Aromaticity of ring carbo-mers of [N]annulenes and [N]cycloalkanes

Maps of current density induced by a perpendicular external magnetic field are calculated at the ipsocentric CTOCD-DZ/6-31G**//B3PW91/6-31G** level for ring carbo-mers of [N]-annulenes (closed-shell singlet states of C(3N)H, N = 3 to 7, with q = -1, 0, +1, 0, -1, respectively, and also the triplet ground state for N = 4) and of [N]-cycloalkanes (C(3N)H(qN), N = 3, 4, 5). Strong four-electron diatropic ring currents indicate conventional pi aromaticity for all the singlet and triplet carbo-[N]annulenes studied, with the exception of C(12)H(4), where instead the strong two-electron paratropic ring current is the signature of pi antiaromaticity. The carbo-[N]cycloalkanes (also known as [N]pericyclynes) show only localized pi currents, consistent with non-aromaticity. There is no indication of a 'homo-aromatic' ring current attributable to the in-plane pi orbitals of the inserted C2 units in any of the maps. Consequences for the interpretation of ELF (electron localisation function) populations are discussed.     

Synthesis and crystal structures of Cd[AlCl4]2 and Cd2[AlCl4]2

Colorless single crystals of Cd[AlCl₄]₂ grow from the melt of CdCl₂ and AlCl₃ upon slow cooling from 250°C. The crystal structure [monoclinic, P1a1, Z = 2, a = 1288.7(2), b = 660.2(1), c = 705.1(1) pm, β = 92.89(1)º] may be derived from hexagonally closest packed layers of Cl^?. Octahedral and tetrahedral holes are filled with Cd²⁺ and Al³⁺ in a 1:2 ratio between all layers stacked in the [104] direction. Cd[GaCl₄]₂ and Cd[AlBr₄]₂ are isotypic. Reduction of Cd[AlCl₄]₂ with excess cadmium shot and slow cooling from 350°C yields plate-like very moisture-sensitive, colorless single crystals of Cd₂[AlCl₄]₂. The crystal structure [triclinic, C1 , Z = 2, a = 655.47(3), b = 1135.26(1), c = 935.23(6) pm, α = 89.70(2)º, β = 103.61(1)º, γ = 90.455(1)º] is built from slabs stacked in the [100] direction consisting of ethane-like [Cd₂Cl₆] units with a Cd? Cd distance of 256.1 pm sharing common vertices with [AlCl₄] tetrahedra.     

Synthesis of tris(tetrathiafulvaleno)dodecadehydro- [18]annulenes and their self-assembly

[reaction: see text] Synthesis of electroactive tris(tetrathiafulvaleno)dodecadehydro[18]annulenes with ester substituents has been carried out with palladium-mediated cyclotrimerization of 4,5-diethynyl-TTFs. The TTF[18]annulenes produce stacked dimmers in solution and exhibit solvatochromism and thermochromism. The TTF[18]annulene-hexabutyl ester forms a molecular wire from an aqueous THF solution with cooperative S-S and pi-pi stacking interactions.     

Theoretical (DFT, GIAO-NMR, NICS) study of carbocations (M+H)+, dications (M2+) and dianions (M2-) from dihydro-dicyclopenta[ef,kl]heptalene (dihydro-azupyrene), dihydro-dicyclohepta[ed,gh]pentalene, and related bridged [14]annulenes

The annulenium ions of protonation, the two-electron oxidation dications, and the two-electron reduction dianions derived from dihydro- and dimethyldihydro derivatives (cis and trans) of dicyclopenta[ef,kl]heptalene (azupyrene) (1) and dicyclohepta[ed,gh]pentalene (2), which are the nonalternant isomers of pyrene, were studied by density functional theory (DFT) at the B3LYP/6-31G(d), 6-31+G(d,p), or 6-31++G(d,p) levels. Charge delocalization modes in the energetically most favored annulenium ions, as well as in the singlet and triplet dications and dianions, were assessed based on gauge-including atomic orbital (GIAO) Deltadelta](13)C values and via changes in natural population analysis (NPA) charges. Relative aromaticity/antiaromaticity in the annulenes were gauged via nucleus-independent chemical shift (NICS) and DeltaNICS. Annulenium ions of monoprotonation, the dications, and dianions derived from bismethano- and propanediylidene [14]annulenes were also studied by DFT for comparison with the cis-dihydro isomers derived from . Computed GIAO NMR data and the optimized geometries were compared with the experimental data when available, and the optimized geometries were compared with the X-ray data if known. A basis-set dependency study of the computed GIAO chemical shifts was also undertaken. The present DFT work represents the first detailed comparative theoretical study of charged annulenes derived from the dihydro derivatives of and .     

Synthesis and structural, electrochemical, and stacking properties of conical molecules possessing buckyferrocene on the apex

A series of conical molecules featuring a [60]fullerene/ferrocene hybrid and five aralkyl side chains (Fe[C60{C6H4-(OCO-C6H3-(OR)2-3,4)-4}5]Cp) have been synthesized and examined for their structural and electrochemical properties as well as their ability to form supramolecular structures in crystals and liquid crystals. When the R group on the side is a methyl group, the compound forms crystals in which the dipolar conical molecules are stacked head-to-tail to form a columnar structure. When the R group is as long as a C18H38 group, the compound forms liquid crystals. Oxidation of the liquid crystalline compound by an aminium salt [(4-BrC6H4)3N][SbCl6] produces the corresponding paramagnetic Fe(III) compound that also exhibits liquid crystalline properties.     

Synthesis and Crystal Structure of 1-（4-Fluorophenyl）-2-hexylthiobenzo[4,5]-furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5（1H）-one

The crystal structure of the title compound 1-(4-fluorophenyl) -2-hexylthio-benzo [4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5(1H) -one(C23H21FN4O2S,Mr = 436.5) has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic,space group P21/n with a = 13.9854(3) ,b = 17.2678(4) ,c = 18.1828(5) ,β = 99.364(2) °,V = 4332.58(18) 3,Z = 4,Dc = 1.338,F(000) =1824,μ = 0.185 mm-1,MoKa radiation(λ = 0.71073) ,R = 0.0538 and wR = 0.1162 for 4728 observed reflections with I > 2σ(I) . X-ray diffraction analysis reveals the fused rings of benzo[4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a] pyrimidin-5(1H) -one system are nearly coplanar. The crystal packing is mainly stabilized by weak intermolecular C-H···O hydrogen bond and π-π interactions.     

[C6N2H18]2[Mo5O15(HPO4)2]·H2O的水热合成与结构表征

通过水热法合成了一个新化合物[C6N2H18]2[Mo5O15(HPO4)2]·H2O,并通过IR光谱、ICP、元素分析、差热与热重分析和X射线单晶衍射分析等手段进行了表征.结果表明,晶体属三方晶系,P3(2)21空间群,a=1.1231(1)nm,c=2.2802(5)nm,V=2.4911(7)nm3,Dx=2.835Mg/m3,Z=6,最后的一致性因子R=0.0227,wR=0.0675.阴离子中Mo5O15构成一环状结构,2个HPO4一个连在环的下方,一个连在环的上方,形成类似于“飞碟”状的结构,阳离子为2个质子化的四甲基乙二胺.     

Generation and characterization of highly strained dibenzotetrakisdehydro[12]- and dibenzopentakisdehydro[14]annulenes

To generate dibenzotetrakisdehydro[12]- and dibenzopentakisdehydro[14]annulenes ([12]- and [14]DBAs) having a highly deformed triyne moiety, [4.3.2]propellatriene-anneleted dehydro[12]- and dehydro[14]annulenes were prepared as their precursors. UV irradiation of the precursors resulted in the photochemical [2 + 2] cycloreversion to generate the strained [12]- and [14]DBAs, respectively. The [12]DBA was not detected by 1H NMR spectroscopy, but it was intercepted as Diels-Alder adducts in solution, suggesting its intermediacy. Its spectroscopic characterization was successfully carried out by UV-vis spectroscopy in a 2-methyltetrahydrofuran (MTHF) glass matrix at 77 K and by FT-IR spectroscopy in an argon matrix at 20 K. On the other hand, the [14]DBA was stable enough for observation by 1H and 13C NMR spectra in solution, though it was not isolated because of the low efficiency of the cycloreversion. The [14]DBA was also characterized by interception as Diels-Alder adducts in solution and by UV-vis spectroscopy in a MTHF glass matrix at 77 K. The kinetic stabilities of the DBAs are compared with the related dehydrobenzoannulenes with respect to the topology of the pi-systems. In addition, the tropicity of the [14]DBA is discussed based on its experimental and theoretical 1H NMR chemical shifts.     

Ring-opening protonolysis of sila[1]ferrocenophanes as a route to stabilized silylium ions

The ring-opening reactions of a series of sila[1]ferrocenophanes with protic acids of anions with various degrees of noncoordinating character have been explored. Ferrocenyl-substituted silyl triflates FcSiMe2OTf (5 a) and Fc(3)SiOTf (5 b) (Fc=(eta5-C5H4)Fe(eta5-C5H5)) were synthesized by means of HOTf-induced ring-opening protonolysis of strained sila[1]ferrocenophanes fcSiMe2 (3 a) and fcSiFc2 (3 b) (fc=(eta5-C5H4)2Fe). Reaction of 3 a and 3 b with HBF4 yielded fluorosubstituted ferrocenylsilanes FcSiMe2F (6 a) and Fc3SiF (6 b) and suggested the intermediacy of a highly reactive silylium ion capable of abstracting F- from the [BF4]- ion. Generation of the solvated silylium ions [FcSiMe2THF]+ (7a+), [Fc3SiTHF]+ (7b+) and [FcSiiPr2OEt2]+ (7c+) at low temperatures, by reaction of the corresponding sila[1]ferrocenophanes (3 a, 3 b, and fcSiiPr2 (3 c), respectively) with H(OEt2)(S)TFPB (S=Et2O or THF; TFPB=tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) was monitored by using low-temperature 1H, 13C, and 29Si NMR spectroscopy. In situ reaction of 7a+, 7b+, and 7c+ with excess pyridine generated [FcSiMe2py]+ (8a+), [Fc3Sipy]+ (8b+), and [FcSiiPr2py]+ (8c+), respectively, as observed by 1H, 13C, and 29Si NMR spectroscopy. A preparative-scale reaction of 3 b with H(OEt2)(THF)TFPB at -60 degrees C and subsequent addition of excess pyridine gave isolable red crystals of 8b-[TFPB]CHCl3, which were characterized by 1H and 29Si NMR spectroscopy as well as by single-crystal X-ray diffraction.     

Monocarbaborane anion chemistry. The elusive C-arylated [PhCB11H11]-, [PhCB9H9]- and [PhCB8H8]- anions

B10H14 and PhCHO yield [6-Ph-nido-6-CB9H11]- (94%), from which the nine-vertex C-phenyl monocarbaborane anion [4-Ph-closo-4-CB8H8]- (68%) can be obtained by heating at 200 degrees C, and from which the twelve- and ten-vertex analogues [1-Ph-closo-1-CB11H11]- (50%) and [4-Ph-closo-4-CB9H9]- (25%) can be obtained by heating at 210 degrees C with BH3(NEt3).     

Synthesis and Crystal Structure of 1-（4-Bromobenzoyl）-3- [5-（E）-styryl-1,3,4-thiadiazol-2-yl]urea

1 INTRODUCTION 1,3,4-Thiadiazole derivatives represent an interes- ting class of compounds possessing broad spectrum biological activities[1~4]. Aroyl ureas are known to exhibit diverse biological effects, such as insecticidal, fungicidal, herbicidal and plant growth regulating activities[5~8]. Therefore, it is worthwhile to investi- gate the compounds incorporating both 1,3,4-thiadia- zole nucleus and aroyl urea group. In the previous paper[9], a series of aroyl ureas containing 1,3,4-t…     

Synthesis and structure of [K(+)-(2,2)diaza-[18]-crown-6][K3Ge9]-2ethylenediamine: stabilization of the two-dimensional layer (2)(infinity)[K3Ge9(1-)

Large bright-red, transparent crystalline plates of [K-(2,2)diaza-[18]-crown-6]K3Ge9-2en are obtained, in high-yield, from a reaction of (2,2)diaza-[18]-crown-6 in toluene with a solution of K4Ge9/potassium metal (K) in ethylenediamine (en). The compound crystallizes in the monoclinic space group P2(1)/m (a = 10.740(1) A, b = 15.812(1) A, c = 12.326(1) A, beta = 114.74 degrees; Z = 2). The crystal structure of [K-(2,2)diaza-[18]-crown-6]K3Ge9-2en features two-dimensional [K3Ge9] layers formed by uncomplexed K(+) cations and Ge94(-) anions. The "not-so-bare" cluster compound features a unique Ge94(-) cluster that exhibits a slightly distorted C(2v) geometry that is closer to D(3h) than the expected C(4v). Use of noncryptand sequestering agents in the isolation of Ge cluster anions from en solutions opens new avenues in understanding important cation-anion interactions in the stability and reactivity of Zintl ions, as well as a viable route to isolating Zintl anions with higher charges per atom.     

Electronic, spectroscopic, and ion-sensing properties of a dehydro[m]pyrido[14]- and [15]annulene isomer library

An isomeric series of dehydro[m]pyrido[n]annulenes incorporating strained 1,4-buta-1,3-diyne units have been synthesized, where m = 2, n = 14 (1a-d); m = 2, n = 15 (2a,b); and m = 3, n = 15 (3). The number of pyridine rings and annulene ring π-electrons are denoted by m and n, respectively. The X-ray crystal structures of 1b and 1c confirmed their cyclic formulation. All macrocycles were found to be luminescent chromophores with differing isomer-dependent proton and metal ion-sensory emission responses, which appear collectively as analyte-specific color patterns. Within the series studied, 1a was singular in displaying the highest luminescence quantum yield and sharing the strongest emission energy and molar absorption changes upon protonation and Hg(II) binding. Spectroscopic and electrochemical results were supported by density functional theory calculations in showing 1a, 2a, and 3 to be low bandgap materials with lowest unoccupied molecular orbitals delocalized over the 1,4-di(pyridin-4-yl)buta-1,3-diyne bridges that provide a pathway for electronic communication between the nitrogens. Overall, the investigations suggest that 1a, 2a, and 3 would be excellent ligands for the construction of novel conjugated hybrid metallosupramolecular nanostructures, polymers, and ion-sensory systems.     

C6F5Xe]+ and [C6F5XeNCCH3]+ salts of the weakly coordinating borate anions, [BY4]- (Y = CN, CF3, or C6F5)

New examples of [C6F5Xe]+ salts of the weakly coordinating [BY4]- (Y = CN, CF3, or C6F5) anions were synthesized by metathesis of [C6F5Xe][BF4] with MI[BY4] (MI = K or Cs; Y = CN, CF3, or C6F5) in CH3CN at -40 degrees C, and were crystallized from CH2Cl2 or from a CH2Cl2/CH3CN solvent mixture. The low-temperature (-173 degrees C) X-ray crystal structures of the [C6F5Xe]+ cation and of the [C6F5XeNCCH3]+ adduct-cation are reported for [C6F5Xe][B(CF3)4], [C6F5XeNCCH3][B(CF3)4], [C6F5Xe][B(CN)4], and [C6F5XeNCCH3][B(C6F5)4]. The [C6F5Xe]+ cation, in each structure, interacts with either the anion or the solvent, with the weakest cation-anion interactions occurring for the [B(CF3)4]- anion. The solid-state Raman spectra of the [C6F5Xe]+ and [C6F5XeNCCH3]+ salts have been assigned with the aid of electronic structure calculations. Gas-phase thermodynamic calculations show that the donor-acceptor bond dissociation energy of [C6F5XeNCCH3]+ is approximately half that of [FXeNCCH3]+. Coordination of CH3CN to [C6F5Xe]+ is correlated with changes in the partial charges on mainly Xe, the ipso-C, and N, that is, the partial charge on Xe increases and those on the ipso-C and N decrease upon coordination, typifying a transition from a 2c-2e to a 3c-4e bond.     

非MAO的茂钛均相催化体系催化苯乙烯间规聚合——[Cp~*TiMe_3]/[Ph_3C]~+[B(C_6F_5)_4]~-催化体系

非ＭＡＯ的茂钛均相催化体系催化苯乙烯间规聚合———［ＣｐＴｉＭｅ３］／［Ｐｈ３Ｃ］＋［Ｂ（Ｃ６Ｆ５）４］－催化体系许光学林尚安（中山大学高分子研究所广州５１０２７５）关键词茂钛络合物，茂金属催化剂，苯乙烯，间规聚苯乙烯间规聚苯乙烯（ｓＰＳ）由于具...     

1-[1-(4-氯苯基)环丁基]-3-甲基丁胺席夫碱的合成、表征及晶体结构

采用减肥药盐酸西布曲明的中间体1-[1-(4-氯苯基)环丁基]-3-甲基丁胺分别与水杨醛、3,5-二氯水杨醛缩合,得到相应的席夫碱化合物2-[[1-[1-(4-氯苯基)环丁基]-3-甲基丁亚氨基]甲基]苯酚(1)和2,4-二氯-6-[[1-[1-(4-氯苯基)环丁基]-3-甲基丁亚氨基]甲基]苯酚(2).通过单晶X-射线衍射、红外光谱、核磁共振谱、元素分析等表征确定了两个席夫碱化合物的组成及结构.1是单斜晶体,空间群C2/c.2是三斜晶体,空间群P-1.化合物主要通过氢键或π-π相互作用形成超分子结构.两个席夫碱化合物具有相似的荧光性质,是潜在多功能蓝色荧光材料.     

Redox non-innocence of thioether crowns: elucidation of the electronic structure of the mononuclear Pd(III) complexes [Pd([9]aneS3)2]3+ and [Pd([18]aneS6)]3+

The Pd(II) complexes [Pd([9]aneS(3))(2)](PF(6))(2)·2MeCN (1) ([9]aneS(3) = 1,4,7-trithiacyclononane) and [Pd([18]aneS(6))](PF(6))(2) (2) ([18]aneS(6) = 1,4,7,10,13,16-hexathiacyclooctadecane) can be oxidized electrochemically or chemically oxidized with 70% HClO(4) to [Pd([9]aneS(3))(2)](3+) and [Pd([18]aneS(6))](3+), respectively. These centers have been characterized by single crystal X-ray diffraction, and by UV/vis and multifrequency electron paramagnetic resonance (EPR) spectroscopies. The single crystal X-ray structures of [Pd(III)([9]aneS(3))(2)](ClO(4))(6)·(H(3)O)(3)·(H(2)O)(4) (3) at 150 K and [Pd([18]aneS(6))](ClO(4))(6)·(H(5)O(2))(3) (4) at 90 K reveal distorted octahedral geometries with Pd-S distances of 2.3695(8), 2.3692(8), 2.5356(9) and 2.3490(6), 2.3454(5), 2.5474(6) ?, respectively, consistent with Jahn-Teller distortion at a low-spin d(7) Pd(III) center. The Pd(II) compound [Pd([9]aneS(3))(2)](PF(6))(2) shows a one-electron oxidation process in MeCN (0.2 M NBu(4)PF(6), 293 K) at E(1/2) = +0.57 V vs. Fc(+)/Fc assigned to a formal Pd(III)/Pd(II) couple. Multifrequency (Q-, X-, S-, and L-band) EPR spectroscopic analysis of [Pd([9]aneS(3))(2)](3+) and [Pd([18]aneS(6))](3+) gives g(iso) = 2.024, |A(iso(Pd))| = 18.9 × 10(-4) cm(-1); g(xx) = 2.046, g(yy) = 2.041, g(zz) = 2.004;?|A(xx(Pd))| = 24 × 10(-4) cm(-1), |A(yy(Pd))| = 22 × 10(-4) cm(-1), |A(zz(Pd))| = 14 × 10(-4) cm(-1), |a(xx(H))| = 4 × 10(-4) cm(-1), |a(yy(H))| = 5 × 10(-4) cm(-1), |a(zz(H))| = 5.5 × 10(-4) cm(-1) for [Pd([9]aneS(3))(2)](3+), and g(iso) = 2.015, |A(iso(Pd))| = 18.8× 10(-4) cm(-1); g(xx) = 2.048 g(yy) = 2.036, g(zz) = 1.998; |a(xx(H))| = 5, |a(yy(H))| = 5, |a(zz(H))| = 6 × 10(-4) cm(-1); |A(xx(Pd))| = 23× 10(-4) cm(-1), |A(yy(Pd))| = 22 × 10(-4) cm(-1), |A(zz(Pd))| = 4 × 10(-4) cm(-1) for [Pd([18]aneS(6))](3+). Both [Pd([9]aneS(3))(2)](3+) and [Pd([18]aneS(6))](3+) exhibit five-line superhyperfine splitting in the g(zz) region in their frozen solution EPR spectra. Double resonance spectroscopic measurements, supported by density functional theory (DFT) calculations, permit assignment of this superhyperfine to through-bond coupling involving four (1)H centers of the macrocyclic ring. Analysis of the spin Hamiltonian parameters for the singly occupied molecular orbital (SOMO) in these complexes gives about 20.4% and 25% Pd character in [Pd([9]aneS(3))(2)](3+) and [Pd([18]aneS(6))](3+), respectively, consistent with the compositions calculated from scalar relativistic DFT calculations.     

Large pressure-induced red shift of the luminescence band originating from nonstacked square-planar [Pt(SCN)4]2- in a novel trimetallic complex

Luminescence of the novel trimetallic complex {Pt(SCN)2[(mu-SCN)Mn(NCS)(bipy)2]2} originates from a d-d transition of the square-planar [Pt(SCN)4]2- moiety. The band maximum shows a red shift of -99 cm(-1) kbar(-1) under external pressure up to 32 kbar at room temperature. This red shift is comparable to values for crystals where Pt-Pt interaction between stacked complexes is enhanced by pressure, but the crystal structure for the trimetallic complex shows that no metal-metal interaction can occur.     

pH-dependence of the aqueous electrochemistry of the two-electron reduced alpha-[Mo18O54(SO3)] sulfite Dawson-like polyoxometalate anion derived from its triethanolammonium salt

The electrochemistry of the Dawson-like sulfite polyoxometalate anion alpha-[Mo18O54(SO3)2]6-, derived from the TEAH6{alpha-[Mo18O54(SO3)2]} salt (TEAH+ is the triethanolammonium cation; pKa=7.8), has been investigated in aqueous media using cyclic and rotated disk voltammetry at glassy carbon electrodes and bulk electrolysis, with a focus on the pH-dependence for oxidation to alpha-[Mo18O54(SO3)2]4-. In buffered media at pH>or=4, the cyclic voltammetric response for alpha-[Mo18O54(SO3)2]6- reveals two partially resolved one-electron oxidation processes corresponding to the sequential generation of alpha-[Mo18O54(SO3)2]5- and alpha-[Mo18O54(SO3)2]4-. At lower pH, using electrolytes containing sulfuric acid, the two waves coalesce but the individual apparent E0' reversible formal potential values for the two processes can be extracted down to pH 2 by assuming that reversible protonation accompanies fast electron transfer. The results for 2相似文献   

Synthesis,crystal structure,and density functional theory study of a new compound 4-(2-chlorobenzyl)-1-(5-fluoro-2-hydroxy-3-(thiomorpholinomethyl)phenyl [1,2,4]triazolo[4,3-a]quinazolin-5(4H)-one

In this paper, a novel SHP244 derivative 4-(2-chlorobenzyl)-1- (5-fluoro-2-hydroxy-3- [thiomorph-olinomethyl] phenyl)- [1,2,4]triazolo [4,3-a] quinazolin-5(4H)-one was synthesized through five steps. The single crystals were grown in a suitable solvent system (dichloromethane and methanol). Its structure was confirmed by ¹H NMR, ¹³C NMR spectroscopy, ESI-MS, m/z: 534.12[M-H] (MS), FT-IR, and X-ray single crystal diffraction. The crystal structure of the title compound was optimized by density functional theory (DFT) calculation. The crystal structure after X-ray single crystal diffraction was compared with the structure optimized by DFT calculation, and the result shows that the two structures are consistent. In order to explore certain physical and chemical properties, the frontier molecular orbital and molecular electrostatic potential of the title compound were analyzed. In addition, the docking of the title compound to the target protein was studied to understand the docking effect of the compound with the target protein.