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1.
Phosphaneimine and Phosphoraneiminato Complexes of Boron. Synthesis and Crystal Structures of [BF3(Me3SiNPEt3)], [BCl2(NPPh3)]2, [BCl2(NPEt3)]2, [B2Cl3(NPEt3)2]+BCl4?, and [B2Cl2(NPiPr3)3]+BCl4? The title compounds have been prepared from the corresponding silylated phosphaneimines and boron trifluoride etherate and boron trichloride, respectively. The compounds form white moisture sensitive crystals, which were characterized by 11B-nmr-spectroscopy, IR-spectroscopy and by crystal structure determinations. [BF3(Me3SiNPEt3)] : Space group P21/c, Z = 4, R = 0.032 for reflections with I > 2σ(I). Lattice dimensions at ?70°C: a = 1361.0, b = 819.56, c = 1422.5 pm, β = 109.86°. The donor acceptor complex forms monomeric molecules with a B? N bond length of 157.8 pm. [BCl2(NPPh3)]2 · 2 CH2Cl2 : Space group P21/c, Z = 2, R = 0.049 for reflections with I > 2σ(I). Lattice dimensions at ?50°C: a = 1184.6, b = 2086.4, c = 843.0 pm, β = 96.86°. The compound forms centrosymmetric dimeric molecules in which the boron atoms are linked to B2N2 four-membered rings with B? N distances of 152.7 pm via μ2-N bridges of the NPPh3 groups. [BCl2(NPEt3)]2 : Space group Pbca, Z = 4, R = 0.029 for reflections with I > 2σ(I). Lattice dimensions at ?90°C: a = 1269.5, b = 1138.7, c = 1470.3 pm. The compound has a molecular structure corresponding to the phenyl compound with B? N ring distances of 151.0 pm. [B2Cl3(NPEt3)2]+BCl4? : Space group Pbca, Z = 8, R = 0.034 for reflections with I > 2σ(I). Lattice dimensions at ?70°C: a = 1309.3, b = 1619.8, c = 2410.7 pm. Within the cations the boron atoms are linked to planar, asymmetrical B2N2 four-membered rings with B? N distances of 155.1 and 143.1 pm via the μ2-N atoms of the NPEt3 groups. [B2Cl2(NPiPr3)3]+BCl4? · CH2Cl2: Space group Pna2, Z = 4, R = 0.033 for reflections with I > 2σ(I). Lattice dimensions at ?70°C: a = 1976.5, b = 860.2, c = 2612.7 pm. Within the cations the boron atoms are linked to planar, asymmetrical B2N2 four-membered rings with B? N distances of 153.7 and 150.5 pm via the μ2-N atoms of two of the NPiPr3 groups. The third NPiPr3 group is terminally connected to the sp2-hybridized boron atom with a B? N distance of 133.5 pm and with a B? N? P bond angle of 165.3°.  相似文献   

2.
Reaction of powdered Zr with ZrCl4, BaCl2 and Be in suitable proportions in a Ta container at 800°C produces the title compound. Suitable monocrystals for X-ray diffraction were obtained from reactions to which a comparable amount of Hg2Cl2 had been added. The structure of Ba3Zr6Cl18Be is a superstructure of the K2ZrCl6 · Zr6Cl18H type (R3 c, Z = 6; a = 9.6852 (9) Å, c = 52.52 (1) Å; R, Rw = 2.7, 3.2% for 826 independent reflections, 2θ ≤ 50°). Trigonally compressed [Zr6(Be)Cl12i]Cl6a clusters are interconnected by six-coordinate barium atoms that lie in Cla antiprisms (a twisted version of the ZrIV site) while (9 + 3)-coordinate barium substitutes for potassium within chlorine layers. Distortions associated with the size and field of barium are responsible for the superstructure and for differences from other analogues.  相似文献   

3.
Preparation and Crystal Structures of Silver(I) Mixed Ligand Complexes with Bibenzimidazole and Triphenylphosphane: [Ag(PPh3)2(bbimH2)](COOCH3) · 2 CH2Cl2 and [{Ag(PPh3)2}2(μ-bbim)] · 4 CH2Cl2 The title compounds are obtained from silver acetate, 2,2′-bibenzimidazole and PPh3. They are characterized by their IR, 1H-NMR, 31P-NMR spectra and crystal structure determinations. [Ag(PPh3)2(bbimH2)](COOCH3) · 2 CH2Cl2: Reaction in CH2Cl2. Space group C2/c, Z = 4, 3129 observed unique reflections, R = 0.033. Lattice parameters at 203 K: a = 1450.8; b = 1556.2; c = 2316.4 pm; β = 99.69°. The crystal structure is built up by monomeric molecules with distorted tetrahedral coordination of the silver atom (AgP2N2) and bibenzimidazole as a bidentate ligand. The acetate ion is linked to the NH-groups of the bibenzimidazole by hydrogen bonds. [{Ag(PPh3)2}2(μ-bbim)] · 4 CH2Cl2: Reaction in fused PPh3 at 180 °C. Space group P 1, Z = 1. 9227 observed unique reflections, R = 0.051. Lattice parameters at 203 K: a = 1276.5; b = 1352.1; c = 1408.1 pm; α = 96.97; β = 115.87; γ = 96.84°. The crystal structure is built up by centrosymmetric molecules with distorted tetrahedral coordination of the silver atoms (AgN2P2) and bibenzimidazolate(2–) as tetradentate bridging ligand.  相似文献   

4.
Crystal Structures of [TiF3(NPPh3)(HNPPh3)]2 and of HNPPh3 The phosphoraneiminato-phosphaneimine complex [TiF3(NPPh3)(HNPPh3)]2 was obtained by the reaction of TiF4 with Me3SiNPPh3 in boiling dichloromethane. It crystallizes from 1,2-dichloroethane as yellow crystals which include four molecules C2H4Cl2 per dimeric formula unit. Space group P21/n, Z = 2, structure solution with 7270 independent reflections, R = 0.060 for reflections with I > 2σ(I). Lattice dimensions at ?50°C: a = 1417.5, b = 1896.9, c = 1586.6 pm, β = 101.22°. The compound forms centrosymmetric dimeric molecules via μ2-F bridges with TiF distances of 194.6 and 223.3 pm, the longer one being in trans-position to the N atom of the (NPPh3)? ligand. Its TiN bond length of 177.7 pm corresponds with a double bond. The TiN bond length of the HNPPh3 donor molecule of 213.4 pm is typical for a donor acceptor bond. According to the crystal structure determination the phosphaneimine HNPPh3 forms monomeric molecules without intermolecular hydrogen bridges with a PN bond length of 152.4 pm. Space group P21/c, Z = 4, structure solution with 3229 independent reflections, R = 0.062 for reflections with I > 2σ(I). Lattice dimensions at ?70°C: a = 1460.4, b = 928.9, c = 1096.6 pm, β = 93.35°.  相似文献   

5.
[W(NPPh3)4]Cl2 — a Phosphoraneiminato Complex with a Dication of Tungsten The title compound has been prepared by the reaction of Me3SiNPPh3 with WNCl3 and WO2Cl2, respectively, in acetonitrile, forming colourless crystals, which were characterized by IR spectroscopy and by an X-ray structure determination. Space group P21/n, Z = 4, 4 424 observed unique reflections, R = 0.045. Lattice dimensions at 20°C: a = 1 206.5(2), b = 2 225.3(2), c = 2 421.0(3) pm, β = 101.09(1)°. In the dication [W(NPPh3)4]2+ the tungsten atom is surrounded in a tetrahedral fashion by the four nitrogen atoms of the phosphoraneiminato ligands. The bond lengths WN and PN correspond with double bonds.  相似文献   

6.
By alternating‐current electrochemical synthesis crystals of {Cu[H2NC5H4N(C3H5)]Br2} ˙ H2O ( I ), {Cu[H2NC5H4N(C3H5)]Br0.65Cl1.35} ˙ H2O ( II ) and {Cu[H2NC5H4N(C3H5)]Cl2} ( III ) π‐complexes have been obtained and structurally investigated. The I and II compounds are isostructural and crystallize in a monoclinic sp. gr. P21/c, I : a = 7.359(2)Å, b = 12.3880(6)Å, c = 13.637(3)Å, β = 107.03(1)°, V = 1188.7(4)Å3, Z = 4 for C8H13N2OBr2Cu composition, R = 0.0293 for 2140 reflections. II : a = 7.2771(6)Å, b = 12.3338(3)Å, c = 13.4366(7)Å, β = 107.632(2)°, V = 1149.3(1)Å3, Z = 4 for C8H13N2Br0.65Cl1.35Cu composition, R = 0.0463 for 2185 reflections. Metal and halogen atoms form centrosymmetric Cu2X4 dimers. Each copper atom is surrounded by three halogen atoms and by a weakly bonded C=C‐group of the onium moiety. Isolated {Cu[H2NC5H4N(C3H5)]}2X4 dimers are combined into a three‐dimensional network due to a bridging function of water molecules via a system of rather strong hydrogen bonds. Chlorine derivative III crystallizes in another structure type: sp. gr. C2/c, a = 21.568(7)Å, b = 7.260(2)Å, c = 13.331(3)Å, β = 95.65(2)°, V = 2077(2)Å3, Z = 8 for C8H11N2Cl2Cu composition. Copper atom, included in CuCl2 isolated fragment, is coordinated to a C=C‐bond of ligand moiety. N‐H…Cl hydrogen bonds unite Cu[H2NC5H4N(C3H5)]Cl2 subunits into infinite ribbons. π‐Interaction in III appears to be more effective than in I and II .  相似文献   

7.
Phosphorane Iminato Complexes of Sulfur. Synthesis and Crystal Structures of [SO(Cl)(NPPh3)], [SO2(Cl)(NPPh3)], and [SCl(NPPh3)2]Cl The title compounds have been prepared by the reaction of Me3SiNPPh3 with SOCl2, SO2Cl2, and SCl2, respectively. They form colourless, moisture sensitive crystals, which were characterized by IR spectroscopy and by crystal structure determinations. [SO(Cl)(NPPh3)]: Space group P21/n, Z = 4, structure determination with 2 434 observed unique reflections, R = 0.047. Lattice dimensions at 19°C: a = 1 304.8, b = 996.5, c = 1 339.5 pm, β = 93.75°. The compound forms monomeric molecules with a remarkably long S? Cl bond of 234.2 pm and distances SN and PN of 154.6 and 161.6 pm, respectively, which agree with double bonds. [SO2(Cl)(NPPh3)]: Space group P21/n, Z = 4, structure solution with 2 872 observed, unique reflections, R = 0.047. Lattice dimensions at 20°C: a = 956.9, b = 1 909, c = 1 002.0 pm, β = 106.06°. The compound forms monomeric molecules with distances S? Cl of 207.1 pm, SN of 154.5 pm, and PN of 161.6 pm. [SCl(NPPh3)2]Cl: Space group P21/c, Z = 4, structure solution with 5 224 observed, unique reflections, R = 0.042. Lattice dimensions at 20°C: a = 1 108.6, b = 1 603.8, c = 1 840.5 pm, β = 99.98°. The compound forms ions [SCl(NPPh3)2]+ and Cl?. In the cation the sulfur atom is φ-tetrahedrally coordinated with a long S? Cl distance of 248.5 pm and SN bond lengths of 154.5 and 156.0 pm.  相似文献   

8.
Phosphorane Iminato Complexes of Titanium(IV) and Titanium(III). The Crystal Structures of [TiCl2(OMe)(NPPh3)]2, [TiBr2(NPPh3)]2 · 3C7H8, and [Ph3PNH2]Br · CH2Cl2 TiCl3(NPPh3) reacts with a solution of methyllithium in diethyl ether in the presence of lithiummethylate forming yellow [TiCl2(OMe)(NPPh3)]2. On reaction with benzyl magnesium bromide TiCl3(NPPh3) in diethyl ether is converted into green [TiBr2(NPPh3)]2 under reduction and ligand exchange. [TiBr2(NPPh3)]2 crystallizes from toluene with three molecules C7H8. [Ph3PNH2]Br · CH2Cl2 originates as a side product of this reaction. The products are characterized by their i.r. spectra and by crystal structure analyses. [TiCl2(OMe)(NPPh3)]2 . Space group P1 , Z = 2, structure solution with 2909 independent reflections, R = 0.063. Lattice dimensions at 20°C: a = 1005.1, b = 1044.5, c = 1068.6 pm, α = 66.98°, β = 89.35°, γ = 80.24°. The compound forms centrosymmetric dimeric molecules with μ2-OMe bridges and five-fold coordinated titanium atoms. The (NPPh3?) ligand is terminally connected with a Ti = N distance of 174.8 pm and with a TiNP bond angle of 165.3°. [TiBr2(NPPh3)]2 · 3 C7H8 . Space group P1 , Z = 2, structure solution with 5548 independent reflections, R = 0.053. Lattice dimensions at ?70°C: a = 983.3, b = 1162.7, c = 1376.5 pm, α = 100.53°, β = 110.30°, γ = 105.24°. The compound forms centrosymmetric dimeric molecules with μ2-NPPh3 bridges and tetrahedral coordination at the titanium atoms. With 195.9 pm the Ti–N bonds correspond with single bonds. The Ti …? Ti distance of 260.0 pm is exceptionally short. [Ph3PNH2]Br · CH2Cl2 . Space group P1 , Z = 1, structure solution with 3091 independent reflections, R = 0.049. Lattice dimensions at 20°C: a = 909.4, b = 1004.4, c = 1158.5 pm, α = 108.09°, β = 94.67°, γ = 91.92°. The bromide ions are bonded to a one-dimensional infinite network via hydrogen bridge bonds of the cation and of the dichloromethane.  相似文献   

9.
Micro- and mesoporous carbide-derived carbons (CDCs) were synthesised from TiC powder via a gas-phase reaction using HCl and Cl2 within the temperature range of 700–1,100 °C. Analysis of X-ray diffraction results show that TiC-CDCs consist mainly of graphitic crystallites. The first-order Raman spectra showed the graphite-like absorption peaks at ~1,577 cm?1 and the disorder-induced peaks at ~1,338 cm?1. The low-temperature N2 sorption experiments were performed, and specific surface areas up to 1,214 and 1,544 m2?g?1 were obtained for TiC-CDC (HCl) synthesised at T?=?800 °C and TiC-CDC (Cl2) synthesised at T?=?900 °C, respectively. For the TiC-CDC powders synthesised, a bimodal pore size distribution has been established with the first maximum in the region up to 1.5 nm and the second maximum from 2 to 4 nm. The energy-related properties of supercapacitors based on 1 M (C2H5)3CH3NBF4 in acetonitrile and TiC-CDC (Cl2) and TiC-CDC (HCl) as electrode materials were also investigated by cyclic voltammetry, impedance spectroscopy, galvanostatic charge/discharge and constant power methods. The specific energy, calculated at U?=?3.0 V, are maximal for TiC-CDC (Cl2 800 °C) and TiC-CDC (HCl 900 °C), which are 43.1 and 31.1 W?h?kg?1, respectively. The specific power, calculated at cell potential U?=?3.0 V, are maximal for TiC-CDC (Cl2 1,000 °C) and TiC-CDC (HCl 1,000 °C), which are 805.2 and 847.5 kW?kg?1, respectively. The Ragone plots for CDCs prepared by using Cl2 or HCl are quite similar, and at high power loads, the TiC-CDC material synthesised using Cl2 at 900 °C, i.e. the material with optimal pore structure, delivers the highest power at constant energy.  相似文献   

10.
Crystals of the formula (An)3[Cu4Cl7] (I) and (An)3[Cu8Cl10(C? CCH2OH)]· 2H2O (II) were obtained in the system AnCl-CuCl-H2O-HC? CCH2OH [An is the anilinium cation (C6H5NH 3 + )] and studied by X-ray diffraction analysis (DARCH diffractometer, λMoKα, θ/2θ scan mode; 1121 and 2433 unique reflections with F≥4Σ(F), R = 0.064 and 0.044 for I and II, respectively). Ciystals I are orthorhombic, space group Pbnm, Z = 4. a = 21.65(1), b = 11.006(5). c = 11.068(6) Å; ciystals II are triclinic, space group P-l, Z = 2, a = 14.94(1), b = 12.242(8). c = 11.341(7) Å, α = 106.77(5), β = 92.05(6), γ = 113.38(5)°. In contrast to I, the anionic copper acetylenide π-complex contains the propargylium ion whose terminal C? C group acts as a double bridging π, Σ-ligand sim ultaneously bonded to four copper(I) atoms. Structural genesis of [Cu4Cl7]3? n] (I) and [Cu8C110(C = CCH2OH)]3? n (II) anions is considered.  相似文献   

11.
In the isomeric title compounds, viz. 2‐, 3‐ and 4‐(chloro­methyl)pyridinium chloride, C6H7ClN+·Cl?, the secondary interactions have been established as follows. Classical N—H?Cl? hydrogen bonds are observed in the 2‐ and 3‐isomers, whereas the 4‐isomer forms inversion‐symmetric N—H(?Cl??)2H—N dimers involving three‐centre hydrogen bonds. Short Cl?Cl contacts are formed in both the 2‐isomer (C—Cl?Cl?, approximately linear at the central Cl) and the 4‐isomer (C—Cl?Cl—C, angles at Cl of ca 75°). Additionally, each compound displays contacts of the form C—H?Cl, mainly to the Cl? anion. The net effect is to create either a layer structure (3‐isomer) or a three‐dimensional packing with easily identifiable layer substructures (2‐ and 4‐isomers).  相似文献   

12.
By alternating‐current electrochemical technique crystals of copper(I) π‐complex with 1‐allylpyridinium chloride of [C5H5N(C3H5)][Cu2Cl3] ( 1 ) composition have been obtained and structurally investigated. Compound 1 crystallizes in monoclinic system, space group C2/c a = 24.035(1) Å, b = 11.4870(9) Å, c = 7.8170(5) Å, β = 95.010(5)°, V = 2150.0(2) Å3 (at 100 K), Z = 8, R = 0.028, for 4836 independent reflections. In the structure 1 trigonal‐pyramidal environment of π‐coordinated copper(I) atom is formed by a lengthened to 1.376(2) Å C=C bond of allyl group and by three chlorine atoms. Other two copper atoms are tetrahedrally surrounded by chlorine atoms only. The coordination polyhedra are combined into an original infinite (Cu4Cl62—)n fragment. Structural comparison of 1 and the recently studied copper(I) chloride π‐complexes with 3‐amino‐, 2‐amino‐, 4‐amino‐1‐allylpyridinium chlorides of respective [LCu2Cl3] ( 2 ), [L2Cu2Cl4] ( 3 ), and [LCuCl2] ( 4 ) compositions allowed us to reveal the trend of the inorganic fragment complication which depends on pKa (base) value of the corresponding initial heterocycle.  相似文献   

13.
Interaction of copper(II) chloride with 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine leads to formation of copper(II) complex [CuCl2·2C3N3(OC3H5)3] ( I ). Electrochemical reduction of I produces the mixed‐valence CuI, II π, σ‐complex of [Cu7Cl8·2C3N3(OC3H5)3] ( II ). Final reduction produces [Cu8Cl8·2C3N3(OC3H5)3]·2C2H5OH copper(I) π‐complex ( III ). Low‐temperature X‐ray structure investigation of all three compounds has been performed: I : space group P1¯, a = 8.9565(6), b = 9.0114(6), c = 9.7291(7) Å, α = 64.873(7), β = 80.661(6), γ = 89.131(6)°, V = 700.2(2) Å3, Z = 1, R = 0.0302 for 2893 reflections. II : space group P1¯, a = 11.698(2), b = 11.162(1), c = 8.106(1) Å, α = 93.635(9), β = 84.24(1), γ = 89.395(8)°, V = 962.0(5) Å3, Z = 1, R = 0.0465 for 6111 reflections. III : space group P1¯, a = 8.7853(9), b = 10.3602(9), c = 12.851(1) Å, α = 99.351(8), β = 105.516(9), γ = 89.395(8), V = 1111.4(4) Å3, Z = 1, R = 0.0454 for 4470 reflections. Structure of I contains isolated [CuCl2·2C3N3(OC3H5)3] units. The isolated fragment of I fulfils in the structure of II bridging function connecting two hexagonal prismatic‐like cores Cu6Cl6, whereas isolated Cu6Cl6(CuCl)2 prismatic derivative appears in III . Coordination behaviour of the 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine moiety is different in all the compounds. In I ligand moiety binds to the only copper(II) atom through the nitrogen atom of the triazine ring. In II ligand is coordinated to the CuII‐atom through the N atom and to two CuI ones through the two allylic groups. In III all allylic groups and nitrogen atom are coordinated by four metal centers. The presence of three allyl arms promotes an acting in II and III structures the bridging function of the ligand moiety. On the other hand, space separation of allyl groups enables a formation of large complicated inorganic clusters.  相似文献   

14.
Phosphorane Iminato-Trichloroselenates(II): Syntheses and Crystal Structures of [SeCl(NPPh3)2]+SeCl3? and [Me3SiN(H)PMe3]2+[Se2Cl6]2? [SeCl(NPPh3)2]+SeCl3? has been synthesized by the reaction of Se2Cl2 with Me3SiNPPh3 in acetonitrile solution, forming orangered crystals, whereas red crystals of [Me3SiN(H)PMe3]2+[Se2Cl6]2? were obtained by the reaction of Me3SiNPMe3 with SeOCl2 in acetonitrile solution. Both complexes were characterized by X-ray structure determinations. [SeCl(NPPh3)2]+SeCl3?: Space group P21/n, Z = 4, structure solution with 7 489 observed unique reflections, R = 0.057. Lattice dimensions at ?60°C: a = 1 117.0; b = 2 241, c = 1 407.5 pm, β = 95.61°. In the cation [SeCl(NPPh3)2]+ the selenium atom is φ-tetrahedrally coordinated by the chlorine atom and by the nitrogen atoms of the phosphorane iminato ligands, whereas the anion SeCl3? has a T-shaped structure with φ-trigonal-bipyramidale surrounding of the selenium atom. [Me3SiN(H)PMe3]2+[Se2Cl6]2?: Space group P21/c, Z = 4, structure solution with 2 093 observed unique reflections, R = 0.080. Lattice dimensions at ?70°C: a = 956, b = 828, c = 1 973 pm, β = 93.80°. The structure consists of [Me3SiN(H)PMe3]+ ions and planar [Se2Cl6]2? anions, in which the selenium atoms are bridged nearly symmetrically by two chlorine atoms.  相似文献   

15.
Alkylammonium Hexachlorometallates. I. Crystallization Properties and Crystal Structure of Diethylenetriammonium Hexachlororhodate, [H3N(CH2)2NH2(CH2)2NH3][RhCl6] The reaction of RhCl3 · 3H2O with diethylenetriamine in 12 m hydrochloric acid yielded diethylenetriammonium hexachlororhodate [H3N(CH2)2NH2(CH2)2NH3][RhCl6] ( 1 ). Dark red single crystals of the compound were grown under hydrothermal conditions at a temperature interval of 180°C to 125°C in closed glass ampoules over several weeks (space group C2/c, a = 30.956(4) Å, b = 7.371(2) Å, c = 12.9736(15) Å, β = 113.787(11)°, Z = 8, 2385 reflections with I > 0, wR2(obs.) = 0.0279, R1(I > 2σ(I)) = 0.0271). The crystal structure is determined by a complex framework of hydrogen bonds between the hexachlororhodate anions and the diethylenetriammonium cations.  相似文献   

16.
Single crystals of [(C5H4NH)NC4H8NH(C3H5)]2+[Cu3Cl5]2? are obtained by ac synthesis in ethanol from 1-(2-pyridyl)-4-allyl-piperazinium and Cu(II) dichlorides and their structure is studied by X-ray diffraction analysis (space group P-1, a = 7.246(7) Å, b = 8.54(1) Å, c = 16.41(1) Å, α = 70.76(8)°, β = 77.24(8)°, λ = 80.42(9)°, V = 30(4) Å3, Z = 2, R(F) = 0.0686. In the structure of this π-complex, the Cu and Cl atoms form unusual centrosymmetrical Cu6Cl10 fragments, each fragment being bonded to two 1-(2-pyridyl)-4-allyl-piper-azinium cations via π-interaction Cu-(C=C). A three-dimensional structure is formed by means of N-H…Cl hydrogen bonds. The trigonal-pyramidal surrounding of the Cu(1) atom includes three Cl atoms and the C=C bond, while the tetrahedral surrounding of Cu(2) and the trigonal surrounding of Cu(3) involve the Cl atoms only.  相似文献   

17.
黎安勇  闫秀花  王素纹 《化学学报》2007,65(24):2809-2816
运用量子化学从头算方法, 在MP2/6-311++G(d,p), MP2/6-311++G(2df,2p), MP2/6-311++G(3df,3pd)和QCISD/6-311++G(d,p)水平上, 研究了CH3F, CH3Cl和CH3Br作为质子给体与Cl, Br作为质子接受体形成的氢键CH3…Y. 计算结果表明: 6种复合物中C—H键收缩, 伸缩振动频率增大, 形成蓝移氢键. 分子中原子(Atoms in Molecules, AIM)分析表明, 这些复合物的电子密度拓扑性质与普通氢键有着本质的不同, 在Y…H之间不存在键临界点, 而在Y与C之间存在键临界点, 因此这些相互作用严格地不能称为氢键. 自然键轨道(Natural bond orbital, NBO)分析表明, 在这些复合物中弯曲的CH…Y的特殊结构使得分子间超共轭n(Y)®σ*(C—H)减小到可以忽略; 质子接受体的电子密度没有转移到σ*(C—H)上, 而是转移到了σ*(C—X) (X=F, Cl, Br)上; 存在一定程度的重杂化; 分子内超共轭相互作用减小使得σ*(C—H)的电子密度减少. 这些因素共同导致C—H伸缩振动频率的蓝移.  相似文献   

18.
Two crystal modifications of a novel complex bis(μ2-chloro)tetrachlorodicuprate(II) bis[(18-crown-6)potassium, [K{(18-crown-6)}2Cu2Cl6] were synthesized and studied by X-ray diffraction. The structures of two monoclinic modifications—Iα (space group P21/n, a = 9.053, b = 33.815, c = 13.469 Å, β = 101.29°, Z = 4) and Iβ (space group P21/c, a = 10.991, b = 8.187, c = 22.542 Å, β = 98.15°, Z = 2) were solved by the direct method and refined by the full-matrix least-squares method in anisotropic approximation to R = 0.073 (Iα) and 0.068 (Iβ) for 4883 (Iα) and 3525 (Iβ) independent reflections (CAD-4 automated diffractometer, λMoK α). The molecules of Iα and Iβ consist of the central binuclear complex anion [Cu2Cl6]2? and two peripheral host-guest cationic fragments [K(18-crown-6)]+, each linked with the [Cu2Cl6]2? anions through the K-Cl bonds. The molecule of Iα and centrosymmetric Iβ molecule have different structures, since they have different orientation of the [K(18-crown-6)]+ fragments relative to the central [Cu2Cl6]2? anion. The coordination polyhedron of the Cu2+ cation in the latter anion in Iα and Iβ is intermediate between flattened tetrahedron and square. In the [K(18-crown-6)]+ ions of Iα and Iβ, the K+ cation has the distorted hexagonal pyramidal coordination polyhedron with six O atoms of the 18-crown-6 ligand in a base and bifurcate vertex at two Cl atoms of the [Cu2Cl6]2? anion. The 18-crown-6 ligands of Iα and Iβ have standard crown conformation.  相似文献   

19.
Synthesis and Crystal Structures of the Phosphoraneiminato Complexes [SbF2(NPEt3)]2 and [SbF(NPEt3)2]2 as well as of NMe4+SbF4? The title compounds have been prepared from antimony trifluoride with the silylated phosphaneimine Me3SiNPEt3 and [NMe4]F, respectively. They were characterized by IR spectroscopy and by crystal structure determinations. [SbF2(NPEt3)]2 : Space group Pbca, Z = 8, structure determination with 1264 unique reflections, R1 = 0.028 for reflections with I > 2σ(I). Lattice dimensions at ?80°C: a = 1284.8, b = 1162.4, c = 1380.4 pm. The compound forms centrosymmetric dimeric molecules, in which the Ψ-trigonal-bipyramidal coordinated antimony atoms are linked via μ2-N bridges of the NPEt3? ligands. [SbF(NPEt3)2]2 : Space group P21/c, Z = 4, structure determination with 2270 unique reflections, R1 = 0.029 for reflections with I > 2μ(I). Lattice dimensions at ?75°C: a = 815.8, b = 1121.2, c = 2068.5 pm, β = 101.09°. The compound forms centrosymmetric dimeric molecules, in which the Ψ-trigonal-bipyramidal coordinated antimony atoms are linked via μ2-N bridges of one of the two NPEt3? ligands. The other NPEt3? group is terminally connected. NMe4+SbF4? : Space group P21/c, Z = 4, structure determination with 1503 unique reflections, R1 = 0.069 for reflections with I > 2μ(I). Lattice dimensions at ?50°C: a = 539.80, b = 896.10, c = 1760.3 pm, β = 90.338°. The compound includes monomeric SbF4? ions with distorted Ψ-trigonal-bipyramidal environment of the antimony atoms.  相似文献   

20.
Crystal structure of the 2-hydroxy-3,3,4-trimethyl-2-oxo-5-cyanimino-1,4,2-diazaphospholidine diethylammonium salt (I) was studied by X-ray diffraction analysis: space group P21/c, a=9.773(1), b=12.7617(8), c=12.064(2) Å, β=95.02(1)°, Z=4; R=0.041 (CAD-4 automatic diffractometer, λCuKα, 2518 independent reflections with I≥3δ). In anion I, the P atom (forming two Pō sesquibonds) has a considerably distorted tetrahedral coordination. In the extended flattened molecular fragment of anion I involving 7 atoms [P?N?C(?N)=N?C≡N], the π-electron densities of the atoms are conjugated. The five-membered heterocycle of anion I has a distorted P,C3-half-chair conformation. The crystal structure of compound I has interionic hydrogen bonds linking anions I into centrosymmetric H-dimers and also linking anions I and Et2NH 2 + into centrosymmetric H-tetramers.  相似文献   

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