Effect of permodified β‐cyclodextrin on the photophysical properties of poly[2,7‐(9,9‐dioctylfluorene)‐alt‐(5,5′‐bithiophene)] main chain polyrotaxanes

The photophysical properties of two polyrotaxanes ( PFBTh?PSβCD and PFBTh?PMeβCD ) composed of fluorene and bithiophene encapsulated into permodified β‐cyclodextrin cavities have been investigated and compared with those of the reference PFBTh . Rotaxane formation results in improvements of the thermal stability, solubility in common organic solvents, as well as better film forming ability combined with a high transparency. As expected PFBTh and its encapsulated forms absorb at wavelengths beyond 510 nm, and time‐resolved photoluminescence (PL) in solution shows a well‐define vibronic structures with a predominance of the 0‐0 transitions and an energy difference of 0.16 eV. The fluorescence lifetimes follow a monoexponential decay with a value τ = 630 ± 30 ps. Atomic force microscopy, AFM, indicated a tendency of polyrotaxanes to organize into fibers. The advancing contact angles indicated higher surface hydrophobicity and lower surface free‐energy values for polyrotaxanes compared with their unthreaded analogues. The device based on PFBTh?PSβCD: PCBM in a 1/1 w/w ratio under simulated AM 1.5G illumination at 100 mW cm^?2 exhibited improved photovoltaic parameters of cells, resulted in high V_oc (0.68 V), J_sc (1.65 mA cm^?2), FF (31.6%), and PCE (0.35) values, compared with PFBTh or PFBTh?PMeβCD , respectively. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 460–471     

基于ATmega128单片机的点阵广告屏设计

为了实现AVR单片机对LED点阵显示系统的控制,采用ATmega128作为下位机MCU,通过接收上位机发送的显示内容和显示模式的串行信号,实现16×32高亮点阵屏的一行多个文字或符号的显示。系统实际运行稳定,显示效果良好,便于多块点阵屏的扩展,作为高职学生的大学生实践创新有较高的实践意义。     

基于单片机的GPS定位系统的设计与实现

针对民用定位产品存在的精确度低、携带不轻便、性价比低等问题,从硬件、上位机软件等方面研究并设计了一种基于C8051F020单片机的GPS定位系统,由GPS接收模块、通信模块、单片机控制模块和上位机控制模块组成。采集数据可由多种方式上传至上位机,上位机采用卡尔曼滤波器对该GPS定位系统的测试数据进行处理和误差分析,分析结果表明该定位系统定位误差小,误差率在0-1%之间,定位精确度高,具有较高实用价值,适合应用于民用定位产品之中。     

Effect of cucurbit[n]urils on tropicamide and potential application in ocular drug delivery

The supramolecular interactions of the ocular drug tropicamide (TR) with cucurbit[7]uril (CB7) and cucurbit[8]uril (CB8) were investigated in aqueous solutions by using ¹H NMR, ESI-MS and UV–vis spectroscopic techniques. The results indicate a 1:1 binding stoichiometry of TR with CB7 and CB8. The binding constants of TR in its protonated form were higher (e.g. K = 4 × 10⁶ M^? 1 with CB8) than in its neutral form (e.g. K = 1.4 × 10⁴ M^? 1 with CB8), which led to a complexation-induced increase in its pK _a value of ca. 0.5 and 2 units with CB7 and CB8, respectively. In the presence of about 1% (w/v) CB8, the ionisation degree of 0.1% (w/v) TR was increased from 2% to 62% at neutral pH. The increase in the pK _a value and thus stabilisation of the protonated TR species at neutral pH is discussed in the context of supramolecular drug delivery of ophthalmologic drugs.     

Ethylene spacer-linked bis-acetamidopyridine for dicarboxylic acid recognition and polymeric new wave-like anti-perpendicular arrangement of a host–guest in the solid state

In this paper, 1,2-bis(2-acetamido-6-pyridyl)ethane, receptor 1, having an ethylene spacer is reported to recognise dicarboxylic acids. The binding study in the solution phase is carried out using ¹H NMR (1:1) and UV–vis experiments and in the solid phase by single-crystal X-ray analysis. In ¹H NMR, the downfield shifts of specific amide protons of receptor 1 in 1:1 complexes of receptor and guest diacids, and in the UV–vis experiment, the appearance of an isosbestic point as well as significant binding constants are observed, which thus unambiguously support the complexation of receptor 1 with dicarboxylic acids in solution. Receptor 2, simple 2-acetamido-6-methylpyridine, has lower binding constants than receptor 1 due to cooperative binding of two pyridine amide groups with two acid groups of diacids. In the solid phase, the ditopic receptor 1 shows a grid-like polymeric hydrogen-bonded network that changes to a polymeric wave-like 1:1 anti-perpendicular network instead of the syn–syn polymeric 1:1 (Goswami, S.; Dey, S.; Fun, H.-K.; Anjum, S.; Rahman, A.-U. Tetrahedron Lett. 2005 (a) Goswami, S., Ghosh, K. and Dasgupta, S. 2000. J. Org. Chem., 65: 1907–1914. (b) Goswami, S.; Ghosh, K.; Mukherjee, R. Tetrahedron2001, 57, 4987–4993. (c) Goswami, S.; Ghosh, K.; Halder, M. Tetrahedron Lett.1999, 40, 1735–1738. (d) Goswami, S.; Dey, S.; Fun, H.-K.; Anjum, S.; Rahman, A.-U. Tetrahedron Lett.2005, 46, 7187–7191. (e) Goswami, S.; Jana, S.; Dey, S.; Razak, I.A.; Fun, H.-K. Supramol. Chem.2006, 18, 571–574. (f) Goswami, S.; Jana, S.; Fun, H.-K. Cryst. Eng. Comm.2008, 10, 507–517. (g) Goswami, S.; Jana, S.; Dey, S.; Sen, D.; Fun, H.-K.; Chantrapromma, S. Tetrahedron2008,64, 6426–6433. (h) Goswami, S.; Dey, S.; Jana, S. Tetrahedron2008, 64, 6358–6363 [Google Scholar], 46, 7187–7191), anti–anti polymeric 1:1 (Goswami, S.; Jana, S.; Dey, S.; Razak, I.A.; Fun, H.-K. Supramol. Chem. 2006 (a) Goswami, S., Ghosh, K. and Dasgupta, S. 2000. J. Org. Chem., 65: 1907–1914. (b) Goswami, S.; Ghosh, K.; Mukherjee, R. Tetrahedron2001, 57, 4987–4993. (c) Goswami, S.; Ghosh, K.; Halder, M. Tetrahedron Lett.1999, 40, 1735–1738. (d) Goswami, S.; Dey, S.; Fun, H.-K.; Anjum, S.; Rahman, A.-U. Tetrahedron Lett.2005, 46, 7187–7191. (e) Goswami, S.; Jana, S.; Dey, S.; Razak, I.A.; Fun, H.-K. Supramol. Chem.2006, 18, 571–574. (f) Goswami, S.; Jana, S.; Fun, H.-K. Cryst. Eng. Comm.2008, 10, 507–517. (g) Goswami, S.; Jana, S.; Dey, S.; Sen, D.; Fun, H.-K.; Chantrapromma, S. Tetrahedron2008,64, 6426–6433. (h) Goswami, S.; Dey, S.; Jana, S. Tetrahedron2008, 64, 6358–6363 [Google Scholar], 18, 571–574; Goswami, S.; Jana, S.; Fun, H.-K. Cryst. Eng. Comm. 2008, 10, 507–517; Goswami, S.; Jana, S.; Dey, S.; Sen, D.; Fun, H.-K.; Chantrapromma, S. Tetrahedron 2008, 64, 6426–6433), syn–syn 2:2 (Karle, I.L.; Ranganathan, D.; Haridas, V. J. Am. Chem. Soc. 1997 (a) Garcia-Tellado, F., Goswami, S., Chang, S.K., Geib, S.J. and Hamilton, A.D. 1990. J. Am. Chem. Soc., 112: 7393–7394. (b) Geib, S.J.; Vicent, C.; Fan, E.; Hamilton, A.D. Angew. Chem. Int. Ed. Engl.1993, 32, 119–121. (c) Garcia-Tellado, F.; Geib, S.J.; Goswami, S.; Hamilton, A.D. J. Am. Chem. Soc.1991, 113, 9265–9269. (d) Karle, I.L.; Ranganathan, D.; Haridas, V. J. Am. Chem. Soc.1997, 119, 2777–2783. (e) Moore, G.; Papamicaël, C.; Levacher, V.; Bourguignon, J.; Dupas, G. Tetrahedron2004, 60, 4197–4204. (f) Korendovych, I.V.; Cho, M.; Makhlynets, O.V.; Butler, P.L.; Staples, R.J.; Rybak-Akimova, E.V. J. Org. Chem.2008, 73, 4771–4782. (g) Ghosh, K.; Masanta, G.; Fröhlich, R.; Petsalakis, I.D.; Theodorakopoulos, G. J. Phys. Chem. B2009, 113, 7800–7809 [Google Scholar], 119, 2777–2783) or top–bottom-bound 1:1 (Garcia-Tellado, F.; Goswami, S.; Chang, S.K.; Geib, S.J.; Hamilton, A.D. J. Am. Chem. Soc. 1990 (a) Goswami, S., Ghosh, K. and Dasgupta, S. 2000. J. Org. Chem., 65: 1907–1914. (b) Goswami, S.; Ghosh, K.; Mukherjee, R. Tetrahedron2001, 57, 4987–4993. (c) Goswami, S.; Ghosh, K.; Halder, M. Tetrahedron Lett.1999, 40, 1735–1738. (d) Goswami, S.; Dey, S.; Fun, H.-K.; Anjum, S.; Rahman, A.-U. Tetrahedron Lett.2005, 46, 7187–7191. (e) Goswami, S.; Jana, S.; Dey, S.; Razak, I.A.; Fun, H.-K. Supramol. Chem.2006, 18, 571–574. (f) Goswami, S.; Jana, S.; Fun, H.-K. Cryst. Eng. Comm.2008, 10, 507–517. (g) Goswami, S.; Jana, S.; Dey, S.; Sen, D.; Fun, H.-K.; Chantrapromma, S. Tetrahedron2008,64, 6426–6433. (h) Goswami, S.; Dey, S.; Jana, S. Tetrahedron2008, 64, 6358–6363 [Google Scholar], 112, 7393–7394) co-crystals.

     

Dimerisation and complexation of 6-(4′-t-butylphenylamino)naphthalene-2-sulphonate by β-cyclodextrin and linked β-cyclodextrin dimers

This study shows that stereochemical factors largely determine the extent to which 6-(4′-t-butylphenylamino)-naphthalene-2-sulphonate, BNS^?  and its dimer, (BNS^? )₂, are complexed by β-cyclodextrin, βCD, and a range of linked βCD dimers. Fluorescence and ¹H NMR studies, respectively, show that BNS^?  and (BNS^? )₂ form host–guest complexes with βCD of the stoichiometry βCD.BNS^?  (10^? 4 K ₁ = 4.67 dm³ mol^? 1) and βCD.BNS₂ ^2 ?  (10^? 2 K ₂′ = 2.31 dm³ mol^? 1), where the complexation constant K ₁ = [βCD.BNS^? ]/([βCD][BNS^? ]) and K ₂′ = [βCD. (BNS^? )₂]/([βCD.BNS^? ][BNS^? ]) in aqueous phosphate buffer at pH 7.0, I = 0.10 mol dm³ at 298.2 K. (The dimerisation of BNS^?  is characterised by 10^? 2 K _d = 2.65 dm³ mol^? 1.) For N,N-bis((2^AS,3^AS)-3^A-deoxy-3^A-β-cyclodextrin)succinamide, 33βCD₂su, N-((2^AS,3^AS)-3^A-deoxy-3^A-β-cyclodextrin)-N′-(6^A-deoxy-6^A-β-cyclodextrin)urea, 36βCD₂su, N,N-bis(6^A-deoxy-6^A-β-cyclodextrin)succinamide, 66βCD₂su, N-((2^AS,3^AS)-3^A-deoxy-3^A-β-cyclodextrin)-N′-(6^A-deoxy-6^A-β-cyclodextrin)urea, 36βCD₂ur, and N,N-bis(6^A-deoxy-6^A-β-cyclodextrin)urea, 66βCD₂ur, the analogous 10^? 4 K ₁ = 11.0, 101, 330, 29.6 and 435 dm³ mol^? 1 and 10^? 2 K ₂′ = 2.56, 2.31, 2.59, 1.82 and 1.72 dm³ mol^? 1, respectively. A similar variation occurs in K ₁ derived by UV–vis methods. The factors causing the variations in K ₁ and K ₂ are discussed in conjunction with ¹H ROESY NMR and molecular modelling studies.     

Cup-shaped E,E-stilbenophane: synthesis,crystal structure and supramolecular chemistry

A new E,E-stilbenophane was synthesised and characterised. The crystal structure of this cyclophane shows that this molecule has a cup-shaped structure, which hosts a phenyl ring of neighbouring molecule as guest in its cavity with a π–π distance of about 3.7 Å. Moreover, the NMR spectra and theoretical analysis (gauge-independent atomic orbitals (GIAO) and quantum theory of atoms in molecules (QTAIM)) suggest that the silver recognition by E,E-stilbenophane host molecules is based on cation–π interactions in which the π-electrons of the double bonds play a major role.     

Interaction between tetramethylcucurbit[6]uril with α-furaldehyde-isonicotinyl-hydrazone hydrochloride

Interaction between tetramethylcucurbit[6]uril (TMeQ[6], host) and the hydrochloride salt of α-furaldehyde-isonicotinyl-hydrazone hydrochloride (FIHH⁺, guest) was investigated using X-ray crystallography and spectroscopic methods. X-ray crystallography showed that the π–π stacking effect and hydrogen bonding resulted in the formation of a dumbbell-shaped supramolecule which contained two FIHH⁺@TMeQ[6] host–guest inclusion complexes. The host–guest interaction provided identifiable changes in the vibrational frequencies in the IR spectra. ¹H NMR spectral analysis established a similar interaction model and revealed that TMeQ[6] preferred to include the furan moiety over the pyridine moiety of the FIHH⁺ guest molecule. Absorption spectrophotometric analysis suggested that the host and guest interact in a ratio of 1:1 with a stability constant K _s = (3.52 ± 0.74) × 10⁶ l mol^? 1.pH titration confirmed that the host–guest interaction led to a clear change in the protonation constant of the title guest. Quantum chemical calculations were used to determine the possible mechanism of formation of the dumbbell-shaped complex.