Search

The early detection of cancer cells and their visualization before and after surgery are essential for successful pre‐ and post‐operative disease management. Although fluorescence imaging is a sensitive and versatile tool that is finding increasing use in clinical applications, there is a lack of tumour‐targeting fluorophores. We report here a family of fluorescent Schiff base organotin dyes (1: Et2N−L‐SnPh2, 2: Et2N−L‐SnBu2, 3: MeO−L‐SnPh2, 4: MeO−L‐SnBu2, 5: HO−L‐SnPh2, and 6: HO−L‐SnBu2, where L=2‐hydroxybenzylidene‐4‐hydroxybenzhydrazine). In addition to one‐photon‐excited fluorescence, efficient two‐photon excitation was demonstrated in compounds 1–4. Two of the compounds (5 and 6), both with hydroxyl substituents, were capable of selective accumulation in HeLa cells, allowing differentiation from normal cells (periodontal ligament cells). Compounds 1 and 3 showed excellent cancer cell staining (HeLa) using two‐photon bioimaging, which is promising for biomedicine applications. [ABSTRACT FROM AUTHOR]

Four organotin compounds bearing Schiff bases were prepared via a multicomponent microwave-assisted reaction among 2-hydroxy-1-naphthaldehyde, 2-aminophenol derivatives and the corresponding diorganotin oxide (R2SnO, R = nBu or Ph), with high yields and a low economic/environmental impact. All of the compounds were fully characterized by NMR (1H, 13C, and 119Sn) spectroscopy, high-resolution mass spectrometry, X-ray diffraction, cyclic voltammetry, UV/Vis spectroscopy, and fluorescence spectroscopy. All of the compounds absorb in the visible region around 480–490 nm, close to the maximum solar emission, with an optical band gap of around 2.3 eV and low fluorescence quantum yields. According to the electrochemical study, they present LUMO values close to that of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM-C60), a typical electron acceptor organic photovoltaic material. Based on this combined optical/electrochemical study and as it allows the preparation of homogeneous spun films, the n-butyltin complex with carboxylic acid was selected for the investigation of its possible photovoltaic properties in organic solar cells. Charge photogeneration was obtained only using this organotin compound as an electron acceptor material with poly(3-hexylthiophene, P3HT) (typical electron donor material) with an open circuit voltage of 300 mV, a short-circuit current density of 0.11 mA cm−2 and an efficiency of 5.2 × 10−3%. Despite the fact that the efficiency is much lower with respect to the reference device P3HT/PCBM-C60, this preliminary result suggests that, after chemical and device processing optimization, tin complexes with Schiff bases could be applied as electron acceptor materials in organic photovoltaic devices. [ABSTRACT FROM AUTHOR]

The reaction of N , N -bis(2-hydroxy-4-R-benzylidene)-1,2-phenylendiimine ( 1 R = OH, 2 R = OMe) with R′ 2 SnO (R′ = Me, n -Bu, Ph) provided six new organotin derivatives: dimethyl-di- n -butyl- and diphenyl[ N , N ′-bis(3-hydroxysalicylaldehyde)-1,2-phenylenediiminato]tin(IV) ( 1a ), ( 1b ), ( 1c ) as well as dimethyl-di- n -butyl- and diphenyl[ N , N ′-bis(3-methoxysalicylaldehyde)-1,2-phenylenediiminato]tin(IV), ( 2a ), ( 2b ), ( 2c ), respectively. All compounds were characterized by 1 H, 13 C and 119 Sn-NMR, elemental analysis, UV, IR, and mass spectrometry. Compounds 2a , 2b and 2c were characterized by single-crystal X-ray structure analysis. In the solid state, 2a , 2b , and 2c showed the Schiff bases backbone in a bent arrangement containing a tin atom with distorted octahedral geometry, where the ligand occupies the four equatorial positions and the methyl, n-butyl, or phenyl groups occupy the trans axial positions. The second-order nonlinear optical response of representative organotin compounds 2a – c was estimated by electric field induced second harmonic (EFISH) measurements where interesting β μ values in the promising range of 10–60 × 10 −30 esu were evaluated. [ABSTRACT FROM AUTHOR]

Five novel organoboron complexes were synthesized in just 15 min via microware irradiation, by one pot multicomponent reactions between diverse aryl aldehydes with benzoylhydrazide, or 4‐nitrobenzoylhidrazine and diphenyl boronic acid, in a 1:1:1 ratio in benzene. The products were characterized by 1H, 13C, 11B NMR, UV, IR, spectroscopy and high‐resolution mass spectrometry (HRMS). The molecular structure was also determined by single‐crystal X‐ray diffraction for two complexes, which showed the tetra‐coordination of the boron atoms giving rise to distorted tetrahedral molecular geometry with a strong intermolecular C‐H···π interactions. In spite of the low quantum yields exhibited by the series in solution, some complexes stained uniformly the silk fibroins emitting enough fluorescence to allow its characterization by confocal microscopy. Boron as chelate center of the five complexes resulted not to be toxic for B16F10 cells, these compounds are appropriate for their used in medical applications. Five novel organoboron complexes were synthesized via microwave irradiation and one pot multicomponent reactions. The products were characterized by 1H, 13C, 11B NMR, UV, IR, and HRMS. Molecular structure was determined by single‐crystal X‐ray diffraction for two complexes, which showed the tetra‐coordination of boron atoms giving rise to distorted tetrahedral molecular geometry. Complexes were used to produce luminescent silk fibroin and were characterized by confocal microscopy. Cell viability assays showed that the compounds are suitable for use in medical applications. [ABSTRACT FROM AUTHOR]

• New two organotin derivatives of C 3 - symmetry Schiff bases were obtained by microwave-assisted multicomponent synthesis. • Both organotin complexes exhibit good quantum yields in solution and thermally stable up to 300°C. • The photophysical, electrochemical, and theoretical studies reveal that the three Sn-nuclei do not electronically interact. Two new fluorescent organotin compounds bearing C 3 -symmetric Schiff base were synthesized by microwave irradiation via multicomponent reaction (3-MCR), in one pot in just 30 mins with excellent yields. Both tin complexes were fully characterized by NMR, IR, UV-vis, fluorescence spectroscopy, high-resolution mass spectrometry and by ciclyc voltametry. The δ 119Sn and 3 J (1H,119Sn) of new organotin complexes 4 and 5 showed the high molecular symmetry and the trinuclearity through high resolution mass spectrometry. Both Sn-complexes are thermally stable up to 300°C. The small-wide angle X-ray scattering pattern in powder and the 2D monomolecular film by scanning tunneling microscopy (STM) of 5 showed a lamellar like assembly with dimension of 2.38 and 2.80 nm, respectively, meaning that molecules adopt a face-on arrangement, where molecules are flat-lying on the HOPG surface. Monolayer of 5 is mesoporous and rigid but covers large surface areas. The photophysical, electrochemical, and theoretical studies reveal that the three Sn-nuclei do not electronically interact. Since, both organotin complexes exhibit good quantum yield in solution (Φ 4 : 52.4 % and 5 : 51.7 %), with lifetimes in the range τ =∼3 ns, their emission properties are appealing for OLED applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The 2-arylbenzoxazoles 3a–f were produced in moderate to excellent yields merely by stirring a potassium cyanide (3equiv)-containing methanol solution of the borobicyclic compounds 1a–f at room temperature. These compounds were fully characterized spectroscopically [IR, 1H, and 13C NMR and X-ray analysis (3a)] and by elemental analysis. [Copyright &y& Elsevier]