Abstract  Polymeric nanoparticles (NPs) with two-photon (TP) activity were prepared by grafting a naphthalimide fluorophore onto poly(acrylic acid) to yield an amphiphilic polymer, which self-assembled in water. The NPs were characterized using various analytical techniques such as transmission electron microscopy, dynamic light scattering and spectroscopic measurements. The in vitro and in vivo biocompatibilities of the NPs were assessed by a cytotoxicity assay using HeLa cells and a feeding assay using Caenorhabditis elegans (C. elegans) as a small animal model, respectively. Finally, TP fluorescence imaging (FI) of living cells and C. elegans labelled with the NPs were observed by TP confocal microscopy. The experimental outcomes demonstrated that the NPs had sufficient water-dispersity and biocompatibility, had TP fluorescence activity, were resistant to pH variation and illumination, and were physically stable. TP FI revealed that the NPs could enter living cells and were primarily located in the cytoplasm. In addition, the NPs were ingested by C. elegans during the feeding process and were recognized and taken up by the active transport system of the intestinal cells. These findings indicated the feasibility of using the developed NPs as a nanolabel for TP FI. Moreover, with numerous modifiable carboxyl groups on its surface, the NPs could act as a platform to build multifunctional probes for potential applications in biosensing and assay labeling.

Abstract  Two dimensional conjugated polymers have emerged as excellent polymer donor components in recent years. Here, all-polymer solar cells based on two conjugated side-chain isolated polythiophene derivatives (PT4TV and PT4TV-C) as donors and perylene diimide (PDI)-based polymer (PPDI-DTT) as acceptor are fabricated and investigated in detail. The structure similarity of the two polymers provides more insightful structure-property relationships. PT4TV based device displays a power conversion efficiency (PCE) of 0.99%, higher than that of PT4TV-C based device (0.55%). The high fill factor of larger than 50% in PT4TV based device is ascribed to the balanced hole and electron mobility of the donor and the acceptor. By adding chloronaphthalene solvent in PT4TV: PPDI-DTT solution, the PCE of PT4TV based solar cells is enhanced to 1.17%. Such improvement is interpreted in terms of the refined morphology of the film and ideality factor of the solar cell diode. (C) 2013 Elsevier B.V. All rights reserved.

Abstract  We report an easy-to-prepare fluorescent chemosensor, 4-benzoylamido-N-butyl-1,8-naphthalimide, which is sensitive to fluoride ions. The sensor shows spectral shifts and intensity changes in the presence of fluoride, in a wavelength-ratiometric and -colorimetric manner, which can detect fluoride concentrations in a range of 20-100 mu M at visible wavelengths. The striking colorless-to-yellow color change and blue-to-orange emission color change are thought to be due to the deprotonation of the 4-amido moiety of the naphthalimide fluorophore. The sensor compound shows great promise for the selective detection of fluoride in the presence of other halides because none of those are likely to deprotonate the amide.

Abstract  We developed a series of highly efficient blue electroluminescent polymers with dopant-host systems and molecular dispersion features by selecting 1,8-naphthalimide derivatives as the light blue emissive dopant units, choosing polyfluorene as the deep blue emissive polymer host and covalently attaching the dopant units to the side chain of the polymer host. The polymers' EL spectra exhibited both deep blue emission from the polymer host and light blue emission from the dopant units because of the energy transfer and charge trapping from the polymer host to the dopant units. By modifying the chemical structures of the dopant units, we controlled the energy transfer and charge trapping from the polymer host to the dopant units and consequently tuned the emission colors of the resulting polymers. Thermally annealed single-layer devices (ITO/PEDOT/polymer/Ca/Al) based on these polymers emitted deep blue light with a luminous efficiency of 2.89 cd A(-1), a power efficiency of 2.01 lmW(-1) and CIE coordinates (0.16, 0.17), or emitted sky-blue light with a luminous efficiency of 6.84 cd A(-1), a power efficiency of 4.28 lm W-1 and CIE coordinates (0.15, 0.22). Their excellent EL performances were due to the energy transfer and charge trapping from the polymer host to the highly fluorescent dopant units.

Abstract  Fluorescent probes for hydrogen sulfide have received considerable attention because of the biological significance of H2S recognized recently. Two-photo microscopy offers advantages of increased penetration depth, localized excitation, and prolonged observation time. However, two-photon fluorescent probes for H2S are still rare. In this work, we introduced a dinitrophenyl ether group into the 4-position of 1,8-naphthalimide, which acts as the H2S reactive site, to efficiently yield compound NI-NHS as a two-photo fluorescent probe for H2S. The probe NI-NHS has a high selectivity for H2S over competitive anions and sulfide-containing analytes. This probe exhibits turn-on fluorescence detection of H2S in bovine serum and two-photon fluorescent imaging of H2S in living cells. (C) 2013 Elsevier Ltd. All rights reserved.

Abstract  In this work, a new asymmetrically five-membered O-heterocyclic annulated perylene diimide (O-PDI) has been synthesized. The compounds O-PDI and asymmetrically five-membered S-heterocyclic annulated perylene diimide (S-PDI) self-assembled into nanoneedle and nanosheet, respectively. Photo physical, electrochemical and thermal properties were investigated by UV-vis absorption, fluorescence, cyclic voltammetric, thermogravimetric and differential scanning calorimetry techniques. Optical, fluorescence, scanning and transmission electron microscopies were employed in the molecular self assembly studies. Due to significant electronic coupling between their heteroatom/heterocycles and perylene diimide (PDI) cores, the intermolecular pi-pi actions are neglectable, providing high luminescence efficiency. At the same time, the space between perylene chromophores is still very short (3.3 angstrom for O-PDI and 3.23 angstrom for S-PDI), which is favorable for the hopping transportation of charge carrier from one molecule to a neighboring one. These compounds could be candidate materials for acquiring well defined organic nanostructures with both excellent charge-transporting and good light-emitting capabilities. (C) 2016 Elsevier Ltd. All rights reserved.

Abstract  When isolated conjugated polymer (CP) chains are studied by single molecule spectroscopy, excitation power density in the range of 10-1000 W cm(-2) is normally used. We show that at such excitation power densities the fluorescence ability of CPs is significantly reduced. A new methodological approach allowed us to measure the fluorescence quantum yield (QY) of thin matrix polymer films doped with fluorophores at very low concentration using fluorescence microscopy. Fluorescence QYs of different conjugated polymers (P3HT, MEH-PPV, PFBV and cyclodextrin-coated PFBV-Rtx) and a reference perylene diimide dye dispersed in the PMMA matrix were measured as a function of the excitation power density that ranged from similar to 10(-4) to 100 W cm(-2). Already at an excitation power of 0.1 W cm(-2) (the power density of the sunlight at the Earth) a detectable reduction of the fluorescence QY was observed for most of the polymers. The origin of the QY reduction is exciton annihilation by photo-generated triplet and/or change-transfer states. Insulation by cyclodextrin was found to decrease significantly the effect of non-emissive quenching states.

Abstract  A series of naphthalimides has been synthesized; 2,6-dimethyl-2,3H-furo[2,3-b][1]naphtho[4a,7a-e,f]pyrida-5,7-dione was obtained in a one-pot synthesis through the rearrangement and acidification of N-methyl-4-allyloxy-1,8-naphthalimide. The absorption and fluorescence of these furonaphthalimides and their precursors were recorded.

Abstract  Stimulated by strongly directional C-I center dot center dot center dot N noncovalent halogen bonding, pi-hole center dot center dot center dot pi and pi-pi interactions, cocrystals of nonplanar 4-arylated-2,2'-bipyridine (ArB) derivatives with 1,4-diiodo-tetrafluorobenzene (D) were generated which exhibit a promising columnar/lamellar packing arrangement. Hirshfeld surface, quantum theory of atoms in molecules, and electrostatic potential surface analyses were employed to examine the weak intermolecular interactions governing the packing arrangement in ArB crystals and corresponding cocrystals with D (ArB center dot D). Cocrystals of 4-phenyl-2,2'-bipyridine (PhB) and 4-(naphthalen-1-yl)-2,2'-bipyridine (NaB) with D [PhB center dot D1, PhB center dot D2, (NaB)(2)center dot D-2,D-5, and (NaB)(3)center dot D-2] exhibited C-I center dot center dot center dot N directed infinite one-dimensional chains of alternate ArB and D units. In contrast, C-I center dot center dot center dot Ninteraction's guide the formation of termolecular complexes in the cocrystal of 4-(phenanthren-9-y1)-2,2'-bipyridine with D (PhenB center dot D-0.5). Successful implementation of C-I center dot center dot center dot N interactions aided, by 2,2'-bipyridine and D enabled the tuning of threedimensional close packing in planar polyaromatic hydrocarbons into a columnar/lamellar arrangement suitable for optoelectronic devices.

Abstract  A series of molecules containing a carboxylic acid and a 1,8-naphthalimide group joined by different linkers (HLC1 = CH2; HLC2 = CH2CH2; HLC3 CH2CH2CH2; HLophen = ortho-C6H4; HLC4 = para-C6H4; HLala, = S-CHCH3) have been prepared and structurally characterized. The structures of HLC1, HLC3, and HLala are similar, with alternating hydrogen bonding of the carboxylic acids and pi center dot center dot center dot pi stacking interactions of the naphthalimide groups assembling the molecules into parallel chains that are linked into sheets by a second set of pi center dot center dot center dot pi stacking interactions. Hydrogen bonding and pi center dot center dot center dot pi stacking interactions of the naphthalimide groups also assemble HLC2 into chains, but the chains are alternately oriented at nearly right angles causing the interchain pi center dot center dot center dot pi stacking interaction to organize the chains in an open three-dimensional structure. Three of these open structural units interpenetrate forming a unique three-dimensional network. The rigid ortho-arene linker in HLophen directs the orientation of the pi center dot center dot center dot pi stacking interaction of the naphthalimide rings to be at 60 degrees; when combined with the hydrogen bonding interactions helical one-dimensional chains form that pack into a unique rhombohedral architecture. In the structure of HLC4 center dot DMF, each acid group is hydrogen bonded with the dimethylformamide (DMF) molecule; the structure contains one-dimensional ribbons supported only by the pi center dot center dot center dot pi stacking interactions from the 1,8-naphthalimide groups. All six molecules show fluorescence in the 432-449 nm region. Overall these structural studies show that the 1,8-naphthalimide supramolecular synthon is extremely versatile because it can simultaneously enter into multiple noncovalent interactions.

Abstract  A general methodology for producing ca. 100 nm core-shell colloidal particles in which the shell has an elevated alkyne functionality and yet remains thermoplastic is presented. The availability of accessible alkyne groups on the surface of the aqueous-phase particles allows for the in situ surface modification of the particles through a copper(I) catalyzed Huisgen 1,3-dipolar cycloaddition with an azide-terminated surface agent. The core is an extensively crosslinked polymer which can be easily removed by dispersing the particles in a solvent and centrifuging and collecting the cores, leaving the solubilized shells. This allows for the complete characterization of the colloidal surface reactions in the absence of the volumetrically dominant core. The technique is demonstrated with a core-shell colloid composed of a 135 nm crosslinked polystyrene (PS) core coated with a ca. 10 nm thick uncrosslinked poly(methyl acrylate-co-propargyl acrylate) shell. Due to the applicability of this technique for generating particles useful in biomedical imaging or drug delivery applications, the core-shell particles are surface modified with a variety of azide-terminated poly(ethylene glycol) (PEG) derivatives, including a poloxamer which was terminated on either end by an azide and a naphthalimide chromophore. The resulting fluorescent particles had an absorbance at 413 nm and peak emission at 525 nm. The PEG derivatives could be attached to the particles at a grafting density of ca. 0.2-0.3 groups/ nm(2).

Abstract  The synthesis and sensing properties of a new fluorescent probe designed to have a 4-amino-1,8-naphthalimide fluorescent platform functionalized with a 3-hydroxy-4-pyridinone bidentate chelating unit at the 4-position and a terminal aliphatic dimethylamino group at the imide site, are reported. The absorption and fluorescence properties of the ligand were investigated in DMSO and in aqueous solution at variable pH and in the presence of increasing concentration of Fe3+, Cu2+ and Zn2+. Analysis of the UV-Vis spectra at variable pH allowed the determination of three pK(a) values (PKa1 = 3.19, pK(a2) = 8.38, pK(a3) = 9.95) and establishment of the corresponding speciation diagram. Fluorescence spectra obtained in the same conditions show that the fluorescence intensity of the probe decreases with increasing pH and are off above pH 9 as a result of photo-induced electron transfer arising from the aliphatic dimethylamino group. Under physiological pH conditions, the probe shows an absorption band centred at 439 nm and emits in the green at lambda = 536 nm. Analysis of UV-Vis and EPR spectra of the ligand in the presence of Fe3+ and Cu2+ is consistent with the formation of the corresponding metal ion complexes. The fluorescence intensity of the ligand is quenched in the presence of variable concentrations of Fe3+, Cu2+ and Zn2+ and under physiological pH conditions the fluorescence of the probe is ca 92%, 88% and 91% quenched in the presence of Fe3+, Cu2+ and Zn2+ respectively. (C) 2013 Elsevier Ltd. All rights reserved.

Abstract  We present a time-resolved Kelvin Probe Force Microscopy (KPFM) technique that can record carrier motion on the scale of milliseconds, appropriate for polycrystalline materials like organic semiconductors. The organic semiconductors are studied in a transistor geometry to which we apply a step voltage to the back-gate. We record the change in potential at a specific location and observe the times associated with filling and emptying majority carrier traps, observed in hole majority carrier poly(3-hexylthiophene- 2,5-diyl) (P3HT) and a perylene diimide electron majority carrier, PDI-CN2. We see signs of bias stress with repeated measurements in P3HT. (C) 2016 Elsevier B.V. All rights reserved.

Abstract  UNLABELLED: Development of substituted 1,8-naphthalimides for photochemical cross-linking of biomolecules is the focus of this research. This study describes limited cross-linking of collagen in the artery wall to control recoil and buckling in arteries following balloon angioplasty. Isolated porcine arteries were overstretched (25%) with balloon angioplasty (BA) +/- light-activated naphthalimide treatment (NVS). Lumen size and recoil were measured as retention of stretch after angioplasty. Cross-sectional compliance and distensibility coefficients were measured as slope of cross-sectional area versus increasing hydrostatic pressure. Buckling was measured, with 30% axial pre-stretch and 200 mmHg, as deviation from the center line. Electron microscopy evaluation of collagen fibers was conducted.

RESULTS: Uninjured arteries have low compliance and low levels of buckling, whereas the BA-injured arteries demonstrated much greater compliance and buckling behavior. Treatment of the injured artery with NVS reduced buckling and demonstrated compliance midway between the two groups while retaining the increased luminal diameter imparted by angioplasty compared to untreated vessels. In summary, limited collagen cross-linking with NVS treatment resulted in lumen retention, as well as improved compliance without the accompanying rigidity and stiffness of conventional stent therapy or current cross-linking materials. This treatment shows great promise for dilation, repair and strengthening of arteries damaged by injury or vascular disease.

Abstract  We present a time-dependent density functional theory investigation of the excitation energy transfer (EET) between a typical chromophore (perylene diimide) and a small metal cluster (Au(20)). Two different physical descriptions are tested for the metal: the real (nonplasmonic) cluster and a hypothetical nanoparticle characterized by a bulk gold dielectric response (which thus sustains surface plasmons). By comparing the results obtained for the same EET process with the two types of metal particles, we show that, surprisingly, nonplasmonic small metal clusters can be as intrinsically effective as plasmonic particles in EET, a finding that is also relevant for applications in several field ranging from analytical chemistry to nanoscience.

Abstract  An inorganic-organic silica material (SBA-P2), prepared by immobilization of the 1,8-naphthalimide-based receptor P2 within the channels of the mesoporous silica material SBA-15, is characterized by transmission electron microscopy and several spectroscopic methods. SBA-P2 features a high affinity Cu2+-specific fluorescence response in aqueous solution with a detection limit for Cu2+ of ca. 0.65 ppb (10 x 10(M)(-9)) under optimized conditions. It can extract Cu2+ from the solution with only trace amounts remaining. Through isolating of the toxic ions within the mesopores of the silica, SBA-P2 has the potential to work as a toxicide for Cu2+ in living systems. The fluorogenical responses are reversible and do not vary over a broad (4.0 to 9.0) pH range suitable for application under physiological conditions. The fluorescence responses of Cu2+ in vitro (human breast cancer cells) and in vivo (five-day-old zebrafish) demonstrate the possibility of further application in biology.

Abstract  The fluorescence photoswitching of photochrome-fluorophore (PF) mixtures based on 1,2-bis(5'-ethoxy-2'(2 ''-pyridyl) thiazolyl) perfluorocyclopentene (P) and pyrromethene 597 (F) were studied. Polymethylmethracrylate (PMMA) films were fabricated with respective concentrations of 1.0 x 10(-2) mol L-1 for P, and 9.2 x 10(-4) and 9.2 x 10(-1) mol L-1 for F. By alternate UV (lambda(OF) = 334 nm) and visible (lambda(CF) = 547 nm) irradiations, inducing the reaction between the opened (P-OF) and closed (P-CF) forms of P, both fluorescence intensity and lifetime can be reversibly modified and visualized in the micrometer scale by fluorescence imaging. Switching (writing/erasing) and reading functions are respectively borne by P and F. The interaction between the two units owes to an energy transfer based quenching of fluorescence, which operates in the P-CF state but not P-OF. The reading process alters only very weakly the state of P. During the writing process, the presence of F accelerates the P-CF to P-OF reaction, as evidenced by following the absorption spectrum change. The efficiency of the energy transfer was determined by Gosele's model for the two concentrations of F and for concentrations of P-CF from 0 to 1.0 x 10(-2) mol L-1. This model fits well with the experimental fluorescence intensity change during the photoreaction and can account for the origin of the above-mentioned acceleration. In addition, we demonstrated that switching one molecule of P-OF to P-CF could quench up to eight molecules of F. This "amplification" of the fluorescence signal was modeled as a function of the concentrations of both species, providing a tool to optimize the PF system composition.

Abstract  In order to investigate the effect of the geometries of perylene diimide (PDI)-based small molecules, five different isomers were synthesized by using a cyclohexane core as a simple sp(3)-sigma core. Diaminocylohexane is such an effective core for the systematic development of many kinds of isomers via geometric tuning as well as for reducing the self-aggregation tendency of PDIs. Depending on the anchoring position of the PDI units on the cyclohexane core (ortho-, meta- and para-), isomers exhibited differences in solubility and crystallinity. Among the studied isomers, ortho-substituted t-OCP was found to have a highly twisted molecular structure which minimizes the strong tendency towards crystallization due to individual PDI moieties. The unique geometrical nature of the t-OCP isomer led to the highest power conversion efficiency (PCE = 6.23%) of bulk heterojunction (BHJ) polymer solar cells (PSCs) with a higher short-circuit current density (J(sc)) and fill factor (FF). It is mainly ascribed to the formation of a nanophase interpenetrating network with well-balanced carrier mobility in the blend film.

Abstract  The development of probes for selective detection of mercury ions (Hg2+) is an important mission to accomplish because of the toxicity and ubiquity of Hg2+. Herein, we designed and synthesized a novel fluorescent probe O-(N-butyl-1,8-naphthalimide)-4-yl-O-phenyl carbonothioate (CBONT) for selective and sensitive detection of Hg2+ by turn-on fluorescence spectroscopy. Probe CBONT exhibited a fast response for Hg2+ with excellent sensitivity (limit of detection = 1.9 nM, 3 sigma/slope), and it might be attributed to the adoption of a new recognition receptor of carbonothioate moiety. Additionally, probe CBONT could serve as a "naked-eye" indicator for Hg2+. Finally, probe CBONT could be successfully applied to detect the concentrations of Hg2+ in real water samples. Our proposed recognition receptor would open up new, exciting opportunities for designing highly selective and ultrasensitive fluorescent probes for the determination of Hg2+ in real water samples.

Abstract  A series of mononuclear M(II) complexes, namely, [Mn(L1)(2)(H2O)(4)] (1), [Cu(L1)(2)(pyr)(2)(H2O)(2)] (2), [Zn(L1)(2)(pyr)(2)(H2O)(2)] (3), [Cd(L1)(2)(pyr),(H2O)(2)] (4), [Co(L2)(2)(pyr)(2)(H2O)(2)]center dot pyr (5), [Cu(L2)(2)(pyr)(2)]center dot 2pyr center dot 2H(2)O (6), and [Cd(L2)(2)(pyr)(2)(H2O)(2)center dot pyr (7) (where L1H = 4-(1,3-dioxo-1,3-dihydro-isoindol-2-ylmethyl)-cyclohexanecarboxylic acid, L2H = 4-(1,3-dioxo-1H,3H-benzo[de]isoquinolin-2-ylmethyl)-cyclohexanecarboxylic acid, and pyr = pyridine) were synthesized and structurally characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses, powder X-ray diffraction, and single crystal X-ray diffraction. Coordination environments around the metal centers and subtle differences in weak interactions affect the dimensionality and features of supramolecular architectures of these complexes. In the case of M(II) complexes of L1H, 1 shows a zigzag 3D architecture, whereas other complexes exhibit 3D channel-like structures containing the coordinated pyridine rings inside these channels. The coordination environments around the M(II) centers are the same in the complexes 5 and 7; however, the former is composed of 3D architecture containing channels and voids, whereas the latter reveals a 2D sheet structure. The 3D supramolecular architecture of complex 6 is sustained by helical channels, which are filled by lattice water and pyridine molecules. Solid state fluorescence emission properties of L1H and its M(II)) complexes show resemblance to each other, whereas they have different characteristics in the case of L2H and its M(II) complexes. Cyclic voltammetry of redox-active ligand L2H and its complexes 5 and 6 are also studied.

Abstract  A new photochromic diarylethene dyad based on perylene diimide (PDI-DTE) has been synthesized. The photochromic reaction of PDI-DTE induced the significant change of the absorption spectra and fluorescence intensity. The color of PDI-DTE in THF solution was not changed obviously upon ultraviolet irradiation, while the fluorescence intensity is increased unexpectedly with the photochromic cyclization of the diarylethene units. With not visible change of color accompanied to the enhanced fluorescence. PDI-DTE can be potentially applied to anti-counterfeiting technology. (C) 2010 Elsevier Ltd. All rights reserved.

Abstract  Multilayer films of water-soluble anionic and cationic perylene diimide (PDI) moieties have been prepared using the molecular layer-by-layer method described in an earlier publication (Tang, T. J.; Qu, J. Q.; Müllen, K.; Webber, S. E. Langmuir 2006, 22, 26-28) and the fluorescence intensity compared with and without a base layer prepared using an anionic terrylene diimide dye (n-TDI), which serves as an energy-trapping layer for the PDI exciton. The fluorescence quenching data could be fit equally well to a modification of a model used by Kuhn to describe energy transfer from a J aggregate or a model developed by Kenkre and Wong to describe excitonic transfer. For both models, we obtain a characteristic energy-transfer distance on the order of 5.4 nm. Fluorescence quenching of the PDI via a single Förster energy-transfer step to the n-TDI layer is ruled out on the basis of the observed power-law dependence. We also consider a model in which the excitation is trapped at the outermost surface. This model provides a reasonable fit to the data only if the Kuhn relationship is used.

Abstract  Energetic barriers to charge separation are examined in photovoltaic polymer blends based on regioregular-poly(3-hexylthiophene) (P3HT) and two classes of electron acceptors: a perylene diimide (PDI) derivative and a fullerene (PCBM). Temperature-dependent measurements using ultrafast vibrational spectroscopy are used to directly measure the free energy barriers to charge separation. Charge separation in P3HT:PDI polymer blends occurs through activated pathways, whereas P3HT:PCBM blends exhibit activationless charge separation. X-ray scattering measurements reveal that neither the PDI derivative nor PCBM form highly crystalline domains in their polymer blends with P3HT. The present findings suggest that fullerenes are able to undergo barrierless charge separation even in the presence of structural disorder. In contrast, perylene diimides may require greater molecular order to achieve barrierless charge separation.

Abstract  The spectral-luminescent properties and electrochemistry of the N,N'-bis-n-butyl derivative of naphthalene diimide were studied. The main photophysical parameters (quantum yield, rate constants of fluorescence and of non-radiative deactivation and fluorescence lifetime) were determined. The LUMO value (-3.51 eV) was determined by cyclic voltammetry. The N,N'-bis-n-butyl derivative of naphthalene diimide (BBND) shows 2 reversible reduction steps (-1.19 V and -1.75 V vs. Ferrocene) in chloroform. Quenching the fluorescence emissions of aromatic donor molecules in acetonitrile revealed the electron acceptor ability of the studied naphthalene diimide derivative. It has been found that, in contrast to perylene diimide derivatives, which form 7-electron donoracceptor complexes with aromatic donor molecules of naphthalene, phenanthrene, pyrene and perylene, BBND does not form pi-electron-clonor acceptor complexes with aromatic donor molecules.

Abstract  In this paper, the dyeing and fastness properties of three monoazo naphthalimide dyes including different imide groups (dye 1: ethyl amine, dye 2: ethyl glycinate and dye 3: glycine) on a polyester fabric were investigated in the presence of two gemini cationic surfactants (symbolized as 12-4-12 or 14-4-14) and a conventional single chain surfactant, dodecyltrimethylammonium bromide (DTAB). The color strength (K/S) of naphthalimide dyes on polyester fabric was measured through the reflectance spectrophotometric method, and the values obtained in the presence of different cationic surfactants increased in the order of dye 3 < dye 2 < dye 1. Although the K/S values indicated that the gemini cationic surfactants had almost no effect on the dyeing behavior of dye 1, but they were effective in dyeing ability of dye 2 and dye 3. The data for dye 2 demonstrated that build up of polyester fabrics in the presence of gemini surfactants are more than the conventional cationic surfactant, and also K/S values of dye 3 on polyester fabrics were in the order: DTAB > 12-4-12 > 14-4-14. It was found that the washing and rubbing fastness properties improved with increasing the concentration of surfactants. In addition, the sublimation fastness of dye 3 was more than the other dyes owing to the presence of a polar group in its chemical structure, and the light fastness of naphthalimide dyes on polyester fabrics was generally moderate.