5-N,N-二乙氨基-2-(吡啶-2’-亚氨甲基)苯酚的合成及其对Zn~(2+)的识别

本文利用2-氨基吡啶与4-N,N-二乙氨基水杨醛反应合成了5-N,N-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚(探针L),并对其结构进行了表征。在DMSO/Tris(体积比6∶4,p H=7. 4)溶液中,探针L高选择性荧光"关-开"识别Zn2+,在365nm紫外灯照射下,由无荧光变成蓝色荧光。实验表明,探针L与Zn2+的结合比为1∶1,结合常数为2. 6×103L/mol,检测限为9. 39×10-7mol/L,p H适用范围为7～11,并可检测水样中的Zn2+。     

一种7-羟基四氢喹喔啉-6-甲醛衍生物对H2S的比色和荧光识别

本文利用1,4-二乙基-7-羟基四氢喹喔啉-6-甲醛与2-甲基苯并噻唑盐反应制备了荧光探针L,并对其结构进行了表征。实验结果表明,探针L在DMSO溶液中对H_2S具有快速荧光"关-开"响应以及高选择性和较好的抗干扰能力,检测限为2. 5×10~(-6)mol/L。在365nm紫外灯照射下,L的荧光颜色由无荧光变成黄绿色强荧光;此外,加入H_2S后探针L的DMSO溶液颜色由蓝紫色变为无色,通过裸眼即可识别H_2S。     

一种“关-开”H_2S荧光探针的合成及其性能研究

以2-羟基-1-萘甲醛为原料,合成了一种"关-开"型荧光探针2-(苯并噻唑-2-基)萘酚衍生物(L),经NMR,IR,ESI-MS和元素分析表征。利用紫外-可见吸收光谱和荧光发射光谱对探针L识别H_2S的性能进行了测试。结果表明,在pH为6至8范围时,探针L对H_2S表现出高选择性、高灵敏度和抗干扰性,检测限低至19.8 nM,实际应用研究表明,探针L可用于实际水样中一定浓度范围内H_2S的检测。     

肼二腙类多功能长波发射荧光探针的合成及其铜配合物对H_2S的识别

以1,4-二乙基-7-羟基四氢喹喔啉-6-甲醛为基础,设计合成了一种具有长波长发射、较大斯托克斯位移的新型肼二腙类荧光探针L.在探针L的二甲基亚砜(DMSO)溶液中加入Cu~(2+)和CO~(2+)后,溶液颜色由黄色分别变为粉色和无色,可裸眼识别Cu~(2+)和Co~(2+).利用L与Cu~(2+)形成的配合物,在DMSO/H_2O(V:V=7:3,HEPES,1×10~(-2)mol/L,pH=7.4)缓冲溶液中可荧光"OFF-ON"识别H_2S.试纸条实验表明,L-Cu~(2+)对不同浓度H_2S显色明显,可以通过裸眼和荧光双通道快速检测H_2S.此外,利用Discovery Studio分子模拟软件,通过分子L结构反向找靶,并用CDOCKER程序进行分子对接,发现分子L对2x0v蛋白(来自人类的P53蛋白)有很好的结合作用,有望在医药领域得到应用.     

一种响应速率匹配的双反应探针用于荧光识别硫化氢

以6-氟-7-氨基香豆素为荧光基团,氟代叠氮和7-硝基苯并氟咱(NBD)-哌嗪为H_2S反应基团和荧光淬灭基团,合成一种双反应H_2S荧光探针.探针对H_2S的识别性质研究表明,探针的两个反应基团与H_2S响应速率匹配,探针对H_2S具有高选择性和灵敏性,其荧光增强约3600倍,检测极限为4.0×10~(-8)mol/L.酶活性测试表明,探针可用于胱硫醚β合成酶(CBS)酶活性检测和抑制剂筛选.细胞成像实验表明,探针可用于细胞内H_2S的成像研究.     

pH调控下基于分子内电荷转移(ICT)机理的硫化氢荧光探针

硫化氢(H_2S)和pH在环境和细胞内的许多过程中起着至关重要的作用.为了更好地研究其功能,需要一种快速、灵敏地检测H_2S和pH的荧光探针.设计合成了以萘二酰亚胺为荧光基团,叠氮为识别位点,基于分子内电荷转移(ICT)机制的反应型荧光探针L.该探针L在较宽的pH范围(4～11)内稳定性好,对H_2S的选择性高,响应速度快(3 min),检测限(1.18μmol·L~(-1))较低,在0～20μmol·L~(-1)的范围内,荧光强度与H2S浓度呈良好的线性关系(R~2=0.99823).此外,当体系中存在30倍的H_2S时,在2≤pH≤6.5的范围内, L对pH变化显示线性关系(R~2=0.98764),可用作pH探针.该探针在检测H_2S和30倍H_2S存在条件下研究细胞微环境pH变化的方法,在分析检测和病理分析等方面具有潜在的应用前景.     

5-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚的合成及其对Zn2+的识别

本文利用2-氨基吡啶与4-二乙胺基水杨醛反应合成了5-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚(探针L),对其结构进行了表征。在DMSO/Tris(6:4, v/v, pH =7.4)溶液中,探针L高选择性荧光“关-开”识别Zn₂₊,在365 nm紫外灯照射下,由无荧光变成蓝色荧光。实验表明,探针L与Zn₂₊的结合比为1:1,结合常数为2.6×10₃ L. mol_-1,检测限为 9.39×10_-7mol/L,pH适用范围为7-11,并可检测水样中的Zn₂₊。     

一种1,8-萘酰亚胺Cr~(3+)离子荧光探针的研究

以4-硝基-1,8-萘酐、N,N-二甲基乙二胺为主要原料合成了一种荧光探针:4-(2′-N,N-二甲基氨基乙基)氨基-N-(2-N,N-二甲基氨基)乙基-1,8-萘酰亚胺(DDN)。研究了其紫外可见吸收和荧光发射光谱。考察了Fe3+,Cr3+,Mn2+,Ni2+,Zn2+,Cu2+和Co2+离子对该化合物荧光发射光谱的影响,结果表明Cr3+离子能使DDN荧光显著增强。滴定实验结果推测DDN与Cr3+的结合比为1∶2。在DDN浓度为1.0×10-5mol/L时,Cr3+浓度在5.0×10-7~2.0×10-5mol/L范围内,DDN荧光强度(F)与Cr3+离子浓度[Cr3+]呈良好的线性关系,线性方程为F=9430.3527+14600.2973[Cr3+],相关系数r=0.9976。检测限为4.3×10-7mol/L。     

基于2,6-二甲酰基-4-甲基苯酚的双Schiff化合物的合成及Zn~(2+)识别

以2-氨基苯并噻唑、水合肼和硫酸为原料,合成2-肼基苯并噻唑,与2,6-二甲酰基-4-甲基苯酚进行反应得到2,6-二甲酰基-4-甲基苯酚缩二(2-肼基苯并噻唑)(L),在DMF与H_2O (3:2,V:V)的混合溶液中,通过紫外和荧光测定该探针(L)对金属离子的识别性能。结果发现,该荧光探针(L)对Zn~(2+)具有较好的选择性和灵敏度,探针溶液的荧光强度与Zn~(2+)有良好的线性关系,线性方程为I=196.46+1654.12c,相关系数R~2=0.9864,检出限为38.5 nmol/L。该方法可以定量检测水中Zn~(2+)。     

一种吡啶-水杨醛类席夫碱的合成及对Zn2+的特异性识别

通过席夫碱反应将2-氨基4-甲基吡啶与4-(二乙氨基)水杨醛结合,设计并合成出一种新型的荧光探针L,该探针能特异性识别Zn²⁺。通过质谱、¹H NMR以及¹³C NMR表征其结构,并利用荧光光谱、紫外-可见吸收光谱研究了探针L在CH₃OH-H₂O(V:V=8:2,Tris-HCl缓冲液,pH=7.4)中对各种离子的选择识别能力。实验结果显示,向探针L中加入Zn2+之后,溶液从无荧光变成蓝色荧光,且457 nm处出现一发射峰。Job’s plot工作曲线结果和密度泛函理论(DFT)计算表明探针L与Zn2+结合计量比为1:1。荧光滴定结果表明探针L对Zn2+的检测极限可低至2.7×10^-8 mol·L^-1,结合常数为1.32×10⁴ L·mol^-1,pH应用范围4.0～10.0。对真实水样中的Zn2+进行检测,平均回收率大于98%,RSD小于1.61%,表明探针L能够检测真实水样中的Zn2+。     

Facile synthesis of an optical sensor for CO32− and HCO3− detection

A novel fluorogenic signalling probe (E)-3-(4-methoxyphenyl)-4-[(4-nitrobenzylidene)amino]-1H-1,2,4-triazole-5(4H)-thione (6) for the carbonate and bicarbonate ions has been developed through microwave assisted Schiff base formation reaction. The anion recognition occurs through hydrogen bonding assessed by ¹H NMR titration experiments. The photophysical results of probe 6 corroborates its applicability as an optical sensing platform for carbonate as well as bicarbonate ions in mixed aqueous organic media depending on pH of reaction solution. The fluorescence emission signal enhancement at 424 nm and considerable shift in the signal position as well as molar absorptivity to the probe absorption bands upon CO₃^2? and HCO₃^? addition suggest the affinity of probe 6 towards these ions in comparison to a variety of competitive ions in aqueous/ethanol (7:3, v/v) at neutral pH and ambient temperature. From the fluorescence titration experiment, the limit of detection was calculated to be 1.91 μM.     

A Highly Selective Two‐Photon Fluorescent Probe for Detection of Cadmium(II) Based on Intramolecular Electron Transfer and its Imaging in Living Cells

A new quinoline‐based probe was designed that shows one‐photon ratiometric and two‐photon off–on changes upon detecting Cd²⁺. It exhibits fluorescence emission at 407 nm originating from quinoline groups in Tris‐HCl (25 mM , pH 7.40), H₂O/EtOH (8:2, v/v). Coordination with Cd²⁺ causes quenching of the emission at 407 nm and simultaneously yields a remarkable redshift of the emission maximum to 500 nm with an isoemissive point at 439 nm owing to an intramolecular charge‐transfer mechanism. Thus, dual‐emission ratiometric measurement with a large redshift (Δλ=93 nm) and significant changes in the ratio (F₅₀₀/F₄₃₉) of the emission intensity (R/R₀ up to 27) is established. Moreover, the sensor H₂L displays excellent selectivity response, high sensitive fluorescence enhancement, and strong binding ability to Cd²⁺. Coordination properties of H₂L towards Cd²⁺ were fully investigated by absorption/fluorescence spectroscopy, which indicated the formation of a 2:1 H₂L/Cd²⁺ complex. All complexes were characterized by X‐ray crystallography, and TD‐DFT calculations were performed to understand the origin of optical selectivity shown by H₂L. Two‐photon fluorescence microscopy experiments have demonstrated that H₂L could be used in live cells for the detection of Cd²⁺.     

Reactivity of 6-(2-tolyl)- and 6-(2,6-xylyl)-2,2′-bipyridines with palladium(II) derivatives. Selective C(sp)H vs. C(sp)H activation

Two new 6-substituted 2,2′-bipyridines, L, 6-(2-tolyl)bipy, L¹, and 6-(2,6-xylyl)bipy, L², have been synthesized. Their reactions with Na₂[PdCl₄] or {Pd(OAc)₂} afford either 1:1 adducts [Pd(L)X₂] (X=Cl, OAc) or five-membered cyclometallated derivatives [Pd(L¹-H)X] arising from C(sp²)H activation. From the chloro-alkyl intermediates [Pd(L)(Me)Cl], in the presence of Na[BAr′₄] (Ar′=3,5-(CF₃)₂C₆H₃), cationic species [Pd(L)(Me)(S)]⁺ (L=L¹, L²; S=CH₃CN) can be obtained. At variance, in less coordinating solvents, e.g. dichloromethane, unexpected activation of a C(sp³)H bond occurs with loss of methane, to afford 6-membered cyclometallated derivatives. The latter species were isolated as [Pd(L-H)(PPh₃)][BAr′₄].     

An Aggregation-Induced Emission-Based Fluorescence Turn-On Probe for Efficient Detection of HS− in Water,Wine, and Living Cells

Hydrogen sulfide (H₂S), as one of the important endogenous biological regulators, plays a critical role in mediating a wide range of physiological processes. The development of rapid, sensitive, and reliable detection techniques for H₂S would be highly appealing. In this paper, a new type of AIE-based fluorescence turn-on probe TPA-M for the detection of H₂S has been constructed, involved the rapid release of AIE-based fluorophore TPA-CHO with a remarkable fluorescence turn-on phenomenon in THF/H₂O (2/8, v/v, HEPES=20 μM, pH=7.3) medium, exhibiting the attractive advantages such as high sensitivity with the detection limit as low as 1.92×10⁻³ ppm, excellent selectivity over other anion analytes and biothiols, significant anti-interference ability and fast response time (within 10 min). What's more, the practical application evaluation indicated that the probe TPA-M could be efficiently employed in imaging exogenously added H₂S in living MCF-7 cells and detecting H₂S in actual water and wine samples.     

Determination Co2+ in vitamin B12 based on enhancement of 2-(4-substituted-phenyl)-4,5-di(2-furyl) imidazole and H2O2 chemiluminescence reaction

In this paper, three kinds of imidazole derivatives, 2-(4-methylphenyl)-4,5-di(2-furyl) imidazole (MDFI), 2-(4-nitrophenyl)-4,5-di(2-furyl) imidazole (NDFI), and 2-(4-tert-butylphenyl)-4,5-di(2-furyl) imidazole (t-BDFI) were synthesized. In an alkaline medium, the chemiluminescence (CL) reaction of imidazole derivatives with H₂O₂ has been investigated. It was also found that MDFI/H₂O₂ and t-BDFI/H₂O₂ systems gave strong CL. When Co²⁺ was added into the two CL systems, the CL intensity was remarkably enhanced. In the optimum conditions, the CL intensity is linearly related to the logarithm of concentration of Co²⁺. The linear ranges are 5 × 10⁻⁹–2.5 × 10⁻⁷ mol/L for MDFI/H₂O₂ system and 5 × 10⁻⁹–2.5 × 10⁻⁷ mol/L for t-BDFI/H₂O₂ system, and the corresponding detection limits are 1.2 × 10⁻⁹ mol/L and 1.1 × 10⁻⁹ mol/L, respectively. The method was applied to the determination of Co²⁺ in vitamin B₁₂ injection. Furthermore, the CL mechanism was also discussed.     

Complexes of organolead and organotin ions with 1-(2-pyridylazo)-2-naphthol

The stability constants of the complexes of 1-(2-pyridylazo)-2-naphthol with several organotin and lead ions were determined spectrophotometrically in aqueous 20% (v/v) dioxane and were shown to have very high values. The extraction of the complex of (C₂H₅)₂Pb²⁺ from water into chloroform was studied, and the formation of an extractable (C₂H₅)₂Pb(PAN)(OH) complex is postulated.     

Development of [(2E,6E)-2,6-bis(4-(dimethylamino)benzylidene)cyclohexanone] as fluorescence-on probe for Hg2+ ion detection: Computational aided experimental studies

Selective metal ion detection is highly desired in fluorometric analysis. In the current study a curcumin-based fluorescence-on probe/[(2E,6E)-2,6-bis(4-(dimethylamino) benzylidene) cyclohexanone]/probe was designed for the removal of one of the most toxic heavy metal ion i.e. Hg²⁺. The structure of the probe was confirmed by FTIR and ¹H NMR spectroscopic analysis displaying distinctive peaks. The complex formation between probe and Hg²⁺ ion was also studied by density functional theory to support the experimental results. Chelation enhanced fluorescence was observed upon interaction with Hg²⁺ ion. Different parameters like pH, effect of mercury ion concentration, contact time, interference study and effect of probe concentration on the fluorescence enhancement were also investigated. A rapid response was detected for Hg²⁺ ion with limit of detection and quantification as 2.7 nM and 3 nM respectively with association constant of 1 × 10¹¹ M^?2. The probe displayed maximum fluorescence intensity at physiological pH. The results showed that the synthesized probe can be employed as an excellent probe for the detection and quantification of Hg²⁺ ions in aqueous samples with high selectivity and sensitivity due to its higher binding energy and larger charge transferring ability.     

Influence of the anion on stabilization and Coordination of Cu(II) and Cu(I) Complexes with Bis-[2-(4,6-Dimethylpyrimidyl)] Disulphide

Complexes of the type Cu(L? S? S? L)X₂ (X = Cl, Br) and Cu(L? S? S? L)₂X (X = ClO₄, BF₄) were prepared in CHCl₃? MeOH solution from CuX₂ · 6 H₂O (X = Cl, Br, ClO₄, BF₄) and bis-[2-(4, 6-dimethylpyrimidyl)]disulphide (L? S? S? L), and examined in the mid-(4000–250 cm^?1) and far-i.r. (5000–60 cm^?1) regions. Assignments for metal-ligand and metalhalogen vibrations were made. On the basis of these assignments, conductivity measurements and from magnetic moments and visible absorption data, the stereochemistry of the compounds was tentatively inferred. For Cu(L? S? S? L)X₂ (X = Cl, Br) species may be proposed an essentially [CuN₂X₂] in-plane microsymmetry achieved through two pyrimidyl nitrogen atoms of a ligand molecule, to form a seven-membered chelate ring and two halide ions, with probable interaction along the z axis with adjacent molecules. The Cu(L? S? S? L)₂X (X = ClO₄, BF₄) species, may be considered to contain isolated complexes cations, Cu(L? S? S? L) , or polynuclear cationic polymers, Cu_n(L? S? S? L), in which Cu(I) is, probably via N₃S, tetrahedraly coordinated.