Synthesis and sensor activity of photostable blue emitting 1,8-naphthalimides containing s-triazine UV absorber and HALS fragments

Using a Dendritic Sensor as a Feasible Method for Detection of Copper in Water Samples

Due to the severe dangers of copper on human health, development of identification and measurement copper methods in aquatic environments as well as prevention transfer methods of these substances to water resources have received much attention. Among of this expansion, rapid, simple, safe, sensitive and economically viable detection methods are more considerable. In this paper, the sensor activity of the poly(amidoamine) dendrimer containing eight methoxy groups modified with naphthalimide fluorescent derivative is studied. The sensor potential of dendrimer-naphthalimide fluorescence was evaluated in various solvents with different polarities, and results indicated that the detection of cuprum cations (Cu²⁺) is possible at low concentration. Also, the fluorescence properties of dendrimer-naphthalimide system are measured in the presence of diverse metal cations. In light of above, from the obtaining results, it can be concluded that dendritic sensor can be used as a feasible method to detect of copper in water samples in low concentrations.

Synthesis and In Vitro Antimicrobial Evaluation of Photoactive Multi-Block Chalcone Conjugate Phthalimide and 1,8-Naphthalimide Novolacs

Herein we report new multiblock chalcone conjugate phthalimide and naphthalimide functionalized copolymers with a topologically novel architecture synthesis using nucleophilic substitution and polycondensation methodology. The structures of the synthesized novolacs were elucidated on the basis of their spectroscopic analysis including FTIR, ¹H NMR, and ¹³C NMR spectroscopy. Further, the number-average and weight-average molecular weights of the novolac polymers were determined by gel permeation chromatography (GPC). We examined the solubility of the synthesized polymers in various organic solvents including CHCl₃, CH₃CN, THF, H₂O, CH₃OH, DMSO, and DMF and found they are insoluble in both methanol and water. The novolac polymers were evaluated for their photophysical properties and microbial activities. The investigation of the antimicrobial activities of these polymers reveals significant antimicrobial activity against the pathogens E. coli, S. aureus, C. albicans, and A. niger.

A chemosensoring molecular lab for various analytes and its ability to execute a molecular logical digital comparator

We reported here the unique ability of a Rhodamine 6G-based probe (3) to detect discriminately several targets, including H⁺, HO^-, Cu²⁺, Hg²⁺, Fe³⁺, Co²⁺, Cd²⁺, Zn²⁺, Sn²⁺, Ni²⁺, Al³⁺, Pb²⁺, Ce³⁺and Ag⁺, by unambiguously colorimetric and fluorimetric outcomes. In aqueous solutions, the presence of proton induced the ring-opening of rhodamine moiety but the presence of hydroxide induced the conversion of 2-hydroxyphenyl hydrazone moiety from the non-fluorescent benzenoid form into the fluorescent quinoid form. The probe could to distinguish between different cations in DMF and to work like an artificial tongue at molecular level. Several logic gates including OR, INHIBIT and TRANSFER, were performed by the probe. Moreover, the probe is able to execute three INHIBIT logic gates by two inputs, which was exploited to execute a digital molecular comparator.

New photostable naphthalimide-based fluorescent probe for mitochondrial imaging and tracking

Monitoring mitochondria morphological changes temporally and spatially exhibits significant importance for diagnosing, preventing and treating various diseases related to mitochondrial dysfunction. However, the application of commercially available mitochondria trackers is limited due to their poor photostability. To overcome these disadvantages, we designed and synthesized a mitochondria-localized fluorescent probe by conjugating 1,8-naphthalimide with triphenylphosphonium (i.e. NPA-TPP). The structure and characteristic of NPA-TPP was characterized by UV-vis, fluorescence spectroscopy, (1)HNMR, (13)CNMR, FTIR, MS, etc. The photostability and cell imaging were performed on the laser scanning confocal microscopy. Moreover, the cytotoxicity of NPA-TPP on cells was evaluated using (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The results showed that NPA-TPP not only has high sensitivity and specificity to mitochondria, but also exhibits super-high photostability, negligible cytotoxicity and good water solubility. In short, NPA-TPP indicates great potential for targeting mitochondria and enables a real-time and long-term tracking mitochondrial dynamics changes.

A highly selective ratiometric fluorescent pH probe based on a PAMAM wavelength-shifting bichromophoric system

A novel PAMAM wavelength-shifting bichromophoric system has been successfully developed. Novel compound was configured as a light harvesting antenna where the system surface is labeled with yellow-green emitting 4-(N,N-dimethylamino)ethylamino-1,8-naphthalimide "donor" units capable of absorbing light and efficiently transferring the energy to a focal Rhodamine 6G "acceptor". The periphery of the system was designed on the "fluorophore-spacer-receptor" format, capable of acting as a molecular fluorescence photoinduced electron transfer based probe. Due to the both effects, photoinduced electron transfer in the periphery of the system and pH dependent rhodamine core absorption, novel antenna is able to act as a selective ratiometric pH fluorescence probe in aqueous medium. Thus, the distinguishing features of the fluorescence resonance energy transfer systems were successfully combined with the properties of classical ring-opening charge transfer systems, which may be beneficially for monitoring pH variations in complex samples.

Synthesis and sensor activity of a PET-based 1,8-naphthalimide Probe for Zn(2+) and pH determination

A novel blue-emitting 1,8-naphthalimide fluorophore designed as a molecular PET-based probe for determination of pH and detection of transition metal ions in the environment was successfully synthesized. Novel compound was configured on the "fluorophore-spacer-receptor" format. Due to the tertiary amine receptor the novel system showed "off-on" switching properties under the transition from alkaline to acid media (FE = 3.2) and in the presence of Zn(2+) ions (FE = 2.5). The results obtained illustrate the high potential of the synthesized blue-emitting 1,8-naphthalimide fluorophore as an efficient pH chemosensing material and a selective probe for Zn(2+) ions.

A novel fluorescent sensor for Cr3+ based on rhodamine-cored poly (amidoamine) dendrimer

A novel poly (amidoamine) (PAMAM) dendrimer, comprising rhodamine B unit in the core and 1-phenyl-3-methyl-5-pyrazolone unit at the periphery, has been synthesized and characterized. The dendrimer shows dramatic increase in its fluorescence intensity in the presence of proton and metal cations, especially in the presence of Cr(3+). The complex formed by dendrimer and Cr(3+) in ethanol solution has also been studied, considering the potential application for Cr(3+) fluorescent sensor. The influence of the unique chemical structure and resulted photoinduced electron transfer, as well as spirolactam ring-opening on the photophysical properties of the product has been investigated.