Fluorescent Emission In Solid State Research Articles

Phenalenyl-based boron–fluorine complexes: Synthesis, crystal structures and solid-state fluorescence properties

A novel series of phenalenyl-based boron–fluorine complex-type fluorophores, with a drastic fluorescence quenching in solution but high fluorescence emission in the solid-state, have been synthesized. The X-ray structure demonstrates that the bulky substituents result in steric hindrance and prevent the fluorophores forming short intermolecular interaction thereby enhancing the solid-state fluorescence emission.

Structural diversification and metal-directed assembly of coordination architectures based on tetrabromoterephthalic acid and a bent dipyridyl tecton 2,5-bis(4-pyridyl)-1,3,4-oxadiazole

A series of mixed-ligand coordination complexes have been prepared using diffusion method, by reacting the CoII, NiII, ZnII, AgI, CdII, CuII, or PbII nitrate with tetrabromoterephthalic acid (H2tbta) and 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (4-bpo). These complexes show various 0D, 1D, 2D, and 3D coordination motifs with different geometries of the metal centers, indicating a metal-directed assembly. The synthetic condition will also affect the resulting crystalline products for ZnII species. Crystal structure analysis reveals that secondary interactions such as hydrogen bonding and aromatic stacking will further extend the coordination arrays to diverse supramolecular architectures. All complexes have been characterized by IR, elemental analysis, and powder X-ray diffraction techniques. In addition, the polymeric coordination systems with d10 metal centers show solid-state fluorescent emissions at room temperature, which thus may be applied as potential hybrid luminescent materials.

Solvothermal synthesis and characterization of a new ZnII-PMIDA phosphonate

A new Zn(II) phosphonate, (NH4)[Zn(HPMIDA)(H2O)2] (1) (H4PMIDA = N-(phosphonomethyl)iminodiacetic acid), has been solvothermally synthesized and characterized by elemental analysis, IR, TGA fluorescence, and X-ray single-crystal diffraction. Compound 1 is an example of a six-coordinate Zn-carboxylate-phosphonate and possesses a 3-D supramolecular structure built from mononuclear anions through hydrogen bonding. Compound 1 exhibits a solid-state fluorescent emission band at 593 nm under excitation of 413 nm.

Design and construction of two new polymers featuring macrocyclic subunits based on a rigid clamp-like ligand

Abstract Reaction of a rigid conjugated clamp-like ligand N,N′-bis(pyridin-3-yl)-2,6-pyridinedicarboxamide (bppdca) with ZnSO 4 ·7H 2 O or CoSO 4 ·7H 2 O resulted in the formation of two new polymers, namely, {[Zn 2 (bppdca)(SO 4 ) 2 (DMF) 2 ]·(DMF)} n ( 1 ) and {[Co(bppdca)(SO 4 )(CH 3 OH)(DMF)]·H 2 O} n ( 2 ). Both 1 and 2 feature one-dimensional double-chain structures with macrocyclic subunits, and the chains further self-assemble into a higher-dimensional framework via the hydrogen-bonding and π–π stacking interactions. Fluorescence studies show that the free ligand displays a strong fluorescence emission in solid state at room temperature, but in 1 and 2 , the complexation of the ligand with metal ions and weak intermolecular interactions make the fluorescence emission partial quenching.

Adsorption state of naphthoic acids on folded sheets mesoporous materials with different pore sizes

Adsorption properties of 1- and 2-naphthoic acids (1- and 2-NPAs), model compounds of medicines that have naphthalene moiety such as naproxen, naphazoline, rifampicin etc., in the presence of folded sheets mesoporous materials (FSM-16) were investigated by solid-state fluorescence emission spectroscopy. The molecular states of NPAs adsorbed onto FSM-16 mesopores changed depending on the NPA concentration on the FSM-16 surface. The redshift of the fluorescence emission spectra was attributed to intermolecular overlapping of the naphthalene moieties of the NPA molecules. Results of differential scanning calorimetry indicated that 2-NPA was selectively adsorbed onto FSM-16(Oc). The maximal amounts of 1-NPA and 2-NPA adsorbed onto FSM-16(Oc), having a pore diameter of 16 Ǻ, were estimated as 4.4% and 14.2%, respectively. In contrast, the maximal amounts of adsorbed NPAs onto FSM-16(Do), having a pore diameter of 21 A, were almost the same, i.e., about 40%. The amount of 2-NPA adsorbed onto FSM-16(Oc) was significantly higher than that of 1-NPA; this shows that it is possible to selectively separate 1-NPA and 2-NPA by using FSM-16(Oc) as a mesoporous molecular sieve.

Chiral substituent containing perylene monoanhydride monoimide and its highly soluble symmetrical diimide: synthesis, photophysics and electrochemistry from dilute solution to solid state

A new chiral perylene monoanhydride monoimide (1) with a sterically hindered chiral amine was successfully synthesized for further selective functionalization at terminal positions. At the same time, the chiral perylene diimide (2) with the same amine has been synthesized. The synthesized products were characterized using the data from NMR, IR, MS, UV-vis, DSC, TGA, elemental analysis and cyclic and square wave voltammetry. Compound 2 shows an excellent solubility of 200 mg mL(-1) in chloroform. The band gap energy (Eg), LUMO and HOMO energy values were 2.28, -3.77 and -6.05 eV for 2, respectively in chloroform. In solid state, the band gap energy (Eg), LUMO and HOMO energy values were 1.96, -4.22 and -6.18 eV for 1 and 1.92, -4.13 and -6.05 eV for 2, respectively. Whereas 1 (solid state: -0.58 and -0.69 V vs. ferrocene/ferrocenium couple) and 2 (in chloroform: -1.03 and -1.22 V vs. ferrocene/ferrocenium couple) show two reversible reduction steps, 2 exhibits only one reversible wave (solid state: -0.67 V vs. ferrocene/ferrocenium couple). The diffusion coefficients were determined as 1.91 x 10(-7) and 8.47 x 10(-7) cm2 s(-1) for 1 and 2 in solid state, respectively, and 1.27 x 10(-5) cm2 s(-1) for 2 in solution. The solid state emission ability of the chiral products ( is much more emissive than ) remains a challenge for photonic, electronic and sensor applications. 1 and 2 showed high thermal stability. Efficient prevention of intermolecular pi-pi contacts of fluorophores results in an excellent fluorescence emission in solid state and solubility for 2.

Synthesis, Structures, and Optical Properties of Cadmium Iodide/Phenethylamine Hybrid Materials with Controlled Structures and Emissions

A new type of organic-inorganic hybrid materials based on cadmium iodide (CdI2) and phenethylamine (PEA) has been synthesized and characterized. The reaction of CdI2 with PEA in a 1:2 molar ratio yields a four-coordinate hybrid material CdI2(PEA)2 (1) with extended 1D (CdI2)n chains, while the reaction of CdI2 with PEA in a 1:4 molar ratio produces a six-coordinate hybrid material CdI2(PEA)4 (2) with a discrete linear structure of CdI2 moiety. By introducing a trace amount of Na2S to the reaction for CdI2(PEA)2, we obtained a new compound [CdI2(PEA)2](CdS)0.038 (3) with uniformly doped CdS nanoparticles. Steady and transient photoluminescence studies reveal that compounds 1 and 2 exhibit bright blue (465 nm) and green (512 nm) fluorescent emissions in solid state at room temperature, respectively, while compound 3 gives a broad and complex emission ranging from 450 to 700 nm. Theoretical studies of electronic structures were carried out using density functional theory in order to gain a good understanding of the luminescent behaviors of these hybrid materials.

A facile synthesis of solid-emissive fluorescent dyes: dialkylbenzo[b]naphtho[2,1-d]furan-6-one-type fluorophores with strong blue and green fluorescence emission properties

A new type of organic fluorophores, dialkylbenzo[b]naphtho[2,1-d]furan-6-one-type fluorophores, exhibiting strong blue and green emission in the solid state has been easily synthesized by an one-step reaction. The X-ray crystal structure demonstrated that the structural form with a chair-shape with the sterical hindered dialkyl substituents and the 9-dibutylamino group prevents the fluorophores from forming short intermolecular contacts and produces intense solid-state fluorescence emission.

Bisindolylmaleimide derivatives as non-doped red organic light-emitting materials

A new series of bisindolylmaleimide (BIM) derivatives were synthesized. The absorption and fluorescence properties of these compounds were investigated in solution and solid state. Dramatic difference in solid-state fluorescence emission spectra was observed by changing the substituents on the fluorophores skeleton from methyl to benzyl. We performed X-ray crystallographic analyses to elucidate the effect of the substituents of the non-conjugated linkage on the solid-state fluorescence emission spectra. The relationships between the solid-state photophysical properties and the chemical and crystal structures of 2,3-bis( N-benzyl-2′methyl-3′-indolyl)- N-methylmaleimide ( 1S) and 2,3-bis( N-benzyl-2′methyl-3′-indolyl)- N-benzylmaleimide ( 5S) are discussed on the basis of the X-ray crystal data. Bis[2,3-bis( N-ethyl-2′methyl-3′-indolyl)- N-(prop-2-ynyl)maleimide] ( 1B) and 1S were utilized in non-doping host red EL device. The brightness reaches 393 cd m −2 at 100 mA cm −2 for 1S.

Synthesis, Crystal Structures and Properties of Two Novel Co(II) and Cd(II) Complexes of N‐Acetyl‐L‐glutamic Acid and Imidazole Ligands

AbstractTwo novel complexes {(Co(A‐glu)(Im)2(·0.5H2O}n (1) and (Cd(A‐glu)(Im)3(n (2) (H2A‐gluN‐acetyl‐L‐glu‐ tamic acid, Im=imidazole) have been synthesized from the reaction of H2A‐glu with Co(CH3COO)2·4H2O or Cd(CH3COO)2·2H2O in the presence of Im. Both of the complexes display different coordination environment and similar one‐dimensional chain structure. The magnetic susceptibility measurements for 1 show a weak antiferromagnetic interaction between two cobalt(II) ions bridged by A‐glu ligand. The complex 2 exhibits an intense fluorescent emission in solid state at room temperature.

Synthesis, structure and luminescent property of a 2D polymer containing silver ions

Silver(I) complex with 4,5-dicarboxyimidazole (H 3dcbi) has been synthesized by hydrothermal method and proven to be a novel 2D coordination polymer [Ag(H 2dcbi)] n ( 1), which crystallized in monoclinic crystal system and space group of P2(1)/ c. Each Ag(I) ion is coordinated to three O atoms and one N atom, which completes the trigonal pyramidal geometry of Ag(I) ion. Solid-state fluorescent emission spectra of 1 were investigated.

Heterocyclic Quinol‐Type Fluorophores: Synthesis, X‐ray Crystal Structures, and Solid‐State Photophysical Properties of Novel 5‐Hydroxy‐5‐substituent‐benzo[b]naphtho[1,2‐d]furan‐6‐one and 3‐Hydroxy‐3‐substituent‐benzo[kl]xanthen‐2‐one Derivatives

Novel heterocyclic quinol-type fluorophores (4 a-c) and (5 a-c) that contain substituents (R = Me, Bu, Ph) with nonconjugated linkages to the chromophore skeleton have been synthesized and their photophysical properties have been investigated in solution and in the solid state. Considerable differences in the absorption and fluorescence spectra were observed between the two states. Quinols 4 a-c and 5 a-c exhibited almost the same absorption and fluorescence spectra in solution; however, their solid-state fluorescence excitation and emission spectra in the crystalline state were quite different. We performed X-ray crystallographic analyses to elucidate the dramatic effect of the substituents of the nonconjugated linkage on the solid-state fluorescence excitation and emission spectra. The relationships between the solid-state photophysical properties and the chemical and crystal structures of 4 a-c and 5 a-c are discussed on the basis of the X-ray crystal structures.

A novel three-dimensional metal–organic network, Zn2(btec)(pipz)(H2O) (btec=1,2,4,5-benzenetetracarboxylate, pipz=piperazine), with blue fluorescent emission

A novel metal–organic compound Zn2(btec)(pipz)(H2O) (1) (btec=1,2,4,5-benzenetetracarboxylate, pipz=piperazine ) has been hydrothermally synthesized and characterized by elemental analyses, IR spectrum, TG analysis, luminescent spectrum and single-crystal X-ray diffraction. The title compound exhibits a novel three-dimensional network, which consists of two-dimensional wave-like sheets linked by zinc metal centers and piperazine. Compound 1 provides the first coordination network structure constructed together by bridging piperazine and btec mixed ligand. The study of the physical properties of 1 demonstrates that it exhibits a fluorescent emission in solid state at room temperature.

Synthesis and Spectroscopic Studies of Endohedral Metallofullerenes Tb@C2N

Endohedral metallofullerenes Tb@C2n were synthesized and extracted with high-yield by K-H carbon-are evaporation and an effective pyridine extraction technique at high-temperature high-pressure. Laser-desorption-ionization time-of-flight (LD-TOF) mass spectrometry, X-ray photoelectron spectroscopy (XPS), solid-state fluorescent emission spectroscopy and gas phase derivation reaction with the self-chemical ionization mass spectrometric ion system of vinyl acetate were employed for studying the electronic structures, fluorescent properties and gas phase reactivities of metallofullerenes Tb@C2n. The experimental results suggest that endohedral metallofullerenes Tb@C2n would have the approximate structures of Tb3+@C2n 3+ similar to other metallofullerenes, good fluorescent emission properties and active reactivities in gas phase ion-molecular reactions.

Solid-state electronic absorption, fluorescence and13C CPMAS NMR spectroscopic study of thermo- and photo-chromic aromatic Schiff bases

Solid-state electronic absorption, fluorescence emission and 13C CPMAS spectroscopies have been applied to a series of aromatic Schiff bases displaying both ground and excited state intramolecular proton transfer phenomena. All the results can be explained on the basis of a thermal equilibrium between enolimine and keto–enamine tautomeric forms in the crystalline state. Most of the studied compounds are thermochromic. However, a few are photochromic. The carbon-13 NMR data in the solid state show, in general, residual (13C, 14N) dipolar coupling effects. In certain cases, however, where fast proton transfer occurs in the ground state, these effects are shown to be self-decoupled.

Electrosynthesis and spectroscopic characterization of poly- para-phenylene films prepared by oxidation of benzene in liquid sulfur dioxide

Poly- para-phenylene (PPP) films were prepared electrochermcally onto a thin layer Pt electrode by electrooxidation of 0.1 M benzene in liquid sulfur dioxide medium, at several temperatures ranging between −75 and + 15°C, in the presence of 0.1 M tetrabutylammonium perchlorate (TBAClO 4) or 0.1 M tetrabutylammonium tetrafluoroborate (TBABF 4), as electrolyte. A passivating film was formed with TBAClO 4 after successive potential scans between 0 and 2.5 V, whereas electroactive films were produced with TBABF 4. Degree of polymerization (DP) values ranging between 14 (−75°C) and 38 phenyl groups (−25°C) were evaluated by FTIR spectroscopy for films prepared with TBABF 4. At −75°C the chains are linear, while at −25°C they are characterized by a low reticulation, which is also increased in the presence of P 2O 5 in the medium. Electronic π-π * transitions were located at about 3.5 and 2.8–2.9 eV for UV absorption spectra and between 2.7 and 2 eV for solid-state fluorescence emission spectra, consistent with the presence of bipolarons in solid-state PPP films.

Solid state room-temperature fluorescence of p-oligophenylenes and of poly(paraphenylene) films prepared electrochemically

Fluorescence excitation and emission spectra of p-terphenyl, p-quaterphenyl and p-quinquephenyl were measured in sodium chloride pressed pellets at room temperature (293 K). Significant red-shifts of fluorescence spectra are found, upon increasing the number of phenyl rings in the oligomer chain. Polyparaphenylene (PPP) films were prepared by a new method of electro-oxidation of p-terphenyl in dichloromethane. Their solid-state fluorescence excitation and emission spectra were determined at room temperature. The excitation wavelength-dependent changes of fluorescence emission bands as well as their highly structured components are attributed to the occurence in the excited singlet state of a variety of planar or nearly planar configurations of PPP films with relatively long chains.

Spectrofluorimetric study of electrosynthesized and chemically prepared poly( N-vinylcarbazole) films

A spectrofluorimetric method is proposed for the study of chemically prepared and electrosynthesized poly( N-vinylcarbazole) (PVCA) films on Pt thin layers. Solid-state fluorescence excitation and emission spectra of PVCA are obtained at room temperature. The effects of electrochemical doping and polymer film growth on fluorescence spectral properties are investigated. ClO − 4 electrochemical doping of PVCA films causes fluorescence quenching. In situ measurements of the changes in fluorescence intensity of PVCA films during electrochemical cycles are described. The sensitivity of the spectrofluorimetric method is very high for the quantitative determination of polymer films, with a detectable minimal mass of about 2.5 × 10 −10 mol cm −2 of PVCA, corresponding approximately to the equivalent of a monolayer.

Note on Solid State Fluorescence Emission of Ochratoxins A and B on Silica Gel

Abstract The fluorescence emission spectra of ochratoxins A and B on silica gel have been determined. The emission maxima for both toxins were found to be around 475 nm, with excitation maxima at 340 nm for ochratoxin A and 325 nm for ochratoxin B.

Solid State Fluorescence Emission of Aflatoxins on Silica Gel

Abstract The solid state fluorescence emission maxima of aflatoxins B1, B2, G1, and G2 on silica gel range from 427 to 455 mµ, with excitation maxima at 368—369 mµ. Both the order and the magnitude of the relative fluorescence intensities of individual aflatoxins are different in solution and in the solid state on silica gel.