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1.
Dipropynylbenzenes with alkyl groups (CH3C ≡ CRC6H2RC≡CCH3,
R=n-C6H13, n-C8H17,
n-C10H21, 1a–c, respectively) were polymerized with Mo(CO)6 to afford
solvent-soluble poly(2,5-dialkyl-p-phenyleneethynylene)s (2a–c). The polymers (2a–c) had high molecular weight over 3×104, and gave
free-standing membranes by solution casting method. According to thermogravimetric analysis (TGA), these
poly(p-phenyleneethynylene)s showed high thermal stability (T0
≥380 °C). The densities of membranes of poly(2,5-dialkyl-p-phenyleneethynylene)s (2a–c) were 0.936–0.965, and their
fractional free volume (FFV) were relatively large (ca. 0.14–0.15). The oxygen permeability coefficients
(PO2) of membranes of 2a–c were 4.88, 7.06, and 16.6 barrers, respectively. 相似文献
2.
1,4-Diiodobenzenes bearing oligo-ethylene glycols [IRC6H2IR, R = OCH2CH2OCH3 (1a), O(CH2CH2O)2CH3 (1b), O(CH2CH2O)3CH3 (1c)] were polymerized with 1,4-diethynylbenzene in the presence of Pd/Cu catalyst to afford poly(p-phenyleneethynylene)s bearing oligo-ethylene glycols (2a–c), respectively. Polymer 2a was insoluble in any solvents, but the other polymers (2b, 2c) were soluble in CHCl3. The weight-average molecular weights of 2b and 2c were 5.4 × 104 and 9.6 × 104, respectively, and they gave free-standing membranes by solution-casting method. The densities of membranes of 2b and 2c were 1.26 and 1.22 g/cm3, respectively, and their carbon dioxide permeability coefficients were 12.9 and 13.5 barrers, respectively. The CO2/N2 separation factor of membrane of 2b was as large as 33.7. Membrane of 3b, which contains triethylene glycols, exhibited higher CO2 permselectivity, and the CO2/N2 separation factor was 50.0. 相似文献
3.
We synthesized 23 6-alkoxycoumarin derivatives, 20 of which are novel compounds. The structures of all compounds were confirmed
by NMR, MS, and elemental analysis, and their antifeedant and termiticidal activities against Coptotermes formosanus Shiraki were examined. In a no-choice test, 6-(2-pentynyloxy)coumarin (2v), 6-(2-butynyloxy)coumarin (2u), 6-(2-octynyloxy)coumarin (2w), and 6-methoxycoumarin (2a), demonstrated high termiticidal activity at a concentration of 10 μmol. At a concentration of 5 μmol, 6-(2-butynyloxy)coumarin
(2u) produced the highest mortality among the compounds tested. On the other hand, all of the 6-alkoxycoumarins showed antifeedant
activity at both concentrations, except 6-octadecyloxycoumarin (2j) that was inactive at 5 μmol. Among the 23 compounds and the control, 6-ethoxycoumarin (2b), 6-isopropoxycoumarin (2d), and 6-isobutoxycoumarin (2f) exhibited the highest antifeedant activity with no mass loss (0.00%) at a concentration of 10 μmol. Our findings indicate
that the presence of alkenyloxy and alkynyloxy groups was important for the termiticidal activity, while the incorporation
of alkoxy groups with longer alkyl chains tended to reduce both the termiticidal and antifeedant activities. Furthermore,
short chain alkoxy and arylalkoxy-substituted analogs showed good antifeedant activity, but methoxy groups on the benzene
ring had a negative effect. 相似文献
4.
The reaction of Hf(CH2
tBu)4 with a silica surface treated at 800 °C affords the unique single site (≡SiO)Hf(CH2
tBu)3,
1, ((≡SiO) = silica surface ligand). Reaction of 1, with dihydrogen at temperatures (θ) ranging from 100 °C to 250 °C leads to different surface hydrides. At θ ≤ 100 °C, there
is formation of [(≡SiO)Hf(CH2
tBu)(H)2], 2. For 100 ≤ θ ≤ 200 °C, 2 affords, [(≡SiO)2Hf(H)2], 3, and [(≡SiO)3SiH]. For 150 ≤ θ ≤ 250 °C, 3, is totally converted into [(≡SiO)3Hf(H)], 4, and [(≡SiO)2Si(H)2]. These different surface hafnium hydrides 2–4, which are obtained simultaneously but in various proportions were referred to as [Hf]θ–H, (θ = 75, 100, 125, 150 and 250 °C). [Hf]150–H is the most active catalyst in α olefin (ethylene, propene, isobutylene) polymerization at 25 °C and in polyolefin depolymerization
at 150 °C under H2 atmosphere. Although, there is a clear correlation between the catalytic activity both in polymerization and in depolymerization,
and the amount of 3 and 4, it is not possible to establish which between the mono and the bis-hydride is the most active. 相似文献
5.
Six new optically active poly(amide-imide)s were synthesized by poly condensation reaction of 2,5-bis(4-aminophenyl)-1,3,4-oxadiazole
(8) with six chiral N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)-bis-l-amino acids (3a–f) in a medium consisting of N-methyl-2-pyrrolidone (NMP), triphenylphosphite (TPP), calcium chloride (CaCl2), and pyridine. Chiral N,N′-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)-bis-l-amino acids (3a–f) were obtained by the reaction of bicyclo[2.2.2]-oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (1) with two equimolar of l-alanine (2a), l-valine (2b), l-leucine (2c), l-isoleucine (2d), l-phenyl alanine (2e), and l-2-aminobutyric acid (2f) in acetic acid. The poly condensation reaction produced a series of novel poly(amide-imide)s (9a–f) in high yield and with inherent viscosities between 0.30 and 0.52 dL/g. The resulting polymers were characterized by elemental
analysis, viscosity measurement, solubility testing, thermo-gravimetric analysis (TGA), 1H-NMR, and FT-IR techniques. 相似文献
6.
Takeshi Nakato Masayuki Tomida Atsushi Kusuno Minako Shibata Toyoji Kakuchi 《Polymer Bulletin》1998,40(6):647-650
Summary
The polycondensations of L-aspartic acid (1) with aromatic aminocarboxylic acid, 4-aminobenzoic acid (2a), 4-aminophenylacetic acid (2b), 4-aminomethylbenzoic acid (2c), 4-(4-aminophenyl)butyric acid (2d), and 4-aminocinnamic acid (2e) were carried out using phosphoric acid as a catalyst. The obtained copolymers consiting of the succinimide and amide units,
poly(succinimide-co-amide) (3), were soluble in DMF and DMSO except for that with 2e. The thermal properties differed with varying the 2 unit in 3, i.e., the Tgs of 3a–c (99 ∼ 138°C) were higher than those of 3d (81 ∼ 1 01°C), the apparent difference in the Tm between 3a–d did not observed, and the Td decreased in the order of 3a, 3c > 3d > 3b.
Received: 24 February 1998/Revised version: 3 April 1998/Accepted: 13 April 1998 相似文献
7.
We measured the absolute rate constants for the hydrogen peroxide oxidation of two different octyl dimethyl amines in isopropanol/water
mixtures at 23°C. The amines were 1-octyl dimethyl amine (1) and 2-ethylhexyl dimethyl amine (2); their structures were analogous to those most often encountered in commercial alkyl dimethyl amine oxide production. The
observed first-order rate constants for the disappearance of amine across a range of H2O2 concentrations (0.5–8 M) indicated that the overall rate was first-order in amine and 3/2-order in H2O2. Calculations showed k
1=0.16 M−1h−1, k
2=0.046 M−1h−1, and k
1/k
2=3.5. The rates appeared to decrease with increasing steric hindrance around the nitrogen atom. We also investigated the effect
of water on the reaction rates. When [H2O]<∼4.5 M in isopropanol, the rates increased with increasing [H2O]; for [H2O]>∼4.5 M, the rates were insensitive to [H2O]. 相似文献
8.
Wai-Yeung Wong Suk-Yue Poon 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(1):155-162
A novel approach based on conjugation interruption was developed for a luminescent and thermally stable platinum(II) polyyne
polymer trans-[–Pt(PBu3)2C≡C(C6H4)CH2(C6H4)C≡C–]
n
(1) containing the diphenylmethane chromophoric spacer. Particular attention was focused on the photophysical properties of
this group 10 polymetallayne and comparison was made to its binuclear model complex trans-[Pt(Ph)(PEt3)2C≡C(C6H4)CH2(C6H4)C≡CPt(Ph)(PEt3)2] (2) and their closest group 11 gold(I) and group 12 mercury(II) neighbors, [MC≡C(C6H4)CH2(C6H4)C≡CM] (M = Au(PPh3) (3), HgMe (4)). The regiochemical structures of these angular-shaped compounds were studied by various spectroscopic analyses. Upon photoexcitation,
each of them emits an intense purple-blue fluorescence emission in the near UV region in dilute fluid solutions at room temperature.
Harvesting of organic triplet emissions harnessed through the strong heavy-atom effects of group 10–12 transition metals was
examined. These metal-containing phenyleneethynylenes spaced by the conjugation-breaking CH2 unit were found to have high optical gaps and high-energy triplet states. The influence of metal and sp3-hybridized methylene conjugation-interrupters on the intersystem crossing rate and the spatial extent of the lowest singlet
and triplet excitons was fully elucidated. Our investigations indicate that high-energy triplet states in these materials
intrinsically give rise to very efficient phosphorescence with fast radiative decays.
Dedicated to Professor Didier Astruc in recognition of his outstanding contribution to metallodendrimers and polymers. 相似文献
9.
Dawn M. Jennings Sarah E. Brady Ginger V. Shultz Lev N. Zakharov David R. Tyler 《Polymer Bulletin》2012,68(9):2243-2254
The (CH3)2Si[CpMo(CO)3]2 complex (1) was synthesized and used to explore ring-opening polymerization (ROP) as a method to prepare high molecular weight polymers
containing Mo–Mo bonds along their backbones. Attempts to initiate ROP of 1 using n-BuLi or PtCl2 did not yield any polymers. The X-ray crystal structure of 1 shows that the Si center is not strained, and it is suggested that no ROP occurred because 1 is less strained than other organometallic ROP monomers, such as the silicon-bridged ferrocenophanes. Thermal ROP (TROP)
of 1 was successful and yielded a polymer (M
w = 210,000 g mol−1) containing both Mo–Mo single bonds and Mo≡Mo triple bonds. When CO(g) is passed over the polymer in the solid state, the Mo≡Mo triple bonds are converted to Mo–Mo single bonds. Attempts to increase
the yield of the TROP polymer by increasing the reaction times led to polymer decomposition. The decomposition is likely caused
by the weakness of the Mo–Mo bond, cleavage of which causes the polymer to degrade. 相似文献
10.
Summary The coupling of alkali ethynides with CSCl2, SOCl2, or SO2Cl2 results in new carbonaceous polymeric products; their structures were studied by FTIR and XPS spectra, and the assumptions
on reaction mechanism were made with respect to the found elemental composition and model calculations. These macromolecular
products, obtained in the yields of 80–92%, contain chlorine in the chain terminals, and alkyne sequences along with inserted
C=S, S=O or SO2 groups. These inserted sulphur groups contribute to the stability of alkyne sequences as evidenced by FTIR spectra. Soluble
thioketone iPr3SiC≡C–CS–C≡CSiiPr3 (2) prepared by similar coupling of iPr3SiC≡CLi (1) with CSCl2 in the yield of 72%, was considered as a support of the suggested coupling mechanism. Similarly monomolecular sulfoxide iPr3SiC≡C–SO–C≡CSiiPr3 (3) was prepared by coupling of iPr3SiC≡CLi (1) with SOCl2 in the yield 75%. 相似文献
11.
Mohammad Reza Vakili Saeed Zahmatkesh Tahereh Jafarizadeh Mohammad Javad Panahiyan 《Polymer Bulletin》2012,68(1):85-94
N-trimelliticimido-l-aspartic acid (1) was prepared from the reaction of trimellitic anhydride with l-aspartic acid in a mixture of glacial acetic acid and pyridine solution (3/2 ratio) under refluxing conditions. The solution
polycondensation of the corresponding activated monomer with eight aromatic diamines were carried out in DMAc. The resulting
poly(amide-imide)s were obtained in quantitative yields, showed admirable inherent viscosities (0.20–0.36 dl g−1), good optical activity (+7.32o to +15.24o), and were readily soluble in polar aprotic solvents. They start to decompose
(T
10%) above 170 °C and display glass-transition temperatures at 120–237 °C. All of the above polymers were fully characterized
by UV, FT–IR, and 1HNMR spectroscopy, elemental analysis, thermogravimetric analyses, DSC, inherent viscosity measurement, and specific rotation. 相似文献
12.
Pushpa Ann Kurian C. Vijayan K. Sathiyamoorthy C. S. Suchand Sandeep Reji Philip 《Nanoscale research letters》2007,2(11):561-568
Stable films containing CdS quantum dots of mean size 3.4 nm embedded in a solid host matrix are prepared using a room temperature
chemical route of synthesis. CdS/synthetic glue nanocomposites are characterized using high resolution transmission electron
microscopy, infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. Significant blue shift
from the bulk absorption edge is observed in optical absorption as well as photoacoustic spectra indicating strong quantum
confinement. The exciton transitions are better resolved in photoacoustic spectroscopy compared to optical absorption spectroscopy.
We assign the first four bands observed in photoacoustic spectroscopy to 1s
e
–1s
h
, 1p
e
–1p
h
, 1d
e
–1d
h
and 2p
e
–2p
h
transitions using a non interacting particle model. Nonlinear absorption studies are done using z-scan technique with nanosecond
pulses in the off resonant regime. The origin of optical limiting is predominantly two photon absorption mechanism. 相似文献
13.
Synthesis of poly(ethyl vinyl ethers) containing two dipolar electronic systems and their properties
Summary
5-Nitro-2-(2′-vinyloxyethoxy)benzylidenemalononitrile (2a), methyl 5-nitro-2-(2′-vinyloxyethoxy)benzylidenecyanoacetate (2b), 3-nitro-4-(2′-vinyloxyethoxy)benzylidenemalononitrile (4a), and methyl 3-nitro-4-(2′-vinyloxyethoxy)benzylidenecyanoacetate (4b) were prepared by the condensation of 5-nitro-2-(2′-vinyloxyethoxy)benzaldehyde (1) and 3-nitro-4-(2′-vinyloxyethoxy)benzaldehyde (3) with malononitrile or methyl cyanoacetate, respectively. Vinyl ether monomers 2a-b and 4a-b were polymerized with boron trifluoride etherate as a cationic initiator to yield poly(vinyl ethers) 5-6 having nitrooxybenzylidenemalononitrile and nitrooxycyanocinnamate, which is effective chromophore for second-order nonlinear
optical applications. Polymers 5-6 were soluble in common organic solvents such as acetone and DMSO. T
g
values of the resulting polymer were in the range of 70–81°C. Electrooptic coefficient (r33) of the poled polymer films were in the range of 19–27 pm/V, which was improved by introducing of nitro group. Polymers 5–6 showed a thermal stability up to 300°C in TGA thermograms, which is acceptable for NLO device applications.
Received: 24 November 1998/Revised version: 19 January 1999/Accepted: 29 January 1999 相似文献
14.
Marcelo C. Murguía Laura M. Machuca María C. Lurá María I. Cabrera Ricardo J. Grau 《Journal of surfactants and detergents》2008,11(3):223-230
A series of new N-acetylated non-ionic and cationic gemini surfactants (3a–f) having dimeric structures derived from primary and tertiary amines with variably long tails (C8–C12–C18) were synthesized. In addition, N-acetylated monomeric analogues 6a and 6b were prepared and their antifungal potency and surface properties were also determined. Critical micelle concentration (CMC),
effectiveness of surface tension reduction (γCMC), surface excess concentration (Γ), and area per molecule at the interface (A) were also determined and the resulting values indicate that the cationic series is characterized by good surface-active
and self-aggregation properties. For the first time, all surfactants were tested to evaluate their antifungal properties using
the method for the broth macrodilution test (M27-A2, NCCLS). Four microbial strains were used to perform the study: Candida parapsilosis (ATCC 22019), C. albicans (ATCC 64548), and a wild-type strain of C. parasilosis and Saccharomyces cerevisiae (ATCC 9763). The antimicrobial activity was measured by yeast growth inhibition expressed as minimum inhibitory concentration
(MIC) values. Results were compared to those obtained for their monomeric analogues and for a commercially available reference
compound (Fluconazole). Gemini 3b, 3e and 3f were found to be the most potent compounds. The results show S. cerevisiae as the most sensitive strain. In contrast, the wild strain of C. parapsilosis was resistant.
相似文献
Ricardo J. Grau (Corresponding author)Email: |
15.
Katsuyuki Tsuda Wataru Hirahata Kazuaki Yokota Toyoji Kakuchi Takashi Ishizone Akira Hirao 《Polymer Bulletin》1997,39(2):173-178
The radical polymerizations of 2-, 3-, and 4-(trimethylsilylethynyl)styrenes (1 a – c) and copolymerizations of 1 a – c (M1) with styrene (M2) have been studied. Copolymerization parameters were determined as r1 = 1.22 and r2 = 0.54 for 1 a, 1 = 1.10 and r2 = 0.90 for 1 b, and r1 = 1.42 and r2 = 0.38 for 1 c. The deprotection of the trimethylsilyl groups in poly[(trimethylsilylethynyl)styrene] (2 a – c) and poly[(trimethylsilylethynyl)styrene-co-styrene] (4 a – c) using (C4H9)4NF smoothly proceeded to yield poly(ethynylstyrene) (3 a – c) and poly(ethynylstyrene-co-styrene) (5 a – c), respectively, which underwent curing reactions at elevated temperature to form crosslinking polystyrenes.
Received: 31 March 1997/Revised: 2 June 1997/Accepted: 3 June 1997 相似文献
16.
C. Pagliero N. A. Ochoa P. Martino J. Marchese 《Journal of the American Oil Chemists' Society》2011,88(11):1813-1819
Vegetable oil extraction, as performed today by the oilseed-crushing industry, usually involves solvent extraction with commercial
hexane. After this step, the vegetable oil–hexane mixture (miscella) must be treated to separate its components by distillation.
If solvent-resistant membranes with good permeation properties can be obtained, membrane separation may replace, or be used
in combination with, conventional evaporation. Two tailor-made flat composite membranes, poly(vinylidene fluoride) (PVDF–Si
and PVDF–CA) and a commercially available composite membrane (MPF-50), were used to separate a crude sunflower oil–hexane
mixture. The effects of temperature, cross-flow velocity (v), transmembrane pressure (Δp), and feed oil concentration (C
f) on membrane selectivity and permeation flux were determined. The PVDF–Si membrane achieved the best results, being stable
in commercial hexane and having promising permselectivity properties for separation of vegetable oil–hexane miscella. Improved
separation performance was obtained at C
f = 25%, Δp = 7.8 bar, T = 30 °C, and v = 0.8 m s−1; a limiting permeate flux of 12 Lm−2 h−1 and 46.2% oil retention were achieved. Low membrane fouling was observed under all the experimental conditions studied. 相似文献
17.
Summary
o-(2-Vinyloxyethoxy)benzylidenemalononitrile (3a), methyl o-(2-vinyloxyethoxy)benzylidenecyanoacetate (3b), 1,3-di-(2'-dicyanovinyl)-5-methyl-2-(2'-vinyloxyethoxy)benzene (4a), methyl 1,3-di-(2'-carbomethoxy-2'-cyanovinyl)-5-methyl-2-(2'-vinyloxyethoxy)benzene (4b), 2,3,4-tri-(2'-vinyloxyethoxy)benzylidenemalononitrile (5a), methyl 2,3,4-tri-(2'-vinyloxyethoxy)benzylidenecyanoacetate (5b), 2,4,6-tri-(2'-vinyloxyethoxy)benzylidenemalononitrile (6a), and methyl 2,4,6-tri-(2'-vinyloxyethoxy)benzylidenecyanoacetate (6b) were prepared by the condensation of o-(2-vinyloxyethoxy) benzaldehyde (1a), 2-(2'-vinyloxyethoxy)-5-methylisophthaldehyde (1b), 2,3,4-tri-(2'-vinyloxyethoxy)benzaldehyde (2a), 2,4,6-tri-(2'-vinyloxyethoxy)benzaldehyde (2b) with malononitrile or methyl cyanoacetate, respectively. Vinyl ether compounds 3a–b and 5a–b were polymerized readily by free radical initiators to give optically transparent swelling poly(vinyl ethers) 7a–b and 9a–b. Compounds 4a–b and 6a–b did not polymerize by radical initiators due to the steric hindrance. Polymers 7a–b and 9a–b were not soluble in common organic solvents such as acetone and DMSO due to crosslinking. Polymers 7a–b and 9a–b showed a thermal stability up to 300°C in TGA thermograms.
Received: 1 December 1999/Revised version: 14 February 2000/Accepted: 16 February 2000 相似文献
18.
Ayşegül Şenocak Ahmet Karadağ Ertan Şahin Yusuf Yerli 《Journal of Inorganic and Organometallic Polymers and Materials》2011,21(3):438-449
Characterization and synthesis of novel cyano bridged coordination compounds [Ni(bishydeten)Pt(CN)4] (1), [Cu(bishydeten)Pt(CN)4] (2), [Zn(bishydeten)Pt(CN)4] (3), [Cd(bishydeten)Pt(CN)4] (4) [bishydeten = N,N′-bis(2-hydroxyethyl)ethylenediamine (C6H16N2O2)] were reported herein. The IR spectra of these coordination compounds verified the formation of aforementioned complexes. The ground state of the paramagnetic
electron in the CuII located in tetragonal distorted octahedral sites (D
4h
) was found to be dx2−y2 for complex 2. As for complex 1, an EPR signal was not observed because of diamagnetic property of the PtII and momentary relaxation times of the NiII. All complexes followed identical decomposition mechanism in thermal analysis and thermal stabilities of complexes changed
in the order of 1 > 4 > 3 > 2. Both 3 and 4 exhibit polymeric structure according to X-ray single structure analysis. While bishydeten coordinated with three donor atoms (N,N′, and O) in complex 3, it acts as a bidentate ligand (N, and N′) in complex 4. Magnetic properties of complexes 1–2 at 15–300 K temperature range were determined as antiferromagnetic with Weiss constants = −2.619 and −0.847 K respectively. 相似文献
19.
Summary Propargyl esters (HC≡CCH2OC(=O)R; 1: R = n-C5H11, 2: R = CH3, 3: R = CHBrCH3, 4: R = C6H5, 5: R = C(C6H5)3) were polymerized by using (nbd)Rh+(η6-Ph-B-Ph3) (nbd = 2,5-norbornadiene) to produce poly(1)–poly(5) with molecular weights in the range of Mn = 4,900–40,000. Poly(1), poly(3) and poly(4) were readily soluble in common organic solvents such as toluene, THF and CHCl3, and poly(2) showed similar solubility behavior except that it was insoluble in THF. Poly(5) did not dissolve in any organic solvent. Poly(1) was yellow oil, while poly(2)–poly(5) were yellow solids. Poly(1)–poly(4) exhibited UV-vis absorptions in a range of 300–425 nm, which are attributed to the conjugation of the main chain. All the
polymers were thermally stable up to 150–200 °C. 相似文献
20.
Feng Guo Xiuling Zhang Baoyong Zhu Jianchao Qiu 《Journal of Inorganic and Organometallic Polymers and Materials》2010,20(1):38-45
Four novel compounds [Co(Hdpa) 2(4,4′-bipy)2]n (1), {[Ni(dpa)(2,2′-bipy)(H2O)](H2O)}n, (2), [Ni(dpa)(im)3]n (3) and [Zn(dpa)(im)]n (4) [H2dpa = 2,4′-diphenyl-dicarboxylic acid, 4,4′-bipy = 4,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine and im = imidazole] were synthesized
and characterized by elemental analysis, IR and single-crystal X-ray diffraction. X-ray crystallography shows that the 2,4′-diphenic
acid exhibits three coordination modes to link the metal ions: μ
1
−η1: η1/μ
0
−η0: η0, μ
1−η
1: η
0/μ
2−η
1: η
1 and μ
1−η
1: η
0/μ
1−η
1: η
0. Compound 1 has a 1D supramolecular structure. Compounds 2 and 3 are 3D supramolecular structures. Compound 4 is a 2D supramolecular structure. All the compounds, 1–4, are self-assembled to form supramolecular structures through hydrogen bonding interactions. 相似文献