Theoretical studies on Ru(fppz)_2(CO)L (L=N-heterocyclic ligand):Electronic structure,absorption,phosphorescence,and solvatochromism

A series of ruthenium(II) complexes Ru(fppz)2(CO)L [fppz = 3-trifluoromethyl-5(2-pyridyl)pyrazole; L = pyridine (1), 4-dimethylaminopyridine (2), 4-cyanopyridine (3)] were designed and investigated theo-retically to explore their electronic structures, absorption, and emissions as well as the solvatochrom-ism. The singlet ground state and triplet excited state geometries were fully optimized at the B3LYP/LANL2DZ and CIS/LANL2DZ level, respectively. The HOMO of 1-3 is composed of dyz(Ru) atom and π(fppz). The LUMO of 1 and 2 is dominantly contributed by π*(fppz) orbital, but that of 3 is con-tributed by π*(L). Absorption and phosphorescence in vacuo, C6H12, and CH3CN media were calculated using the TD-DFT level of theory with the PCM model based on the optimized ground and excited state geometries, respectively. The lowest-lying absorption of 1 and 2 at 387 and 391 nm is attributed to {[dyz(Ru) + π(fppz)] → [π*(fppz)]} transition, but that of 3 at 479 nm is assigned to {[dyz(Ru) + π(fppz)] → [π*(L)]} transition. The phosphorescence of 1 and 2 at 436 and 438 nm originates from 3{[dyz(Ru) + π(fppz)] [π*(fppz)]} excited state, while that of 3 at 606 nm is from 3{[dyz(Ru) + π(fppz)] [π*(L)]} excited state. The calculation results showed that the absorption and emission transition character can be changed from MLCT/ILCT to MLCT/LLCT transition by altering the substituent on the L ligand. The phosphorescence of 1 and 2 does not have solvatochromism, but that of 3 at 606 nm (vacuo), 584 nm (C6H12), and 541 nm (CH3CN) is strongly dependent on the solvent polarity, so introducing elec-tron-withdrawing group on ligand L will induce remarkable solvatochromism.

Surface-state triggered solvatochromism of carbonized polymer dot and its two-photon luminescence

This study reports a new nitrogen-doped carbonized polymer dot(CPD)-based solvatochromic probe.Its color-changing for different solvents was explored in detail by the measurements of photophysical parameters(involving Stokes shifts,fluorescence quantum yield,fluorescence lifetime,radiative decay rate constant,and non-radiative decay rate constant)and the following analyses according to Lippert–Mataga equation and Kamlet–Taft model.The hydrogen bonding effect of the CPD in protonic solvents was semi-quantitatively assessed.It takes charge of the solvatochromic phenomenon,especially in proton solvents.Interestingly,this CPD exhibits two-photon solvatochromism.Moreover,the relations between the photophysical parameters and the surface states of CPD in aprotic and proton solvents were depicted.The results reveal the nitrogen doping in the CPD impacts the up-and down-conversion solvatochromic features from the comparison between N-free and N-doped CPDs in many characterizations.In addition,this N-doped CPD was dispersed into polymer matrices to fabricate tunable solid-state luminescent films,which is another model for evidencing the interactions of the CPD with surroundings.This study is of significance in understanding the surface-state controlled luminescence in the CPDs,and will be beneficial for developing new smart,responsive carbon-based nanoprobes.

Synthesis, Characterization and Solvatochromism Investigation of Mixed Ligand Chelate Copper（Ⅱ） Complexes with Acetyleacetonate and Three Diamine Ligands

The syntheses of three mixed ligand chelate copper（II） complexes of the type [Cu（L）（acac）（H2O）]BPh4 where acac=acetyleacetonate; L=N,N-dimethyl,N′-benzylethane-1,2-diamine （L1）, N,N-dimethyl, N′-2-methylbenzylethane-1,2-diamine （L2） or N,N-dimethyl,N′-2-chlorobenzylethane-1,2-diamine （L3） are reported and characterized by elemental analyses, spectroscopic and molar conductance measurements. The X-ray structure of complex 1 shows that the central copper atom is placed in a distorted square pyramidal geometry made by acac and diamine chelate in the base and a H2O molecule on the apex. The prepared complexes are fairly soluble in a large number of organic solvents and show positive solvatochromism. Calculations of SMLR （stepwise multiple linear regression） method was utilized to find the best model explaining the observed solvatochromic behavior and showed that among different solvent parameters, donor number （DN） is a dominant factor responsible for the shift in the d-d absorption band of the complexes to the lower wavenumber with increasing its values. The importance of substituent effect in diamine ligand on the spectral and SMLR measurements is also discussed.

Bio-organic adaptive photonic crystals enable supramolecular solvatochromism

Photonic crystals(PCs)exhibit promising structural coloration properties and possess extensive application prospects in diverse optical fields.However,state-of-the-art inorganic or polymeric PCs show limited adaptivity as their configurations are fixed once formed.Herein,bio-organic adaptive PCs are fabricated via drop-casting of amphiphilic guanine-based peptide nucleic acid selfassembled microspheres.The high formation activation energy of up to 81.8 kJ·mol−1 suggests that the self-assembly step dominates the entire process.Therefore,the configurations along with the structural coloration of the supramolecular PCs are sensitive to self-assembly influencing parameters,showing temperature-encoded structural color evolution and solvent polaritydependent solvatochromism.Our findings demonstrate that the supramolecular PCs are adaptive,thus showing promising potential for detection of organic solvents of different polarities in a visual and real-time manner for environmental protection or optical applications.

Synthesis and Non-linear Optical(NLO) Properties of a Series of Alkoxysilane Derivative Chromophores

1 Introduction Nonlinear optical materials（NLO） have drawn a great intrest of some scholars and scientists in the last dacades because of their tremendous potential application in optoelectronic. The fabrication of efficient optoelectron devices is a challenging task because such systems need to meet the stringentable requirements for high optical quality and large and sustainable electro-optical（EO） response. In pursuit of NLO materials with excellent optoelectronic property,

Synthesis of 6-chloro and 6-fluoro-4-hydroxyl-2-quinolone and their azo disperse dyes

In this study,6-chloro-4-hydroxy-2-quinolone and 6-flouro-4-hydroxy-2-quinolone were synthesized from corresponding dianilides.These compounds were coupled with some diazotized aromatic amines to give the corresponding azo disperse dyes.The structures of the quinolone derivatives and new azo dyes were confirmed by UV-vis,FT-IR,;H NMR and elemental analysis.

Synthesis and Characterization of (E)-5-[2-(N-hexylcarbazolyl)vinyl] furan Derivatives with Acceptor Groups

A new series of (E)-5-[2-(N-hexylcarbazolyl)vinyl]furan chromophores with various accepters have been synthesized by the Knoevenagel condensation of (E)-5-[2-(N- hexylcarbazolyl) vinyl]-2-furaldehydes with malononitrile, 1,3-diethyl-2-thiobarbituric acid, or 3-phenyl-5-isoxazol one, respectively. They are characterized by H-1-NMR, FT- IR, UV-VIS, MS and elemental analysis, and have shown strong solvatochromism and high thermal stability.

Solvatochromic Parameters and Preferential Solvation Behavior for Binary Mixtures of 1,3-Dialkylimidazolium Ionic Liquids with Water

Binary mixtures of 1,3-dialkylimidazolium based ionic liquids （ILs） and water were selected as solvent systems to investigate the solute-solvent and solvent-solvent interactions on the preferential solvation of solvatochromic indicators at 25 ℃. Empirical solvatochromic pa- rameters, dipolarity/polarizability （π^＊）, hydrogen-bond donor acidity （α）, hydrogen-bond acceptor basicity （β）, and Reichardt＇s polarity parameters （ET^N） were measured from the ultraviolet-visible spectral shifts of 4-nitroaniline, 4-nitroanisole, and Reichardt＇s dye. The solvent properties of the IL-water mixtures were found to be influenced by IL type and IL mole fraction （XIL）. All these studied systems showed the non-ideal behavior. The max- imum deviation to ideality for the solvatochromic parameters can be obtained in the XIL range from 0.i to 0.3. For most of the binary mixtures, the π^＊ values showed the synergistic effects instead of the ETN, α and β values. The observed synergy extent was dependent on the studied systems, such as the dye indicator and IL type. A preferential solvation model was utilized to gather information on the molecular interactions in the mixtures. The dye indicator was preferentially solvated on the following trend： IL〉IL-water complex〉water.

Synthesis and Electronic Structure of A2B Type Halogen Atoms Substituted H3-Triarylcorroles

Seven electron-deficient A_2 B type H_3-triarylcorroles have been synthesized and characterized. The solvent dependence of the electronic absorption and magnetic circular dichroism（MCD） spectra and a series of TD-DFT calculations have been used to analyze trends in the electronic structures. Significant differences are observed in the optical spectra when solvents of differing polarity are used,which can be assigned to the effect of NH-tautomerism.

Spectroscopic Properties and Three-photon Absorption Induced Optical Limiting of Series of Novel Nonlinear Chromophores

Three novel nonlinear chromophores with symmetric D-π-D molecular structure and extended conjugated length were synthesized. Solvatochromism analysis shows great symmetric intramolecular charge transfer occurring in chromophores by the enhancement in the dipole moment between the ground and excited states. The properties of optical power limiting induced by three-photon absorption （3PA） are demonstrated. Large 3PA coefficients and the corresponding molecular cross sections as high as 10^-74 cm^6s^2 were obtained for nanosecond laser pulses at 1.06μm from nonlinear transmission measurements.

A KIND OF FLUORESCENCE PROBE TO STUDY THE KINETICS OF POLYMERIZATION PROCESS

Fluorescence properties of 1-pheny1-3-(4'-nitrophenyl) pyrazoline (PNP) were studied inbulk polymerization process of methylmethacrylate (MMA). The fluorescence intensity of PNPwas enhanced and the emission maximum was blue shifted with the polymerization progress. Inthe period of auto-acceleration of the polymerization the enhancement of fluorescence intensityand blue shift of peak wavelength in spectra could be observed evidently. This means that thesolvatochromic properties of PNP are influenced not only by the solvent polarity but also by theviscosity of the medium (especially by the phase transitiott). In solid state PNP emits from thecharge transfer excited state without solvent relaxation. The transient emission spectra and theresults from Bakhshiev model of solvent relaxation coincide with that from the polymerizationexperiment.

Aggregation Properties of an Amphiphilic Methanofullerene Derivative in THFH_2O Solvent Mixtures

Amphiphilic methanofullerene 1 exhibits strong tendency to form aggregates in THFH2O solvent mixtures. Two different aggregation processes induced by either varying the solvent composition or upon standing have been found. Concentration has great influence on the aggregation process. Paralleling to the UV-Vis changes, an unusual solvatochromism has been observed in these two different processes.

Solvent and Temperature Effects on Spectral Properties of Two Poly(3-alkyl)thiophene Derivatives

Two alkyl substituted polythiophene derivatives: poly(3-hexylthiophene)(P3HT) and poly(3-decylthiophene)(P3DT), have synthesized by oxidation coupling polymerization of 3-alkylthiophene using iron(III) chloride as catalyst in chloroform. While both polymers in pure chloroform solution have maximum absorption at approximately same wavelength of 440nm, they behave differently with respect to changes observed on their UV-visible and photoluminescence spectra when the quality of the poor solvent is changed in good solvent (chloroform) / poor solvent (methanol) mixtures. With increasing volume fraction of methanol in mixtures, the absorption spectra of P3HT and P3DT red-shift, peaking at maximum wavelength of 495nm (P3HT) and 510nm(P3DT). Furthermore, the absorption spectra of the two polymers in chloroform blue-shift as the temperature rises. P3HT shows 4.73nm blue-shifts at 50℃ in contrast to the case at 20℃, while P3DT blue-shifts about 5.04nm. The photoluminescence spectra of the two polymers in mixed solution are also investigated, which show that the luminescence spectra shift to longer wavelength with an accompanying drop in the PL intensity as methanol is increased. The absorption and emission spectra of the two polymers in a poor solvent and a thin film are similar, which indicate that a similar longer conjugation length in the two cases. It could conclude that the polymers exist almost the same conformations and aggregations in both a poor solvent and a thin film. P3DT exhibits more sensitive spectra properties (big red-shifts in both absorption and luminescence spectra in poor solvents and large blue-shifts at high temperature) with contrast to P3HT, which imply that long side alkyl may improve the chromic properties of the polymer.

Synthesis and Solvatochromic Behavior of Hexaphenylbenzenes and Indeno[1,2-<i>b</i>]fluorene Derivatives with Hydroxy Groups

Hexakis(4-methoxyphenyl)benzene (HPB-OMe(1)) and hexakis(2,6-dimethyl-4-methoxyphenyl)benzene (HPB-OMe(2)) were synthesized via organometallic complex catalysis. The treatment of HPB-OMe(1) with FeCl3 caused cyclodehydrogenation at two positions to yield an oligophenylene with an indeno[1,2-b]fluorene structure (IF-OMe). Deprotection of the methoxy groups of these compounds was conducted by treatment with BBr3. Deprotonation of the OH groups of HPB-OH(1), HPB-OH(2), and IF-OH through treatment with NaH caused a bathochromic shift in the absorption and photoluminescence (PL) peaks. The bathochromic shift of the deprotonated species increased with the donor number (DN) of the solvents. These observations can be explained as the consequence of intramolecular charge transfer (ICT) from the ONa groups to the inner benzene rings.

The First Hyperpolarizabilities of Merocarbocyanines

The dot products mu(g)beta(CT) of first hyperpolarizability and ground state dipole moment of two merocarbocyanines were measured experimentally with solvatochromism and compared to the values obtained by AM1/FF calculation. The comparable result was also obtained by the measurement of second harmonic generation (SHG) for LB film of dye II. The mu(g)beta(CT) of dye II is larger than that of the well known NLO chromophore 4-N, N-dimethylamino-4'-nitrostilbene (DANS).

Study on the Phase Behavior of Supercritical CO2/Dynol-604/Water System and Solubilization of Methyl Orange in the Microemulsions

It was found that Dynol-604, a non-fluorous and no silicon-containing nonionic surfactant, was soluble in supercritical (SC) CO2. The phase behavior of SC CO2/Dynol-604/water system was studied. The results showed that one-phase water-in-CO2 microemulsions could be formed. The solubilization of methyl orange in the microemulsions proved further the existence of water domain in the microemulsions.

Solvatochromic Probe Based on Nanocellulose Membrane Coated with Zn-terpyridine Complex in a Layer-by-Layer Manner

Solvatochromic materials have recently attracted increasing attention owing to their great significance in the security and sensor fields.In this study,ultrafast explicit and implicit information was collected regarding a fluorescent nanocellulose membrane produced from nanocellulose membranes coated with a Zn-terpyridine complex(Zn-tpy)in a layer-by-layer manner.The fluorescent emissions of the nanocellulose membrane changed from yellow(CIE:x=0.37,y=0.45)to green(CIE:x=0.32,y=0.47)under a dichloromethane environment and 365-nm irradiation.Due to the ease of dichloromethane volatilization,fluorescent emissions quickly returned to the original state.These solvatochromic nanocellulose membranes,with ultrafast explicit and implicit information,exhibited valuable application prospects in anti-counterfeiting techniques.

Synthesis and Spectroscopic Properties of Ferrocenyl Derivative Containing Donor and Acceptor Groups

Much interest has been devoted to organometallic NLO materials. We have become interested in exploring the utility of ferrocenyl group as the conjugating bridge. Thus, we synthesized 1-{{[1,3-(5-methylbenzo)dithiol]-2-yli- dene}methyl}-1’-[2-(p-nitrophenyl)-(E)-ethenyl]ferrocene (1). This new ferrocenyl compound has a donor and an acceptor group in 1,1’-positions. Investigations of the solvatochromic property of the compound revealed that it has polarized structure in a polar solvent, such as DMF. SHG efficiency of the compound was estimated by an SHEW (second-harmonic generation with the evanescent wave) method.

Synthesis and Photophysical Properties of Novel Highly Stable Zero/Bis-Zero Methine Cyanine Dyes Based on N-Bridgehead Heterocycles

Cyanine dyes of zero/bis-zero methine incorporating imid-azo(1,2-a)Pyridine (quinoline) or pyrazino(1,2-a)pyridine (quinoline) with stable C-N bond were synthesized using keto-oxime methylene C-link heterocyclic quaternary salts [1-phenyl-3-methyl-pyrazolino-4-keto-oxime-α-methylene-bis-pyridin-(quinoin)-1(4)-di-ium-iodide(ethiodide) salts and 1-phenyl-3-methyl-pyrazolino- 4-ketooxime-α-methylene-N-2-methyl-bis pyridin (quinoin)-1(4)-di-ium-iodide(ethiodide) salts]. Such heterocyclic precursors and related dyes were identified by elemental and spectral analyses. The absorption spectra properties of such dyes were investigated in 95% Ethanol to attempt and throw some light on the influence of such new heterocyclic nuclei and to compare or evaluate spectral behaviors. The absorption spectra of dyes in different pure solvents were examined in the visible region showing solvatochromism and the colour changes of dyes with solvents having different polarities. This permits a selection of the optimal solvent (fractional solvent) when such dyes are applied as photosensitizers. The spectral behavior of some selected newly synthesized cyanine dyes is observed in mixed solvents of different polarities and progressively increasing quantities of one solvent over the other were studied and showed an increase in the absorbance of CT band with increasing proportion of that solvent. Evidence for hydrogen bond formation between the solute molecules and solvent molecules allows measurement of certain energies such as hydrogen bonding, orientation, and free energies.

A New Method to Investigate the Clustering Phenomena in Supercritical Fluids

The solvatochromic behavior of acetone in supercritical CO? was investigated from 75 bar to 239 bar and at 318.15K. A clustering model is proposed to investigate the formation of solute-solvent and solute-solute clusters, based on the solvatochromic study and some reasonable assumptions. At lower pressures, there were more than one solute molecules in one cluster. At higher pressures, however, each cluster only contained one solute and the clustering of solute-solvent was dominant.