In this work, an amphiphilic diblock copolymer (PEG43‐b‐PSDTE29) bearing photochromic dithienylethene (DTE) pendants is synthesized by reversible addition fragmentation chain transfer radical polymerization. The diblock copolymer was characterized by spectroscopic methods and gel permeation chromatography. The analyses proved the well‐defined structure and narrow molecular weight distribution of the diblock copolymer. The DTE pendants could undergo reversible photoisomerization between their open and closed forms in solution when irradiated with UV and visible light as indicated by 1H NMR and UV‐vis spectroscopy. Hollow vesicle‐like structures were formed by gradually adding deionized water to the colorless PEG43‐b‐PSDTE29open (DTE in open form) tetrahydrofuran solution. Under the same conditions, the aggregates formed in the blue PEG43‐b‐PSDTE29close (DTE in closed form) solution were colloidal spheres with solid interiors. The isomerization of DTE pendants could cause the deformation of the vesicle‐like structures. The above results demonstrate a kind of novel photo‐modulated self‐assembly behavior of the amphiphilic diblock copolymer, which could be used for drug‐delivery and other applications.
Syntheses and full characterisation data (including single crystal diffraction) of three 1,2‐diphosphonium dicationic species with the naphthalene‐1,8‐diyl (Nap) backbone are reported. The oxidation of Nap[P(NMe2)2]2 with P2I4 to its 1,2‐dication was achieved. meso‐ and rac‐forms of “all carbon” 1,2‐diphosphonium dications were obtained in good yields and purity by double alkylation of the parent diphosphine (1,2‐diphenyl‐1,2‐diphosphaacenaphthene) with methyl triflate or trimethyloxonium tetrafluoroborate. Each methylating reagent produces one of the rac‐ or meso‐forms of the dication diastereospecifically. Structural parameters of the new dications are discussed with respect to other phosphorus 1,2‐dications. DFT (B3LYP) computations revealed the significant role of the naphthalene backbone in stabilisation of the dicationic motif and helped to assess the energy cost of the steric clash of a variety of groups attached to the peri‐positions of naphthalene. The synthesis and single crystal X‐ray data of the extremely crowded Nap[P(?Se)(OiPr)2]2 are discussed, and are contrasted with the unsuccessful synthesis of Nap(PtBu2)2 from NapLi2 and ClPtBu2. 相似文献
tBu2P–PLi–PtBu2·2THF reacts with [cis‐(Et3P)2MCl2] (M = Ni, Pd) yielding [(1,2‐η‐tBu2P=P–PtBu2)Ni(PEt3)Cl] and [(1,2‐η‐tBu2P=P–PtBu2)Pd(PEt3)Cl], respectively. tBu2P– PLi–PtBu2 undergoes an oxidation process and the tBu2P–P–PtBu2 ligand adopts in the products the structure of a side‐on bonded 1,1‐di‐tert‐butyl‐2‐(di‐tert‐butylphosphino)diphosphenium cation with a short P–P bond. Surprisingly, the reaction of tBu2P–PLi–PtBu2·2THF with [cis‐(Et3P)2PtCl2] does not yield [(1,2‐η‐tBu2P=P–PtBu2)Pt(PEt3)Cl]. 相似文献
Fluorinated indolylfulgides are a class of photochromic organic compounds that meet many of the requirements for use as optical memory media and optical switches. The X‐ray crystal structures of a series of five photochromic fluorinated indolylfulgides have been determined, namely (3Z)‐3‐[1‐(1,2‐dimethyl‐1H‐indol‐3‐yl)‐2,2,2‐trifluoroethylidene]‐4‐(1‐methylethylidene)dihydrofuran‐2,5‐dione (trifluoromethylisopropylideneindolylfulgide), C19H16F3NO3, (I), (3Z)‐3‐[1‐(1,2‐dimethyl‐1H‐indol‐3‐yl)‐2,2,3,3,3‐pentafluoropropylidene]‐4‐(1‐methylethylidene)dihydrofuran‐2,5‐dione (pentafluoroethylisopropylideneindolylfulgide), C20H16F5NO3, (II), (3Z)‐3‐[1‐(1,2‐dimethyl‐1H‐indol‐3‐yl)‐2,2,3,3,4,4,4‐heptafluorobutylidene]‐4‐(1‐methylethylidene)dihydrofuran‐2,5‐dione (heptafluoropropylisopropylideneindolylfulgide), C21H16F7NO3, (III), (3Z)‐3‐[1‐(1,2‐dimethyl‐1H‐indol‐3‐yl)‐2,2,2‐trifluoroethylidene]‐4‐(tricyclo[3.3.1.13,7]decylidene)dihydrofuran‐2,5‐dione (trifluoromethyladamantylideneindolylfulgide), C26H24F3NO3, (IV), and (3Z)‐3‐[1‐(1,2‐dimethyl‐1H‐indol‐3‐yl)‐2,2,3,3,4,4,4‐heptafluorobutylidene]‐4‐(tricyclo[3.3.1.13,7]decylidene)dihydrofuran‐2,5‐dione (heptafluoropropyladamantylideneindolylfulgide), C28H24F7NO3, (V). The photochromic property of fulgides is based on the photochemically allowed electrocyclic ring closure of a hexatriene system to form a cyclohexadiene. For each fulgide examined, the bond lengths within the hexatriene system alternate between short and long, as expected. Comparing the structures of the five fulgides with each other demonstrates no significant difference in bond lengths, bond angles or dihedral angles within the hexatriene systems. The distance between the bond‐forming C atoms at each end of the hexatriene system does vary. Correlations of structural properties with optical properties are addressed. 相似文献
Diarylethene (DTE) has been widely used in fluorescence probes, molecular logic gates, optical data-storage devices owing to the excellent photochromic property, while constructing high-performance photochromic DTE in aqueous media remains a big challenge. Herein we present several host-guest systems formed between cucurbit[n]uril (CB[n], n=7, 8, 10) and two water-soluble DTE derivatives 1 and 2 . It was found that host-guest interactions not only affect the photophysical properties of photochromic guests, but also make great differences on the photoreaction process. Different host-guest binding behaviors also lead to different effects on the photochromic properties of guests. In the presence of CB[n], both 1 and 2 showed enhanced emission and higher fluorescence quenching ratio at photostationary state. Besides, CB[10] ⋅1 exhibited faster response rate in cyclization reaction and better photofatigue resistance than free 1 in aqueous solution, while the supramolecular assembly of (CB[8])n ⋅ ( 2 )n showed slower response rate in both directions of the reversible photoreaction. Besides, the photofatigue resistance of 2 can be greatly improved through binding with CB[7]. Our results suggest that host-guest interactions could be an efficient way to improve photochromic properties of DTE in aqueous solution. 相似文献
Synthesis and Crystal Structure of Bis(1,2-dimetyl-5-nitro-imidazole)dichlorocobalt(II) Bis(1,2-dimethyl-5-nitro-imidazol)dichlorocobalt(II) was obtained by reaction of CoCl2 · 6 H2O with 1,2-dimethyl-5-nitro-imidazole in methanol. The compound forms blue crystals which were characterized by IR and UV-vis spectroscopy and by an X-ray crystal structure determination. Co(C5H7N3O2)2Cl2: tetragonal, space group I4 2d, Z = 8, a = 1142.1(1) pm, c = 2577.3(2) pm. R = 0.036 for 670 independent reflexions. The Co atom is tetrahedrally surrounded by two chlorine and two N atoms at distances of 222.8(2) and 203.5(4) pm. 相似文献
1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane and 1,2-Bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine: Synthesis and Structure as well as Calculations on the Molecular Structure The diphosphides K2[(C6H5)P? (C6H5)P? P(C6H5)], 4 or K2[(tBuP)? (tBuP)2? P(tBu)], 5 , react with (ClBNMe2)2 to form the binary 5-membered ring system 1,2-bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane (C6H5P)3(BNMe2)2, 2a , and the 6-membered ring system 1,2-bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine, (tBuP)4(BNMe2)2, 3a , respectively. 2a and 3a could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analyses. The two ring systems are folded; 2a exists in the ?envelope”?- 3a in the ?boat”?-conformation. Ab initio computations for 3,4,5-triphospha-1,2-diborolane M5 show that the global minimum is characterized by one B? P double bond. The parent compound geometry M6 is characterized by transannular bonding in the PH? BH? BH? PH moiety which differs in character from those in the four- and five-membered rings (BH)2(PH)2 and (BH)2(PH)3 M5 d , respectively. Explicit calculation of the influence of amino substituents on boron improved agreement of the bond length between computed and X-ray data. 相似文献
Treatment of N,N‐chelated germylene [(iPr)2NB(N‐2,6‐Me2C6H3)2]Ge ( 1 ) with ferrocenyl alkynes containing carbonyl functionalities, FcC≡CC(O)R, resulted in [2+2+2] cyclization and formation of the respective ferrocenylated 3‐Fc‐4‐C(O)R‐1,2‐digermacyclobut‐3‐enes 2 – 4 [R = Me ( 2 ), OEt ( 3 ) and NMe2 ( 4 )] bearing intact carbonyl substituents. In contrast, the reaction between 1 and PhC(O)C≡CC(O)Ph led to activation of both C≡C and C=O bonds producing bicyclic compound containing two five‐membered 1‐germa‐2‐oxacyclopent‐3‐ene rings sharing one C–C bond, 4,8‐diphenyl‐3,7‐dioxa‐2,6‐digermabicyclo[3.3.0]octa‐4,8‐diene ( 5 ). With N‐methylmaleimide containing an analogous C(O)CH=CHC(O) fragment, germylene 1 reacted under [2+2+2] cyclization involving the C=C double bond, producing 1,2‐digermacyclobutane 6 with unchanged carbonyl moieties. Finally, 1 selectively added to the terminal double bond in allenes CH2=C=CRR′ giving rise to 3‐(=CRR′)‐1,2‐digermacyclobutanes [R/R′ = Me/Me ( 7 ), H/OMe ( 8 )] bearing an exo‐C=C double bond. All compounds were characterized by 1H, 13C{1H} NMR, IR and Raman spectroscopy and the molecular structures of 3 , 4 , 5 , and 8 were established by single‐crystal X‐ray diffraction analysis. The redox behavior of ferrocenylated derivatives 2 – 4 was studied by cyclic voltammetry. 相似文献
Summary The investigations concerning the thermal behaviour of a series of Ni(II) and Cu(II) complexes of type [MLCln]·mH2O ((1) M:Ni, L:L(1), n=1, m=2; (2) M:Cu, L:L(2), n=1, m=2; (3) M:Ni, L:L(3), n=2, m=0; (4) M:Cu, L:L(3), n=1, m=2) are presented in this paper. The ligands L(1)-L(3) have been synthesised by template condensation of 1,2-diaminoethane
with formaldehyde and 2-amino-1,3,4-thiadiazole-5-thiole or 2-acetamino-1,3,4-thiadiazole-5-sulfonamide. The bonding and stereochemistry
of the complexes have been characterised by IR, electronic and magnetic studies at room temperature. The thermal behaviour
provided confirmation of the complex composition as well as the number and the nature of water molecules and the intervals
of thermal stability. The different nature of the ligands and/or the metallic ions generates a different thermal behaviour
for complexes. The complexes do not show biological activity against HIV virus. 相似文献
A Rh(I) complex [κ2(P,N)-{P(Oquin)3}RhCl(PPh3)] ( 1 ) bearing the P,N ligand tris(8-quinolinyl)phosphite, P(Oquin)3, has been synthesized and structurally characterized. The molecular structure of complex 1 shows that P(Oquin)3 acts as a bidentate P,N chelate ligand. Reactivity studies of 1 reveal that the triphenylphosphine ligand can be replaced by Pcy3 or removed upon oxidation with concomitant coordination of a second 8-quinolyl unit of P(Oquin)3. In addition, the Rh(III) complex [RhCl2{OP(Oquin)2}] ( 3 ), resulting from treating 1 with either wet CDCl3 or, sequentially, with HCl and water, was identified by X-ray diffraction analysis. Complex 1 catalyzes the 1,2-regioselective hydroboration of pyridines and quinolines, affording N-boryl-1,2-dihydropyridines (1,2-BDHP) and N-boryl-1,2-hydroquinolines (1,2-BDHQ) in high yield (up to >95 %) with turnover numbers (TONs) of up to 130. The system tolerates a variety of substrates of different electronic and steric nature. In comparison with other transition-metal-based hydroboration catalysts, this system is efficient at a low catalyst loading without the requirement of base or other additives. 相似文献
A new mononuclear Zn(II) complex, [ZnL(HOAc)] (1) (H2L = 6,6′-diethoxy-2,2′-[1,2-ethylenedioxybis(nitrilomethylidyne)]diphenol), was synthesized by reaction of H2L and Zn(II) acetate under solvothermal conditions. Complex 1 acts as a metallohost possessing a pentadentate O5 donor. Complex 1 molecules bonded to one Sr(II) or Ba(II) form two new hetero-trinuclear complexes, [(ZnL)2M(OAc)2] (M = Sr (2), Ba (3)). In 2 and 3, Zn(II) ions are 5-coordinate, but the Sr(II) or Ba(II) ion is 10-coordinate by four μ-phenolic oxygens from two L2? units, four oxygens from four ethoxy groups and two oxygens from two μ-acetato ligands. Furthermore, 1–3 exhibit blue emissions with the maximum emission wavelengths λmax = 477, 500, and 471 nm when excited at 360 nm. 相似文献
Cyclohexadiene, bensene, and methylcyclopentadienes are mainly formed from the hexatriene in the presence of silica gel and Al2O3 at 300–450°C. Increase in temperature (from 550 to 1100°C) and in the length of calcination of the silica gel (1–6 h) reduces the specific surface area and acidity of the catalyst and the degree of 1–5 and 1–6 cyclization of the triene.
2.
In the presence of ZnO and Bi2O3, 1–6 cyclization of hexatriene to cyclohexadiene and benzene mostly occurs; methylcyclopentadienes are formed in insignificant amounts.
3.
The 1–5 cyclization of hexatriene on silica gel and Al2O3 evidently takes place by a mechanism of acidic intramolecular alkylation. At 300–450°C, catalytic 1–6 cyclization of hexatriene is observed in addition to the thermal reaction. The idea was put forward that the catalytic 1–6 cyclization is facilitated by acceleration of the isomerization of the trans-triene to the cis isomer and by the effect of the catalyst surface on the conformation of the cis-hexatriene molecules.
The ion transfer reaction of 2-benzoylpyridine-thiosemicarbazone (HL), which has antimicrobial and antifungal properties and anticancer activity, has been studied to determine its lipophilicity by cyclic voltammetry at the water/1,2-dichloroethane (1,2-DCE) interface. The physicochemical parameters such as standard partition coefficient (lgPI) and the standard Gibbs energy of transfer ( ) of the protonated form of the ligand were measured as a function of pH in aqueous phase. The protonated form of the ligand exhibited reversible or quasi-reversible voltammograms at the 1,2-DCE in the range of pH 1–5. The protonation constants of the ligand, pKa1 and pKa2, were determined spectrophotometrically and were found to be 12.14 and 3.24, respectively. The standard Gibbs energy of transfer ( ) and the partition coefficient of neutral species (lgPN) were also determined by the shake-flask method. The standard Gibbs energy of transfer of this compound across the water/1,2-DCE interface was evaluated as the quantitative measure of its lipophilicity. The difference between lgPI and lgPN was related to the degree of charge delocalization and was used to evaluate qualitatively the lipophilicity of the ligand. 相似文献
A novel electron-deficient chiral diphosphine ligand bearing trifluoromethyl groups at the 6- and 6′-positions of the biphenyl backbone, (Sa,R,R)-(CF3)2-C3-TunePhos, has been synthesized from the commercially available chiral 2,4-pentanediol. The above ligand was successfully applied to palladium-catalyzed asymmetric hydrogenation of linear and cyclic α-iminophosphonates with up to 99%?ee. 相似文献
Contributions tot he Chemistry of Phosphorus. 148. Synthesis and Properties of the 1,2-Diphospha-3,4-diboretane (t-BuP)2(BNMe2)2 The first 1, 2-diphospha-3,4-diboretane (1,2-diphospha-3, 4-diboracyclobutane) (t-BuP)2(BNMe2)(1) was prepared by [2+2] cyclocondensation of K(t-Bu)P? P(t-Bu)K with Cl(Me2N)B? B(NMe2)Cl. 1 could be isolated in the pure state and was NMR spectroscopically characterized as a compound with a planar P2 B2 ring skeleton. 相似文献
When rac- or meso-1,2-bis(tert-butylchlorophosphino)-1,2-dicarba-closo-dodecaborane(12) (1a or 1b) is reacted with [M(CO)4(NBD)] (M = Cr, Mo, NBD = norbornadiene), [Mo(CO)4(EtCN)2] or [W(CO)6], rac-[Cr(CO)4{1,2-(PtBuCl)2C2B10H10}] (2), rac- or meso-[Mo(CO)4{1,2-(PtBuCl)2C2B10H10}] (3a or 3b) and rac-[W(CO)4{1,2-(PtBuCl)2C2B10H10}] (4) could be isolated as pure diastereomers. UV irradiation of 1 with [Cr(CO)6] in moist THF proceeds with hydrolysis and formation of [Cr(CO)4{1,2-(P(OH)tBu)2C2B10H10}] (5) which contains the metal complex-stabilized phosphinous acid. Compounds 2–5 were characterized spectroscopically (1H, 31P, 11B, 13C NMR), by mass spectrometry and by X-ray structure determination. 相似文献