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1.
X-ray measurements on hexakis(4-(4'-alkyloxy)biphenoxy)cyclotriphosphazenes [PN-(OC6H4C6H4OCnH2n + 1)2]3 (HACP, n = 7-9), confirm the previous mesophase identification. The apparent molecular length measured in the mesophase compares to twice the length of an alkyloxybiphenyl side group. Specific features are added to the usual features of the nematic and smectic diffraction patterns which show that the molecular arrays in directions parallel and perpendicular to the director both reflect the peculiar shape of the cyclotriphosphazenes.  相似文献   

2.
The synthesis, characterization and mesogenic properties of Schiff base compounds arising from the reaction of 4-alkoxybenzaldehydes with 4-aminothiophenol or 4-bromoaniline are described. Whereas the Schiff base thiol with two benzene rings in the molecule, HSC6H4NC(H)C6H4OC16H33 (2), is non-mesogenic, the bromo analogue, BrC6H4NC(H)C6H4OC16H33 (3), is mesogenic. The introduction of a third benzene ring into the molecular architecture of 2 and 3 produced thiol- and bromo-Schiff base compounds, HSC6H4NC(H)C6H4OC(O)C6H4OC16H33 and BrC6H4NC(H)C6H4OC(O)C6H4OC16H33, respectively, that are both mesogenic. The thiol compounds react with nickelocene to form [(η 5-C5H5)Ni(μ 2-SC6H4NC(H)C6H4OC16H33)]2 and [(η 5-C5H5)Ni(μ 2-SC6H4NC(H)C6H4OC(O)-C6H4OC16H33)]2, but the nickel complexes are not mesogenic.  相似文献   

3.
A homologous series of di(4-alkyloxybenzoates) of 4,4'-dimercaptobiphenyl: CH3(CH2)n-1O-C6H4-COS-C6H4-C6H4-SOC-C6H4-O(CH2)n-1CH3,n=1-7, has been synthesized and the thermotropic liquid-crystalline behaviour investigated. All compounds exhibit enantiotropic mesomorphism over a remarkable temperature range. While the mesophase thermal stability is moderately higher than that found for the corresponding oxygenated analogues, the smectic stability is definitely lower. In fact, all the compounds are nematic but smectic mesomorphism (SC) is observed for n = 7. Compounds with n = 6 or 7 exhibit enantiotropic highly ordered smectic (or disordered crystal) phases, probably SG in type.  相似文献   

4.
在本研究中,使用(iPrC6H4SAg)n作为合成银硫纳米簇合物的前驱体。当存在辅助的双膦配体1, 3-双(二苯基膦)丙烷(dppp)及可溶性银盐(CF3SO3Ag),在超声合成条件下,获得了一例二十五核银硫簇合物Ag25,并借助X射线单晶衍射技术确定相应的分子结构。该银硫簇合物具有夹心三明治的骨架结构:分别由两个结构相似的圆柱体共享一个七核纯银簇所构成的金属簇平面。固态紫外可见漫反射光谱测试表明该簇合物的能级带隙为2.5 eV,属于半导体材料的范畴。固态发光测试显示,该簇合物在室温下发射绿光。  相似文献   

5.
The reactions of RNHSi(Me)2Cl (1, R=t-Bu; 2, R=2,6-(Me2CH)2C6H3) with the carborane ligands, nido-1-Na(C4H8O)-2,3-(SiMe3)2-2,3-C2B4H5 (3) and Li[closo-1-R′-1,2-C2B10H10] (4), produced two kinds of neutral ligand precursors, nido-5-[Si(Me)2N(H)R]-2,3-(SiMe3)2-2,3-C2B4H5, (5, R=t-Bu) and closo-1-R′-2-[Si(Me)2N(H)R]-1,2-C2B10H10 (6, R=t-Bu, R′=Ph; 7, R=2,6-(Me2CH)2C6H3, R′=H), in 85, 92, and 95% yields, respectively. Treatment of closo-2-[Si(Me)2NH(2,6-(Me2CH)2C6H3)]-1,2-C2B10H11 (7) with three equivalents of freshly cut sodium metal in the presence of naphthalene produced the corresponding cage-opened sodium salt of the “carbons apart” carborane trianion, [nido-3-{Si(Me)2N(2,6-(Me2CH)2C6H3)}-1,3-C2B10H11]3− (8) in almost quantitative yield. The reaction of the trianion, 8, with anhydrous MCl4 (M=Ti and Zr) in 1:1 molar ratio in dry tetrahydrofuran (THF) at −78 °C, resulted in the formation of the corresponding half-sandwich neutral d0-metallacarborane, closo-1-M[(Cl)(THF)n]-2-[1′-η1σ-N(2,6-(Me2CH)2C6H3)(Me)2Si]-2,4-η6-C2B10H11 (M=Ti (9), n=0; M=Zr (10), n=1) in 47 and 36% yields, respectively. All compounds were characterized by elemental analysis, 1H-, 11B-, and 13C-NMR spectra and IR spectra. The carborane ligand, 7, was also characterized by single crystal X-ray diffraction. Compound 7 crystallizes in the monoclinic space group P21/c with a=8.2357(19) Å, b=28.686(7) Å, c=9.921(2) Å; β=93.482(4)°; V=2339.5(9) Å3, and Z=4. The final refinements of 7 converged at R=0.0736; wR=0.1494; GOF=1.372 for observed reflections.  相似文献   

6.
Treatment of p-tert-butylcalix[6]areneH6 (H6L) with [Mo(OBut)2{[2,2′-(N)-C6H4]2(CH2CH2)}] in refluxing toluene affords, after work-up, the complex [Mo(2-NC6H4CH2CH2C6H4NHC(Me)NH-2/)LH2]·4MeCN (1), which contains an 11-membered metallocyclic ring as characterised by Synchrotron X-radiation.  相似文献   

7.
The reactions of HL 1 [where HL is 1N-(2-pyridyl-2-methyl)-2-arylazoaniline and is formulated as ArN = NC6H4N(H)(CH2C5H4N); Ar = C6H5 (for HL1) or p-MeC6H4 (for HL2) or p-ClC6H4 (for HL3)] with K2PtCl4 and Co(ClO4)3 · 6H2O afforded the (L)PtCl and [(L)2Co]ClO4 complexes, respectively. The HL ligands bind the platinum(II) and cobalt(III) centres in a tridentate (N,N,N) fashion, forming new diazoketiminato chelates upon dissociating the amino proton. The X-ray structures of (L3)PtCl and [(L3)2Co]ClO4 were determined. Redox properties of the new complexes have been examined.  相似文献   

8.
A new tellurium-containing heterocyclic compound, 2,2,6,6-tetramethyl-1-oxa-4-tellura-2,6-disilacyclohexane (C6H16OSi2Te) (1), has been prepared by treatment of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane with sodium telluride. Mononuclear and dinuclear palladium complexes of this telluride have been prepared by the reaction of 1 with PdCl2(PhCN)2 and Na2PdCl4, respectively. The following new derivatives of 1 have also been produced: C6H16OSi2TeI2 (2), C6H16OSi2TeBr2, C6H16OSi2TeCl2, C6H16OSi2Te(CH3)I, and C6H16OSi2Te(CH2Ph)Br. IR, 1H and 13C NMR and mass spectral data of these new compounds are reported and discussed. 1H NMR studies revealed that in CDCl3 solution both telluronium salts reductively eliminate alkyl halide. The crystal structure of compound 2 has been determined by X-ray diffraction. The compound crystallizes in the monoclinic space group, P21/c, with four molecules in a unit cell of dimension a 12.960(3), b 8.846(2), c 13.754(4) Å, β 92.44(2)°, R = 0.049, and Rw = 0.067 for 3599 unique reflections with |F0| > 3σ(F0). The compound forms a six-membered ring of a slightly displaced boat type. The geometry about the Te atom is pseudo-octahedral, with two carbon atoms (Te-C = 2.156(7) and 2.137(6) Å) and two iodine atoms of the neighbouring molecules (weak intermolecular bonds, Te · I = 3.769 and 3.806 Å) in the equatorial positions and two iodine atoms (Te-I = 2.909(1) and 2.913(1) Å) in the axial positions.  相似文献   

9.
Twentyfour liquid crystalline esters of the type 4-(n-CnH2n+1O)C6H4COOC6H4OOCC6H4-X-4 have been investigated for their phase behaviour. These compounds constitute six homologous series that differ from each other by the substituent X. The latter varies between CH3O, CH3, Cl, CN, NO2, and n-CnH2n+1O, and the number (n) of carbons varies, within a homologous series, between 6, 8, 14, and 16. All possible binary mixtures made from any two homologues were prepared and characterized for their mesophase behaviour by differential scanning calorimetry and polarizing optical microscopy.  相似文献   

10.
用INDO系列方法对由(C59N)2和苯甲醚合成的衍生物C59(C6H4OCH3)N进行了理论研究,得到了分子的稳定构型.结果表明,C59(C6H4OCH3)N具有Cs对称性.以优化构型为基础讨论了分子的UV-Vis光谱、NMR谱线数,结果与实验符合得很好.本文还计算了C59(C6H4OCH3)N的二阶非线性光学系数βμ,结果表明这种物质具有较大的二阶非线性光学系数.  相似文献   

11.
The cluster [Os3(CO)10(MeCN)2] reacts with indazole (C7H6N2) to give two isomeric products [0s3(μ-H)(μ-C7H5N2)(CO)10] in which the five-membered ring has been metallated with N-H cleavage to give an N,N-bonded isomer or with C-H cleavage to give a C,N-bonded isomer. These two isomers have very similar X-ray structures but can be clearly distinguished by 1H NMR methods. They are shown to correspond to related clusters derived from pyrazole. Benzotriazole (C6H5N3) also reacts (as shown earlier by others) to give two isomers: an N,N-bonded species [Os3(μ-H)(μ-C6H4N3)(CO)10] coordinated only through the five-membered ring and a minor C,N-bonded isomer [Os3(μ-H)(μ-C6H4N3)(CO)10], metallated at the C6 ring and coordinated through both rings. The former isomer reacts with Me3NO in acetonitrile to give [Os3(μ-H)(μ-C6H4N3)(CO)9(MeCN)] which thermally looses MeCN to produce the coupled product [Os6(μ-H)2(μ3-C6H4N3)2(CO)18] which was shown by X-ray structure determination to have all six nitrogen atoms coordinated to osmium, a novel situation for coordinated benzotriazole. The two Os3 units are linked together by an OsNNOsNN ring in a boat conformation with the whole cluster adopting C2 symmetry.  相似文献   

12.
采用密度泛函理论PBE0方法, 在aug-cc-pVTZ水平上理论预测了含平面五配位硅和锗原子的XBe5H6 (X=Si, Ge)团簇. 势能面系统搜索及高精度量化计算表明, 它们均为全局极小结构. XBe5H6(X=Si, Ge)团簇整体呈完美的扇形结构: Si/Ge原子被5个金属Be原子配位; 4个H原子以桥基方式与Be原子相键连, 剩余的2个 H原子以端基方式与两端的Be原子成键. 化学键分析表明, XBe5H6(X=Si, Ge) 团簇中XBe5单元具有完全离域的1个π及3个σ键, 外围铍氢间形成4个Be—H—Be 三中心二电子(3c-2e)键及2个定域的Be—H键. XBe5单元上离域的2π及6σ电子赋予体系πσ双重芳香性, 并使Si/Ge原子满足八隅律(或八电子规则). 能量分解-化学价自然轨道分析揭示, Si/Ge和Be5H6之间主要为电子共享键.  相似文献   

13.
Reaction of [Cp*TiF3] (Cp* = (ν5-C5Me5)) with Me3SiOSO2- p-C6H4CH3, Me3SiOPOPh2 and 1,2-(Me3SiOCO)2C6H4 yields the dinuclear complexes [{Cp*TiF(μ-F)(μ-OSO2-p-C6H4CH4)}2] (1), [{Cp*TiF(μ-F)(μ-OPOPh2)}2] (2) and [{Cp*TiF(μ-F)(μ-OCO-o-C6H4CO2SiMe3)}2] (3). The molecular structures of 1 and 2 have been determined by single-crystal X-ray analysis. In complexes 1-3, the two titanium atoms are connected by bridging fluorine atoms as well as bridging sulfonate, phosphinate and carboxylate groups respectively. Each titanium atom is also bonded to a terminal fluorine atom. Reaction of [Cp2*ZrF2] with 1,2-(Me3SiOCO)2C6H4 leads to the mononuclear pentacoordinate 18-electron species [Cp2*ZrF(μ-OCO-o-C6H4CO2SiMe3)] (4) and its structure was determined by X-ray crystallographic methods.  相似文献   

14.
The new diphenolato complexes [{Mo(NO){HB(dmpz)3}Cl}2Q] where dmpz = 3,5-dimethylpyrazolyl and Q = OC6H4(C6H4O (n = 1 or 2), OC6H4CR=CRC6H4O (R = H or Et), and OC6H4CH=CHC6H4CH=CHC6H4O have been prepared and their electrochemical properties (cyclic and differential pulse voltammetry) compared with previously reported analogues where Q = OC6H4O, OC6H4EC6H4O (E = SO2, CO and S), OC6H4 (CO)C6H4 C6H4(CO)C6H4O and 1,5- and 2,7-O2C10H6. The electrochemical interaction between the redox centres in the new complexes is very weak, in contrast to that in the 1,4-benzenediolato and naphthalendiolato species. The EPR spectra of the reduced mixed-valence species [{Mo(NO){HB(dmpz)3}Cl}2Q] where Q = 1,3- and 1,4-OC6H4O and OC6H4SC6H4O shows that they are valence-trapped at room temperature, whereas those of the dianions [{Mo(NO){HB(dmpz)3}Cl}2Q]2− where Q = 1,4-OC6H4O, OC6H4EC6H4O (E = CO or S) and OC6H4CH=CHC6H4CH=CHC6H4O shows that the unpaired spins on each molybdenum centre are strongly correlated (J, the spin exchange integral AMo, the metal-hyperfine coupling constant). The electrochemical properties and the comproportionation constants for the reaction [{Mo(NO){HB(dmpz)3} Cl}2Q] + [{Mo(NO){HB(dmpz)3}Cl}O]2]2−2[{Mo(NO) {HB(dmpz)3}Cl}2Q] where Q = diphenolato bridge, are compared with related compounds containing benzenediamido and dianilido bridges.  相似文献   

15.
The P–Ph cleavage of phenyldibenzophosphole (1) with lithium in THF gives lithium dibenzophospholide (2). Reaction of 2 with ethyleneglycol ditosylate produces the known chelate ligand 1,2-bis(dibenzophospholyl)ethane (3) in good yield. Similarly, 2 and (2R,3R)-butanediol ditosylate give the new chiral chelate ligand (2S,3S)-bis(dibenzophospholyl)butane (4). Ligand exchange of [CpRu(PPh3)2Cl] with 3 or 4 yields the halfsandwich complexes [CpRu(C12H8PC2H4PC12H8)Cl] (5) and [CpRu((S,S)-C12H8PCHMeCHMePC12H8)Cl] (6). Complex 6 was characterized crystallographically (monoclinic, space group P21 (no. 4), a=820.6(4), b=1501.0(3), c=1172.8(6) pm, β=108.87(2)°, V=1.367(1)×109 pm3, Z=2). The most conspicuous feature of the structure of 6 is the perfect coplanarity of the two dibenzophosphole moieties imposed by their steric interaction with the Cp ligand. Complex 6 and the thiophene complex [CpRu((S,S)-C12H8PCHMeCHMePC12H8)(SC4H4)]BF4 (7) derived therefrom are remarkably unreactive with regard to ligand substitutions. A possible explanation is the lack of intramolecular –C stabilization en route to the transition state of ligand substitution. The enantiomeric purity of 6 and 7 could nevertheless be demonstrated by conversion to diastereomerically pure [CpRu((S,S)-C12H8PCHMeCHMePC12H8)((S)-CNCHMePh)]BF4 (8).  相似文献   

16.
Thermal displacement of coordinated nitriles RCN (R = CH3, C2H5 or n-C3H7) in [C5H5Fe(L2)(NCR)]X complexes (L2 = P(OCH3)3)2, (P(OC6H5)3)2 or (C6H5)2PC2H4P(C6H5)2 (DPPE)) by E(CH3)2 affords high yields of [C5H5Fe(L2)(E(CH3)2)]X compounds (E = S, Se and Te; X = BF4 or PF6). Spectroscopic data and ligand displacement reactions are presented and discussed together with related observations on [C5H5Fe(CO)2(E(CH3)2)]BF4 compounds. The molecular structure of [C5H5Fe(P(OCH3)3)2(S(CH3)2)]PF6 was determined by a single-crystal X-ray diffraction study: monoclinic, space group P21/n-C52h (No. 14) with a = 8.4064(12), b = 11.183(2), c = 50.726(8) Å, β = 90.672(13)° and Z = 8 molecules per unit cell. The coordination sphere of the iron atom is pseudo-tetrahedral with an Fe---S bond distance of 2.238 Å.  相似文献   

17.
A new series of 1,1'-disubstituted ferrocene compounds of the type [(η5-C5H4(CH2)nOC6H4C6H4CN]2Fe (3a-d, n = 5, 6, 8, 11) incorporating a variable length alkyloxy cyanobiphenyl unit has been prepared and their mesomorphic properties have been investigated. Compounds 3b, c and d exhibit a thermotropic smectic C phase and 3c also exhibits a monotropic smectic A phase over a fairly wide range near ambient temperature.  相似文献   

18.
Structures and energies have been calculated, in the MNDO approximation, for PH3, P2H4, P2H2, and P3H5, for their molecular cations, for all the ions in their mass spectra, and for the corresponding neutral mass spectral fragments. With the exception of the conformation of P2H4, which is calculated to be anti rather than gauche, the calculated structures and energies are in good agreement with those found experimentally, where these are known. Appearance potentials have been calculated, and allow deductions to be made concerning fragmentation pathways.  相似文献   

19.
硫代嘧啶碱基是光动力疗法潜在的重要光敏剂,其最低单重激发态的光物理研究已有广泛报道。然而,其较高激发态的跃迁性质和反应动力学研究较为稀少。因此,本文采用共振拉曼光谱和密度泛函理论计算方法研究2,4-二硫代尿嘧啶的紫外光谱和几个较高单重激发态的短时结构动力学。首先,基于共振拉曼光谱强度与电子吸收带振子强度f的关系,将紫外光谱去卷积成四个吸收带,分别为358 nm(f=0.0336)中等强度吸收带(A带),338 nm(f=0.1491)、301 nm(f=0.1795)和278 nm(f=0.3532)强而宽的吸收带(B、C和D带)。这一结果既吻合密度泛函理论计算结果,又符合共振拉曼光谱强度模式对紫外光谱带的预期。据此,去卷积得到的四个吸收带被分别指认为S0→S2跃迁、S0→S6跃迁、S0→S7跃迁和S_0→S_8跃迁。同时,分别对B,C和D带共振拉曼光谱进行了详细的指认,获得了短时动力学信息。结果表明,S_8态短时动力学的显著特征是在Franck-Condon区域或附近发生了S8(ππ~*)/S(nπ~*)势能面交叉引发的、伴随超快结构扭转的非绝热过程。S7和S6态短时动力学的主要特征是反应坐标的多维性,它们分别沿C_5C_6/C_2S_8/C_4S_(10)/N_2C_3+C_4N_3H_9/N_1C_2N_3/C_2N_1C_6/C_6N_1H_7/C_5C_6H_(12)和C_5C_6/N_3C_2/C_4S_(10)/C_2S_8+C_6N_1H_7/C_5C_6H_(12)/C_5C_6N_1/C_5C_6H_(12)/C_2N_1C_6/N_1C_2N_3/C_4N_3H_9/N_1C_2N_3等内坐标演化。  相似文献   

20.
The synthesis, characterization and thermal behaviour of several new series of copper(II) complexes derived from carbonylic compounds and their Schiff's bases are reported. The complexes are of two types; [Cu(C6H3O(R)-C(X) = O)2], (type I) and [Cu(C6H3O(R)-C(X) = N-R')2] (type II) where R = - OOC-C6H4OC10H21-p, and the position of R is 4 or 5; R' = CH3, n-C10H21, p-n-C10H21O(C6H4)-; X = H, CH3. In type I complexes, only the compound with X = H and R in position 5 showed mesomorphism. For type II complexes, all the Schiff's bases complexes of copper(II) derived from 2,4-dihydroxybenzaldehyde showed thermotropic mesophases (smectic C and nematic), whereas the complexes derived from 2,5-dihydroxybenzaldehyde were only mesogenic when the imine was derived from methylamine. None of the complexes derived from the ketone (2,4 or 2,5-dihydroxy derivatives) showed liquid-crystalline properties. X-ray studies of four complexes of type II were carried out. The anisotropy of the magnetic susceptibility has a negative sign for complexes with R in position 4 and a positive sign for 2,5-derivative complexes. The relationship between molecular structure and mesomorphic behaviour is discussed.  相似文献   

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