Stable meso-Fluorenyl Smaragdyrin Monoradical.

The facile synthesis and physical characterization of a meso-fluorenyl smaragdyrin monoradical 4, which is stable due to efficient spin delocalization and kinetic blocking, is reported. It has a small energy gap and can be oxidized and reduced into the respective cation and anion, showing different charge distribution and electronic absorption properties.

Mixed Boron(III) and Phosphorous(V) Complexes of meso-Triaryl 25-Oxasmaragdyrins.

Two unprecedented mixed B(III) /P(V) complexes of meso-triaryl 25-oxasmaragdyrins were synthesized in appreciable yields under mild reaction conditions. These unusual 25-oxasmaragdyrin complexes containing one or two seven-membered heterocyclic rings comprised of five different atoms (B, C, N, O, and P) were prepared by reacting B(OH)(Ph)-smaragdyrin and B(OH)2 -smaragdyrin complexes, respectively, with POCl3 in toluene at reflux temperature. The products were characterized by HRMS and 1D- and 2D-NMR spectroscopy.

Ring Opening of a meso-Triaryl 25-Oxasmaragdyrin Macrocycle by m-Chloroperoxybenzoic Acid.

Smaragdyrin, a class of expanded porphyrin macrocycles, upon treatment with meta-chloroperoxybenzoic acid (mCPBA) underwent oxidative ring opening to form an unprecedented linear pentaheterocyclic compound. The linear pentaheterocyclic compound was freely soluble in common organic solvents and characterized in detail by HRMS, 1D and 2D NMR spectroscopy, and X-ray crystallography. Our preliminary studies indicated that the linear pentaheterocyclic compound can specifically sense anions such as H PO and CN ions, which was corroborated by absorption and fluorescence studies.

A Stable Seven-Membered Heterocycle, Containing B, C, N, O, and P Atoms, inside a Smaragdyrin Macrocycle.

Unprecedented examples of smaragdyrin macrocycles containing seven membered heterocyclic rings were synthesized under simple reaction conditions in high yields. The heterocycle formed inside smaragdyrin macrocycle is rare example of heterocycle containing five different atoms, such as B, C, N, O, and P atoms. The mixed B(III) and P(V) complexes of smaragdyrin macrocycles showed new structural, spectral, and electrochemical properties.

meso-Pyrrole-Substituted 22-Oxacorroles: Building Blocks for the Synthesis of BODIPY-Bridged 22-Oxacorrole Dyads.

Novel boron-dipyrromethene (BODIPY)-bridged 22-oxacorrole dyads, using meso-pyrrolyl 22-oxacorrole as a key synthon, have been synthesized. The reactivity of the meso-pyrrolyl group of 22-oxacorrole was exploited to synthesize the first examples of BODIPY-bridged 22-oxacorrole dyads in ≈40 % yield. The dyads are stable and exhibited interesting spectral and electrochemical properties.

Phosphorus complexes of meso-triaryl-25-oxasmaragdyrins.

The aromatic PO2 complexes of meso-triaryl-25-oxasmaragdyrins were synthesized by treating the free base 25-oxasmaragdyrins with POCl3 in toluene/triethylamine at refluxing temperature. The complexes are stable and characterized by X-ray and different spectroscopic techniques. In these complexes, the phosphorus(V) ion was bound to two pyrrolic nitrogen atoms of the smaragdyrin macrocycle and two oxygen atoms in tetrahedral geometry.

Synthesis of meso-pyrrole-substituted 22-oxacorroles by a "3+2" approach.

Unsymmetrical 22-oxacorrole containing two aryl groups and one pyrrole group at the meso position was synthesized by condensing one equivalent of 16-oxatripyrrane with one equivalent of meso aryl dipyromethane under mild acid-catalyzed conditions followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). This [3+2] condensation approach was expected to yield meso-free 25-oxasmaragdyrin but unexpectedly afforded unsymmetrical meso-pyrrole-substituted 22-oxacorrole. We demonstrated the versatility of the reaction by synthesizing four new meso-pyrrole-substituted 22-oxacorroles.

Synthesis, structure, spectral and electrochemical properties of B(OR)2-smaragdyrin complexes.

A series of B(OR)2-smaragdyrin complexes were synthesized by treating BF2-smaragdyrin complex with various aliphatic and aromatic alcohols in the presence of AlCl3 in CH2Cl2 at room temperature. The compounds are stable and characterized by various spectroscopic and electrochemical techniques. The X-ray structure solved for one of the B(OR)2-smaragdyrin complex showed that the macrocycle is planar and the boron atom is in tetrahedral geometry coordinated to two pyrrole nitrogens of the macrocycle and two oxygen atoms of the axial -OR groups.

Synthesis and functionalization of BF2-complexes of meso-free 25-oxasmaragdyrin.

BF2-complex of meso-free 25-oxasmaragdyrin is synthesized under simple reaction conditions in high yield, and the reactivity of meso-free carbon atom was demonstrated by carrying out functionalization followed by coupling reactions.