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The structural and physicochemical properties of the manganese-corrolazine (Cz) complexes (TBP8Cz)MnV≡O (1) and (TBP8Cz)MnIII (2) (TBP = p-tert-butylphenyl) have been determined. Recrystallization of 2 from toluene/MeOH resulted in the crystal structure of (TBP8Cz)MnIII(CH3OH) (2·MeOH). The packing diagram of 2·Me·H reveals hydrogen bonds between MeOH axial ligands and meso N atoms of adjacent molecules. Solution binding studies of 2 with different axial ligands (Cl-, Et3PO, and Ph3PO) reveal strong binding, corroborating the preference of the MnIII ion for a five-coordinate environment. High-frequency and field electron paramagnetic resonance (HFEPR) spectroscopy of solid 2·MeOH shows that 2·MeOH is best described as a high-spin (S = 2) MnIII complex with zero-field splitting parameters typical of corroles. Structural information on 1 was obtained through an X-ray absorption near-edge structure (XANES)/extended X-ray absorption fine structure (EXAFS) study and compared to XANES/ EXAFS data for 2·MeOH. The XANES data for 1 shows an intense pre-edge transition characteristic of a high-valent metal-oxo species, and a best fit of the EXAFS data gives a short Mn-O bond distance of 1.56 Å, confirming the structure of the metal-oxo unit in 1. Detailed spectroelectrochemical studies of 1 and 2 were performed revealing multiple reversible redox processes for both complexes, including a relatively Iow potential for the MnV → MnIV process in 1 (near 0.0 V vs saturated calomel reference electrode). Chemical reduction of 1 results in the formation of a MnIIIMnIV(μ-O) dimer as characterized by electron paramagnetic resonance spectroscopy. [ABSTRACT FROM AUTHOR]

For in vivo NMR studies, starting from pyrroles, a series of fluorinated porphyrins were synthesized by following the MacDonald reaction conditions. Upon reaction with osmium tetroxide, a fluorinated porphyrin containing four trifluoromethyl groups (12 fluorine units) was converted into the related chlorin and bacteriochlorin which exhibited long-wavelength absorptions at 652 and 720 nm, respectively. All compounds produced good singlet oxygen production efficiency. A comparative study of nine porphyrins with and without fluorine substituents indicated no adverse effects of the presence of fluorinated groups in the photophysical properties of the porphyrins, chlorins or bacteriochlorins. The first and second one-electron reduction potentials (vs SCE) of the investigated compounds range between −1.29 and −1.49 V and between −1.66 and −1.84 V in PhCN containing 0.1 M TBAP. UV–visible spectroelectrochemical data suggested the formation of π-anion and π-cation radicals upon the first reduction and first oxidation. The in vivo 19F MR study of a representative fluorine labeled compound with twelve equivalent fluorines confirmed the presence of the fluorine labeled sensitizer in mouse (C3H/HeJ) implanted with RIF tumors on mouse foot dorsum by inoculating 2×105 cells (the studies were repeated on four tumored mice to confirm the feasibility and reproducibility). All fluorinated compounds were found to be quite effective in vitro. In a comparative intracellular localization study with Rhodamine-123 in RIF tumor cells, the most soluble porphyrin containing two propionic ester side chains was found to localize in mitochondria as well as the related chlorin and bacteriochlorin. [Copyright &y& Elsevier]

Following a previous report on the synthesis and physicochemical characterization of a novel class of porphyrazines carrying peripherally annulated seven-membered rings, i.e., tetrakis-2,3-(5,7-diphenyl1,4-diazepino)porphyrazine [Ph[SUBa]DzPzH[SUB2]]·4H[SUB2]0 and its metal derivatives [Ph[SUB8]DzPzM]·.xH[SUB2]O (x = 2-7, M = Mg[SUPII]H[SUB2]O), Cu[SUPII], and Zn[SUPII]), a new more convenient procedure is reported here, allowing the preparation in high yields of the Li[SUPI] and Na[SUPI] derivatives of formulas [Ph[SUB8]DzPzLi[SUB2]]·5H[SUB2]0 and [Ph[SUB8]DzP[SUBz]Na2]-60, which can be directly converted into other metal derivatives under mild conditions (room temperature) and in good yields. The series studied has been extended to include the Mn[SUPII] and Co[SUPII] complexes also reported here for the first time. Physicochemical characterization of the new "diazepinoporphyrazines" was based on fast atom bombardment (FAB) mass spectrometry and X-ray powder patterns, infrared (IR), electron paramagnetic resonance (EPR), and room-temperature magnetic susceptibility measurements. A detailed discussion of the UV-vis spectra emphasizes the role played by the external diazepine rings in electron delocalization through their tautomeric or protonated forms present in neutral, basic, and acidic media. The nonlinear optical effect of optical limiting for the different species [M = 2H, Mg[SUPII](H[SUB2]O), Mn[SUPII], Co[SUPII], Cu[SUPII], and Zn[SUPII]] has also been measured. It has been observed that the extent of the optical limiting depends on the specific M center. The observed nonlinear optical features are analyzed and discussed in terms of the electronic and magnetic properties exhibited by some of the metal ions and taking into account the model of the excited-state absorption in which the nature of M determines the kinetics of formation of the highly absorbing state of the specific complex examined. As evidenced by the detailed electrochemical and spectroelectrochemical study carried out on this new class of macrocycles, one of the most important aspects is the facilitated electron delocalization for the oxidized and reduced species allowed by a 1H-6H tautomerism taking place on the peripheral diazepine rings. [ABSTRACT FROM AUTHOR]