Stereochemistry and Solid-State Structure of an Intrinsically Chiral <i>Meso</i>-Patterned Porphyrin: Case Study by NMR and Single-Crystal X‑ray Diffraction Analysis

A <i>C</i>₁-symmerical <i>meso</i>-substituted ABCD-type porphyrin, [5-phenyl-10-(2-hydroxynaphthyl)-15-(4-hydroxyphenyl)­porphyrinato]­zinc­(II) (<b>1</b>), has been synthesized and characterized. The molecular structure of <b>1</b> has been determined by single-crystal X-ray diffraction analysis. The complex <b>1</b> crystallizes in a triclinic system with one pair of enantiomeric molecules per unit cell. Resolution of the racemic mixture has been achieved by chiral HPLC techniques. In particular, the absolute configurations of the enantiomers have been assigned from NMR spectroscopic analysis with l-Phe-OMe as the chiral solvating agent (CSA). The assignments have also been unambiguously confirmed by single-crystal X-ray diffraction analysis. The present results suggest that the CSA–NMR anisotropy strategy is applicable for the stereochemistry determination of chiral host–guest complexes with multiple intermolecular interactions. In addition, the multiple intermolecular interactions between the enantiomerically pure porphyrin <i>S</i>-<b>1</b> and l-Phe-OMe are proved in the solid state by single-crystal X-ray diffraction analysis

Stereochemistry and Solid-State Structure of an Intrinsically Chiral <i>Meso</i>-Patterned Porphyrin: Case Study by NMR and Single-Crystal X‑ray Diffraction Analysis

A <i>C</i>₁-symmerical <i>meso</i>-substituted ABCD-type porphyrin, [5-phenyl-10-(2-hydroxynaphthyl)-15-(4-hydroxyphenyl)­porphyrinato]­zinc­(II) (<b>1</b>), has been synthesized and characterized. The molecular structure of <b>1</b> has been determined by single-crystal X-ray diffraction analysis. The complex <b>1</b> crystallizes in a triclinic system with one pair of enantiomeric molecules per unit cell. Resolution of the racemic mixture has been achieved by chiral HPLC techniques. In particular, the absolute configurations of the enantiomers have been assigned from NMR spectroscopic analysis with l-Phe-OMe as the chiral solvating agent (CSA). The assignments have also been unambiguously confirmed by single-crystal X-ray diffraction analysis. The present results suggest that the CSA–NMR anisotropy strategy is applicable for the stereochemistry determination of chiral host–guest complexes with multiple intermolecular interactions. In addition, the multiple intermolecular interactions between the enantiomerically pure porphyrin <i>S</i>-<b>1</b> and l-Phe-OMe are proved in the solid state by single-crystal X-ray diffraction analysis

Stereochemistry and Solid-State Structure of an Intrinsically Chiral <i>Meso</i>-Patterned Porphyrin: Case Study by NMR and Single-Crystal X‑ray Diffraction Analysis

A <i>C</i>₁-symmerical <i>meso</i>-substituted ABCD-type porphyrin, [5-phenyl-10-(2-hydroxynaphthyl)-15-(4-hydroxyphenyl)­porphyrinato]­zinc­(II) (<b>1</b>), has been synthesized and characterized. The molecular structure of <b>1</b> has been determined by single-crystal X-ray diffraction analysis. The complex <b>1</b> crystallizes in a triclinic system with one pair of enantiomeric molecules per unit cell. Resolution of the racemic mixture has been achieved by chiral HPLC techniques. In particular, the absolute configurations of the enantiomers have been assigned from NMR spectroscopic analysis with l-Phe-OMe as the chiral solvating agent (CSA). The assignments have also been unambiguously confirmed by single-crystal X-ray diffraction analysis. The present results suggest that the CSA–NMR anisotropy strategy is applicable for the stereochemistry determination of chiral host–guest complexes with multiple intermolecular interactions. In addition, the multiple intermolecular interactions between the enantiomerically pure porphyrin <i>S</i>-<b>1</b> and l-Phe-OMe are proved in the solid state by single-crystal X-ray diffraction analysis

Synergistic Coupling of Fluorescent “Turn-Off” with Spectral Overlap Modulated FRET for Ratiometric Ag⁺ Sensor

A useful strategy for ratiometric fluorescent detecting of Ag⁺ is demonstrated. Upon selective binding of Ag⁺ to a BODIPY-porphyrin dyad (<b>1</b>), the synergistic coupling of two functions, namely the suppressing of FRET from BODIPY donor to porphyrin acceptor and the fluorescence quenching of porphyrin acceptor, leads to exceptionally large changes in the intensity ratio of two distinct emissions (<i>F</i>₅₁₃<i>/F</i>₆₅₄) which allow for the ratiometric detecting of Ag⁺ with excellent sensitivity in solution and living cells

Ratiometric Fluorescent Detection of Pb²⁺ by FRET-Based Phthalocyanine-Porphyrin Dyads

Sensitive and selective detection of Pb²⁺ is a very worthwhile endeavor in terms of both human health and environmental protection, as the heavy metal is fairly ubiquitous and highly toxic. In this study, we designed phthalocyanine–porphyrin (Pc-Por) heterodyads, namely, H₂Pc-α-ZnPor (<b>1</b>) and H₂Pc-β-ZnPor (<b>2</b>), by connecting a zinc­(II) porphyrin moiety to the nonperipheral (α) or peripheral (β) position of a metal-free phthalocyanine moiety. Upon excitation at the porphyrin Soret region (420 nm), both of the dyads exhibited not only a porphyrin emission (605 nm) but also a phthalocyanine emission (ca. 700 nm), indicating the occurrence of intramolecular fluorescence resonance energy transfer (FRET) processes from the porphyrin donor to the phthalocyanine acceptor. The dyads can selectively bind Pb²⁺ in the phthalocyanine core leading to a red shift of the phthalocyanine absorption and thus a decrease of spectral overlap between the porphyrin emission and phthalocyanine absorption, which in turn suppresses the intramolecular FRET. In addition, the binding of Pb²⁺ can highly quench the emission of phthalocyanine by heavy-metal ion effects. The synergistic coupled functions endow the dyads with remarkable ratiometric fluorescent responses at two distinct wavelengths (<i>F</i>₆₀₅/<i>F</i>₇₀₃ for <b>1</b> and <i>F</i>₆₀₅/<i>F</i>₇₀₀ for <b>2</b>). The emission intensity ratio increased as a linear function to the concentration of Pb²⁺ in the range of 0–4.0 μM, whereas the detection limits were determined to be 3.4 × 10^–9 and 2.2 × 10^–8 M for <b>1</b> and <b>2</b>, respectively. Furthermore, by comparative study of <b>1</b> and <b>2</b>, the effects of distance and relative orientation between Pc and ZnPor fluorophores on the FRET efficiency and sensing performance were highlighted, which is helpful for further optimizing such FRET systems