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Abstract Meso‐nitrile oxide group in 1,7‐Diphenyl‐containing BODIPYs can be involved in highly unusual [3+2] intramolecular cycloaddition reaction with the formation of the dihydrobenzo[d]isoxazole‐containing BODIPYs. Oxidation of these compounds results in the formation of unprecedented either benzisoxazole‐ or benzo[b]azepine‐fused fully conjugated NIR absorbing BODIPYs. The photophysical properties and electronic structures of the target compounds were studied by an array of experimental and theoretical methods. 

Abstract The transient absorption spectra of the series of diamagnetic H₂TFcP, ZnTFcP, PdTFcP, and FcInTFcP compounds (TFcP(2‐)=5,10,15,20‐tetraferroceneporphyrin dianion) were investigated in polar (DMF) and non‐polar (toluene) solvents using excitation at 650 nm. The formation and the deactivation of the charge‐separated (Fc⁺‐Porphyrin^−.) state were observed in all cases. The lifetime of the charge‐separated state is nearly constant for all compounds (∼20 ps) and independent of the nature of the central ion and solvent. The formation of the triplet state in all the complexes was not observed. The third, minor long‐lived (160–480 ps) component was observed in polar DMF solvent. This component was tentatively assigned to the porphyrin species that are weakly bound to the carbonyl oxygen in DMF. DFT and TDDFT calculations on the ground state, excited state, and triplet state of the target compounds were in agreement with the experimental data. 

Abstract A sterically strained 32π‐electron antiaromatic bis‐BODIPY macrocycle in which two BODIPY fragments are linked byp‐divinylbenzene groups was prepared and characterized. Unlike regular BODIPYs, the fluorescence in this macrocycle is quenched. The broad signals in the NMR spectra of the macrocycle were explained by the vibronic freedom of thep‐divinylbenzene fragments. The possible diradicaloid nature of the macrocycle was excluded on the basis of variable‐temperature EPR spectra in solution and in solid state, which is indicative of its closed‐shell quinoidal structure. Themeso‐C−H bond in the macrocycle and its precursor BODIPY dialdehyde3forms a weak hydrogen bond with THF and is susceptible for the nucleophilic attack by organic amines and cyanide anion. The reaction products of such a nucleophilic attack havemeso‐sp³carbon atoms and were characterized by NMR, mass spectrometry and, in one case, X‐ray crystallography. Unlike the initial bis‐BODIPY macrocycle, the adducts have strong fluorescence in the 400 nm region. The electronic structure and spectroscopic properties of new chromophores were probed by density functional theory (DFT) and time‐dependent DFT (TDDFT) calculations and correlate well with the experimental data. 

Abstract The preparation of radicals with intense and redox‐switchable absorption beyond 1000 nm is a long‐standing challenge in the chemistry of functional dyes. Here we report the preparation of a series of unprecedented stable neutral nickel(II) and copper(II) complexes of “Manitoba dipyrromethenes” (MB‐DIPYs) in which the organic chromophore is present in the radical‐anion state. The new stable radicals have an intense absorption atλ_max∼1300 nm and can be either oxidized to regular [M^II(MB‐DIPY)]⁺(M=Cu or Ni) or reduced to [M^II(MB‐DIPY)]⁻compounds. The radical nature of the stable [M^II(MB‐DIPY)] complexes was confirmed by EPR spectroscopy with additional insight into their electronic structure obtained by UV‐Vis spectroscopy, electro‐ and spectroelectrochemistry, magnetic measurements, and X‐ray crystallography. The electronic structures and spectroscopic properties of the radical‐based chromophores were also probed by density functional theory (DFT) and time‐dependent DFT (TDDFT) calculations. These nickel(II) and copper(II) complexes represent the first stable radical compounds with a MB‐DIPY ligand.