Multifractal analysis for Cu/Ti bilayer thin films

Two bilayer thin films with different stacking sequences, Cu/Ti/Si and Ti/Cu/Si, were deposited by DC magnetron sputtering technique. X‐ray diffraction technique was used to measure the crystallization structures, and scanning electron microscopy and atomic force microscopy were used to measured surface morphology. The multifractal spectra f(α)‐α was used to characterize the surface morphology. The result of |q|_max ≤ 53 is obtained by multifractal analysis. The shape of the multifractal spectra f(α) ? α is hook‐like for Cu/Ti/Si and bell jar‐like for Ti/Cu/Si. The spectrum width Δα = α_max ? α_min and Δf(=f(α_min) ? f(α_max)) of the multifractal spectra is able to quantitatively analyze the growth and surface roughness of the Cu/Ti bilayer thin films. The surface of Ti/Cu/Si thin film is more uniform and smoother than the film of Cu/Ti/Si. Copyright © 2013 John Wiley & Sons, Ltd.     

Multifractal analysis of drop‐casted copper (II) tetrasulfophthalocyanine film surfaces on the indium tin oxide substrates

This paper applies multifractal spectrum theory to characterize the structural complexity of 3D surface roughness of copper (II) tetrasulfophthalocyanine (CuTsPc) films on the indium tin oxide (ITO) substrate, obtained with atomic force microscopy (AFM) analysis. CuTsPc films were prepared by drop cast method on ITO substrate. CuTsPc films surface roughness was studied by AFM in tapping‐mode?, in air, on square areas of 2500 µm². A novel approach, on the basis of computational algorithms for analysis of 3D roughness surface applied for AFM data, was presented. Results revealed that the 3D surface roughness of CuTsPc films prepared by drop cast method on ITO substrate can be described using the multifractal geometry. The generalized dimensions D_q and the multifractal spectrum f(α) provided quantitative values that characterize the local scale properties of CuTsPc films surface geometry at nanometer scale. Data provide valuable information to describe the spatial arrangement of 3D surface roughness of CuTsPc films on ITO substrate, which was not taken into account by classical surface statistical parameters. Copyright © 2014 John Wiley & Sons, Ltd.     

Crystal structure,vibrational studies,optical properties,and Hirshfeld surface analysis of (C5H6N5)2[Cr2O7]

Single crystals of a new organic–inorganic compound, (C₅H₆N₅)₂Cr₂O₇ (1), adeninium dichromate, were grown by the slow evaporation technique and characterized by X-ray diffraction, infrared absorption, and the optical properties were also investigated by UV-vis absorption spectroscopy. The compound crystallizes in the triclinic system and P-1 space group with a = 11.6850(2) Å, b = 11.7531(5) Å, c = 14.5603(7) Å, α = 83.956(3)°, β = 70.481(4)°, γ = 61.863(2)°, V = 1658.70(12) Å³. The structure of the compound consists of four adeninium, (C₅H₅N₂)⁺, cations, and two dichromate dianions with all the atoms situated in general positions. Each dichromate anion is formed by two tetrahedral CrO₄ joined through shared O atoms and are linked to the cations with several weak hydrogen bonding interactions resulting in an extended network. 3-D Hirshfeld surface analysis and 2-D fingerprint plots indicate that the packing is dominated by H?O/O?H and H?N/N?H contacts.     

Autopoisoning reactions over rough surface: A multifractal scaling analysis

The effect of surface roughness and number of reaction event on the decay type diffusion limited reaction (DLR) over rough surface of random deposition model was studied to examine the surface morphological effect on the surface reaction. Effect of decay profiles on the reaction probability distribution (RPD) of the reaction was then analyzed with multifractal scaling techniques. The dynamics of these autopoisoning reactions is controlled by the two parameters, namely, the initial sticking probability ( P _ini) of every site and the decay rate (m). More the rough surface, less are the number of active sites and wider is the distribution of reaction probability. More the number of reaction events, more are the number of active sites and more is the homogeneity in the RPD. The q‐τ(q) multifractal curves are found to be nonlinear for all the cases which give wide range of α values in α‐f(α) multifractal spectrum. Smaller the decay rate, narrower is the range of α values. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 175–182, 2005     

Construction of zinc–organic frameworks by flexible aliphatic dicarboxylates plus 2-(1H-imidazolyl-1-methyl)-1H-benzimidazole ligand

Three new Zn(II) complexes, [Zn(ox)(imb)] (1), [Zn₂(mal)₂(imb)₂] (2), and [Zn(suc)(imb)]·H₂O (3) (imb = 2-(1H-imidazolyl-1-methyl)-1H-benzimidazole, H₂ox = oxalic acid, H₂mal = malonic acid, H₂suc = succinic acid), have been synthesized and structurally characterized. Complex 1 is a 3-D framework with a 4-connected diamond topology with the topological notation of 6⁶. Complex 2 exhibits 2-D layers with (6,3) networks. Complex 3 displays a 3-D framework constructed through unusual 2-D → 3-D parallel interpenetration of corrugated 2-D (6,3) networks. IR spectra, PXRD patterns, thermogravimetric curves, and photoluminescence spectra are addressed.     

Syntheses,structural determination,and binding studies of nine-coordinate multinuclear (mnH)2[EuIII(egta)]2·6H2O and binuclear (mnH)4[EuIII2(dtpa)2]·6H2O

Two lanthanide complexes, (mnH)₂[Eu^III(egta)]₂·6H₂O (1) (H₄egta = ethyleneglycol-bis-(2aminoethylether)-N,N,N′,N′-tetraacetic acid) and (mnH)₄[Eu^III₂(dtpa)₂]·6H₂O (2) (H₅dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), have been synthesized and characterized by FT-IR spectroscopy, thermal analysis, and single-crystal X-ray diffraction. X-ray diffraction reveals that 1 is multinuclear nine-coordinate and crystallizes in the monoclinic crystal system with space group C2/c. The obtained cell dimensions are a = 38.513(3)?Å, b = 13.5877(8)?Å, c = 8.7051(5)?Å, β = 99.6780(10)°, and 4490.6(5)?ų. Each methylamine (mnH⁺) cation in 1, through hydrogen bonds, connects three adjacent [Eu^III(egta)]^? anions. The [Eu^III(egta)]^? anions connect one another forming a 1-D multinuclear zigzag chain structure along the c-axis. Complex 2 is nine-coordinate binuclear structure with tricapped trigonal prismatic conformation and crystallizing in the monoclinic crystal system, but with space group P2₁/n. The obtained cell dimensions are a = 9.9132(8)?Å, b = 24.1027(18)?Å, c = 10.7120(10)?Å, β = 109.1220(10)°, and 2418.2(3)?ų. For 2, there are two kinds of methylamine cations (mnH⁺) connecting [Eu^III₂(dtpa)₂]^4? complex anions and lattice waters through hydrogen bonds, leading to formation of a 2-D ladder-like layer structure.     

Synthesis,structure, and characterizations of a new antiferromagnetic manganese(II) dichloro-bridged 1-D polymer decorated by 5-amino-1-H-tetrazole

[Mn(5-ATZ)₂Cl₂]_n (1) (5-ATZ – 5-amino-1-H-tetrazole) was synthesized from the reaction of 5-ATZ and manganese(II) chloride and isolated by solution evaporation at room temperature. 1 was characterized by elemental analysis, X-ray crystallography, infrared, and EPR spectroscopy as well as magnetic measurements. In the crystal structure, [Mn(5-ATZ)₂Cl₂] units are linked by double μ₂-bridging chlorides to form 1-D chains parallel to the a-axis. The Mn sphere approximates to octahedral with the metal coordinated by four chlorides in the equatorial plane and two 5-ATZ molecules, bound through their ring nitrogens, in axial positions. The intramolecular N–H···Cl hydrogen bond between the 5-ATZ amino group and the adjacent coordinated Cl^? stabilizes the chain. N–H···N hydrogen bonds between adjacent chains form a 3-D supramolecular framework. No hyperfine coupling to the Mn nuclei (I = 5/2) is observed in the powdered EPR spectrum of 1 at 77 K. The frozen solution EPR spectrum provides evidence of the mononuclearity of 1 in methanol. The magnetic properties have been analyzed using the Hamiltonian H = –J∑S_i · S_i+1 with J = ?1.38(3) cm^?1 and g = 2.00(1). A small value of the exchange parameter is typical for 1-D six-coordinate bis(μ₂-chloro) Mn(II) polymers.     

Nanocage containing metal-organic framework constructed from a newly designed low symmetry tetra-pyrazole ligand

1368-Tetra(1H-pyrazol-4-yl)-9H-carbazole (H₄CTP), a tetra-pyrazole ligand with C_s symmetry, has been synthesized based on a carbazole core. A solvothermal reaction of this ligand with NiCl₂·6H₂O gave a three-dimensional (3-D) metal-organic framework (MOF), [Ni(H₄CTP)Cl₂]·nS (BUT-41), which crystallized in the cubic space group Pm-3 in spite of H₄CPT with a central carbazole core and four peripheral pyrazole rings has low symmetry. The framework of BUT-41 can be regarded as a four-connected 3-D net with the rhr topology when both the organic ligand and the metal center are considered as four-connected nodes. Nanocages with internal diameter of 2 nm are present in the framework of BUT-41, which are formed by interconnecting 12 H₄CTP ligands and 20 Ni(II) ions. Each nanocage connects with six adjacent cages through sharing hexagonal windows with diameter over 7 Å, resulting in 3-D intersecting channels of the MOF. Although the tetra-pyrazole ligand is not deprotonated after coordination with the metal ions, powder X-ray diffraction and N₂ adsorption experiments reveal that the framework of BUT-41 is rigid and permanently porous with the Brunauer-Emmett-Teller surface area up to 1551 m² g^?1. Furthermore, gas adsorption experiments show that this MOF selectively adsorbs CO₂ over N₂ and CH₄.     

Solvent-controlled structural variation from 1D+2D→3D network with coexistence of polycatenation and polythreading to the 2D→3D polythreaded array

This article represents two types of entanglements, [Co₂(bibp)(BTB)₂][Co(bibp)₂(H₂O)₂] (1) and [Co₃(bibp)₂(H₂O)₂(BTB)₂]·2H₂O·2DMF (2) (bibp = 4,4′-bis(1-imidazolyl)biphenyl and H₃BTB = 1,3,5-tris(4-carboxyphenyl)benzene), which are 2-D→3-D polycatenated frameworks formed by parallel catenation of 1-D+2-D→2-D polythreaded motifs based on the double-layered sheet penetrated by ribbons of rings (1) and a 2-D→3-D mutual polythreading of three double-layered sheets with dangling arms (2), which is assembled by the same initial materials by simply changing the volume ratio of water/DMF medium.     

Syntheses,crystal structures,and luminescent properties of three metal coordination polymers based on adipic acid and 2-(pyridine-3-yl)-(1H)-benzimidazole

Three new metal coordination polymers constructed from adipic acid and 2-(pyridin-3-yl)-(1H)-benzimidazole ligands, [M(ADP)(3PBI)₂(H₂O)₂]·2H₂O (M = Ni and Co for 1 and 2, respectively) and [Cd(ADP)(3PBI)(H₂O)] (3) [ADP = adipic acid dianion; 3PBI = 2-(pyridin-3-yl)-(1H)-benzimidazole], have been synthesized by hydrothermal reactions and were characterized by X-ray single-crystal diffraction, elemental analyses, IR, powder X-ray diffraction, and thermogravimetry. Complexes 1 and 2 are isostructural. Both form a 1-D linear chain structure, which is further assembled into a 3-D supramolecular framework by π?π stacking and hydrogen bonding interactions. Complex 3 possesses a binuclear unit and displays a 2-D layer which is further extended to a 3-D supramolecular architecture via hydrogen bonding and other weak packing interactions. The luminescent properties of 3 were investigated in the solid state at room temperature.     

2-D metalloporphyrin coordination network of cobalt-meso-tetra(4-carboxyphenyl)porphyrin

A new metalloporphyrin coordination framework [Co(H₃TCPP)] (H₆TCPP = meso-tetra(4-carboxyphenyl)porphyrin) has been synthesized hydrothermally. Single-crystal X-ray analysis revealed it exhibits a 2-D layered coordination network structure. Hydrogen bonds are observed between carboxyl groups within the 2-D layer as well as from adjacent layers. The UV–Vis diffuse reflectance spectrum indicates the presence of the expected B (410 nm) and Q (540 and 690 nm) absorption bands. The fluorescence spectrum shows four emission bands centered at 648 nm.     

Syntheses,crystal structures,and magnetic properties of a series of Fe2Ln complexes

A family of phenoxo-bridged heterometallic Schiff base trinuclear complexes, [Fe₂LnL₂(C₃H₇COO)(H₂O)]·CH₃OH·CH₃CN·H₂O (Ln = Sm, 1; Gd, 2; Tb, 3; Dy, 4) is reported. Those complexes were afforded by “one-pot” reaction of a polydentate Schiff base ligand 2-hydroxy-3-methoxy-phenylsalicylaldimine (H₂L) with Fe(NO₃)₃·9H₂O, Ln(NO₃)₃·6H₂O and sodium butyrate (C₃H₇COONa) in a mixture of methanol and acetonitrile in the presence of triethylamine as a base. Single-crystal X-ray diffraction analysis reveals that the structures of the four complexes are isomorphic. In each complex, two anionic [FeL₂]^? units coordinate to the central lanthanide ion as a tetradentate ligand using its four phenoxo oxygens, forming a two-blade propeller-like molecular shape. Magnetic properties of 1–4 were investigated using variable temperature magnetic susceptibility, and weak ferromagnetic exchange between the Fe^III and Ln^III ions has been established for the Gd derivative. The Tb and Dy complexes show no evidence of slow relaxation behavior above 2.0 K.     

Supramolecular architecture built of Co(II) and a tripodal ligand containing 1-D water tapes with (H2O)16 cluster units

The reaction of Co(NO₃)₂?·?6H₂O with a tripodal ligand leads to a new complex {[Co(L)]?·?2NO₃?·?8H₂O} (1) confirmed by single-crystal X-ray diffraction, infrared spectroscopy, and elemental analysis. The particular interest of 1 is in the formation of a 1-D water tape consisting of (H₂O)₁₆ cluster units, the neighboring water tapes are connected by free nitrate anions via hydrogen bonds into a 2-D guest layer. These guest layers are alternately packed face-to-face with the 2-D host layers along the a-axis to form a 3-D supramolecular architecture. There exist C–H?···?N and C–H?···?O weak hydrogen bonds between the guest layer and host layer. These weak hydrogen bonds and water–nitrate, water–water hydrogen bonds are important for the stability of the overall structure.     

Two new Cu(II) m-hydroxybenzoato complexes with chloro- and carboxylato-bridged dinuclear [Cu(µ2−Cl)(µ2−COO)Cu] cores

In aqueous methanolic solution, reactions of CuCl₂, m-hydroxybenzoic acid (HL), and NaOH with 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen) at room temperature afforded {[Cu(bpy)L](µ₂?Cl)(µ₂?L)[Cu(bpy)L]}?1.2H₂O (1) and {[Cu(phen)Cl](µ₂?Cl)(µ₂?L)[Cu(phen)L]} (2) with chloro- and carboxylato-bridged dinuclear [Cu(µ₂?Cl)(µ₂?COO)Cu] cores. The Cu₂ dimers in 1 are pairwise aggregated to form H-bonded tetranuclear motifs, which are extended by H₂O into 1-D H-bonded chains and further assembled into 2-D supramolecular networks. The Cu₂ dimers in 2 are also linked into 1-D H-bonded chains and further assembled into 2-D supramolecular layers. Magnetic measurements indicate that significant antiferromagnetic interactions (J = ?15.9, ?12.2 cm^?1) between Cu²⁺ ions are dominant in these dinuclear [Cu(µ₂?Cl)(µ₂?COO)Cu] cores. To the best of our knowledge, 2, crystallizing in the acentric polar orthorhombic space group Pna2₁, represents the first example of metal m-hydroxybenzoato complexes with ferroelectric properties with a remnant polarization (Pr) of ca. 0.04?µC cm^?2, coercive field (Ec) of ca. 2.52 kV cm^?1, and saturation of the spontaneous polarization (Ps) at ca. 0.195?µC cm^?2.     

A fluorescent 3-D metal-organic framework with unusual tetranuclear zinc secondary building units

A 3-D metal-organic framework (MOF) {Zn₄(μ₃-OH)₂(bdc)₃(pad)₂}·2H₂O (1, H₂bdc = 1,4-benzenedicarboxylic acid, pad = 1,10-phenanthroline-5,6-dione) with unusual Zn₄(μ₃-OH)₂(COO)₆(N₂)₂ secondary building units (SBUs) has been hydrothermally synthesized and characterized by single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, elemental analysis, and infrared spectroscopy. The tetranuclear Zn₄ SBU was formed through two dinuclear Zn₂ clusters by sharing two μ₃-OH bridges. Considering this Zn₄ SBU as a six-connected node, the overall framework of 1 has a pcu topology. This tetranuclear Zn₄ SBU can be used as a node in construction of MOFs.     

Crystal structures and luminescence of two cadmium(II) polymers constructed from aromatic polycarboxylate and bis(1,2,4-triazol-1-yl)methane ligands

Two new coordination compounds, {[Cd₂(btrm)(ip)₂(H₂O)₂]?·?2H₂O} _n (1) and {[Cd₂(btrm)(hip)₂(H₂O)₄]?·?3H₂O} _n (2) (btrm?=?bis(1,2,4-triazol-1-yl)methane, H₂ip?=?isophthalic acid, H₂hip?=?5-hydroxy isophthalic acid), have been synthesized and structurally characterized. Compound 1 is a 3-D network with CdSO₄ topology. Compound 2 contains 1-D ladder structures, which are interconnected by classical hydrogen-bonding interactions (O–H?···?O) to lead to 3-D supramolecular architectures. Luminescence was performed on 1 and 2, both of which showed strong fluorescent emissions in the solid state at room temperature.     

Four Co(II)/Zn(II) coordination polymers with a multidentate ligand: syntheses,structures, thermal,and photoluminescent properties

Two pairs of isostructural transition metal coordination polymers, {[Co(L)(H₂O)]_n} (1) and {[Zn(L)(H₂O)]_n} (3), {[Co(L)(4,4′-bipy)(H₂O)]·H₂O}_n (2) and {[Zn(L)(4,4′-bipy)(H₂O)]·H₂O}_n (4) (H₂L = N-pyrazinesulfonyl-glycine acid and 4,4′-bipy = 4,4′-bipyridine), have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental and thermogravimetric analyses. The structures show that 1 and 3 display 2-D polymeric grid frameworks with a 3-connected (4, 8²) topology. 2 and 4 also exhibit a 2-D polymeric grid structure, but are constructed by a 4-connected (4, 4) topology. The adjacent 2-D polymeric grid frameworks for 1–4 are further linked by hydrogen bonding O–H?O interactions to form 3-D supramolecular interweaved orderly networks. The fluorescent properties of 3 and 4 were investigated in the solid state.     

Synthesis,structure and magnetic properties of a two-dimensional polymer based on sandwich-type tetra-cobalt(II)-substituted polyoxotungstate anions and 1-D potassium-chains

A 2-D coordination polymer, (C₇N₄H₁₆)₂{NH(CH₃)₃}[{K(H₂O)}₄Na(H₂O)₅{Co₄(H₂O)₂(B-α-PW₉O₃₄)₂}]·2H₂O (1), was hydrothermally synthesized and structurally characterized by IR spectroscopy, elemental analysis, X-ray powder diffraction, and X-ray single-crystal crystallography. Crystal structure analysis shows a triclinic space group Pī with a?=?12.4677(8)?Å, b?=?12.5054(8)?Å, c?=?18.5745(1)?Å, α?=?73.3220(1)°, β?=?87.1890(1)°, γ?=?62.2710(1)°, and V?=?2443.4(3)?ų. Sandwich-type tetra-cobalt(II)-substituted [Co₄(H₂O)₂(B-α-PW₉O₃₄)₂]^10? of 1 consists of two trivacant Keggin [B-α-PW₉O₃₄]^9? moieties and a rhomb-like Co₄O₁₆ unit. Each sandwich-type polyoxotungstate subunit connects 12 K(1) and K(2) centers from two adjacent 1-D K-chain units resulting in an interesting 2-D layer framework. Magnetic properties of 1 have been investigated.