Infinite Helical Chains Research Articles

Synthesis and Structural Characterization of Yttrium Polyphosphates AY(PO3)4 (A = Rb, Tl, Cs) and Site‐selective Spectroscopy of Eu3+ Doped Samples

AbstractAbstract. Three new long‐chain polyphosphates of yttrium AIY(PO3)4 (AI = Rb, Tl, Cs) were synthesized by heating stoichiometric mixtures of alkaline or thallous carbonates A2CO3, yttrium oxide Y2O3, and ammonium dihydrogen phosphate in a platinum crucible at temperatures ranging from 400 °C (Rb and Tl) to 450 °C (Cs). Their crystal structures were solved from single‐crystal X‐ray diffraction data. All colorless compounds are isotypic and belong to the type IV of the long‐chain polyphosphates (monoclinic, P21/n, No. 14). The crystal structure is built of infinite helical chains of corner‐sharing PO4 tetrahedra with a repetition unit of eight tetrahedra. These chains are further linked by corner sharing to isolated YO8 square antiprisms, thus forming a three‐dimensional framework. The ions AI are located in hexagonally shaped channels running along [100] and are surrounded by eleven oxygen atoms in distorted environments. The luminescence properties of Eu3+ doped samples were investigated and used as structural probe in these polyphosphates. They are proving to be in good agreement with the crystallographic data.

Three coordination polymers constructed from various polynuclear clusters spaced by 2,2′-azodibenzoic acid: syntheses and fluorescent properties

Solvothermal reactions of M(OAc)2·2H2O (M = Zn, Cd, Pb) with 2,2'-azodibenzoic acid (H2L) in MeOH-H2O (MeOH = methanol) at 120 °C gave rise to three coordination polymers, [Zn12(μ4-O)3L9]n (1), [CdL(H2O)]n (2) and [Pb3(μ4-O)L2]n (3). Compounds 1-3 are characterized by elemental analysis, IR, powder X-ray diffraction and single-crystal X-ray diffraction. Compound 1 has two similar tetranuclear [Zn4(μ4-O)(μ2-CO2)6] units as nodes and displays an intriguing three-dimensional (3D) 6-connected network with a 4(12)6(3) topology. Compound 2 exhibits a 3D framework constructed by linking infinite helical Cd-carboxylate chains through L ligands. Compound 3 holds a 3D structure in which each hexanuclear [Pb6(μ4-O)2(CO2)4] unit works as a six-connecting node to connect its equivalent ones via sharing L ligands. In addition, the fluorescent properties and thermal stabilities of 1-3 were also investigated.

Supramolecular design of coordination complexes of silver(I) and cadmium(II) with chiral bidentate bridging ligands

Two diastereopure ligands, N,N′-bis(4-pyridyl)idene(1R,2R)- diaminocyclohexane (L1) and N,N′-bis(3-pyridyl)idene(1R,2R)-diaminocyclohexane (L2), have been synthesized and characterized. The interaction of L1 with Ag(I) ions and L2 with Cd(II) ions has been investigated. The structure of {[Ag(L1)2](CF3SO3)·4H2O}n (1) exhibits a (4,4)-connected two-dimensional sheet with a corrugated surface and the complex [Cd(L2)2(NO3)(3H2O)]n·NO3·2H2O (2) forms an infinite single helical chain with a pitch of 47.25Å. When viewed from the top of the chain, the infinite helical chain forms the wall of a hexagonal nanochannel with an opening of ∼1.2×1.2nm.

Iodine networks in polyiodides of M(III) urea complexes: Crystal structures of [V(Ur)6][I3]3 and [Dy(Ur)8][I5][I3]2[I2

Unique [V(Ur)6][I3]3 and [Ln(Ur)8][I5][I3]2[I2] (Ln=Dy, La) were prepared by reactions of hexaureavanadium(III) and tetraaquatetraurealanthanide(III) iodides with iodine and the crystal structures of the vanadium and dysprosium compounds are reported. Metal ions are located at the centres of distorted octahedral and square-antiprismatic arrangements, respectively, of oxygen atoms of covalent-coordinated urea. The triiodide anions in the vanadium polyiodide are united in infinite helical chains fitting between the columns of complex cations and binding them together by hydrogen bonding. In the dysprosium polyiodide, the V-shaped I5− ions are united in infinite planar twisting chains. The chains are connected by short contacts through bridging V-shaped I5− ions (combined of I2 molecule and I3− ion) and symmetric I3− ions. Another I3− ion is isolated. The bonded iodine atoms form hexahedral channels, and the columns of the complex cations are localized in these channels and stabilized by hydrogen bonding.

MII(3-(2′-pyridylmethyleneamino)pyridine)(NO3)2], (M = Co, Zn, Cd) coordination polymers; single, mixed and composite crystals

3-(2′-Pyridylmethyleneamino)pyridine (L) and its homo and heterometallic coordination polymers [ML(NO3)2]n, (M=Co, Zn, Cd; 1–3) and [MM′L2(NO3)2]n, (M, M′=Co, Zn, Cd; 4–6) have been synthesized and characterized by CHN analysis, IR and UV–Vis spectroscopy. The crystal structures of the compounds were determined from single crystal X-ray diffraction. Structural studies of compounds revealed the crystals are isomorphous (monoclinic, P 21/c). The coordination polyhedron about the M(II) center in the compounds is best described as distorted octahedral. Each L is chelated to a metal center (M) and also linked to another metal atom to form an infinite helical chain along the b axis. The formation of a series of composite crystals based on epitaxial growth of crystalline layers on preformed crystals has also been reported. The crystal growth of the zinc compound was also studied in the presence of KI. Thermogravimetric investigations of the compounds have also been discussed.

Mixed-linker MOFs with CAU-10 structure: synthesis and gas sorption characteristics

The metal–organic framework compound [Al(OH)(BDC-Br)] (1) (BDC-Br2− = 5-bromo-1,3-benzenedicarboxylate) denoted CAU-10-Br was synthesised under solvothermal reaction conditions. Its structure was successfully refined by Rietveld methods. The framework is based on the connection of infinite helical chains of cis-corner-sharing AlO6-polyhedra via BDC-Br2− ions. Thus non-intersecting parallel channels are formed, each periodically varying in diameter between 1.1 and 6.6 Å. Nevertheless 1 adsorbs CO2 at 298 K, while it is non-porous towards H2 and N2 at 77 K. Employing high-throughput (HT) methods we identified synthesis conditions that lead to the formation of mixed-linker MOFs with CAU-10 topology. Starting with a molar ratio H2BDC:H2BDC-Br = 3:1 we established a synthesis procedure for the partially bromo-functionalised mixed-linker-MOF [Al(OH)(BDC)0.8(BDC-Br)0.2] (2) denoted as CAU-10-H/Br. Starting with a molar ratio H2BDC-NH2:H2BDC-NO2 = 1:1 the partially NO2- and NH2-functionalised mixed-linker MOF [Al(OH)(BDC-NO2)0.55(BDC-NH2)0.23(BDC-NHCHO)0.22] (3) denoted as CAU-10-NO2/NH2 was synthesised, in which the NH2-groups were found to be partially formylated. The partial bromo-functionalisation in CAU-10-H/Br (2) leads to a lower sorption capacity in comparison with the parent structure CAU-10-H, while the pore accessibility is comparable. The incorporation of NO2-, NH2- and NHCHO-groups in CAU-10-NO2/NH2 (3) does not only affect the accessibility of the pores for N2, but results also in an increased capacity for H2 and CO2 in comparison with the parent structure CAU-10-NO2. The reproducibility of the synthesis procedures was tested regarding the composition of the MOFs and the resulting gas sorption properties. In 2 a molar fraction of (BDC)2− = 80 ± 2% is found, while in 3 a molar fraction of (BDC-NO2)2− = 55 ± 2% is observed. Starting from the molar ratio H2BDC:H2BDC-CH3 = 1:1 mixed linker MOFs denoted as CAU-10-H/CH3 (4) were also obtained. In contrast to 2 and 3 the molar ratios of BDC2−/BDC-CH32− and especially the sorption properties differ substantially for every batch. The compounds were further characterised by X-ray powder diffraction, thermogravimetric/elemental analysis, NMR/Vis/IR-spectroscopy, and gas sorption measurements.

A novel 1-D mixed-valence cobalt coordination polymer bridged with (μ-Oalkoxo) and (μ-carboxylate) units: Synthesis, structure and properties

A novel one-dimensional helical mixed-valence cobalt coordination polymer ( 1 ) {[Co II Co III (HL) 2 (OAc)]·CH 3 OH·H 2 O} n , ( H 3 L = 2-ethyl-2-((2-hydroxynaphthalen-1-yl)methyleneamino)propane-1,3-diol) has been synthesized and characterized. Single-crystal X-ray diffraction analyses reveal that complex 1 crystallizes in the tetragonal I4(1)/a space group. It consists of a bimetallic Co II Co III (μ 2 -O) 2 core, and the adjacent Co II (2) centers are sequentially bridged by carboxylate groups in the syn–anti fashion, affording to a one-dimensional infinite helical chain along the c -axis. Adjacent chains are stacked via C H···π interactions to form the overall three-dimensional supramolecular networks. Magnetic and in vitro anticancer activities of the complex have been investigated in detail. Susceptibility data for {[Co II Co III (HL) 2 (OAc)]·CH 3 OH·H 2 O} n in χ M T (○) vs. T (Δ). ► 1D mixed-valented cobalt coordination polymer are synthesized and characterized. ► Carboxylate groups bridge in the syn–anti fashion, leading to right-helice. ► Weak FM exchange interaction may occur in complex. ► In vitro anticancer activity of the complex are determined against A-549 cells.

Synthesis and Characterisation of a Cd(II) Complex with a Chiral Framework Constructed from Achiral 1,1′-[bis-3-(3-pyridyl)pyrazol-5-yl]ferrocene via Spontaneous Resolution

The chiral Cd(II) complex {[Cd(L)(CH3COO)2(H2O)]·H2O} n {L = 1,1′-[bis-3-(3-pyridyl)pyrazol-5-yl]ferrocene} has been synthesised. The Cd(II) ion is coordinated by two pyridyl nitrogen atoms, two chelating acetate anions and one water molecule, showing a distorted pentagonal-bipyramidal coordination environment. Each ligand L serves as a bisconnector, bridging two Cd atoms through its two pyridyl moieties, to afford an infinite 1D left-handed helical chain along the a-axis with a short pitch of 5.8761 (9) Å. Moreover, all of the left-handed helical chains are joined by hydrogen bonds to form a left-handed homochiral crystal.

Catena-Poly[[[iodidocopper(I)]-{μ-N-[(pyridin-2-yl-κN)methylidene]pyridin-3-amine-κ2N3:N1}] acetonitrile hemisolvate

In the asymmetric unit of the title polymeric complex, {[CuI(C11H9N3)]·0.5CH3CN}n, there are two CuI atoms, two N-[(pyridin-2-yl-κN)methyl­idene]pyridin-3-amine (PyPy) ligands and two I atoms. Both CuI atoms have a distorted tetra­hedral geometry, each being coordinated by one I atom, two N atoms of one PyPy ligand and one N atom from an adjacent PyPy ligand. In the crystal, infinite helical chains of [Cu2(PyPy)2]n are formed propagating along the b axis. These chains are linked via weak C—H⋯I hydrogen bonds and π–π stacking inter­actions [shortest centroid–centroid distance = 3.2727 (14) Å]. During the refinement, electron-density peaks were located that were believed to be highly disordered solvent mol­ecules (possibly acetonitrile). The SQUEEZE option in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148–155] indicated there were solvent cavities with a total volume of 196 Å3 containing approximately 60 electrons per unit cell, which equated to one mol­ecule of acetonitrile per asymmetric unit.

A Novel Zinc(II)‐Organic Coordination Framework Involving in situ Tetrazole Ligand Synthesis: Crystal Structure and Luminescent Properties

AbstractThe compound [Zn(5‐(2‐M)ET)2]n (1) [5‐(2‐M)ET = 5‐(2‐methoxyl)ethyltetrazole] was obtained by reaction of ZnSO4, sodium azide, and 3‐methoxyl propionitrile via an in situ [2+3] cycloaddition under hydrothermal conditions. It was characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, and single‐crystal X‐ray diffraction. Compound 1 is a 3D coordination framework with diamond‐like topology that is built up by infinite helical chains, which are interconnected by tetrazole groups.

Synthesis, Crystal Structure, and Characterization of a Novel One-Dimensional Helical Chain Cobalt(II) Coordination Polymer

A novel one-dimensional (1D) helical chain polymer, {[CoL2(H2O)](H3O)(ClO4)}n (1) (HL = 4-N-(2′-pyridylimine)benzoic acid), was synthesized by reaction of Co(II) perchlorate with L anion in ethanol solution, and characterized by element analyses, infrared spectroscopy, and X-ray single-crystal diffraction. In this structure, the Co2+ ion is in a distorted octahedral geometry, an infinite 1D helical chain was constructed by L ligand through bidentate-monodentate bridging modes and are further assembled into three-dimensional supramolecular networks through complicated O–H···O hydrogen bonding interactions.

Highly stable 3D homochiral coordination polymer with interweaving of double-stranded helices and extended metal-SO4-metal chains

Abstract Solvothermal synthesis of an achiral ligand N,N-bis(3-pyridyl) isophthalamide (bpip) with ZnSO4 under 120 °C yield a novel compound, [Zn(bpip)SO4]n, which displays chiral self-assembly into an infinite double-stranded helical coordination polymer consisting of two single-stranded helices with the same P handedness. These chiral infinite double-stranded helical chains are further interwoven by the 1D Zn–SO4–Zn chains to form a novel 3D framework structure with a rare 65.10 topology. On the basis of the results of TG-DSC analyses, the structure is thermally stable up to ~ 467.4 °C.

Four 1D and 2D Cadmium(II) Complexes Based on Different Anions and Two Modified Bipyridyl Ligands: Syntheses, Structures, Thermogravimetric, and Fluorescent Properties

AbstractA series of cadmium(II) coordination polymers constructed from 1, 3‐bis(pyridine‐3‐carbonyl)imidazolidin‐2‐thioxo (3‐bpit) and 1, 3‐bis(pyridine‐4‐carbonyl)imidazolidin‐2‐thioxo (4‐bpit), namely,{[Cd(SCN)2(3‐bpit)2]·2(CH3OH)}n (1), {[Cd(NO3)2(3‐bpit)2]·2(CH3OH)}n(2), [CdI2(4‐bpit)]n (3), and [CdCl2(4‐bpit)4]n (4) were prepared and characterized by single‐crystal X‐ray diffraction. Complexes 1 and 2 display different types of infinite 1D helical chain structures, both of which contain 24‐membered metallocyclic rings. Complex 3 is composed of 1D zigzag chains, which further form a 3D supramolecular architecture by weak C–H···S and S···I interactions. Complex 4 also features a 3D supramolecular network assembled from 2D rhombus‐shaped layer through intermolecular hydrogen bonding. These structures indicate that the conformation of the ligand and the diverse anions take important roles in the formation of different frameworks. Thermogravimetric and fluorescent properties over complexes are also discussed.

Hydrothermal synthesis, structure, fluorescence property of a novel 3D metal-organic framework with high thermal stability

A novel 3D metal-organic framework (MOF) with remarkable thermal stability, Ni(BIC)2·2.5H2O (JUC-86) (HBIC = 1-H-benzimidazole-5-carboxylic acid and JUC = Jilin University China), has been synthesized under hydrothermal conditions. It crystallizes in tetragonal symmetry with P43212 space group. The 3D structure consists of channels assembled from triple helices with a 4.5 × 4.5 A2 aperture, which are formed by the parallel alignment of three infinite helical chains. The thermogravimetric analysis (TGA) and powder X-ray diffractions (PXRD) indicate JUC-86 with high thermal stability (up to 350 °C).

Synthesis and Structural Characterization of [2-(2-1H-Imidazoly)-1H-imidazolium nitrate] and [2-(2-1H-Imidazoly)-2H-imidazolium phthalyl glycinate] Based on the 2,2′-bi-1H-Imidazole Molecule

Two new compounds (H3biim)(NO3)(1) and (H4biim)(phthgly)2 (2) (H2biim=biimidazole; Hphthgly=N-phthaloylglycine) have been synthesized and characterized by luminescence and single crystal X-ray diffraction study. Compound 1 crystallizes in the monoclinic space group C2/c, where a = 14.8078(15), b = 5.9233(6), c = 20.028(2) A, β = 92.7910(10)°, V = 1754.6(3) A3 and Z = 8. Compound 2 crystallizes in the monoclinic space group P2(1)/n, where a = 15.3775(14), b = 5.3200(6), c = 6.4689(18)A, β = 115.418(2)° V = 1216.9(2)A3 and Z = 4. In 1, the N–H groups of H3biim+ and the oxygen atoms of NO3 − are linked by hydrogen bonds leading to H3biim+(N,N)–R 2 2 (10) and N–H···O interactions forming infinite 1D helical chains along the b-axis. Compound 2 consists of a planar diprotonated biimidazole moiety and two phthgly anions which connect to the dication by hydrogen bonds phthgly−(O,O)–R 2 2 (9). The unit crystal structure of (H3biim)(NO3) consists of one H3biim+ cation and one NO3 − anion. The (H3biim)(NO3) units form infinite 1D helical chains along the b axis through robust hydrogen bonds H3biim+(N,N)-R 2 2 (10) involving the N–H groups of H2biim ligands with the oxygen atoms of nitrate anions, and the two adjacent units of [(H3biim)(NO3)] connect each other by a direct side-by-side interaction.

Encapsulated two distinct infinite helical water chains in a cyano-bridged copperII–ironII heterometal complex

A bimetallic oligonuclear complex, [trans-{Cu(pmea)2Fe(CN)6]·9H2O (1) (pmea=bis[(2-pyridyl)methyl]-2-(2-pyridyl)ethylamine), had been synthesized and structurally characterized. 1 crystallizes in monoclinic space group P2(1)/c with a=23.924(5)Å, b=10.911(2)Å, c=21.094(4)Å, β=112.46(3)° and Z=4, which exhibits a three dimensional (3D) framework constructed from the water rich 2D sheets. Of particular interest, two kinds of helical water chains coexist in this complex. Comparing the experimental results, it is comprehensible that hosts constructed from the hexacyanometallates plays crucial roles in the formation of the helical structures and water aggregates. Additionally, the compound was characterized by TGA, IR spectroscopy, magnetism and elemental analysis.

A Molecular Basketwork: Self-Assembly of Coordination Polymers from Zn(II) and Biphenyl-3,4′-dicarboxylate Regulated by Different Flexible Bridging and Chelating N-Donor Ancillary Ligands

Four low-dimensional coordination polymers, [Zn2(bpdc)2(dib)2]n·nH2O (1), [Zn(bpdc)(phen)]n·2nH2O (2), [Zn(bpdc)(bpy)]n·2nH2O (3), and [Zn(bpdc)(H2O)]n (4), (H2bpdc = biphenyl-3,4′-dicarboxylic acid, dib = 1,4-di(1H-imidazol-2-yl)butane, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine), have been successfully prepared under hydrothermal conditions and characterized by IR, single crystal X-ray diffraction, thermogravimetric analysis (TGA), and luminescence analyses. Self-assembly behaviors of these polymers were entirely directed by N-donor ancillary coligands (bridging or chelating). Complex 1 displays an interesting novel two-dimensional (2D) basketwork, in which Zn(II) ions are knitted by both organic molecules, biphenyl-3,4′-dicarboxylic acid and 1,4-di(1H-imidazol-2-yl)butane, to form an infinite network. Polymers 2 and 3 are infinite zigzag helical chains, and both terminated ligands in 2 and 3 prevent self-assembly to higher dimensional polymers. In 4, a water molecule occupies one of four coordin...

Synthesis and Structures of [(Trimethylsilyl)methyl]sodium and ‐potassium with Bi‐ and Tridentate N‐Donor Ligands

Abstract[(Trimethylsilyl)methyl]sodium [NaCH2SiMe3] (1) was prepared by a metathesis reaction of [(trimethylsilyl)methyl]lithium [LiCH2SiMe3] with sodium tert‐butoxide in n‐hexane. Polydentate donors such as N,N,N′,N′‐tetramethylethylenediamine (TMEDA) and N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) form n‐hexane‐soluble complexes of 1 and the potassium congener [KCH2SiMe3] (2). The crystal structures of the polymers [(TMEDA)NaCH2SiMe3] (1a) and [(PMDETA)KCH2SiMe3] (2a) were determined as infinite helical chains exhibiting 31 or 32 screw‐axis symmetry. Compound 2b was obtained as the donor‐deficient heterocubane pseudotetramer [(TMEDA)3(KCH2SiMe3)4], with intermolecular interactions of the TMEDA‐uncoordinated potassium atom with a peripheral methyl group of a neighbouring tetramer to form infinite chains. The relatively easy accessibility and stability should make these (trimethylsilyl)methyl compounds of sodium and potassium valuable starting points for further exploration of the chemistry of these common‐utility heavier alkali metals.

Novel tin supramolecular compounds and coordination polymers: Influence of aromatic dicarboxylates on the crystal structures

Six tin based coordination compounds containing pyridine-2,5-dicarboxylate (pydc), terephthalate (ta), or naphthalene-2,6-dicarboxylate (ndc) ligands have been synthesized hydro-/solvo-thermally and characterized by single crystal X-ray diffraction. Compounds 1 and 2 are polymorphs with chemical composition of Sn(Hpydc) 2 and have strikingly different 1D supramolecular structures due to the different linking mode of the monoprotonated pydc ligand. Compound 1, the major phase, crystallizes in the space group P2 1/ n ( a = 16.4038(8) Å, b = 48.092(2) Å, c = 19.0217(9) Å, β = 90.066(1)°) and compound 2, the minor phase, crystallizes in the space group P2 1/ n ( a = 9.680(3) Å, b = 12.793(4) Å, c = 12.591(4) Å, β = 108.703(7)°). Compound 3, Sn(pydc)(DMF), crystallizes in the space group P2 1/ c ( a = 11.4932(6) Å, b = 8.4885(5) Å, c = 12.0493(6) Å, β = 100.568(1)°,) with infinite 1D helical chains extended along the crystallographic b-axis. Compound 4, Sn 2(O)(pydc), crystallizes in the space group C2/ c ( a = 13.5948(14) Å, b = 6.6759(7) Å, c = 20.200(2) Å, β = 90.007(2)°), and is a 3D coordination polymer that contains edge-shared Sn 4O 2 clusters arranged into 1D stair-like structures that are stacked to form small channels. Compound 5, Sn 3(O)(ta) 2, which crystallizes in the space group P ‾1 ( a = 6.9436(6) Å, b = 7.1505(6) Å, c = 19.1353(16) Å, α = 83.714(1)°, β = 89.686(1)°, γ = 64.034(1)°) and compound 6, Sn 3(O)(ndc) 2, which crystallizes in the space group P ‾1 ( a = 7.0892(10) Å, b = 7.2714(10) Å, c = 23.400(3) Å, α = 86.699(2)°, β = 85.914(2)°, γ = 63.423(2)°), are structurally related and form tin oxide layers consisting of bridged Sn 3O clusters, that are connected to adjacent layers by the ta and ndc ligands, respectively.

ChemInform Abstract: Polychalcogenoaurates(I) with Pseudo-Onedimensional Structures: Preparation and Crystal Structure of Cs2Au2Se3.

Abstract Cs 2 Au 2 Se 3 was obtained as red platelike crystals by reacting a stoichiometric mixture of Cs 2 Se, Au and Se at 670K. It crystallizes in space group C2/c, Z = 4 with a = 9.769(5) A, b = 13.44(1) A, c = 7.178(3) A, β = 90.69(1)°. The crystal structure was determined from single crystal data and refined to a conventional R of 0.042 for 674 Fo's and 34 variables. The characteristic structural feature of this new selenoaurate is the formation of infinite helical anionic chains, ∞ 1 -[AuSeAuSe 2 ] 2− which run parallel to [001] and are separated by the alkali cations. The average Au-Se bond length is 2.402 A, the bond length in the Se 2 -unit is 2.436 A. Au…Au contacts of 3.200 A, are formed within the anionic chains. The cesium atoms are coordinated to seven Se in an irregular configuration.