A reaction-based sensing scheme for gold species: introduction of a (2-ethynyl)benzoate reactive moiety.

To alleviate side reactions identified in an N-propargyl-rhodamine lactam sensing system, we devised the novel reaction-based sensing scheme for gold species based on the alkynophilicity. A fluorescein (2-ethynyl)benzoate underwent Au(III)-promoted ester hydrolysis selectively over other metal ions with high sensitivity, which accompanies a turn-on fluorescence change in pH 7.4 HEPES buffer. The work offers a versatile reactive moiety for the development of gold probes with improved sensing properties.

Reaction-based fluorescent sensing of Au(I)/Au(III) species: mechanistic implications on vinylgold intermediates.

A rhodamine-derived alkyne shows turn-on fluorescence change only toward Au(I)/Au(III) species among various other metal species examined. A formyloxazole compound is formed as the major product in aqueous media, presumably via a vinylgold intermediate, which casts new mechanistic implications on vinylgold intermediates.

Synthetic, cyclic voltammetric, structural, EPR, and UV-Vis spectroscopic studies of thienyl-containing meso-A(2)B-cor(Cr(V)=O) systems: consideration of three interrelated molecular detection modalities.

We report eight new A(2)B-type (M(n+)) corrolate compounds (two structural studies) that include the oxo[5,15-bis(pentafluorophenyl)-10-R-corrolatochromium(V)] [R = 2-/3-thienyl (1a/2a), 3-thianaphthyl (3a)] species. The first examples of meso-A(2) (thienyl)- and Cr-A(2)B-corrole types are represented herein. Characterization includes cyclic voltammetry, electron paramagnetic resonance, 2D ((1)H and (13)C) NMR, and UV-vis spectroscopy, mass spectrometry, and elemental analysis. Compounds 1a-3a have enabled analyte binding capacity studies. [Cu(2+)...O=Cr(cor)] binding represents a new selective mode of corrole-based detection, whereas free-base A(2)B-corroles exhibited limited M(n+) selectivity. The 10-position substitution affects optical profiles in analyte titrations. A limited amount of PPh(3) O-atom uptake from [O=Cr(cor)] was also demonstrated.

A chiral meso-ABC-corrolatochromium(V) complex.

A chiral metallocorrole complex, oxo[5-(4-bromophenyl)-10-(pentafluorophenyl)-15-(2-thianaphthyl)corrolato]chromium(V) (7), was prepared and serves as the first example of an ABC-metallocorrole; meso substituents are of different electron-withdrawing capacity. An adaptation of a multistep protocol (D. T. Gryko) was made, followed by an aerobic oxidation using Cr(CO)(6) (Z. Gross). The X-ray crystal structure reveals the two enantiomers of 7. Electron paramagnetic resonance spectroscopy (g(iso) = 1.99) and cyclic voltammetry of 7 provide comparative data to that of the A(3)[tris(pfp)cCr(V)O] complex.