Structural Diversity of Metallosupramolecular Assemblies from Cu(phen)2+ (phen = 1,10‐Phenanthroline) Building Blocks and 4,4′‐Bipyridine

Attempts to crystal engineer metallosupramolecularcomplexes from Cu(phen)²⁺ building blocks and the prototypical,rod‐like, exo‐bidentate ligand 4,4′‐bipyridine (4,4′‐bipy) by layering techniques are described. Reactions of Cu(phen)²⁺ (phen = 1,10‐phenanthroline) with 4,4′‐bipy in the presence of NO₃^– counterions yielded two distinct, discrete, dinuclear, C_i symmetric, dumbbell‐typecomplexes, [{Cu(NO₃)₂(phen)}₂(4,4′‐bipy)] ( 1 ) and [{Cu(NO₃)(phen)(H₂O)}₂(4,4′‐bipy)](NO₃)₂ ( 2 ), depending upon the mixture of solvents used for crystallization. In compound 1 , a mono‐ and a bidentate nitrato group coordinate to Cu²⁺, whereas in 2 the monodentate nitrato groups are replaced by aqua ligands, which introduce additional hydrogen‐bond donor functionality to the molecule. The crystal structure of 1 was determined by single‐crystal X‐ray analysis at 296 and 110 K. Upon cooling, a disorder‐order transition occurs, with retention of the space group symmetry. The crystal structure of 2 at room temperature was reported previously [Z.‐X. Du, J.‐X. Li, Acta Cryst. 2007 , E63, m2282]. We have redetermined the crystal structure of 2 at 100 K. A phase transition is not observed for 2 , but the low temperature single‐crystal structure determination is of significantly higher precision than the room temperature study. Both 1 and 2 are obtained phase‐pure, as proven by powder X‐ray diffraction of the bulk materials. Crystals of [Cu(phen)(CF₃SO₃)₂(4,4′‐bipy) · 0.5H₂O]_n ( 3 ), a one‐dimensional coordination polymer, were obtained from [Cu(CF₃SO₃)₂(phen)(H₂O)₂] and 4,4′‐bipy. In 3 , Cu(phen)²⁺ corner units are joined by 4,4′‐bipy via the two vacant cis sites to form polymeric zig‐zag chains, which are tightly packed in the crystal. Compounds 1 – 3 were further studied by infrared spectroscopy.     

Structurally-driven metal-insulator transition in Ca2Ru1−xCrxO4 (0≤x<0.14): A single crystal X-ray diffraction study

Correlation between structure and transport properties are investigated in high-quality single-crystals of Ca₂Ru_1−xCr_xO₄ with 0<x<0.14 using single crystal X-ray diffraction and by electronic studies. The parent compound was known to exhibit an intriguing first-order structurally driven metal-insulator (MI) transition at 357 K. Upon chromium doping on the ruthenium site, the metal-insulator transition temperature (T_MI) was drastically reduced, and is related to the competition between structural changes that occur upon Cr doping and with decreasing temperature. A strong suppression of structural distortions with increasing Cr substitution was identified. No clear T_MI can be observed when x>13.5% and the system behaves as an insulator. Such a large, sharp metal-insulator transition and tuneable transition temperature may have potential applications in electronic devices.     

Redox non-innocence of thioether crowns: spectroelectrochemistry and electronic structure of formal nickel(III) complexes of aza-thioether macrocycles

The Ni^II complexes [Ni([9]aneNS₂‐CH₃)₂]²⁺ ([9]aneNS₂‐CH₃=N‐methyl‐1‐aza‐4,7‐dithiacyclononane), [Ni(bis[9]aneNS₂‐C₂H₄)]²⁺ (bis[9]aneNS₂‐C₂H₄=1,2‐bis‐(1‐aza‐4,7‐dithiacyclononylethane) and [Ni([9]aneS₃)₂]²⁺ ([9]aneS₃=1,4,7‐trithiacyclononane) have been prepared and can be electrochemically and chemically oxidized to give the formal Ni^III products, which have been characterized by X‐ray crystallography, UV/Vis and multi‐frequency EPR spectroscopy. The single‐crystal X‐ray structure of [Ni^III([9]aneNS₂‐CH₃)₂](ClO₄)₆?(H₅O₂)₃ reveals an octahedral co‐ordination at the Ni centre, while the crystal structure of [Ni^III(bis[9]aneNS₂‐C₂H₄)](ClO₄)₆?(H₃O)₃? 3H₂O exhibits a more distorted co‐ordination. In the homoleptic analogue, [Ni^III([9]aneS₃)₂](ClO₄)₃, structurally characterized at 30 K, the Ni? S distances [2.249(6), 2.251(5) and 2.437(2) Å] are consistent with a Jahn–Teller distorted octahedral stereochemistry. [Ni([9]aneNS₂‐CH₃)₂](PF₆)₂ shows a one‐electron oxidation process in MeCN (0.2 M NBu₄PF₆, 293 K) at E_1/2=+1.10 V versus Fc⁺/Fc assigned to a formal Ni^III/Ni^II couple. [Ni(bis[9]aneNS₂‐C₂H₄)](PF₆)₂ exhibits a one‐electron oxidation process at E_1/2=+0.98 V and a reduction process at E_1/2=?1.25 V assigned to Ni^II/Ni^III and Ni^II/Ni^I couples, respectively. The multi‐frequency X‐, L‐, S‐, K‐band EPR spectra of the 3+ cations and their 86.2 % ⁶¹Ni‐enriched analogues were simulated. Treatment of the spin Hamiltonian parameters by perturbation theory reveals that the SOMO has 50.6 %, 42.8 % and 37.2 % Ni character in [Ni([9]aneNS₂‐CH₃)₂]³⁺, [Ni(bis[9]aneNS₂‐C₂H₄)]³⁺ and [Ni([9]aneS₃)₂]³⁺, respectively, consistent with DFT calculations, and reflecting delocalisation of charge onto the S‐thioether centres. EPR spectra for [⁶¹Ni([9]aneS₃)₂]³⁺ are consistent with a dynamic Jahn–Teller distortion in this compound.     

Raman Spectroscopic Analysis of Perovskite-Structured Alkali Metal Fluorides Containing Nickel and Copper Ions

ABSTRACT

The mixed metal fluorides containing alkali metals have a range of important applications in optical and electronic devices. Raman spectrums of two such fluorides were examined. Raman spectrum of KCuF₃ at 300 K exhibited bands at 261, 295, 363, 468, 519, and 549 cm^?1, indicating site symmetry (orthorhombic) lower than the tetragonal symmetry as observed from the powder X-ray diffraction pattern. Cubic KNiF₃ showed bands at 410, 468, and 657 cm^?1. The first two bands were attributed to the second-order phonon scattering, and the band at 657 cm^?1 was assigned to two-magnon peak.     

支撑应力对光刻透镜透射波前畸变的影响

为了设计光刻物镜的支撑结构,建立了支撑应力对透镜透射波前影响的模型,研究了该模型中支撑应力与折射率的关系及支撑应力对透镜透射波前畸变的影响。首先,根据晶体理论,建立了融石英透镜波前畸变与支撑应力之间关系的仿真模型。然后,分析了不同支撑结构下支撑应力与融石英透镜波前的关系。最后,分析了支撑应力造成的透射波前畸变的性质,并选择合适的物镜支撑结构。研究结果表明：光刻物镜支撑结构的支撑应力对透镜的透射波前有很大的影响：3点支撑的波前畸变PV值为3.69 nm;随着支撑点数量的增加,支撑应力造成的透射波前畸变逐渐减少;采用大于9点的支撑结构即可满足光刻投影物镜的元件支撑需求。     

Nonlinear Distortion Analyses in IM-DD SCM Lightwave Systems

ＮｏｎｌｉｎｅａｒＤｉｓｔｏｒｔｉｏｎＡｎａｌｙｓｅｓｉｎＩＭ－ＤＤＳＣＭＬｉｇｈｔｗａｖｅＳｙｓｔｅｍｓ￥ＳＯＮＧＨａｉｙａｎ；ＧＵＷａｎｙｉ；ＬＩＧｕｏｒｕｉ；ＸＵＤａｘｉｏｎｇ（ＤｅｐｔｏｆＴｅｌｅｃｏｍｍｕｎｉｃａｔｉｏｎＥｎｇ．Ｂｅｉｊｉｎ...     

C80n (D2,Ih)的Jahn-Teller畸变和电子光谱

用INDO系列方法研究C80n(D2,Ih)的Jahn-Teller畸变,表明C80(D2)比C80(Ih)稳定,与实验一致;C80n(D2)未发生Jahn-Teller畸变,C80n(Ih)的部分离子发生明显的Jahn-Teller畸变,电荷对C80(Ih)稳定性有显著影响.首次计算其电子光谱,不仅得到C80(D2)与实验一致的吸收峰,还预测了C80n(D2,Ih)的电子光谱,对电子跃迁进行理论指认.C80n(D2)光谱与C80(D2)相比发生吸收峰红移,而C80n(Ih)光谱与C80(Ih)相比发生吸收峰兰移,其原因是C80n(D2)的LUMO-HOMO能隙比C80(D2)小,而C80n(Ih)的能隙则比C80(Ih)的能隙大.     

Calibrating camera radial distortion with cross-ratio invariability

The calibration of camera distortion plays an important role in the field of industrial machine vision application. In this paper, a novel approach for calibrating camera radial distortion is presented based on cross-ratio invariability for perspective projection. Assumed to be with one-order radial distortion, the image coordinates and the cross-ratio of only four collinear points in space are needed in this approach. The cross-ratio, easily known from a calibration target, is identical with that of the four corresponding image points. This is called the cross-ratio invariability for perspective projection. A monadic two-order equation is built based on the cross-ratio invariability, which gives an accurate solution to radial distortion coefficients. A digital simulation and a practical image correction prove this approach to be simple, accurate, efficient and time saving.     

Exact analytical expressions for diatomic rotational and centrifugal distortion constants for a Kratzer-Fues oscillator

The exact closed-form expression for the vibrational-rotational eigenvalues of the Kratzer-Fues oscillator served as the starting point for a derivation of exact analytical expressions for the rotational constant B_υ, and the set D_υ to S_υ of centrifugal distortion constants up to 11th-order. The derivations employed the MAPLE symbolic algebra coprocessor. The expressions for B_υ to S_υ were then employed in the calculation of a set of constants for a Kratzer-Fues potential with specified dissociation energy and equilibrium internuclear separation for a hypothetical diatomic molecule with a reduced mass of unity. The tabulated constants serve as a benchmark against which the reliability of various existing or future numerical methods for the determination of rotational and centrifugal distortion constants may be assessed. The near-dissociation behaviour of the calculated constants was also examined and is useful in predicting the behaviour of such constants for real electronic states having pure ionic long-range form.