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1.
The reaction of ammonium tetrathiometalate (NH4)2[MS4] (M = W or Mo) with the R(+) or S(?) forms of the organic amine α‐methylbenzylamine [PhCH(CH3)NH2] results in the formation of the corresponding non‐centrosymmetric bis(α‐methylbenzylammonium) tetrathiometalate complexes [PhCH(CH3)NH3]2[MS4] (R‐ammonium M = W 1 ; R‐ammonium M = Mo 2 ; S‐ammonium M = W 3 , S‐ammonium M = Mo 4 ) which were characterized by elemental analysis, IR, Raman, UV‐Vis and CD spectra, X‐ray powder diffractometry and single crystal X‐ray crystallography. Compounds 1 ‐ 4 crystallize in the chiral space group P21 and constitute the first examples of structurally characterized chiral organic ammonium group VI tetrathiometalates. The structures of 1 ‐ 4 consist of two crystallographically independent chiral organic ammonium cations and a tetrahedral tetrathiometalate dianion. The N‐H···S and C‐H···S interactions between the anions and cations organise them such that the organic ammonium ions always point towards the S atoms of [MS4]2?.  相似文献   

2.
Single crystals of AlBr3 · NH3 and AlI3 · NH3 sufficient in size for X‐ray structure determinations were obtained by evaporation/ sublimation of the respective compound from its melt. The ammoniates were synthesized by the reaction of the pure halide with NH3 at ‐78°C and following homogenization by slowly heating the reaction mixture up to the melting points of the ammoniates (124°C and 126°C, respectively). The X‐ray structure determinations for both monoammoniates were successfully carried out for the heavy atom positions (no hydrogen atoms): AlBr3 · NH3: Pbca, Z = 16, a = 11.529 (5) Å, b = 12.188 (2) Å, c = 19.701 (4) Å AlI3 · NH3: Pbca, Z = 8, a = 13.536 (5) Å, b = 8.759 (2) Å, c = 14.348 (4) Å The structures contain tetrahedral molecules Al(NH3)X3 with X = Br, I. They are not isotypic. The main difference is given for the coordination of NH3 by X from neighbouring molecules. In Al(NH3)Br3 one of the two crystallographically independent NH3 ligands has 6Br and the other 7Br as neighbours whereas in Al(NH)3I3 only 5I surround the one kind of NH3.  相似文献   

3.
杨颙  张为俊  高晓明 《中国化学》2006,24(7):887-893
A theoretical study on the blue-shifted H-bond N-H…O and red-shifted H-bond O-H…O in the complexHNO…H_2O_2 was conducted by employment of both standard and counterpoise-corrected methods to calculate thegeometric structures and vibrational frequencies at the MP2/6-31G(d),MP2/6-31 G(d,p),MP2/6-311 q G(d,p),B3LYP/6-31G(d),B3LYP/6-31 G(d,p) and B3LYP/6-311 G(d,p) levels.In the H-bond N-H…O,the calcu-lated blue shift of N-H stretching frequency is in the vicinity of 120 cm~(-1) and this is indeed the largest theoreticalestimate of a blue shift in the X-H…Y H-bond ever reported in the literature.From the natural bond orbital analy-sis,the red-shifted H-bond O-H…O can be explained on the basis of the dominant role of the hyperconjugation.For the blue-shifted H-bond N-H…O,the hyperconjugation was inhibited due to the existence of significant elec-tron density redistribution effect,and the large blue shift of the N-H stretching frequency was prominently due tothe rehybridization of sp~n N-H hybrid orbital.  相似文献   

4.
The occurrence of bifurcate H‐bonds CAr–H···O=C in the structure of (diaryl)‐tetrahydrofuranones was experimentally demonstrated using different methods and techniques. The consistent increasing spin–spin coupling constants 1J(C,H) of the ortho‐H‐atoms and low‐field shift of vC=O in IR spectra of 2,2‐(diaryl)tetrahydrofuran‐3(2H)‐ones relative to their 5,5‐diaryl counterparts, as well as pronounced dependence of the ortho‐C–H H‐atoms chemical shifts on the temperature and solvent polarity along with X‐ray diffraction analysis data unambiguously point to the existence of weak CAr–H···O=C H‐bonds in these molecules.  相似文献   

5.
On the basis of a comparison of chemical shifts and wavenumbers of several secondary thioamides and amides having monocationic substituents attached to thiocarbamoyl or carbamoyl groups by a polymethylene chain, new intramolecular unconventional N···H+···N hydrogen bonding effects were discovered. It is argued that the CH2—N rotation is hindered and two +H···NHCH3 non‐equivalent protons occur in a proton spectrum of hydrochloride 1a (at 10.68 and 2.77 ppm, respectively) instead of two +NH2CH3 protons. Presumably, the above steric factors inhibit the acidic hydrolysis of 1a (stabilized by strong intramolecular N···H+···N hydrogen bonds) to an amide and prevent intramolecular cyclization of 2a (stabilized by strong intramolecular neutral–neutral N···HN hydrogen bonds) to a cyclic amidine. Postulation of additional dihydrogen bond formation is helpful in understanding the spectroscopic differences of 4 and 5 . The above new bonding is also compared with intramolecular N···H—N+ hydrogen bonds in primary amine salts 7 and 8 . In contrast to 3 , a cooperative hydrogen bonded system is observed in 9 and 10 . The weak hydrogen bonds in 7 – 10 facilitate the hydrolysis and cyclization reactions of secondary thioamides. The spectroscopic data for secondary (thio)amides are especially useful for characterizing the electronic situation at the (thio)carbamoyl nitrogen atoms and they are perfectly correlated with the reactivity. Examples of chelation of protons by thioamides ( 11 and 12 ), which contain strongly electron‐donating pyrimidine groups, are presented to show the contribution of dihydrogen bonding in the protonation reaction similar to 1 and 4 . Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

6.
A three‐dimensional cyano‐bridged copper(II) complex, [Cu(dien)Ag(CN)2]2[Ag2(CN)3][Ag(CN)2] ( 1 ) (dien = diethylenetriamine), has been prepared and characterized by X‐ray crystallography. Complex 1 crystallized in the monoclinic space group P21/n with a = 6.988(2), b = 17.615(6), c = 12.564(4) Å, β = 90.790(5)°. The crystal consists of cis‐[Cu(dien)]2+ units bridged by [Ag(CN)2] to form a zig‐zag chain. The Ag atoms of the free and bridging [Ag(CN)2] link together to form additional infinite zig‐zag chains with short Ag···Ag distances. The presence of Ag···Ag interactions effectively increases the dimensionality from a 1‐D chain to a 3‐D coordination polymer.  相似文献   

7.
IntroductionMolecularpolymerswithonedimensionalormulti dimensionalstructureassembledthroughhydrogenbondsisanimportantresearchcontentinthesupra molecularchemistryandcrystalengineering .1,2 Withthedevelop mentofnewtypefunctionalmaterialssuchasmolecularmagn…  相似文献   

8.
刘志宏  赵莉  胡满成 《中国化学》2003,21(12):1569-1572
Introduction   2MgO·B2 O3(Mg2 B2 O5)and 2MgO·B2 O3·H2 Omightbepreparedaswhiskermaterials .12MgO·B2 O3·H2 OnamedszaibelyiteisamagnesiumboratemineralwithastructuralformulaofMg2 [B2 O4 (OH) 2 ].2 Itisdifficulttosynthesizethiscompoundinthelaboratory .Recently ,weobtainedasimilarcompound 2MgO·B2 O3·1 5H2 Owhenwetriedtopreparewhiskerof 2MgO·B2 O3·H2 Obythephasetransformationof 2MgO·2B2 O3·MgCl2 ·14H2 OinH3BO3solutionunderhydrothermalcondition .Itishope fultopreparewh…  相似文献   

9.
The reaction of silver hexafluoridoantimonate with Ph2PCH2PPh2NSiMe3 ( 1 ) in dichloromethane produces the dimeric complex [Ag(μ‐Ph2PCH2PPh2NSiMe3)]2[SbF6]2 ( 2 ), in which two heterobifunctional ligands 1 in the dication are N, P‐chelated in a head‐to‐tail fashion to a [Ag ··· Ag]2+ unit that exhibits an Ag ··· Ag contact of 2.8530(6) Å. Quantum theory of atoms‐in‐molecules (QTAIM) analysis of the bonding revealed an attractive interaction between the two silver atoms.  相似文献   

10.
Light‐yellow single crystals of the mixed‐valent mercury‐rich basic nitrate Hg8O4(OH)(NO3)5 were obtained as a by‐product at 85 °C from a melt consisting of stoichiometric amounts of (HgI2)(NO3)2·2H2O and HgII(OH)(NO3). The title compound, represented by the more detailed formula HgI2(NO3)2·HgII(OH)(NO3)·HgII(NO3)2·4HgIIO, exhibits a new structure type (monoclinic, C2/c, Z = 4, a = 6.7708(7), b = 11.6692(11), c = 24.492(2) Å, β = 96.851(2)°, 2920 structure factors, 178 parameters, R1[F2 > 2σ(F2)] = 0.0316) and is made up of almost linear [O‐HgII‐O] and [O‐HgI‐HgI‐O] building blocks with typical HgII‐O distances around 2.06Å and a HgI‐O distance of 2.13Å. The Hg22+ dumbbell exhibits a characteristic Hg‐Hg distance of 2.5079(7) Å. The different types of mercury‐oxygen units form a complex three‐dimensional network exhibiting large cavities which are occupied by the nitrate groups. The NO3? anions show only weak interactions between the nitrate oxygen atoms and the mercury atoms which are at distances > 2.6Å from one another. One of the three crystallographically independent nitrate groups is disordered.  相似文献   

11.
Melting reactions of copper, CuI, selenium, and Bi2Se3 yielded black, shiny needles of Cu4BiSe4I = Cu4BiSe2(Se2)I. The compound decomposes peritectically above 635(5) K and crystallizes in the orthorhombic space group Pnma with a = 960.1(1) pm, b = 413.16(3) pm, and c = 2274.7(2) pm (T = 293(2) K). In the crystal structure, strands ${1}\atop{{\infty}}$ [BiSeSe2/2(Se2)2/2]3– run along [010]. Therein, the bismuth(III) cation is coordinated by five selenium atoms, which form a square pyramid. The copper(I) cations are coordinated tetrahedrally by selenide, diselenide and iodide ions. Edge‐sharing of these tetrahedra results in zigzag chains of copper cations with short distances of 262.7(4) pm. Enhanced dispersion of the 3d bands, the Crystal Orbital Hamilton Populations (COHP), and disynaptic ELI‐D basins indicate weakly attractive d10···d10 interactions between the copper cations. The semiconducting properties and the calculated electronic band structure suggest an electron‐precise compound. In copper‐deficient Cu3.824(8)BiSe4I, the Cu···Cu distances are 5 pm shorter, and Raman spectroscopy indicates the presence of diselenide(1–) radical anions besides the diselenide(2–) groups. As a result, in Cu3.824(8)BiSe4I, selenium coexists in the oxidations states –II, –I, and –0.5.  相似文献   

12.
The F–H···YZ2 (Y = C, Si, BH, A1H;Z = H, PH3) systems were examined using density functional theory calculations. The main focus of this work is to demonstrate that the chemistry of Y(PH3)2 exhibits a novel feature which is a central Y atom with unexpected high basicity. Further, the hydrogen bond strength can be adjusted by the substitution of H atoms of YH2 by PH3 groups. The FH···C(PH3)2 system has the strongest hydrogen bond interaction, which is larger than a conventional hydrogen bond. In addition to electrostatic interaction, donor‐acceptor interaction also plays an important role in determining the hydrogen bond strength. Therefore, a carbon atom can not only be the hydrogen bond acceptor but also can create an unusual stabilized hydrogen bond complex. Also, X3B–YZ2 (X = H, F; Y = C, Si, BH, A1H;Z = PH3, NH3) systems were examined, and it was found that the bond strength is controlled predominately by the HOMO‐LUMO gap (ΔIP). The smaller the ΔIP, the larger the bond dissociation energy of the B–Y bond. In addition, NH3 is a better electron‐donating group than PH3, and thus forms the strongest donor‐acceptor interaction between X3B and Y(NH3)2.  相似文献   

13.
Quantum calculations at the MP2/aug‐cc‐pVDZ level are used to analyze the SH···N H‐bond in complexes pairing H2S and SH radical with NH3, N(CH3)3, NH2NH2, and NH2N(CH3)2. Complexes form nearly linear H‐bonds in which the S? H covalent bond elongates and shifts its stretching frequency to the red. Binding energies vary from 14 kJ/mol for acceptor NH3 to a maximum of 22 kJ/mol for N(CH3)3 and N(CH3)2NH2. Analysis of geometric, vibrational, and electronic data indicate that the SH···N interaction involving SH is slightly stronger than that in which the closed‐shell H2S serves as donor. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011  相似文献   

14.
The interactions of axial substituents in monosubstituted cyclohexane rings are studied in this work using an array of different computational techniques. Additionally, the anomalous axial preference for some bulky substituents is related to stabilizing dispersion interactions. We find that the C–Hax···Yax contacts for various substituents with distances ranging from 2 to ~5 Å may include attractive dispersion forces that can affect the conformational equilibrium; these forces co‐exist with Pauli repulsive forces effected by Yax group due to van der Waals sphere penetration. At distances between 2 and 3 Å stabilizing electron transfer interactions were calculated and the combination of natural bond orbital and QTAIM analysis showed that, in certain cases, Yax = tBu, Cax–O or Cax = O or Sax = O or Cax = S this interaction can be characterized as an improper H‐bond. DFT‐D3 and non‐covalent interactions calculations (NCIs) in cyclohexane derivatives with Yax = SiOR3 including HYax···Hcy surfaces at distances ranging between 4 and 6 Å suggest that dispersion has a clear effect on the experimentally observed stabilization of the axial conformer. NCIs computed from the reduced density gradient help to visually identify and analyze these interactions. © 2016 Wiley Periodicals, Inc.  相似文献   

15.
The Crystal Structures of [Cu2Cl2(AA · H+)2](NO3)2 and [AA · H+]Picr? (AA · H+ = Allylammonium; Picr? = Picrat) By an alternating current electro synthesis the crystal-line π-complex [Cu2Cl2(AA · H+)2](NO3)2 has been obtained from CuCl2 · 2H2O, allylamine (AA), and HNO3 in ethanolic solution. X-ray structure analysis revealed that the compound crystallized in the monoclinic system, space group P21/a, a = 7.229(3), b = 7.824(3), c = 26.098(6) Å, γ = 94.46(5)°, Z = 4, R = 0.025 for 2 023 reflections. The crystal structure is built up of CunCln chains which are connected by π-bonding bidentate AA · H+ …? ON(O)O …? H+ · AA units. For comparision with the above complex the structure of [AA · H+]Picr? (Picr? = picrate anion) is also reported.  相似文献   

16.
The reaction of 1H‐tetrazole‐1‐acetic acid (Htza) and perchloric acid with cuprous chloride with slow evaporation at room temperature gave a novel 3D porous CuII coordination polymer, [Cu2(tza)4] · ClO4 · 4H2O ( 1 ), (tza = tetrazole‐1‐acetate). The structure exhibits an unusual 3D microporous coordination framework built up by four coordinated CuII nodes and bidentate bridging tza ligands with lvt‐type topology. Furthermore, the magnetic properties of complex 1 were also investigated.  相似文献   

17.
Te(OH)6 · 2Na3P3O9 · 6H2O, is hexagonal (P63/m) with a = 11,67(1), c = 12,12(1) Å, Z = 2 and Dx = 2,225 g/cm3. Te(OH)6 · K3P3O9 · 2H2O, is monoklin (P21/c) with a = 19,61(5), b = 7,456(1), c = 14,84(6) Å, = 108,01(4), Z = 4 and Dx = 2,506 g/cm3. Both compounds are the first examples of phosphate tellurates in which the anion phosphate is condensed to the ring anion P3O9. As in phosphate tellurates already described the phosphate groups are independent of the TeO6 octahedra.  相似文献   

18.
The organically templated pentaborate [C10N2H9][B5O6(OH)4] · H3BO3 · H2O ( 1a ) was synthesized by boric acid and 4, 4′‐bipyridine in aqueous solution and characterized by single‐crystal X‐ray diffraction, elemental analysis, FTIR spectroscopy, thermogravimetric analysis, powder X‐ray diffraction, and photoluminescence spectroscopy. The compound crystallizes in the triclinic system with space group P$\bar{1}$ (a = 9.196(3) Å, b = 9.822(3) Å, c = 12.113(3) Å, α = 66.243(3)°, β = 76.998(3)°, γ = 75.067(3)°, V = 958.4(5) Å3, and Z = 2). The polyanions form a novel 3D supramolecular network with three kinds of channels by extensive hydrogen bonds. The title compound shows a UV photoluminescence with an emission maximum at 372 nm upon excitation at 248 nm, and the photoluminescence can be modified from UV to blue by means of a simple heat‐treatment process. The pentaborate could be a promising blue component for possible application in the white LED.  相似文献   

19.
Alkaline Earth Fluoromanganates(III): BaMnF5 · H2O and SrMnF5 · H2O Solid BaF2 or SrF2 forms with solutions of Mn3+ in aqueous hydrofluoric acid precipitates of hitherto unknown BaMnF5 · H2 and SrMnF5 · H2O respectively. X-ray structure determination on single crystals of both isotypic compounds (space group P21/m, Z = 2; BaMnF5 · H2O: a = 537.0(3), b = 817.2(2), c = 628.0(4) pm β = 111.17(5)°, Rw = 0.035 for 1403 reflections; SrMnF5 · H2O: a = 510.8(1), b = 792.0(2), c = 610.6(1) pm, β = 110.24(1)° Rw = 0.068 for 539 reflections) reveal pure [MnF6]3? octahedra connected with each other to infinite chains by sharing trans corners. The H2O molecules are coordinated to the alkaline earth ions only and form weak O? H…F hydrogen bonds. The pronounced weakening of the Mn? F bonds within the chain direction (Mn? F 2X 212.7(1)/210.8(5) pm, 2X 183.8(3)/181.8(9) pm, 2X 186.9(2)/187.2(8) pm) may be due by halves to the Jahn-Teller-effect as can be deduced by bond valence calculations.  相似文献   

20.
Three new 2D/3D supramolecular architectures derived from Cu‐organic subunits and Keggin anions, [CuII2(biz)8(HPMoVI10MoV2O40)(H2O)2] · 2H2O ( 1 ), [CuI4(biz)8(SiW12O40)] · 2H2O ( 2 ) and [CuI2(dmbiz)4(Hdmbiz)2(SiW12O40)] ( 3 ) (biz = benzimidazole, dmbiz = 5, 6‐dimethyl benzimidazole), were obtained under hydrothermal conditions. Single crystal X‐ray diffraction analysis reveals that compound 1 has two kinds of [CuII(biz)2]2+ cations, which are further extended by Keggin anions into a 2D (4, 8)‐connected supramolecular network by hydrogen bonding interactions. In compound 2 , four types of [CuI(biz)2]+ subunits link the [SiW12O40]4– anions to form a 3D (2, 6)‐connected supramolecular structure. Compound 3 shows a 3D supramolecular network with a NaCl‐type topology constructed by [CuI(dmbiz)2]+ subunits, anions, and discrete [Hdmbiz]+ cations. Moreover, the electrochemical and photocatalytic properties of compounds 1 and 2 were investigated.  相似文献   

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