A novel approach to study the structure-property relationships and applications in living systems of modular Cu(2+) fluorescent probes

Two water-soluble fluorescence probes based on 5(6)-carboxyl rhodamine for Cu2+ imaging in living cells

Two novel water-soluble fluorescence probes T1 and T2 based on 5(6)-carboxyl rhodamine were designed and synthesized using a regioselective reaction. The probes exhibited highly selective and sensitive recognition toward Cu²⁺ over other metal ions in acetonitrile/Tris-HCl buffer solution (2:98, v/v; pH 7.4). Detection limits were 0.4 μM for T1 and 4.50 μM for T2 based on fluorescence titration analysis. Furthermore, probe T1 was successfully applied in cell imaging experiments to monitor Cu²⁺ in cells.

A “turn-on” fluorescent and colorimetric chemodosimeter for selective detection of Au3+ ions in solution and in live cells via Au3+-induced hydrolysis of a rhodamine-derived Schiff base

A chromogenic and “off–on” fluorogenic chemodosimeter (L) based on a naphthalene–rhodamine B derivative was designed, synthesized and characterized for the selective and sensitive detection of Au³⁺ ions in mixed acetonitrile aqueous media.

Ultrasensitive Optical Chemosensor for Cu(II) Detection

Herein, the main objective of this research is to design and synthesize a novel optical chemosensor, 2,6-Bis(4-dimethylaminophenyl)-4-(dicyanomethylene)-cyclohexane-1,1-dicarbo-nitrile (BDC), for detection of one of the most significant metal ions Cu(II). This novel fluorescent chemosensor exhibits unique optical properties with large Stokes shift (about 170 nm) approximately. The fluorescence and UV–vis absorption performance among the BDC probe and Cu(II) ions were examined in 1:9 (v/v) methanol–HEPES buffer (pH = 7.2) solution. Also, BDC displays high selectivity for Cu(II) concerning other cations. Moreover, this probe provides high selectivity and sensitivity based on their fluorescence properties and recognition abilities within a detection limit of the Cu(II) contents (LOD 2.3 x 10⁻⁷ M). The suggested mechanism of BDC sensor is attributed to the chelation process with Cu(II), to establish a 1:1 metal-ligand ratio complex with a binding constant (K_bind = 7.16 x 10⁴ M⁻¹). The detection process is accompanied by quenching the main emission peak of the BDC at 571 nm. All the experimental data were collected to investigate the effects of several important parameters such as reversibility and the concentration limits. Besides, we study the interference of various metal ions on selectivity and detection capacity of this significant Cu (II) ion. This novel chemosensor shows ultrasensitive, fast tracing of Cu(II) in the physiological pH range (pH 7.2) and therefore may propose a novel promising method for the investigation of the biological functions of Cu(II) in living cells.

Heterometallic ZnII⁻LnIII⁻ZnII Schiff Base Complexes with Linear or Bent Conformation-Synthesis, Crystal Structures, Luminescent and Magnetic Characterization

A series of racemic, heteronuclear complexes [Zn₂Nd(ac)₂(HL)₂]NO₃·3H₂O (1), [Zn₂Sm(ac)₂(HL)₂]NO₃·3CH₃OH·0.3H₂O (2), [Zn₂Ln(ac)₂(HL)₂]NO₃·5.33H₂O (3–5) (where HL is the dideprotonated form of N,N′-bis(5-bromo-3-methoxysalicylidene)-1,3-diamino-2-propanol, ac = acetate ion, and Ln = Eu (3), Tb (4), Dy (5), respectively) with an achiral multisite coordination Schiff base ligand (H₃L) were synthesized and characterized. The X-ray crystallography revealed that the chirality in complexes is centered at lanthanide(III) ions due to two vicinally located μ-acetato-bridging ligands. The presented crystals have isoskeletal coordination units but they crystallize in monoclinic (1, 2) or trigonal crystal systems (3–5) with slightly different conformation. In 1 and 2 the Zn^II–Ln^III–Zn^II coordination core is linear, whereas in isostructural crystals 3–5 the chiral coordination cores are bent and lie on a two-fold axis. The complexes 1, 3–5 show a blue emission attributed to the emission of the ligand. For Zn^II₂Sm^III complex (2) the characteristic emission bands of f-f* transitions were observed. The magnetic properties for compounds 1, 4 and 5 are characteristic for the paramagnetism of the corresponding lanthanide(III) ions.

Synthesis of near-infrared fluorescent rhodamines via an SNArH reaction and their biological applications

Seven rectilinearly π-extended NIR fluorescent rhodamines were synthesized via an intramolecular S_NAr^H reaction under mild conditions without any transition metal catalyst or extra oxidant.

A highly selective and sensitive rhodamine-derived fluorescent probe for detection of Cu2

A novel water-soluble and reversible fluorescent probe was designed and synthesized based on a rhodamine B derivative. It was used for detection of Cu²⁺ in drinking water and in living cells with high sensitivity and excellent selectivity. The tested concentration range and the limit of detection (LOD) of the probe were 0-15.00μmolL^-1 and 0.085μmolL^-1, respectively. In addition, the mode of binding and mechanism of interaction between the probe and Cu²⁺ were analyzed by density functional theory (DFT) calculations.

A β-diketonate–europium(iii) complex-based fluorescent probe for highly sensitive time-gated luminescence detection of copper and sulfide ions in living cells

A strongly fluorescent β-diketonate–europium(iii) complex was developed for highly sensitive imaging of intracellular copper and sulfide ions with time-gated luminescence mode.

Imidazole/benzimidazole-modified cyclotriphosphazenes as highly selective fluorescent probes for Cu2+: synthesis, configurational isomers, and crystal structures

We present a comprehensive work and discuss the fluoroprobe properties of synthesized compounds for copper ion detection with a stereochemical approach using X-ray crystallographic analysis results.