like shapes of the molecules. Non-covalent interactions between the molecules create double helical arrangements for both molecules. Complexes 3 and 4 are isostructural and the core structures feature four distorted hemi-cubanes connected by vertex sharing. Magnetic studies unveil significant magnetic entropy changes for complexes 1, 3 and slow relaxation of magnetization for both dysprosium analogues 2 and 4.
TL;DR: It was observed that the stronger ligand field (imine) resulted in complex 1 with a larger energy barrier for reorientation of the magnetization than 2, and the observed differences were attributed to a synergistic effect between the electron density of the ligand and the small structural changes provoked by a slight alteration of the coordination environment.
Abstract: We investigate and compare the magnetic properties of two isostructural DyIII-containing complexes. The DyIII ions are chelated by hexadentate ligands and possess two apical bidendate nitrate anions. In dysprosium(III) N,N′-bis(imine-2-yl)methylene-1,8-diamino-3,6-dioxaoctane (1), the ligand’s donor atoms are two alkoxo, two pyridine, and two imine nitrogen atoms. Dysprosium(III) N,N′-bis(amine-2-yl)methylene-1,8-diamino-3,6-dioxaoctane (2) is identical with 1 except for one modification: the two imine groups have been replaced by amine groups. This change has a minute effect on the structure and a larger effect the magnetic behavior. The two complexes possess slow relaxation of the magnetization in the presence of an applied field of 1000 Oe but with a larger barrier for reorientation of the magnetization for 1 (Ueff/kB = 50 K) than for 2 (Ueff/kB = 34 K). First-principles calculations using the spin–orbit complete active-space self-consistent-field method were performed and allowed to fit the experiment...
TL;DR: In this article, the structure of coordination complexes has been characterized by relative physical methods, and a number of new coordination complexes have been synthesized, such as [Cd3(H2L)(H2O)7]·6H 2O (1), [Mn3(h2L), H2O (2), [Ni3(L)(teta)4(H 2 O)6], [Ni4(L), Ni3(T), H 2 O (4,6), [Fe3(Fe3,H 2.
Abstract: Ten new coordination complexes, [Cd3(H2L)(H2O)7]·6H2O (1), [Mn3(H2L)(H2O)7]·7H2O (2), [Zn3(H2L)(H2O)6]·6H2O (3), [Co3(H2L)(H2O)6]·5.75H2O (4), [Fe3(H2L)(H2O)8]·6.5H2O (5), [Co3(H2L)(teta)3]·5H2O (6), [Ni4(L)(teta)4]·2.5H2O (7), [Ni3(H2L)(teta)(H2O)6]·6H2O (8), [Cd4(L)(teta)4(H2O)2]·H2O (9), and [Cu2(H4L)(teta)2]·2H2O (10) (H8L = 1,4,8,11-tetrazacyclododecane-N,N′,N″,N‴-tetra-methylene-isophthalic acid and teta = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) have been synthesized. Their structures have been confirmed and further characterized by relative physical methods. Compounds 1 and 2 are isomorphous and demonstrate the identical three-dimensional (3D) (4,6)-connected nets with (64·72)(68·76·8) topologies. Compounds 3–5 are isostructural and unfold 3D 4-fold interpenetrating frameworks with (412·63) topologies. Compound 6 is a 3D 2-fold interpenetrating framework with (412·63) topology. Compound 7 features a 3D 6-connected (412·63) net. Compounds 8 and 9 reveal two-dimensional (2D) laye...
TL;DR: It is shown that the use of aliphatic dicarboxylate (glutarate) results in a non-interpenetrated framework rather than the common interpenetration framework with aromatic dicARboxylates in mixed ligand systems.
Abstract: We report the synthesis, structural characterization and adsorption properties of three new porous coordination polymers {[Cu(Meazpy)0.5(glut)](H2O)}n (2), {[Zn(azpy)0.5(terep)](H2O)}n (3), and {[Zn(Meazpy)0.5(terep)]}n (4) [glut = glutarate, terep = terephthalate, azpy = N,N′-bis-(pyridin-4-ylmethylene)hydrazine and Meazpy = N,N′-bis-(1-pyridin-4-ylethylidene)hydrazine] composed of mixed linkers systems. Structure determination reveals that all three compounds have three-dimensional (3D) coordination frameworks bridged by dicarboxylates and Schiff base linkers. In all cases 2D dicarboxylate layers are supported by paddle-wheel M2(CO2)4 SBUs extended in three dimensions by designed Schiff base linkers. Compound 1, which has been reported in a paper earlier by our group, is a robust porous three-dimensional (3D) framework whose pore surface was found to be decorated with the –CHN– groups of a linear Schiff base (azpy) and it showed reversible single-crystal-to-single-crystal transformation and selective CO2 uptake. By using another linear Schiff base linker Meazpy, we have synthesized compound 2 which is isostructural with 1, having an additional methyl group pointing towards the pore. Like 1 it also shows a reversible single-crystal-to-single-crystal transformation upon dehydration and rehydration. The dehydrated framework of 2 exhibits 50% enhanced CO2 uptake compared to 1. This has been achieved by the pore surface modification effected upon changing the pillar backbone from a –CHN– to –CMeN– group. It also adsorbs water vapour at 298 K. In the case of the two isostructural 3D MOFs 3 and 4, the use of a rigid carboxylate (terephthalate) linker arrested porosity by three-fold interpenetration. We showed that the use of aliphatic dicarboxylate (glutarate) results in a non-interpenetrated framework rather than the common interpenetrated framework with aromatic dicarboxylates in mixed ligand systems.
TL;DR: In this paper, two quaternary tin(IV) antimony(III) sulfides, [TM(en)3][SnSb4S9] [TM = Ni (1), Co (2); en = ethylenediamine], and one mixed-valent thioantimonate (III and V), [Mn(dien)2]2Sb 4S9 (3, dien = diethylenetriamine), were solvothermally synthesized and structurally characterized.
Abstract: Two new isostructural quaternary tin(IV) antimony(III) sulfides, [TM(en)3][SnSb4S9] [TM = Ni (1), Co (2); en = ethylenediamine], and one mixed-valent thioantimonate (III and V), [Mn(dien)2]2Sb4S9 (3, dien = diethylenetriamine), have been solvothermally synthesized and structurally characterized. In the structures of 1 and 2, four neighboring SbS3 trigonal pyramids are condensed via corner-sharing to form bow-like Sb4S9 tetramers, which are further interconnected by SnS6 octahedra into the three-dimensional (3D) chiral [SnSb4S9]2– framework with two types of one-dimensional (1D) chiral channels along the c axis. Compound 3 features a 3D network composed of 1D anionic [Sb4S9]4– chains and [Mn(dien)2]2+ complexes interconnected via various hydrogen bonds. The most interesting structural feature of 3 is the presence of two different oxidation states of antimony centers in the 1D [Sb4S9]4– chain with three different types of coordination environments, respectively. The optical absorption spectra indicate that ...
TL;DR: In this paper, the crystal structures of derivatives of HKUST-1 (Cu-BTC) were analyzed for a set of six functionalized ligands: methyl, ethyl, methoxy, bromo, nitro, and acetamide.
Abstract: Metal–organic framework (MOF) materials are nanoporous crystals that have attracted intense interest in the fields of adsorption and catalysis. MOFs are interesting in part because of the concept of reticular synthesis, which allows families of isostructural crystals to be developed by varying ligand length and functionality. The predictability associated with MOF crystal structures is complicated in situations where ligand functionalization leads to new crystal structures. In this work, we show experimentally how the crystal structures of derivatives of HKUST-1 (Cu-BTC) vary for a set of six functionalized ligands: methyl, ethyl, methoxy, bromo, nitro, and acetamide. Our experiments indicate that synthesizing MOFs with these functionalized ligands leads to multiple distinct crystal structures. We further show that these structures can be rationalized computationally using density functional theory (DFT) and electron localization function (ELF) calculations. This analysis led to a simple “design principle...
TL;DR: The combined results demonstrate the ability of pdmH2 ligand to yield homometallic 4f clusters with interesting magnetic and optical properties.
Abstract: Reaction between Ln(NO3)3·xH2O (x = 5 or 6) and the potentially tridentate (N,O,O) chelating/bridging ligand pyridine-2,6-dimethanol (pdmH2), in the presence of base NEt3, affords a family of isostructural tetranuclear [LnIII4(NO3)2(pdmH)6(pdmH2)2](NO3)4 (LnIII = EuIII, GdIII, TbIII, DyIII, HoIII, ErIII, YbIII) complexes with a rare zigzag topology. All complexes contain a [Ln4(μ-OR)6]6+ core with bridging ligation provided by the alkoxido arms of six η1:η1:η2:μ pdmH– groups. The LnIII ions are eight coordinate with distorted geometries. Direct current magnetic susceptibility studies revealed predominant weak antiferromagnetic exchange interactions between the metal centers, which were quantified in the case of isotropic GdIII4 to give J = −0.09(1) cm–1 and g = 2.00(1). The observation of out-of-phase (χ″M) ac susceptibility signals suggested that the DyIII4 analogue might be a molecular nanomagnet. Solid-state photoluminescence studies showed that the EuIII4 and TbIII4 compounds exhibit intense, sharp, a...