新型I型五聚四硫富瓦烯衍生物的合成和性质

利用2,3-二(2'-氰乙基硫基)-6,7-二烷硫基四硫富瓦烯在甲醇钠的作用下消除一个保护基团生成四硫富瓦烯单钠盐,与1,4-二(氯甲基)苯反应, 形成单桥-双(四硫富瓦烯)衍生物, 生成的单桥-双(四硫富瓦烯)衍生物再次在甲醇钠的作用下消除剩下的保护基团, 形成单桥-双(四硫富瓦烯)衍生物二钠盐, 最后与四(3'-碘丙硫基)四硫富瓦烯反应形成新型I型五聚TTF衍生物, 并通过循环伏安法和化学氧化法分别对其氧化还原性质和紫外光谱进行了研究.     

新型I型五聚四硫富瓦烯衍生物的合成和性质

利用2,3-二(2'-氰乙基硫基)-6,7-二烷硫基四硫富瓦烯在甲醇钠的作用下消除一个保护基团生成四硫富瓦烯单钠盐,与1,4-二(氯甲基)苯反应,形成单桥-双(四硫富瓦烯)衍生物,生成的单桥-双(四硫富瓦烯)衍生物再次在甲醇钠的作用下消除剩下的保护基团,形成单桥-双(四硫富瓦烯)衍生物二钠盐,最后与四(3'-碘丙硫基)四硫富瓦烯反应形成新型I型五聚TTF衍生物,并通过循环伏安法和化学氧化法分别对其氧化还原性质和紫外光谱进行了研究.     

Deselenation of diselenacyclophanes —a new synthetic method of [2.2]cyclophanes—

Several diselena[3.3]cyclophanes were prepared by coupling of bisselenocyanates and bis(bromomethyl)benzenes in good yields. The benzyne Stevens rearrangement-Raney Ni hydrogenolysis method gave good yields of double- and triple-layered cyclophanes from the diselenides, though the flash pyrolysis method gave them in low yields.     

Reactions of diiron(III) tris[(1-hydroxyethylidene)diphosphonate] tetrahydrate and iron(III) tris[(1-hydroxyethylidene)diphosphonate] tetrahydrate with <Emphasis Type="Italic">p</Emphasis>-aminobenzoic acid. Molecular structure of bis(4-carboxyphenylaminium) (1-hydroxyethylidene)diphosphonate

Diiron(III) tris[(1-hydroxyethylidene)diphosphonate] tetrahydrate and iron(III) tris[(1-hydroxyethylidene) diphosphonate] tetrahydrate react with p-aminobenzoic acid in water to form diiron(III) pentakis(4-carboxyphenylaminium) tris(1-hydroxyethylidene)diphosphonate dihydrate and iron(III) hexakis(4-carboxyphenylaminium) tris(1-hydroxyethylidene)diphosphonate dihydrate. The crystal structure of bis(4-carboxyphenylaminium) (1-hydroxyethylidene)diphosphonate obtained by the reaction of (1-hydroxyethylidene)diphosphonic acid with p-aminobenzoic acid in methanol was established.     

Synthesis and photophysical studies of siloxane-tethered cyclophanes

Novel siloxane tethered para divinylarene cyclophanes, containing phenyl, biphenyl and naphthalene rings as the aromatic nuclei, were prepared by the hydrolytic condensation of the corresponding bis{[dimethyl(i-propoxy)silyl]vinyl}arenes under basic conditions.The photophysics of the cyclophanes were investigated using UV and fluorescence spectroscopy.     

Tribenzotriquinacenes Based on Regioselective Bis‐formylation: Optical Resolution and Absolute Configuration of Inherently Chiral Derivatives and Synthesis of the First Cyclophane‐Type Tribenzotriquinacene Dimers

Enantiomerically pure tribenzotriquinacenes (TBTQs) bearing two monofunctionalized aromatic nuclei were synthesized for the first time and their optical properties and absolute configuration determined. A remarkably regioselective bis‐formylation of the fully bridgehead methylated parent TBTQ hydrocarbon with MeOCHCl₂/TiCl₄ afforded a mixture of two C_s‐symmetrical (achiral) difunctionalized derivatives together with one C₁‐symmetrical (chiral) isomer. Reduction and subsequent column chromatography furnished the three respective benzylic TBTQ dialcohols. Optical resolution of the racemic 2,6‐bis(hydroxymethyl) derivative was achieved via the diastereomeric (R)‐1,1′‐bi‐2‐naphthol ethers and the absolute configuration of the enantiomers was determined by CD exciton model analysis. The electronic circular dichroism (ECD) spectra and the specific rotation of the enantiomers were found to agree with the results of DFT calculations. Among the C_s‐symmetrical isomers, the “proximal” 2,11‐dialdehyde and the corresponding benzylic dialcohol were identified by 2D NMR spectroscopy and X‐ray crystallographic analysis, respectively, and used as the starting point for the synthesis of several novel dithiametacyclophanes. These include the first “dimeric” tribenzotriquinacene‐based cyclophanes bearing the bowls of the two TBTQ units attached to each other in a syn (concave–concave) or anti (convex–concave) configuration. The usefulness of such thiacyclophanes as fluorescent chemosensors for different metal ions is also demonstrated.     

Synthesis of [m.n]Cyclophanes: Regiochemistry Transfer from Vinyl Halides to Cyclophanes via Fischer Carbene Complexes

The double benzannulation of bis‐carbene complexes of chromium with α,ω‐diynes generates [m.n]cyclophanes in which all three rings are generated in a single reaction. This triple annulation process is very flexible allowing for the construction of symmetrical [n.n]cyclophanes and unsymmetrical [m.n]cyclophanes as well as isomers in which the two benzene rings are both meta bridged or both para bridged, and isomers that contain both meta and para bridges. The connectivity patterns of the bridges in the cyclophanes can be controlled by regioselectivity transfer from the bis‐vinyl carbene complexes in which the substitution pattern of the vinyl groups in the carbene complexes dictate the connectivity pattern in the [m.n]cyclophanes. This synthesis of [n.n]cyclophanes is quite flexible with regard to ring size and can be used with tether lengths ranging from n=2 to n=16 and thus to ring sizes with up to 40 member rings. The only limitation to regioselectivity transfer from the carbene complexes to the [m.n]cyclophanes was found in the synthesis of para,para‐cyclophanes with four carbon tethers for which the loss of fidelity occurred with the unexpected formation of meta,para‐cyclophanes.     

Syntheses and structures of isomeric [6.6]- and [8.8]cyclophanes with 1,4-dioxabut-2-yne and 1,6-dioxahexa-2,4-diyne bridges

All three isomers (ortho, meta, and para) of [8.8]cyclophane bearing 1,6-dioxahexa-2,4-diyne bridges have been synthesized and structually characterized by single-crystal X-ray crystallography to determine the conformation of the cyclophanes and their cavity dimensions. The three isomeric [6.6]cyclophanes bearing 1,4-dioxabut-2-yne bridges have also been synthesized from but-2-yne-1,4-diol ditosylate and the isomeric dihydroxybenzenes. The [6.6]orthocyclophane has been structurally characterized by single-crystal X-ray crystallography. The energy-minimized structures from the semiempirical AM1 calculations of these cyclophanes compare very well with the structures obtained by X-ray crystallography.     

One-Pot formation of novel [3+3] NH-CH2 bridged cyclophanes

The new [3+3] NH-CH₂ bridged cyclophanes bearing different functional groups and different cavity sizes were prepared in one pot by treating diamine derivatives with dialdehyde derivatives. Factors important for efficiently form-ing these macrocycles include reaction concentration (10 or 100?mmol), temperature (room temperature or 40–50?°C) and solvent (CHCl₃). Preliminary fluorescence spectrometer and HRMS-ESI studies demonstrated the inner cavity of the new [3+3] NH-CH₂ bridged cyclophanes bearing three hydroxyl groups (3c) as a new highly selective probe for the naked eye detection of Ag⁺ in PBS buffer.     

Exploring structural and conformational behaviour of cyclophanes incorporating imidazole-2-thiones

New cyclophanes containing two imidazole-2-thione moieties linked by two xylylene groups have been synthesized by the reaction of imidazolium-linked cyclophanes with sulfur in the presence of K₂CO₃. The conformational behaviour of the new cyclophanes was explored by NMR spectroscopy and X-ray diffraction studies. In cyclophanes containing o-xylylene or 2,4,6-trimethyl-m-xylylene linking groups, the imidazole-2-thione groups were mutually syn in both the solid state and in solution, the cyclophanes adopting a conformation reminiscent of the cone conformation of calix[4]arenes. Cyclophanes containing p-xylylene or m-xylylene linking groups exhibited two conformations in solution, one in which the imidazole-2-thione groups are mutually syn, the other in which they are mutually anti, and these conformations did not interconvert on the NMR timescale. Both conformations co-crystallised in the m-xylylene linked cyclophane, while for the p-xylylene-linked cyclophane the anti conformation crystallised separately.     

Sulfoximine version of double elimination protocol for synthesis of chiral acetylenic cyclophanes

A new strategy for constructing enantiopure acetylenic cyclophanes is described on the basis of one-pot double elimination reaction starting from dialdehydes and bis(sulfoximine)s. In this case, the conventional sulfone protocol affords poorer yields of the desired cyclophanes. Thus, arylene-ethynylene moieties with terminal sulfoximine or formyl functions are linked to binaphthyl cores and these building blocks are then subjected to double elimination reaction. The desired macrocycles are obtained in up to 35 % yield. The corresponding Sonogashira coupling fails to afford cyclophanes indicative of effectiveness of the double elimination methodology.     

Synthesis of meta- and paracyclophanes containing unsaturated amino acid residues

[7.7], [8.8], [9.9] and [13.13] Paracyclophanes and [9.9] and [13.13] metacyclophanes containing two unsaturated amino acid residues have been synthesised. An X-ray crystallographic study of three of the paracyclophanes and molecular modelling of two paracyclophanes and two metacyclophanes revealed two main structural types. The ‘staggered’ structure appears to be favoured by longer hydrocarbon chains, whilst the ‘barrel’ structure appears to be more accessible to compounds containing shorter hydrocarbon chains. The [9.9] paracyclophane has been hydrogenated and deprotected to give a saturated amino acid, and an alternative approach to key aldehydes is reported.     

Combination of Chiral and Achiral Triphenylene Units in a Novel Unsymmetrical Columnar Twin

The synthesis, characterization, and mesomorphic properties of a new type of liquid‐crystalline twin bearing a pentadecyloxytriphenylene subunit tethered via a decyl spacer to a chiral pentakis(3,7‐dimethyloctyloxy)triphenylene are reported. The target compound displays a hexagonal columnar mesophase, which is metastable at room temperature.     

Preparation of syn and anti cyclophanes having oligothiophene units and their spectral properties

Syn and anti cyclophanes consisting of oligothiophene units as a component have been synthesized for the first time. Correlation between the cyclophane structure and fluorescence spectral properties has been examined. Emission from intramolecular excimer-formation is confirmed for the syn cyclophanes and the mobile cyclophanes, but not for the anti cyclophanes.     

Pentakis(trifluoromethyl)phenyl, a sterically crowded and electron-withdrawing group: synthesis and acidity of pentakis(trifluoromethyl)benzene, -toluene, -phenol, and -aniline

A general route to functionalized pentakis(trifluoromethyl)phenyl (C6(CF3)5) derivatives, promising building blocks for designing novel stable carbenes, radical species, superacids, weakly coordinating anions and other practically and theoretically useful species, is presented. This pertrifluoromethylation route proceeds via conveniently pregenerated (trifluoromethyl)copper (CF3Cu) species in DMF, stabilized by addition of 1,3-dimethyl-2-imidazolidinone (DMI). These species react with hexaiodobenzene at ambient temperature to give the potassium pentakis(trifluoromethyl)phenoxide along with hexakis(trifluoromethyl)benzene and pentakis(trifluoromethyl)benzene in a combined yield of 80%. A possible reaction pathway explaining the formation of pentakis(trifluoromethyl)phenoxide is proposed. Pentakis(trifluoromethyl)phenol gives rise to easily functionalized pentakis(trifluoromethyl)chlorobenzene and pentakis(trifluoromethyl)aniline. Pertrifluoromethylation of pentaiodochlorobenzene and pentaiodotoluene allows straightforward access to pentakis(trifluoromethyl)chlorobenzene and pentakis(trifluoromethyl)toluene, respectively. XRD structures of several C6(CF3)5 derivatives were determined and compared with the calculated structures. Due to the steric crowding the aromatic rings in all C6(CF3)5 derivatives are significantly distorted. The gas-phase acidities (Delta Gacid) and pKa values in different solvents (acetonitrile (AN), DMSO, water) for the title compounds and a number of related compounds have been measured. The origin of the acidifying effect of the C6(CF3)5 group has been explored using the isodesmic reactions approach.     

A dendrimer approach to high-spin polycarbenes. Conversion of connectivity from disjoint to non-disjoint by perturbation of nonbonding molecular orbital coefficients

[structure: see text] Pentakis(diazo) compound was prepared by coupling 3,5-bis[4-[diazo(4-tert-butyl-2,6-dimethylphenyl)methyl]-3,5-dibromophenylethynyl]phenylacetylene with bis(4-iodo-2,6-dimethylphenyl)diazomethane under Sonogashira reaction conditions. Pentakis(carbene) generated by irradiation of the pentakis(diazo) compound was shown to have a high-spin state with S = 4.4 at 2.0 K.     

Synthesis of a new class of electron rich chiral cyclophanes with large cavities

BINOL based electron rich chiral cyclophanes possessing large cavities have been synthesized starting from m-terphenyl dibromide and methyl m-/p-cinnamate. The presence of double bonds in the chiral cyclophanes makes them electron rich as revealed by C-T complexation studies of such cyclophanes donors with guests like TCNE, TCNQ and DDQ.     

An enaminone-directed benzannulation/macrocyclization approach to cyclophane ring systems

A straightforward and modular preparative approach to 1,3,5-triaroylbenzene-based functionalized cyclophane ring systems has been developed. The key cyclophane-forming macrocyclization reaction was accomplished during the course of a regioselective cross-benzannulation between bis(aryl ethynyl) ketone and enaminone reactants. Macrocyclic products with ring sizes ranging from 18- to 22-membered were successfully constructed. The composition of the tether connecting the two aryl ethynyl ketone fragments can be easily varied; consequently, this method is suitable for construction of a diverse range of structurally distinct cyclophane products. To illustrate this feature, cyclophanes possessing xylyl, alkyl, di(ethylene triamine), and di(ethylene oxy) bridging units were synthesized in isolated yields of 11-46%. Three new cyclophanes (calixarene-like macrocyles 8 and 9, as well as crownophane 18) were structurally characterized by X-ray diffractometry.     

Oligosaccharide Analogues of Polysaccharides,Part 21 , Towards New Cellulose I Mimics: Synthesis of Dialkynyl C‐glucosides of peri‐Substituted Anthraquinone

The bis‐C‐glucoside 2 has been synthesised as the first representative of a series of templated glucosides and cellooligosaccharides that mimick part of the unit cell of cellulose I. As expected, there are, at best, weakly persistent H‐bonds between the two glucosyl residues in (D₆)DMSO and (D₇)DMF solution. The acetylated oct‐1‐ynitol 7 and deca‐1,3‐diynitol 12 were prepared from the gluconolactone 5 (Scheme 1). Coupling of 12 to PhI and 2‐iodothiophene yielded 13 and 14 , respectively, while dimerisation of the benzylated and acetylated deca‐1,3‐diynitols 10 and 12 afforded the bis‐C‐glucosyloctatetrayne 15 and the less stable 16 , respectively. The 2‐glucosylthiophene 17 was obtained by treating the C‐silylated deca‐1,3‐diynitol 9 with Na₂S. Cross‐coupling of (trimethylsilyl)acetylene (TMSA) with 1,8‐bis(triflyloxy)‐9,10‐anthraquinone ( 20 ) at elevated temperature gave the dialkynylated 21 ; its structure was established by X‐ray analysis (Scheme 2). Sequential coupling of 6 or 7 and TMSA to 20 gave the symmetric dialkyne 21 , the mixed dialkynes 23 (from 6 ) and 25 (from 7 ), and the symmetric diglucoside 36 (from 7 ) in modest yields; a stepwise coupling to the acetylated monotriflate 28 proved advantageous. It led to the oct‐1‐ynitol 29 and the deca‐1,3‐diynitol 33 that were transformed into the triflates 30 and 34 , respectively. Coupling of the triflate 34 to the oct‐1‐ynitol 7 gave the unsymmetric bis‐C‐glucoside 35 ; this was obtained in higher yields by coupling the triflate 30 to the deca‐1,3‐diynitol 12 . Coupling of the bistriflate 20 with either 7 or 12 afforded the symmetric bis‐C‐glucosides 36 and 37 , respectively. Deacetylation (KCN in MeOH) of 35 – 37 provided the unsymmetric bis‐C‐glucoside 2 and the symmetric analogues 3 and 4 .     

Hexahelicenophanes

A reaction sequence was studied for the preparation of cyclophanes 12 , which contain 2,7‐bis(2‐phenylethenyl)naphthalene chromophores and polymethylenedioxy chains of different length. The irradiation of 12 in the presence of I₂ led then, by oxidative cyclization processes, to the hexahelicenophanes 13 , provided that the methylenedioxy chain of 12 is long enough (n = 8, 10). As competitive photoreaction, a twofold [2π+2π] cyclodimerization occurred, which furnished the belt cyclophanes 14 . The latter process is the only photoreaction for 12 with n=6. The hexahelicenophanes 13 have lower racemization barriers and longer spin? lattice relaxation times compared to those of hexahelicenes.