Vanadium(IV) porphyrins: synthesis and spectrochemical characterization of dihalogenovanadium(IV) porphyrins. Extended X-ray absorption fine structural study of dibromo(2,3,7,8,12,13,17,18-octaethylporphyrinato) vanadium(IV)

Abstract

The action of SOX2 or (COX)2 on oxovanadium(1V) porphyrin complexes [V'vL(0)] (L = porphyrinate) under mild conditions affords the corresponding dihalogenovanadium(1V) porphyrins [VIVLX2] (X = CI or Br). These very reactive complexes are remarkable precursors to low-valent vanadium porphyrins. Extended X-ray absorption fine structure spectroscopy at the Br K edge confirms the trans configuration and lNDO/S calculations suggest that the absence of an e.s.r. signal is due to an orbitally degenerate ground state.

Vanadium- and Chromium-Catalyzed Dehydrogenative Synthesis of Imines from Alcohols and Amines

“…The studies began with the preparation of four vanadium­(IV) porphyrin dichloride complexes A – D (Figure ) from the corresponding oxovanadium­(IV) compounds by treatment with SOCl 2 . The four porphyrin ligands were selected since reactions with these ligands were the highest yielding in the corresponding manganese-catalyzed protocol .…”

“…The studies began with the preparation of four vanadium(IV) porphyrin dichloride complexes A−D (Figure 1) from the corresponding oxovanadium(IV) compounds by treatment with SOCl 2 . 15 The four porphyrin ligands were selected since reactions with these ligands were the highest yielding in the corresponding manganese-catalyzed protocol. 12 Benzyl alcohol and cyclohexylamine were selected as the substrates for the initial experiments, and in the first experiment, the trans- formation was performed with 5% of tetraphenylporphyrin (TPP) complex A in refluxing mesitylene to afford Nbenzylidene cyclohexylamine (1) in 51% gas chromatography (GC) yield with some alcohol and amine remaining (Table 1, entry 1).…”

A Novel Route to Organic–Inorganic Hybrid Nanomaterials

“…All analyses were performed on a Shimadzu GC‐16A instrument with a flame ionization detector using silicon DC‐200 or Carbowax 20M columns. Tetraphenylporphyrin, [VO(TPP)] and [V(TPP)Cl 2 ] were prepared according to the literature 44–46…”

Insensitivity of Vanadyl−Oxygen Bond Strengths to Radical Type (2A1u vs 2A2u) in Vanadyl Porphyrin Cation Radicals

“…The organic layer was separated, washed with 0.1 M HCl and then with 0.1 M NaOH followed by washing with distilled water, and dried over sodium sulfate. The chloroform solvent was evaporated on a rotary evaporator, following which the crude OV(TMP) was dissolved in methylene chloride, purified on silica gel column, and recrystalized from methylene chloride/ methanol; yield: 206 mg. 18 OV(TMP) was prepared under a nitrogen atmosphere by a modification of a previously published procedure; 13 i.e., OV(TMP) (90 mg) was dissolved in dry toluene (8 mL), and thionyl chloride (1 mL) was added to the solution which gradually turned from red to brown. The reaction mixture was stirred for 12 h at room temperature and then placed in a freezer (-28 °C) for 12 h. The resulting precipitate [i.e., VCl2(TMP)] was filtered off, washed with hexane, and dried in a vacuum desiccator.…”