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1.
Shinsaku Amano Dimitri Bogdanovski Prof. Dr. Hisanori Yamane Prof. Dr. Masami Terauchi Prof. Dr. Richard Dronskowski 《Angewandte Chemie (International ed. in English)》2016,55(5):1652-1657
For the Ti/O system, three titanium monoxide (TiO) phases (α, β, and γ) with defective NaCl‐type structures and a high‐temperature hexagonal phase (H) have been known for decades. In this work, single crystals of a novel polymorph, ?‐TiO, were synthesized by using a bismuth flux. X‐ray diffraction (XRD) revealed a hexagonal crystal structure (a=4.9936(3) Å, c=2.8773(2) Å, P 2m) that is isotypic with ?‐TaN. While the Ti atoms are surrounded by trigonal prismatic (sixfold coordination) and trigonal planar (threefold coordination) arrangements of O atoms, the O atoms are found in a pseudo‐square‐pyramidal arrangement of Ti atoms. First‐principles calculations of the formation enthalpy and the electron and phonon density of states and crystal orbital Hamilton population (COHP) analysis revealed that ?‐TiO is more stable than α‐TiO, which had previously been regarded as the most stable phase at low temperatures. 相似文献
2.
Zhifei Hao Zhurui Shen Yi Li Haitao Wang Lirong Zheng Ruihua Wang Guoquan Liu Sihui Zhan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(19):6417-6422
The unexpected phenomenon and mechanism of the alkali metal involved NH3 selective catalysis are reported. Incorporation of K+ (4.22 wt %) in the tunnels of α‐MnO2 greatly improved its activity at low temperature (50–200 °C, 100 % conversion of NOx vs. 50.6 % conversion over pristine α‐MnO2 at 150 °C). Experiment and theory demonstrated the atomic role of incorporated K+ in α‐MnO2. Results showed that K+ in the tunnels could form a stable coordination with eight nearby O atoms. The columbic interaction between the trapped K+ and O atoms can rearrange the charge population of nearby Mn and O atoms, thus making the topmost five‐coordinated unsaturated Mn cations (Mn5c, the Lewis acid sites) more positive. Therefore, the more positively charged Mn5c can better chemically adsorb and activate the NH3 molecules compared with its pristine counterpart, which is crucial for subsequent reactions. 相似文献
3.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(25):7241-7246
We herein report the tunable self‐assembly of simple block copolymers, namely polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) diblock copolymers, into porous cubosomes with inverse or mesophases of controlled unit cell parameters as well as hexasomes with an inverse hexagonal (p 6mm ) structure, which have been rarely observed in polymer self‐assembly. A new morphological phase diagram was constructed for the solution self‐assembly of PS‐b‐PEO based on the volume fraction of the PS block against the initial copolymer concentration. The formation mechanisms of the cubosomes and hexasomes have also been revealed. This study not only affords a simple system for the controllable preparation and fundamental studies of ordered bicontinuous structures, but also opens up a new avenue towards porous architectures with highly ordered pores. 相似文献
4.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(11):984-989
Li–B–C alloys have attracted much interest because of their potential use in lithium‐ion batteries and superconducting materials. The formation of the new compound LiBC3 [lithium boron tricarbide; own structure type, space group P m 2, a = 2.5408 (3) Å and c = 7.5989 (9) Å] has been revealed and belongs to the graphite‐like structure family. The crystal structure of LiBC3 presents hexagonal graphene carbon networks, lithium layers and heterographene B/C networks, alternating sequentially along the c axis. According to electronic structure calculations using the tight‐binding linear muffin‐tin orbital‐atomic spheres approximations (TB–LMTO–ASA) method, strong covalent B—C and C—C interactions are established. The coordination polyhedra for the B and C atoms are trigonal prisms and for the Li atoms are hexagonal prisms. 相似文献
5.
Alexander Ovchinnikov Dr. Matej Bobnar Dr. Yurii Prots Dr. Horst Borrmann Dr. Jörg Sichelschmidt Prof. Yuri Grin Dr. Peter Höhn 《Angewandte Chemie (International ed. in English)》2018,57(36):11579-11583
Two new calcium nitridomanganates, Ca12[Mn19N23] (P3, a=11.81341(3) Å, c=5.58975(2) Å, Z=1) and Ca133[Mn216N260] ( , a=39.477(1) Å, c=5.5974(2) Å, Z=1), were obtained by a gas–solid reaction of Ca3N2 and Mn with N2 at 1273 K and 1223 K, respectively. The crystal structure of Ca12[Mn19N23] was determined from high‐resolution X‐ray synchrotron powder diffraction data, whereas single‐crystal X‐ray diffraction was employed to establish the crystal structure of the Ca133[Mn216N260] phase, which classifies as a complex metallic alloy (CMA). Both crystal structures have 2D nitridomanganate layers containing similar building blocks but of different levels of structural complexity. Bonding analysis as well as magnetic susceptibility and electron spin resonance measurements revealed that only a fraction of the Mn atoms in both structures carries a localized magnetic moment, while for most Mn species the magnetism is quenched as a result of metal–metal bond formation. 相似文献
6.
Cornelis Lensink Graeme J. Gainsford Menno J. R. Brandsma 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):m529-m530
The title compound, [Ti(C15H17NO2S)Cl2], has a Ti atom bound to the N and O atoms of a p‐toluenesulfonamide ligand, which is tethered by a three‐carbon chain to a η5‐cyclopentadienyl group. The distorted square‐pyramidal geometry is completed by two Cl atoms. The Ti—N bond length of 2.0375 (13) Å is longer than that in related compounds, the N atom having asymmetric trigonal–planar geometry. Conformational strain relief is noted when compared with ethyl‐tethered compounds. 相似文献
7.
Fangfang Jian Ying Wang Lude Lu Xujie Yang Xin Wang Suchada Chantrapromma Hoong‐Kun Fun Ibrahim Abdul Razak 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):714-716
The crystal structures of tris(2‐methylquinolin‐8‐olato‐N,O)iron(III), [Fe(C10H8NO)3], (I), and aquabis(2‐methylquinolin‐8‐olato‐N,O)copper(II), [Cu(C10H8NO)2(H2O)], (II), have been determined. Compound (I) has a distorted octahedral configuration, in which the central Fe atom is coordinated by three N atoms and three O atoms from three 2‐methylquinolin‐8‐olate ligands. The three Fe—O bond distances are in the range 1.934 (2)–1.947 (2) Å, while the three Fe—N bond distances range from 2.204 (2) to 2.405 (2) Å. In compound (II), the central CuII atom and H2O group lie on the crystallographic twofold axis and the coordination geometry of the CuII atom is close to trigonal bipyramidal, with the three O atoms in the basal plane and the two N atoms in apical positions. The Cu—N bond length is 2.018 (5) Å. The Cu—O bond length in the basal positions is 1.991 (4) Å, while the Cu—O bond length in the apical position is 2.273 (6) Å. There is an intermolecular OW—H?O hydrogen bond which links the molecules into a linear chain along the b axis. 相似文献
8.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(30):9526-9530
Two Pt single‐atom catalysts (SACs) of Pt‐GDY1 and Pt‐GDY2 were prepared on graphdiyne (GDY)supports. The isolated Pt atoms are dispersed on GDY through the coordination interactions between Pt atoms and alkynyl C atoms in GDY, with the formation of five‐coordinated C1‐Pt‐Cl4 species in Pt‐GDY1 and four‐coordinated C2‐Pt‐Cl2 species in Pt‐GDY2. Pt‐GDY2 shows exceptionally high catalytic activity for the hydrogen evolution reaction (HER), with a mass activity up to 3.3 and 26.9 times more active than Pt‐GDY1 and the state‐of‐the‐art commercial Pt/C catalysts, respectively. Pt‐GDY2 possesses higher total unoccupied density of states of Pt 5d orbital and close to zero value of Gibbs free energy of the hydrogen adsorption (|Δ |) at the Pt active sites, which are responsible for its excellent catalytic performance. This work can help better understand the structure–catalytic activity relationship in Pt SACs. 相似文献
9.
Syntheses and Structures of the Titanium(III) Siloxanes [Ti(OSiPh3)3(thf)2] and [Ti(OSiPh3)3(py)2] The new titaniumtrioxysilanes [Ti(OSiPh3)3(thf)2] ( 1 ) and [Ti(OSiPh3)3(py)2] ( 2 ) have been obtained from the reaction of titaniumtrichloride with LiOSiPh3 in the presence of the corresponding bases tetrahydrofurane (thf) and pyridine (py). From the crystal structures of both compounds it is evident that the titanium atoms are in the centres of trigonal‐bipyramidal coordination figures, with the donor atoms in axial positions. The compounds 1 and 2 have slightly different structures (mean values: 1 : Ti‐O(Si) 1.897(9), Ti‐O(C) 2.136(8) Å; 2 : Ti‐O 1.902(9), Ti‐N2.252(8) Å) and have a single absorption band in the visible region of the UV‐spectrum. The exchange of the thf‐ligands in 1 by pyridine (in high molar excess) seems to be hindered as deduced from UV‐spectroscopy. 相似文献
10.
Crystals of anionic Na[CuCl2(HOCH2C≡CCH2OH)]·2H2O π‐complex have been synthesized by interaction of 2‐butyne‐1,4‐diol with CuCl in a concentrated aqueous NaCl solution and characterized by X‐ray diffraction at 100 K. The crystals are triclinic: space group , a = 7.142(3), b = 7.703(3), c = 10.425(4) Å, α = 105.60(3), β = 99.49(3), γ = 110.43(3)°, V = 495.9(4) Å3, Z = 2, R = 0.0203 for 3496 reflections. The structure is built of discrete [CuCl2(HOCH2C≡CCH2OH)]? anionic stacks and polymeric cations among the stacks. The CuI atom adopts trigonal planar coordination of two Cl? anions and the C≡C bond of 2‐butyne‐1,4‐diol, Cu–(C≡C) distance is equal to 1.903(3) Å. Na+ cations environment is octahedral and consists of O and Cl atoms. The crystal packing is governed by strong hydrogen bonds of O–H···Cl and O–H···O types. 相似文献
11.
Graeme J. Gainsford Tim Kemmitt 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(3):m136-m138
In the title compound, [Na4(C8H16BO4)4(C4H10O2)]n, there are two coordination types for the four independent Na+ cations: two Na+ cations bond to six diolate O atoms [Na—O = 2.305 (2)–2.609 (2) Å], while the other two are five‐coordinate via one 1,4‐butanediol [2.289 (2) and 2.349 (3) Å] and four diolate O atoms [2.295 (2)–2.408 (2) Å]. Corresponding to this, there are three‐ and four‐coordinate diolate O atoms, the latter bridging Na atoms. The 1,4‐butanediol molecules lie on inversion centres. The boron stereochemistry shows minor local perturbations from its usual tetrahedral state [B—O = 1.457 (4)–1.503 (4) Å]. The resulting polymer packs as sheets parallel to the (10) plane crosslinked by the butanediol molecules. The structure was solved using data from a multiple crystal. 相似文献
12.
Masood Parvez Moazzam Hussain Bhatti Saqib Ali Muhammad Mazhar Sajid Iqbal Qureshi 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):327-328
The Sn atom in the crystal structure of the title compound,catena‐poly[trimethyltin‐μ‐[(2,5‐dioxo‐2,5‐dihydropyrrol‐1‐yl)acetato‐O:O′]], [Sn(CH3)3(C6H4NO4)], adopts a distorted trigonal bipyramidal coordination geometry with three methyl groups defining the trigonal plane [mean Sn—C 2.117 (11) Å] and the axial positions occupied by O atoms from different carboxylate groups, with significantly different Sn—O bond lengths [2.207 (5) and 2.358 (6) Å]. The structure forms a polymeric chain of complex molecules linked via carboxylate moieties. 相似文献
13.
Manfredo Hrner Vanessa Santana Carratu Regine Herbst‐Irmer Ccilia Maichle Mssmer Joachim Strhle 《无机化学与普通化学杂志》2003,629(2):219-222
The reaction of cadmium acetate in methanol with 1, 3‐bis(4‐nitrophenyl)triazene in THF in the presence of KOH yields K[Cd(O2NC6H4NNNC6H4NO2)3] in form of hexagonal prismatic, red crystals with the trigonal space group R3¯ and a = 12.229(2), c = 48.988(10) Å and Z = 6. In the anionic cadmium complexes, which are located along the threefold axis, the Cd atoms are coordinated in a trigonal prismatic arrangement by the atoms N(1) and N(3) of three triazenido ligands. The potassium cations are coordinated icosahedrally by oxygen atoms of each one nitro group of six neighbouring anionic complexes. The Cd‐N distances are 2.376(4) and 2.350(4) Å, and the K‐O distances are in the range of 2.833(6) to 3.365(6) Å. 相似文献
14.
15.
Masood Parvez Saqib Ali Sajjad Ahmad Moazzam Hussain Bhatti Muhammad Mazhar 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):m334-m335
The crystal structure of catena‐poly[[tri‐n‐butyltin]‐μ‐3‐(1‐naphthylaminocarbonyl)acrylato‐κ2O1:O3], [Sn(C4H9)3(C14H10NO3)]n, is composed of polymeric chains wherein the metal center exhibits a distorted trigonal‐bipyramidal geometry, with three n‐butyl groups defining the trigonal plane [mean Sn—C 2.133 (7) Å] and the axial positions being occupied by the carboxylate O atoms of two different N‐(1‐naphthyl)maleamate ligands with inequivalent Sn—O distances [2.167 (4) and 2.457 (4) Å]. The N‐(1‐naphthyl)maleamate fragment forms an essentially planar seven‐membered ring involving an intramolecular N—H?O hydrogen bond. 相似文献
16.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(45):14240-14244
A dual‐function material in which ferroelectricity and spin crossover coexist in the same temperature range has been obtained. Our synthetic strategy allows the construction of acentric crystal structures in a predictable way and is based on the high directionality of hydrogen bonds. The well‐known iron(II) spin crossover complex [Fe(bpp)2]2+ (bpp=2,6‐bis(pyrazol‐3‐yl)pyridine), a four‐fold noncentrosymmetric H‐bond donor, was combined with a disymmetric H‐bond acceptor such as the isonicotinate (isonic) anion to afford [Fe(bpp)2](isonic)2⋅2 H2O. This low‐spin iron(II) compound crystallizes in the acentric nonpolar I space group and shows piezoelectricity and SHG properties. Upon dehydration, it undergoes a single‐crystal to single‐crystal structural rearrangement to a monoclinic polar Pc phase that is ferroelectric and exhibits spin crossover. 相似文献
17.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(50):16166-16169
Materials in the family of Prussian blue analogues (C3H5N2)2K[ M (CN)6], where C3H5N2 is the imidazolium ion and M =Fe, Co, undergo two phase transitions with temperature; at low temperatures the imidazolium cations have an ordered configuration (C 2/c ), while in the intermediate‐ and high‐temperature phases (both previously reported as ) they are dynamically disordered. We show from high‐resolution powder neutron diffraction data that the high‐temperature phase has zero area thermal expansion in the ab ‐plane. Supported by Landau theory and single‐crystal X‐ray diffraction data, we re‐evaluate the space group symmetry of the intermediate‐temperature phase to . This reveals that the low‐to‐intermediate temperature transition is due to competition between two different tilt patterns of the [ M (CN)6]3− ions. Controlling the relative stabilities of these tilt patterns offers a potential means to tune the exploitable electric behaviour that arises from motion of the imidazolium guest. 相似文献
18.
Konstantin V. Domasevitch 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(3):m105-m107
The title compound, {[Co(C8H7NO2)2(H2O)2](NO3)2}n, is the first d‐metal ion complex involving bidentate bridging of a β‐dialdehyde group. The Co2+ ion is situated on an inversion centre and adopts an octahedral coordination with four equatorial aldehyde O atoms [Co—O = 2.0910 (14) and 2.1083 (14) Å] and two axial aqua ligands [Co—O = 2.0631 (13) Å]. The title compound has a two‐dimensional square‐grid framework structure supported by propane‐1,3‐dionate O:O′‐bridges between the metal ions. The organic ligand itself possesses a zwitterionic structure, involving conjugated anionic propane‐1,3‐dionate and cationic pyridinium fragments. Hydrogen bonding between coordinated water molecules, the pyridinium NH group and the nitrate anions [O...O = 2.749 (2) and 2.766 (3) Å, and N...O = 2.864 (3) Å] is essential for the crystal packing. 相似文献
19.
Lesaw Siero Maria Bukowska‐Strzyewska 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):19-21
In the title dimeric complex, [Cu2(C4H4O4)2(C7H6N2S)4], which possesses a centre of symmetry, the Cu atoms are enclosed in a 14‐membered ring. They adopt a distorted square‐bipyramidal (4+2) coordination. The four closest donor atoms are two N atoms of 2‐aminobenzothiazole ligands and two O atoms of the succinate carboxylate groups. They form a square‐planar cis arrangement, with an average Cu—N distance of 2.003 (3) Å and Cu—O distances of 1.949 (3) and 1.965 (3) Å. Two longer Cu—O bonds of 2.709 (3) and 2.613 (3) Å involving the remaining O atoms of the carboxylate groups complete the sixfold coordination of the Cu atoms. The H atoms of each amino group of the 2‐aminobenzothiazole molecules form intra‐ and intermolecular N—H?O hydrogen bonds. A nearly perpendicular intermolecular C—H?Cg interaction (Cg is the centroid of the imidazole ring) is observed. The intramolecular Cu?Cu distance is 6.384 (2) Å. 相似文献
20.
The β‐Agostic Structure in (C5Me5)2Sc(CH2CH3): Solid‐State NMR Studies of (C5Me5)2Sc−R (R=Me,Ph, Et)
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(30):9664-9667
Multinuclear solid‐state NMR studies of Cp*2Sc−R (Cp*=pentamethylcyclopentadienyl; R=Me, Ph, Et) and DFT calculations show that the Sc−Et complex contains a β‐CH agostic interaction. The static central transition 45Sc NMR spectra show that the quadrupolar coupling constants (Cq) follow the trend of Ph≈Me>Et, indicating that the Sc−R bond is different in Cp*2Sc−Et compared to the methyl and phenyl complexes. Analysis of the chemical shift tensor (CST) shows that the deshielding experienced by Cβ in Sc−CH2CH3 is related to coupling between the filled σC‐C orbital and the vacant orbital. 相似文献