首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
稀土三酞菁夹心化合物混合LB膜的研究   总被引:3,自引:0,他引:3  
将不对称三明治型夹心化合物(Pc)Dy[Pc(OC8H17)8]Dy[Pc(OC8H17)8]与硬脂酸混合成膜,表面压-面积(π-A)曲线表明形成了稳定的单层膜,由透射电子显微镜(TEM)观察,表明硬脂酸的加入有效地改善了分子的聚集行为,分子形成了取向高度有序的结构。用紫外-可见光谱、偏振紫外可见光谱、低角X射线衍射等对LB膜进行了研究,发现该取代稀土三酞菁分子在气/液界面上长链向上伸展,分子之间均以面对面(face-to-face)排列,以一边接触(edge-on)方式取向,大环平面与基片夹角约为52°,每层厚度为2.41 nm。  相似文献   

2.
Synthesis of Gd doped Srx O: CdO (x = 1.4, 1.6, 1.8) nanostructures (NS) was achieved through the coprecipitation method by using CTAB (cetyl trimethyl ammonium bromide) with the purpose to investigate the effect of Gd doping on the optical, structural, morphological, and photoluminescence properties at room temperature. Mixed phase of tetragonal crystal structure verified via X-ray diffraction technique, no structural variation was observed except lattice distortion. Size of the crystallites (D), morphology studied by SEM (scanning electron microscopy) analysis, nanoparticles (NPs) crystalized roughly flake-like morphology with homogeneous particle distribution centered at ~ 78 nm, ~56 nm, ~65 nm, ~88 nm for pure and Gd (x-1) doped Sr xO: CdO nanostructure, respectively. Fourier transform infrared spectroscopic investigation (FTIR) revealed the presence of Gd–O–Gd, Cd–O, Sr–O, and OH peaks appeared at ~1321 cm ?1, ~1550 cm ?1, ~1400 cm ?1–3300 cm ?1 with small variation in vibration modes due to Gd doping. Optical absorptivity observed in the range of 325 nm–359 nm (redshifted) with absorption edges at 346 nm, 364 nm, and 380 nm for Gd (x-1) doped Sr xO: CdO nanostructure, respectively. This redshift on the bandgap was discussed in terms of new band levels below conduction band. The energy gap was calculated using Kubelka-Munk theory and was found to be in the range of 3.22 eV–2.61 eV. X-ray photoelectron spectroscopy (XPS) performed to determine chemical composition and binding energies of Gd 3d 3/2, Sr 3d 3/2, and Cd 3d 3/2, O1s, and C1s observed at 150.8 eV, 141.6 eV, 411.0 eV, 530.4 eV, and 285.6 eV indicating Gd+3 ion replaces Sr+2 in all concentrations. Our results showed that Gd-doped Sr xO: CdO nanoparticles exhibited enhanced photoluminescence (PL) properties in contrast to the pure Gd2O3 with Gd+3 randomly incorporated into crystal structure, probably in tetrahedral sites. The composition of Gd 0.6 doped Sr x O: CdO NS exhibited photoluminescent emission spectra, peaks centered at 433 ± 3 nm, 449 ± 3 nm, and 469 ± 2 nm (λ excitation = 318 nm) and for Gd 0.8 doped Sr x O: CdO nanostructure showed broad emission peak at 412 ± 2 nm to 433 ± 2 nm (λ excitation = 380 nm), which indicates a reduction in defects with an increase in Gd doping. The transitions can be ascertained with shielding of 4f shells of Gd +3 ions by 6s, 5d shells by the interaction of other Gd +3 ions.  相似文献   

3.
The spectral and electrochemical properties of Langmuir-Blodgett (LB) films of homoleptic double-decker cerium bis-[tetra-15-crown-5]-phthalocyaninate Ce[R4Pc]2 and its heteroleptic analog [Pc]Ce[R4Pc] were studied. It was shown that during formation of Langmuir monolayers upon contact of both complexes solutions with water subphase the metal center with valent state IV in the solution transforms into one with the valent state III in the monolayer. Upon cyclic compression-expansion of these monolayers, orientation-induced reversible intramolecular transfers of electron from 4f orbital of cerium ion to the phthalocyanine macrocycle (compression) and in reverse direction (expansion) occur in a planar supramolecular system. Scheme of reversible electrochemical transformations occurring in ultrathin films of double-decker cerium crown-phthalocyaninates, one of which is associated with the Ce+3/Ce+4 redox-transition of metal center of the complex, was proposed and substantiated using the results of spectro-electrochemical investigations. It was shown that one of these transformations is associated with the Ce+3/Ce+4 redox transition of metal center of the complex and upon change of metal center oxidation state its size changes, and, consequently, the distance between the decks of the complex also changes. This change in the distance can lead to a substantial (13–15%) modulation of the linear size of molecular assemblies with a large number of molecules in stack. On the basis of this effect the supramolecular device that can perform mechanical work can be developed. Using surface plasmon resonance technique we have demonstrated that a step change in electrode potential in region of 200–1000 mV induces a corresponding optical response reflected in a step change of the resonance angle. High operation speed and reversibility of switching between stable states can serve as a basis for development of optoelectronic switching systems.  相似文献   

4.
Three new solid lanthanide(III) complexes, [Ln(1-AMUH)3] · (NO3)3 (1-AMUH = 1-amidino-O-methylurea; Ln = Eu(III), Gd(III), or Tb(III)) were synthesised and characterised by elemental analysis, infrared spectra, magnetic moment measurement, and electron paramagnetic resonance (EPR) spectra for Gd(III) complex. The formation of lanthanide(III) complexes is confirmed by the spectroscopic studies. The photophysical properties of Gd(III), Eu(III), and Tb(III) complexes in solid state were investigated. The Tb(III) complex exhibits the strongest green emission at 543 nm and the Eu(III) complex shows a red emission at 615 nm while the Gd(III) complex shows a weak emission band at 303 nm. Under excitation with UV light, these complexes exhibited an emission characteristic of central metal ions. The powder EPR spectrum of the Gd(III) complex at 300 K exhibits a single broad band with g = 2.025. The bi-exponential nature of the decay lifetime curve is observed in the Eu(III) and Tb(III) complexes. The results reveal them to have potential as luminescent materials.  相似文献   

5.
The Raman spectroscopic data in the range 500-1800 cm−1 for a series of 15 rare earth double-deckers with tervalent rare earths MIII[Pc(MeOPhO)8]2 (M = Y, La, …, Lu, except Ce, Pr and Pm), reduced state HPr[Pc(MeOPhO)8]2 and intermediate-valent cerium Ce[Pc(MeOPhO)8]2 have been collected using laser excitation source emitting at 632.8 nm. With excitation at 632.8 nm, which is in close resonance with the main Q absorption band of the phthalocyanine ligand, typical Raman marker bands of the monoanion radical [Pc(MeOPhO)8] were observed at 1500-1528 cm−1 as very strong bands resulting from the coupling of pyrrole CC and aza CN stretchings. For Ce[Pc(MeOPhO)8]2 and HPr[Pc(MeOPhO)8]2, a very strong band at 1499 cm−1 with contributions from both pyrrole CC and aza CN stretchings and also isoindole stretching was the marker Raman band of [Pc(MeOPhO)8]2−. In addition, the influence of ionic radius of the rare earth metal and substituent species on the Raman scatting characteristics of sandwich-type compounds has also been tentatively studied.  相似文献   

6.
New covalently C60‐conjugated phthalocyanine (Pc) analogues in which the Pc and C60 components are connected by means of a four‐membered ring have been synthesized by taking advantage of a [2+2] cycloaddition reaction of C60 with benzyne units generated from either a phthalocyanine derivative ( 8 ) or its precursor ( 1 ). The reaction of 1 with PhI(OAc)2 and trifluoromethanesulfonic acid (TfOH) followed by the [2+2] cycloaddition of C60 in the presence of tetra‐n‐butylammonium fluoride (TBAF) yielded the C60‐substituted Pc precursor ( 3 ). Mixed condensation of 3 and 4,5‐dibutylsulfonylphthalonitrile ( 4 ) in a thermally promoted template reaction using a nickel salt successfully gave the Pc–C60 conjugate ( 5 ). Results of mass spectrometry and 1H and 13C NMR spectroscopy clearly indicate the formation of the anticipated Pc–C60 conjugate. Direct coupling of C60 with the Pc analogue that contained eight peripheral trimethylsilyl (TMS) groups ( 8 ) also proceeded successfully, such that mono and bis C60‐adducts were detected by their mass, although the isolation of each derivative was difficult. The absorption and magnetic circular dichroism (MCD) spectra of 5 and the reference compound ( 7 ) differ from each other in the Q‐band region, thereby suggesting that the presence of the C60 moiety affects the electronic structure of the conjugate. The reduction and oxidation potentials of 5 and 7 obtained by cyclic voltammetry are comparative, except for the C60‐centered reduction couple at ?1.53 V versus Fc+/Fc in o‐dichlorobenzene (o‐DCB). A one‐electron reduction of 5 and 7 in tetrahydrofuran (THF) by using the sodium mirror technique results in the loss of band intensity in the Q‐band region, whereas the characteristic marker bands for Pc‐ring‐centered reduction appear at around 430, 600, and 900 nm for both compounds. The final spectral shapes of 5 and 7 upon the reduction resemble each other, thus indicating that no significant molecular orbital (MO) interactions between the C60 and Pc units are present for the reduced species of 5 . In contrast, the oxidized species of 5 and 7 generated by the addition of NOBF4 in CH2Cl2 show significantly different absorption spectra from each other. Whereas the broad bands at approximately 400–550 nm of 7 + are indicative of the cationic π‐radical species of metallo‐Pcs and can be assigned to a transition from a low‐lying MO to the half‐filled MO, no corresponding bands were observed for 5 +. These spectral characteristics have been tentatively assigned to the delocalized occupied frontier MOs for 5 +. The experimental results are broadly supported by DFT calculations.  相似文献   

7.
In this study, a novel poly[Styrene (ST)-co-Glycidyl Methacrylate (GMA)] copolymer material is used to fabricate Langmuir-Blodgett (LB) thin films and investigate organic vapor sensing properties. Quartz Crystal Microbalance (QCM) system is used to investigate gas sensing performance of copolymer LB films during exposure to Volatile Organic Compounds (VOCs). The poly[Styrene (ST)-co-Glycidyl Methacrylate (GMA)] LB thin film sensor sensitivities are determined to be between 0.12 and 0.25 Hz ppm?1. Detection limits of the copolymer LB thin film are found to be between 23 and 49 ppm against organic vapors. The copolymer LB thin films are more sensitive to chloroform than other vapors used in this study. The results demonstrated that the poly[Styrene (ST)-co-Glycidyl Methacrylate (GMA)] copolymer material is promising as a organic vapor sensing device at room temperature.  相似文献   

8.
By reactions of 1-(2-pyridyl)naphth-2-ol (pynH) with silylamides Ln[N(SiMe3)2]3 (Ln = Sc, Eu, Gd, or Tb), the Ln(pyn)3 complexes of the metals have been synthesized. Only the scandium complex in a THF solution has displayed photoluminescence (band with a maximum at 455 nm and a halfwidth of 65 nm). Electroluminescent properties have been revealed for the scandium and terbium complexes. In an ITO/TPD/Sc(pyn)3/Bath/Yb three-layer light emitting diode, the scandium complex exhibits yellow-green luminescence with a brightness of 4750 cd/m2 at a voltage of 21 V. The terbium complex Tb(pyn)3 in the same device has displayed a single, broad luminescence band with λmax = 570 nm due to excimer emission. By density functional theory quantum chemical calculations, different structures of the complexes have been revealed, mononuclear for Sc(pyn)3 and binuclear for Ln2(pyn)6. This difference in structure seems to be responsible for differences in electroluminescent activity between the synthesized complexes.  相似文献   

9.
Bacteriochlorophyll c (BChl c) solid films were prepared from a carbon tetrachloride solution on CaF2 plates as artificial aggregates. Effects of organic vapor such as acetone and tetrahydrofuran (THF) on the BChl c films were studied by absorption and Fourier-transform infrared spectroscopy. Two major homologs (R[E,E]BChl cF and R[P,E]BChl cF) and one minor homolog (S[I,E]BChl c) isolated from the green photosynthetic bacterium Chlorobium limicola strain 6230 were examined for the experiments. The BChl c polymeric aggregates absorbing at739–753 nm similar to those in the chlorosome were induced for all homologs upon the treatment of BChl c solid film with acetone vapor. The 131-keto C=O stretching band in the R[E,E]BChl cF solid film showed a downward shift from 1651 cm?1to 1643 cm?1 with a concomitant shift of the 31-OH stretching bands from 3337 and 3238 cm?1 to 3163 cm?1. It was suggested that the lower aggregates brought about by Mg…O=C(131) and (31)O…O=C(131) bonds were transformed into the higher aggregates strongly hydrogen-bonded in a Mg…(31)O-H…O=C(13l) interaction. They were transformed to a monomer-like form absorbing at 667 nm upon exposure to THF vapor and were reversibly converted to the higher aggregates upon removal of THF molecules in vacuo.  相似文献   

10.
《Vibrational Spectroscopy》2004,34(1):169-173
The monolayer of the mixture of octadecanoic acid and octadecylamine with molar ratio 1:1 has been investigated at the air–water interface. It was found that the monolayer shows a rather stable state at the surface pressure of 30 mN/m and this monolayer can be transferred onto a CaF2 plate by Langmuir–Blodgett (LB) technique. The infrared spectra of LB films indicated that octadecylammonium octadecanoate is formed by an intermolecular proton exchange between adjacent carboxylic and aminic groups (COO and NH3+). In three-layer LB film, the CH2 scissoring mode of the long hydrocarbon chains of octadecylammonium octadecanoate shows a broad band feature at about 1468 cm−1 while this vibrational mode of three-layer LB film of the mixture (1:1) of deuterated stearic acid and octadecylamine (octadecylammonium octadecanoate-d35, C18H37NH3+C17D35COO) only shows a narrow band. The broad feature of the CH2 scissoring mode in octadecylammonium octadecanoate probably originates from the coupling between the chain of stearic acid and that of octadecylamine while this kind of coupling could be completely removed in octadecylammonium octadecanoate-d35. Another conclusion presented in this paper is that there are no couplings among the chains of fatty acid or among the chains of octadecylamine in LB films of octadecylammonium octadecanoate.  相似文献   

11.
Synthesis and Spectroscopical Properties of Di(phthalocyaninato(1?))lanthanidepolybromide; Crystal Structure of α-Di(phthalocyaninato)samariumpolybromide, α-[Sm(Pc)2]Br1.45 and α-Di(phthalocyaninato)samariumperchlorate, α-[Sm(Pc)2](ClO4)0.63 Bronze-coloured di(phthalocyaninato)lanthanidepolybromide, [Ln(Pc?)2]Bry (Ln = La…(? Ce, Pm)…Lu; y > 1.5) is prepared by oxidation of (nBu4N)[Ln(Pc2?)2] with bromine in excess. The UV-VIS-NIR spectra show the typical B and Q1 bands of the Pc? ligand at ~ 14 kK and ~ 20 kK. For the [Ln(Pc?)2]+ cation a NIR(D) band between 9,14 kK (La) and 11,50 kK (Lu) is characteristic for dimeric cofacial Pc? radicals. Within the row La…Lu, there is a linear relationship of the hypsochromic shift of the strong bands and the LnIII radius. In the case of La? Nd the D band shifts successively with longer time of bromination to ~ 3 kK as a result of increasing electron delocalisation. Characteristic vibrational bands are at ~ 1350/1450 cm?1 (IR) and ~ 560/1120/1170/1600 cm?1 (RR). In the FT-Raman spectra the totally symmetric Ln? N stretching vibration between 141 cm?1 (La) and 172 cm?1 (Lu) is selectively enhanced. As shown by α-[Sm(Pc)2]Br1,45 and α-[Sm(Pc)2](ClO4)0,63 only partially ringoxidized complexes are obtained by the anodic oxidation. Both crystallize in the tetragonal space group P4/nnc. The [Sm(Pc)2] molecular building block contains two nearly planar staggered (~41°) Pc rings packed in columns parallel along [001] leading to the quasi-one-dimensional structure. There is a statistical disorder of the SmIII and the ClO4? resp. Br?/Br3? ions over two incompletely filled crystallographic positions for the cation resp. anion. This results in a partial oxidation of the Pc ligand, which in the picture of localized valence states for α-[Sm(Pc)2](ClO4)0,63 corresponds to [SmPc?Pc2?] · 2[Sm(Pc?)2](ClO4). Accepting the same valence state for [Sm(Pc)2]Br1,45 five positive charges are compensated by two Br? and three Br3?. The spectroscopic differences of the partially and fully oxidized complexes are discussed.  相似文献   

12.
Preparation, Properties and Electronic Raman Spectra of Bis(chloro)-phthalocyaninatoferrate(III), -ruthenate(III) and -osmate(III) Bis(chloro)phthalocyaninatometalates of FeIII, RuIII and OsIII [MCl2Pc(2-)]?, with an electronic low spin ground state are formed by the reaction of [FeClPc(2-)] resp. H[MX2Pc(2?)] (M = Ru, Os; X = Cl, I) with excess chloride in weakly coordinating solvents (DMF, THF) and are isolated as (n-Bu4N) salts. The asym. M? Cl stretch (νas(MCl)) is observed in the f.i.r. at 288 cm?1 (Fe), 295 cm?1 (Ru), 298 cm?1 (Os), νas(MN) at 330 cm?1 (Fe), 327 cm?1 (Ru), and 317 cm?1 (Os); only νs(OsCl) at 311 cm?1 is resonance Raman (r.r.) enhanced with blue excitation. The m.i.r. and FT-Raman spectra are typical for hexacoordinated phthalocyanines of tervalent metal ions. The UV-vis spectra show besides the characteristic π-π* transitions (B, Q, N, L band) of the Pc ligand a number of extra bands at 12–15 kK and 18–24 kK due to trip-doublet and (Pc→M)CT transitions. The effect of metal substitution is discussed. The r.r. spectra obtained by excitation between the B and Q band (λ0 = 476.5 nm) are dominated by the intraconfigurational transition Γ7 Γ 8 arrising from the spin-orbit splitting of the electronic ground state for FeIII at 536 cm?1, for RuIII at 961 cm?1 and OsIII at 3 028 cm?1. Thus the spin-orbit coupling constant increases very greatly down the iron group: FeIII (357 cm?1)< RuIII (641 cm?1)< OsIII (2 019 cm?1). The Γ7 Γ 8-transition is followed by a very pronounced vibrational finestructure being composed in the r.r. spectra by the coupling with νs(MCl), δ(MClN) and the most intense fundamental vibrations of the Pc ligand. In absorption only vibronically induced transitions are observed for the Ru and Os complex at 1 700-2800 rsp. 3100-5800 em?1 instead of the 0-0 phonon transitions. The most intense lines are attributed to combinations of the intense odd vibrational mo-des at ≈ 740 and 1120 cm?1 with ν5(MCI), δ(MClN).  相似文献   

13.
The third-order nonlinear optical properties of the ruthenium (II) complex with tetra-15-crown-5-phthalocyanine and axially coordinated triethylenediamine molecules (R4Pc)Ru(TED)2 were analyzed by means of the z-scanning technique. A solution of (R4Pc)Ru(TED)2 in tetrachloroethane was exposed to nanosecond laser pulses at a wavelength of 1064 nm. It was found that the third-order molecular polarizability of the Ru(II) complex is 4.5 × 10?32 cm4/C (esu). The polarizability per molecule increases by a factor of 3.6 when the single molecule occurs in a supramolecular assembly of (R4Pc)Ru(TED)2 complexes. The photoelectric and photorefractive properties at 1064 nm of polymer composites, determined by the supramolecular assemblies that exhibits optical absorption and photoelectric sensitivity in the near IR region, are reported.  相似文献   

14.
Salicylaldehyde(N-benzoyl)glycyl hydrazone (SalBzGH) has been synthesized and characterized. Metal complexes of the empirical formula [Ln(SalBzGH-2H)OH(H2O)2] where Ln = Y, Pr, Nd, Sm, Eu, Gd and Dy, have been synthesized and their structures studied by infrared, far-infrared, absorption, emission and NMR spectra. 1H and 13C NMR spectra indicate the presence of dynamic equilibrium between two isomers of SalBzGH over the 298–368 K temperature range and stabilization of a single isomer upon complexation with Ln(III). The hypersensitive band profile of the Nd(III) complex indicates a change in metal coordination number due to solvation, while an increase of temperature results in a decrease of εmax of the hypersensitive band. The emission spectrum of [Eu(SalBzGH-2H)OH(H2O)2] at 77 K indicates a low site symmetry. SalBzGH coordinates through imidolic oxygen, azomethine nitrogen and phenolate oxygen.  相似文献   

15.
Radical anion salts of metal‐containing and metal‐free phthalocyanines [MPc(3?)].?, where M=CuII, NiII, H2, SnII, PbII, TiIVO, and VIVO ( 1 – 10 ) with tetraalkylammonium cations have been obtained as single crystals by phthalocyanine reduction with sodium fluorenone ketyl. Their formation is accompanied by the Pc ligand reduction and affects the molecular structure of metal phthalocyanine radical anions as well as their optical and magnetic properties. Radical anions are characterized by the alternation of short and long C?Nimine bonds in the Pc ligand owing to the disruption of its aromaticity. Salts 1 – 10 show new bands at 833–1041 nm in the NIR range, whereas the Q‐ and Soret bands are blue‐shifted by 0.13–0.25 eV (38‐92 nm) and 0.04–0.07 eV (4–13 nm), respectively. Radical anions with NiII, SnII, PbII, and TiIVO have S=1/2 spin state, whereas [CuIIPc(3?)].? and [VIVOPc(3?)].? containing paramagnetic CuII and VIVO have two S=1/2 spins per radical anion. Central metal atoms strongly affect EPR spectra of phthalocyanine radical anions. Instead of narrow EPR signals characteristic of metal‐free phthalocyanine radical anions [H2Pc(3?)].? (linewidth of 0.08–0.24 mT), broad EPR signals are manifested (linewidth of 2–70 mT) with g‐factors and linewidths that are strongly temperature‐dependent. Salt 11 containing the [NaIPc(2?)]? anions as well as previously studied [FeIPc(2?)]? and [CoIPc(2?)]? anions that are formed without reduction of the Pc ligand do not show changes in molecular structure or optical and magnetic properties characteristic of [MPc(3?)].? in 1 – 10 .  相似文献   

16.
The infrared (IR) spectroscopic data and Raman spectroscopic properties for a series of 13 “pinwheel-like” homoleptic bis(phthalocyaninato) rare earth complexes M[Pc(α-OC5H11)4]2 [M = Y and Pr–Lu except Pm; H2Pc(α-OC5H11)4 = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine] have been collected and comparatively studied. Both the IR and Raman spectra for M[Pc(α-OC5H11)4]2 are more complicated than those of homoleptic bis(phthalocyaninato) rare earth analogues, namely M(Pc)2 and M[Pc(OC8H17)8]2, but resemble (for IR) or are a bit more complicated (for Raman) than those of heteroleptic counterparts M(Pc)[Pc(α-OC5H11)4], revealing the decreased molecular symmetry of these double-decker compounds, namely S8. Except for the obvious splitting of the isoindole breathing band at 1110–1123 cm−1, the IR spectra of M[Pc(α-OC5H11)4]2 are quite similar to those of corresponding M(Pc)[Pc(α-OC5H11)4] and therefore are similarly assigned. With laser excitation at 633 nm, Raman bands derived from isoindole ring and aza stretchings in the range of 1300–1600 cm−1 are selectively intensified. The IR spectra reveal that the frequencies of pyrrole stretching and pyrrole stretching coupled with the symmetrical CH bending of –CH3 groups are sensitive to the rare earth ionic size, while the Raman technique shows that the bands due to the isoindole stretchings and the coupled pyrrole and aza stretchings are similarly affected. Nevertheless, the phthalocyanine monoanion radical Pc′ IR marker band of bis(phthalocyaninato) complexes involving the same rare earth ion is found to shift to lower energy in the order M(Pc)2 > M(Pc)[Pc(α-OC5H11)4] > M[Pc(α-OC5H11)4]2, revealing the weakened π–π interaction between the two phthalocyanine rings in the same order.  相似文献   

17.
A novel series of double‐decker lanthanide(III) bis(phthalocyaninato)–C60 dyads [LnIII(Pc)(Pc′)]–C60 (M=Sm, Eu, Lu; Pc=phthalocyanine) ( 1 a – c ) have been synthesized from unsymmetrically functionalized heteroleptic sandwich complexes [LnIII(Pc)(Pc′)] (Ln=Sm, Eu, Lu) 3 a – c and fulleropyrrolidine carboxylic acid 2 . The sandwich complexes 3 a – c were obtained by means of a stepwise procedure from unsymmetrically substituted free‐base phthalocyanine 5 , which was first transformed into the monophthalocyaninato intermediate [LnIII(acac)(Pc)] and further reacted with 1,2‐dicyanobenzene in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU). 1H NMR spectra of the bis(phthalocyaninato) complexes 3 a – c and dyads 1 a – c were obtained by adding hydrazine hydrate to solutions of the complexes in [D7]DMF, a treatment that converts the free radical double‐deckers into the protonated species, that is, [LnIII(Pc)(Pc′)H] and [LnIII(Pc)(Pc′)H]–C60. The electronic absorption spectra of 3 a – c and 1 a – c in THF exhibit typical transitions of free‐radical sandwich complexes. In the case of dyads 1 a – c , the spectra display the absorption bands of both constituents, but no evidence of ground‐state interactions could be appreciated. When the UV/Vis spectra of 3 a – c and 1 a – c were recorded in DMF, typical features of the reduced forms were observed. Cyclic voltammetry studies for 3 a – c and 1 a – c were performed in THF. The electrochemical behavior of dyads 1 a – c is almost the exact sum of the behavior of the components, namely the double‐decker [LnIII(Pc)(Pc′)] and the C60 fullerene, thus confirming the lack of ground‐state interactions between the electroactive units. Photophysical studies on dyads 1 a – c indicate that only after irradiation at 387 nm, which excites both C60 and [LnIII(Pc)(Pc′)] components, a photoinduced electron transfer from the [LnIII(Pc)(Pc′)] to C60 occurs.  相似文献   

18.
在过去的20年里,电致发光(EL)领域的研究显得异常活跃,EL已应用于通讯、信息、显示等许多领域,而占领这一领域的是P-N结无机半导体发光二级管,其发光效率已超过了白炽灯.但由于无机半导体很难实现大面积平面显示,加之成本较高,因此,限制了其进一步的发展[1].有机荧光材料的种类繁多,荧光量子效率高,且可以通过分子结构修饰有目的地控制其发光效率、发光颜色和电学性能[2],因而,越来越多的学术界和工业界的研究小组进入了有机电致发光研究领域[3.4].  相似文献   

19.
The infra-red (IR) spectroscopic data for a series of twelve sandwich-type homoleptic tetrakis[2,3,9,10,16,17,23,24-octa(octyloxy)phthalocyaninato] rare earth(III)-cadmium(II) quadruple-decker complexes [Pc(OC8H17)8]M[Pc(OC8H17)8]Cd[Pc(OC8H17)8]M[Pc(OC8H17)8] (M = Y, Pr–Yb except Pm) have been collected with resolution of 2 cm−1 and their interpretation in terms tried by analogy with the IR characteristics of bis(phthalocyaninato) cerium double-decker [Pc(OC8H17)8]Ce[Pc(OC8H17)8] in which the macrocyclic ligands exist as the phthalocyanine dianion. Similar to the bis/tris(phthalocyaninato) rare earth sandwich counterparts, all the absorptions contributed primarily by or at least containing contribution from the vibrations of pyrrole or isoindole stretching, breathing or deformation or aza stretching in the IR spectra of these quadruple-decker compounds show dependent nature on the rare earth ionic size. The shift toward higher energy direction in the frequencies of these vibrations along with the decrease of the rare earth radii reveals the effective and increasing π–π interactions in these quadruple-decker sandwich compounds in the same order. Nevertheless, the decreased sensitivity of the frequencies of the above mentioned vibration modes in particular the weak absorption band due to the isoindole stretching at 1414–1416 cm−1 for the quadruple-decker on rare earth metal size in comparison with corresponding band for bis(phthalocyaninato) rare earth counterparts indicates the relatively weaker π–π interaction in these quadruple-deckers than in the double-deckers.  相似文献   

20.
Abstract

In this work we report the synthesis, characterization and electrochemistry of the complex trans-[RuCl2(pmp)4], where pmp=3-(pyrrol-l-ylmethyl)pyridine. The complex was characterize by electronic spectroscopy (Λmax = 404 nm and ε = 27000), vibrational FT-IR spectroscopy, 1H and 13C NMR, showing results typically in agreement with trans geometry. Cyclic voltammetry reveals a redox process centered on the Ru(II) center (E1/2 = 0.53V vs. NHE), which is electrochemically and chemically reversible. Spectroelectrochemistry shows the progressive disappearance of bands at 404 and 475 nm and the appearance of a new band at 302 nm during the oxidation process. Cyclic voltammetric experiments were performed to characterize the redox properties of the ruthenium complex; its electropolymerization produced a strongly adhesive conducting polymeric film on platinum and palladium electrodes.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号