Synthesis, chemical properties, and crystal structure of 2,4,6,8-tetra(tert-butyl)-9-hydroxyphenoxazin-1-one

Simakov, V. I.; Gorbanev, Yu. Yu.; Ivakhnenko, T. E.; Zaletov, V. G.; Starikova, Z. A.; Ivakhnenko, E. P.

doi:10.1007/s11172-009-0182-4

Cited by 13 publications

(9 citation statements)

References 10 publications

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“…Ivakhnenko, Minkin, and co-workers recently reported the preparation of an analogue of H(ONO Q ) 43 with a bridging oxygen in place of the 6 and 6′ hydrogens, 2,4,6,8-tetra-tertbutyl-9-hydroxyphenoxazin-1-one (H(DOPO Q ), Figure 1b). 21 We found the published synthesis of H(DOPO Q ) from 2,6dihydroxy-3,5-di-tert-butylaniline and 3,5-di-tert-butylcatechol, in refluxing benzene using catalytic toluenesulfonic acid, to be unreliable. In contrast, treatment of the same starting materials in benzene at room temperature in the air with 10 mol % triethylamine 44 reliably gives H(DOPO Q ) after precipitation from methanol, albeit in modest yields (eq 3).…”

Section: ■ Resultsmentioning

confidence: 99%

“…Pb(ONO Q ) 2 was prepared by a modification of the method of McGarvey and co-workers . 2,6-Dihydroxy-3,5-di- tert -butylaniline was prepared using the method of Minkin and co-workers . Mo 2 Br 4 (CO) 8 and W 2 Br 4 (CO) 8 were prepared using literature procedures.…”

Section: Methodsmentioning

confidence: 99%

“…16 2,6-Dihydroxy-3,5-di-tert-butylaniline was prepared using the method of Minkin and co-workers. 21 Mo 2 Br 4 (CO) 8 23 and W 2 Br 4 (CO) 8 24 were prepared using literature procedures. All other reagents were commercially available and used without further purification.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…This material was synthesized by a modification of the published procedure. 21 In a 250 mL Erlenmeyer flask, in the air, 761.7 mg of 3,5-di-tert-butylcatechol (Aldrich, 3.43 mmol) and 813.1 mg of 2,6-dihydroxy-3,5-di-tert-butylaniline (1 equiv) were dissolved in 25 mL of benzene. A catalytic amount of triethylamine (Aldrich, 107 μL, 10 mol %) was added, and the flask was sealed with Parafilm.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…We also prepared the three homoleptic group 6 complexes of a modified ONO ligand in which the two rings are joined by an oxygen bridge (Figure 1b). This dioxophenoxazine, or DOPO, ligand was recently prepared, 21 and its properties were examined in a number of first-row transition metal (DOPO) 2 M complexes. 22 The group 6 complexes of this ligand provide additional insights into the effects of ligand geometric and electronic properties on the electronic structures of complexes with redox-active ligands.…”

Section: ■ Introductionmentioning

confidence: 99%

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Metal and Ligand Effects on Bonding in Group 6 Complexes of Redox-Active Amidodiphenoxides

et al. 2014

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Group 6 complexes M(ONO)2 (M = Cr, Mo, W; ONO = bis(2-oxy-3,5-di-tert-butylphenyl)amide) are prepared by the reaction of divalent metal halide precursors with Pb(ONO(Q))2. Analogous complexes containing the 2,4,6,8-tetra-tert-butyl-1,9-dioxophenoxazinate ligand (DOPO) are prepared by protonolysis of chromocene with H(DOPO(Q)) or by reaction of Pb(DOPO(Q))2 with M2Br4(CO)8 (M = Mo, W). The molybdenum and tungsten complexes are symmetrical, octahedral compounds for which spectroscopic data are consistent with M(VI) complexes with fully reduced [L(Cat)](3-) ligands. Quantitative analysis of the intraligand bond lengths, by comparison with literature standards, allows calculation of metrical oxidation states (MOS) for the ONO ligands. The MOS values of the tungsten and molybdenum complexes indicate that π donation from the ligand is weak and that differences between the ONO and DOPO ligands are small. In both the solid state and in solution, Cr(DOPO)2 is paramagnetic with localized quinone and semiquinone ligands bound to Cr(III). The geometry and electronic structure of Cr(ONO)2 differ in the solid state and in solution, as determined by crystallography, magnetic measurements, and Cr K-edge X-ray absorption spectroscopy. In solution, the structure resembles that of the DOPO analogue. In contrast, solid Cr(ONO)2 is a singlet, and X-ray absorption near-edge spectroscopy indicates that the chromium is significantly more oxidized in the solid state than in solution. An electronic description compounds to that of the tungsten and molybdenum analogues, but with considerably more charge transfer from the ligand to chromium via π donation, is in agreement with the experimental observations.

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Section: ■ Resultsmentioning

confidence: 99%