Chromotropic Properties Research Articles

Residual-dye-derived carbon dots from wastewater for anti-counterfeiting and information encryption

With the development of resource recycling awareness, the number of research on the synthesis and utilization of carbon dots (CDs) from natural wastes continues to grow. Meanwhile, the little-studied synthesis of CDs originating from industrial waste has also become more relevant. In this work, reactive yellow 95 (Y95) molecules in exhausted dyeing wastewater were used as carbon source. By a simple one-step hydrothermal method, the CDs with stimuli-responsive fluorescent chromotropic properties were obtained. With the addition of hydrochloric acid to the CDs solution, the emission of the CDs was red-shifted from 470 nm to 514 nm, and the fluorescence changed from blue to green. The phenomenon was attributed to the synergistic effect of more CO defects on the surface of CDs and the protonation of the carbonyl groups after adding acid. Based on acid-induced fluorescent chromotropic performance, we designed anti-counterfeiting labels for textiles and a double-switching information encryption anti-counterfeiting ink. This work synthesized responsive fluorescent CDs using waste dyes and showed great potential in the field of resource recycling.

Synthesis, characterization, crystal structure, hirshfeld surface analysis and chromotropic properties of halo- bridged copper(II) complexes

In this study, two novel chromotropic binuclear copper(II) complexes were introduced. The complexes were denoted as [LCu(μ-Cl)Cl]2, 1 and [LCu(μ-Br)Br]2, 2 with L representing the chelating ligand N,N-dimethyl-N'-(9-methylanthracenyl)ethylenediamine. To investigate the structures of these complexes, various analytical techniques were employed, including FT-IR, EPR, UV–Vis spectroscopy, TG-DTA, molar conductivity measurements, and elemental analysis. The geometrical property of [LCu(μ-Br)Br]2 was determined using X-ray crystallography, while the intermolecular interactions were studied through Hirshfeld surface analysis. The characterization data provided strong evidence supporting the proposed binuclear structure, wherein two copper (II) centers are connected by two halogen bridges. Remarkably, these complexes exhibit solvatochromism and thermochromism properties, displaying a diverse range of colors in solutions with varying polarities and/or temperatures. Experimental findings suggest that the observed chromotropism can be attributed to the substitution of solvent molecules with the coordinated halogens in the complexes.

Dynamic acylhydrazone bonds cross-linked chromotropic photonic-ionic skin with self-healing and high resilience for interactive human-machine interface

Advanced skin systems realize perception and interaction with the environment through synergistic electrical and color signals generated by transmitting ions and manipulating photonic structures. Here, inspired by chameleon skins, a novel self-healing and resilient photonic-ionic skin (PI-skin) with electro-optical dual response is ingeniously constructed integrating the ordered micro-nano array and the dynamically covalently cross-linked ionogel. The elaborately designed polycation network with weak inter-chain interactions can promote the uniform distribution of high-content low-viscosity ionic liquid (IL), effectively eliminating energy dissipation and resulting in high resilience. Dynamic acylhydrazone bonds are served as reversible chemical crosslinking to realize high-efficiency self-healing and further enhance resilience. Notably, the artificially manipulated transition of the photonic array from dense packing to non-dense packing endows sensitive chromotropic properties synchronized with electrical response under stretched (Δλ > 130 nm) and compressed (Δλ > 160 nm). Furthermore, by harnessing the correspondence between electrical and optical signals, the control of optical signals over electrical signals is achieved for inputting complex coded information and constructing interactive human–machine interfaces. This work not only inspires the design and construction of high-level artificial skins but also stimulates the development of visual interactive devices and smart electronic/ionic products.

MORPHOLOGICAL PECULIARITIES OF THE SKIN GRANULATION TISSUE IN PATIENTS WITH MALIGNANT NEOPLASMS OF THE ABDOMINAL ORGANS.

The aim: To examine morphological peculiarities of the skin granulation tissue from the laparotomy wound in patients with malignant neoplasms of the abdominal organs. Materials and methods: 36 bodies of deceased people were examined after midline laparotomy performed for surgical treatment of diseases of the abdominal organs. The main group included 22 bodies of deceased people suffering from malignant neoplasms of the abdominal organs, mostly in ІІІ-IV stages of diseases. The group of comparison included 14 bodies of deceased individuals suffering from acute surgical diseases of the abdominal organs. An average length of the laparotomy wound was 24,5 ± 0,28 cm. An average distance from the reticular elements to the external border of the granulation tissue was measured by means of computed histometry (mcm), the optical density (OD) of staining of the collagen fibers was determined by means of computed microdencitometry (expressed in OD absorbance coefficient - the absorbance of the solution per unit length per mole of solute), the specific volume of the blood vessels in the granulation tissue - by means of computed histostereometry (%), the granulation tissue cells were calculated by means of the score test (within eyeshot 10000 mcm2). The specimens were stained with hematoxylin, eosin and methylene blue/Chromotrop 2B. Results: The obtained results of the investigation conducted are indicative of more prominent chromotropic properties in the samples of the main group, confirming certain biochemical changes and features of the collagen fibers respectively. Moreover, slide mounts of the main group possess reliably lower optic density of staining of the collagen fibers which is indicative of their slow formation. It may suggest a reduced solidity of the postoperative scar on the laparotomy wound skin promoting easier wound disruption, that is, occurrence of subcutaneous eventration in patients with malignant neoplasms of the abdominal organs. Conclusions: Oncological process in the body results in the aggravation of swelling and chromotropophilia in the deep layers of derma during more remote terms after surgery and reduced optic density of the collagen fibers staining, which promotes easier laparotomy wound disruption and occurrence of true postoperative eventration.

Copper (II) halide complexes with NNO tridentate ligand as chromotropic probes; synthesis, structural characterization and spectroscopic properties

• Two new copper (II) complexes with halide and NNO ligands were synthesized. • The complexes exhibit solvatochromism, thermochromism, and halochromism. • Copper-halogen bands of the complexes dissociate by increasing solvent polarity. • Reversible structural changes in solution is responsible for observed chromotropism. This study reports chromotropism of two newly synthesized copper(II) complexes of formula [CuLCl 2 ] and [CuLBr 2 ]•MeOH where L = N -(2-pyridylmethyl)-1-hydroxypropylamine. The structure of the complexes was investigated by infrared spectroscopy, electronic absorption spectroscopy, elemental analysis, molar conductance measurements, and thermal analysis. Single Crystal X-ray structure determination reveals both complexes to adopt a distorted square-pyramidal geometry. Their chromotropic properties were investigated using electronic absorption spectroscopy. The complexes are solvatochromic in solvents with different polarities. The aqueous solutions of the complexes exhibit a variety of colors in the pH range of 1.8 to 11.4 showing that the compounds are halochromic. The complexes are also thermochromic and show reversible color changes in different temperatures in dimethyl sulfoxide solutions. The solution study reveals that the observed chromotropism originates from structural changes of the complexes in different conditions.

Chromotropism in halo-bridged dimers. Structural characterization of bis(μ-halo)bis(halo N-(pyridin-2-ylmethyl)cyclohexanamine copper(II))

Two dinuclear copper(II) complexes, [LCu(μ-Cl)Cl]2 (DMF) (1) and [LCu(μ-Br)Br]2 (2), with the bidentate ligand N-(pyridin-2-ylmethyl)cyclohexanamine, L, were synthesized and characterized by physicochemical and spectroscopic (IR, UV–vis) data. The crystal structural analysis of 1 shows that both copper(II) ions are in a distorted square pyramidal N2Cl3 environment with the apical position of the copper(II) being occupied by the bridging chloride anion which is equatorial to the other copper ion, forming a dimeric copper(II) complex. The chromotropic properties of both complexes, including solvato-, thermo-, and halochromism, were investigated. The complexes show reversible thermochromism in solution which is irreversible in the solid state. It was found that the solvatochromism is due to structural change followed by solvation of the vacant sites of the complexes. Their halochromic properties were studied in pH range of 1–11 by visible absorption spectroscopy. The color changes from blue to green and to colorless are due to deprotonation and protonation of the ligands.

Structure and chromotropism properties of an unsymmetrical alkoxo-bridged nickel(II) cubane-like complex

A new tetranuclear cubane-like complex, [Ni4(L)4Cl4(H2O)3(EtOH)]·(H2O), has been synthesized from the reaction of a metal salt with the bidentate ligand 2-hydroxymethylpyridine (LH), and its crystal structure, spectroscopic and chromotropic properties have been studied. The complex has a [Ni4O4] core comprising a distorted cubane arrangement, of which four nickel(II) ions were bridged by μ3-alkoxo moieties. Each nickel(II) was coordinated to three μ3-alkoxo oxygens, one pyridine nitrogen and one chloride. The peripheral ligation was completed by an oxygen atom of water or ethanol ligand, which participated in intramolecular hydrogen bonding. Chromotropism properties of the complex including solvato-, thermo-, and ionochromism were investigated. The complex displayed strong ionochromism and shows high-sensitive and selective activity toward CN− and SCN− anions in the presence of other halides and pseudo-halides. The solvatochromic property of the complex was analyzed by a multi-parametric equation using SPSS/PC software. The stepwise multiple linear regression method demonstrated that the acceptor power of the solvent plays the most important role in the observed negative solvatochromism of the compound. It shows reversible thermochromism in solution due to loss of the weakly coordinated water and ethanol from the nickel(II) units.

Synthesis, structural characterization and chromotropism of a copper(II) complex containing a bidentate ligand

A new coordination compound, [Cu(L)2(OH2)](ClO4)2 where L=N-(pyridin-2-ylmethyl)propane-2-amine, was prepared and characterized by elemental analysis, molar conductance and IR and UV–Vis spectroscopic techniques. X-ray crystal analysis of the complex confirmed that the copper(II) ion has a distorted square pyramidal environment. The complex is chromotropic in solution. The chromotropic properties of the complex, including solvato-, thermo-, halo- and ionochromism, were investigated in detail. The complex displayed strongly pronounced reversible thermochromism in solution due to dissociation and of re-coordination of a water molecule.

Syntheses of dinuclear copper(II) complexes containing of tertiary diamine and amido groups with hydroxo bridges; chromotropic properties

Two new symmetric dinuclear complexes type [Cu(L)(μ-OH)]2(ClO4)2, where either L = N,N-dimethyl,N′-3-propylamide-ethylenediamine or N,N-diethyl,N′-3-propylamide-ethylenediamine were synthesized and characterized on the basis of elemental analysis, conductance measurement, spectroscopic techniques and X-ray crystal analysis. The complexes show halochromism in aqueous solution. The pH effects on the visible absorption spectra of the two complexes were studied which act as pH-induced “off–on–off” switches through protonation and deprotonation in aqueous solution at room temperature. The dinuclear complexes were also observed to exhibit thermochromism, solvatochromism and ionochromism as a result of hemilability of amide groups. The solvatochromism of the complexes was investigated with different solvent parameter models using stepwise multiple linear regression method. The results suggested that the donor number parameter of the solvent has a dominant contribution to the shift of the d–d absorption band of the complexes.

Syntheses, crystal structure and chromotropic properties of dinuclear copper(II) complexes of tertiary diamine with hydroxo bridge

Dinuclear copper(II) complex with the general formula [(diamine)Cu(OH)] 2(ClO 4) 2, where diamine stands for N, N-dialkyl, N′-benzyl-ethylenediamine, were prepared. The complexes were characterized by elemental analysis, spectroscopic, conductance measurements, and X-ray structural analysis. The complexes are soluble in various organic solvents and show positive solvatochromism. Thermochromism was also observed particularly in strong donor solvents.

Structure and chromotropic properties of mono- and binuclear mixed-ligand nickel(II) complexes containing 1,3-diketonate and polyamine ligands

Mixed-ligand Ni II complexes have been syn- thesized with 1,3-diketonate and bulky tri- or tetra-amine ligands. Their structures were determined by X-ray crys- tallography, and solvatochromic behavior was examined by UV-vis-NIR spectroscopy. Steric effects of the bulky ligands on the coordination distances and spectral proper- ties are discussed.

Synthesis, Crystal Structure, and Chromotropic Properties of Mixed-Ligand Nickel(II) Complexes with 1,3-Diketonate and P–N Bidentate Ligands

Abstract Mixed-ligand nickel(II) complexes Ni(acac)(dmap)X, [Ni(acac)(dmap)]BPh4 (1), [Ni(acac)(dmap)]BF4 (2), and [Ni(acac)(dmap)NO3] (3) (where acac = acetylacetonate and dmap = 1-dimethylamino-2-diphenylphosphinoethane) have been obtained for the first time and their X-ray single-crystal structures have also been determined. This series of complexes show different structures, hence colors, in the solid state depending on the coordination strength of the anion X−: the complexes with tetraphenylborate and tetrafluoroborate having no coordination ability are square-planar and orange, while on the contrary, the coordinating nitrate ligand produces an octahedral and pale blue complex. In solution, two types of solvatochromism due to solute–solvent interaction and solute–solute–solvent interaction have been observed and these spectral behaviors are attributed to the changes in their geometries due to the donor/acceptor properties of the solvents. The thermochromic behavior of complex 1 has also been studied with temperature variation UV–vis spectra in various solvents. The behavior of these solvato- and thermo-chromisms of these complexes is due to the intermediate ligand field strength created by the dmap and the acac ligands.

Synthesis, characterization and chromotropic properties of MnII, CoII, NiII and CuII with bis(acesulfamato)bis(3-methylpyridine) complexes

The novel \([\hbox{M(acs)}_{2}(\)3-\(\hbox{pic})_{2}(\hbox{H}_{2}\hbox{O})_{2}]\) [M: MnII, CoII, and NiII] and \([\hbox{Cu(acs)}_{2}(\)3-\(\hbox{pic)}_{2}]\) complexes (acs: acesulfamate; 3-pic: 3-methylpyridine) have been synthesized and characterized using elemental analyses, magnetic moments, UV–Vis and FT-IR spectra. The thermal behaviour of the complexes was also studied by simultaneous TG, DTG and DTA methods in static air atmosphere. The chromotropic properties of all complexes have been studied using thermal and spectral analysis. While the complexes of CoII and NiII show reversible continuous thermochromism, an irreversible discontinuous thermochromism is observed in the MnII and CuII) complexes in the solid state. The observed thermochromism in the MnII, CoII and NiII complexes is due to the different ligand field strength associated with the deaquation reaction. The solvatochromic behaviour of the complexes is also studied and all \([\hbox{M(acs)}_{2}(3 \hbox{-pic})_{2}]\) anhydrous complexes (except MnII) exhibit solvatochromic properties depending on the donor number of the solvent.

Syntheses, crystal structures and chromotropic properties of Nickel(II) mixed ligand complexes containing N-methyl-1,4-diazacycloheptane and various β-diketonates

Six complexes, Ni(medach)(dike)X, have been newly obtained, where medach = N-methyl-1,4-diazacycloheptane, dike = a β-diketonate such as benzoylacetonate (bzac), dibenzoylmethanate (dibm), X = BPh 4 - , NO 3 - or dike: Ni(medach)(bzac)(NO 3) ( 1a), Ni(medach)(dibm)(NO 3) ( 2a), Ni(medach)(bzac)(BPh 4) ( 1b), Ni(medach)(dibm)(BPh 4) ( 2b), Ni(medach)(bzac) 2 ( 1c), Ni(medach)(dibm) 2 ( 2c). X-ray single crystal structures of the complexes 1a, 2a, 1b and 2c have been determined and the structures of the complexes Ni(medach)(acac)(NO 3) ( 3a) and Ni(medach)(acac)BPh 4 ( 3b) (acac = acetylacetonate), reported previously, have also been clarified. In the cases of the tetraphenylborate and the nitrate complexes, two types of solvatochromism due to the donor and the acceptor interactions were observed in organic solvents. These spectral behaviors will be discussed in relation to the complex geometry and the donor and acceptor properties of the solvents, and also compared to those of the corresponding complexes containing a linear diamine such as N, N, N′, N′-tetramethylethylenediamine (tmen), Ni(tmen)(dike)X.

Chromotropic Behavior of Lophine Nitro-Derivatives

The crystal and molecular structures of two novel derivatives of the lophine chromophore with different solvents of crystallization are presented and discussed. Phenol, 2-[4,5-bis(4-methoxyphenyl)-1H-imidazole-2-yl]-4-nitro (1) and phenol, 2-[4,5-bis(4-methyl-phenyl)-1H-imidazole-2-yl]-4-nitro (2) form inclusion compounds with various guest molecules. The guest molecules interconnect host molecules of 1 and 2 through hydrogen bonds. The inclusion compounds showed chromotropic properties upon trituration, heating, or using different solvents for crystallization. The thermochromic properties have been determined by the removal of the guest molecules. To clarify the relations between the color, thermochromic properties, and the role of host in crystal packing, we have determined and compared a single-crystal X-ray analysis of six crystal structures of the two compounds. Thermal behavior in the solid state and spectroscopic behavior at different pH values and at various solvents are presented and discussed.

Polyelectrolyte complexes. III. Binding characteristics of some polydentate anionic azo dyes to polycations with N,N-dimethyl-2-hydroxypropylene ammonium chloride units in the main chain

Formation of the polycation/dye complexes by the interaction between polycations with (N,N-dimethyl-2-hydroxypropylene ammonium chloride) units in the main chain and three anionic dyes with two, three and six sulfonic groups (Crystal Ponceau 6R, Ponceau 4R and Direct Red 80) confirmed the chromotropic properties of these polycations and gave information on the influence of the polycation and the dye structure on the stability of the polycation/dye complex. The interaction between polycations and dyes and the stoichiometry of the polycation/dye complexes were followed by UV-VIS spectrophotometry and viscometry. The presence of the nonpolar side chains in polycation structure did not increase the ability to bind these dyes. The stability of the polycation/dye complexes increased with the increase of the content of quaternary ammonium salt groups in the main chain and with the increase of the sulfonic group number of the dye.

Structural Varieties and Chromotropic Properties of Metal Complexes

Structural Varieties and Chromotropic Properties of Metal Complexes

Syntheses of new copper(II) mixed-ligand complexes and their chromotropic properties in solution and in the solid state

Reaction of acetylacetone (Hacac) with aldehyde (RCHO; R =p-MeOC6H4, p-ClC6H4 or Ph) in 2 : 1 mol ratio resulted in the formation of new triketones (HL2), which were previously characterized as bis(β-diketones) of the type [(MeCO)2CHCHRCH(COMe)2](H2L1). Mixed-ligand copper(II) complexes with N,N,N′,N′-tetramethylethane-1,2-diamine (tmen) and the β-diketonate moiety of these triketones, [CuCl(L2)(tmen)], were synthesized and their solvatochromic properties in organic solvents (due to the acceptor properties of the solvent) investigated. The colour of these five-co-ordinated complexes in the solid state gradually changes from green in [CuCl(L2)(tmen)] through bluish green, [CuCl(L2)(tmen)]·CH2Cl2, to blue, [CuCl(L2)(tmen)]·MeOH·CH2Cl2. Crystallographic studies showed that this phenomenon arises from an intermolecular hydrogen bond between the co-ordinated chloride of one complex and the OH group of a triketonate ligand of an adjacent complex and/or cocrystallized MeOH molecule.

Structures and chromotropic properties of imidazole derivatives produced from 3,6-bis(4,5-diphenyl-2H-imidazol-2-ylidene)cyclohexa-1,4-diene

Addition of acetic acid to 3,6-bis (4,5-diphenyl-2H-imidazol-2-ylidene) cyclohexa-1,4-diene (1) afforded 2-[4-(4-acetoxy-4,5-diphenyl-4H-imidazol-2-yl) phenyl]-4,5-diphenyl-1H-imidazole (2). Lead dioxide oxidation of (2) in acetic acid yielded 1,4-bis(4-acetoxy-4,5-diphenyl-4H-imidazol-2-yl)-benzene (13) but hexacyanoferrate(III) oxidation in alkaline solution gave a 2,2′-imidazolyl dimer (7) derived via 2-[4-(5-oxo-4,4-diphenyl-4,5-dihydro-1H-imidazol-2-yl)phenyl]-4,5-diphenyl-1H-imidazole (4).Irradiation of compounds (2) and (13) with u.v. light resulted in the formation of the starting quinonoid compound (1) as indicated by its deep blue colour. However, the dimeric compound (7) shows chromotropism caused by radical dissociation of the dimer during irradiation, heating, or grinding. Particularly rapid reversible photochromic behaviour was observed for (7).

The crystal structures ofN-salicylideneanilines and their chromotropic properties

The crystal structures of<i>N</i>-salicylideneanilines and their chromotropic properties