Alumazene adducts with triphenylphosphine oxide
| Authors | |
|---|---|
| Year of publication | 2006 |
| Type | Article in Periodical |
| Magazine / Source | Main Group Chemistry |
| MU Faculty or unit | |
| Citation | |
| Field | Inorganic chemistry |
| Keywords | Alumazene; Single-crystal X-ray diffraction; Iminoalane; Triphenylphosphine oxide; Lewis acid-base adducts |
| Description | 1,3,5-trimethyl-2,4,6-tris(2,6-diisopropylphenyl)alumazene [2,6-(i-Pr)2C6H3NAlMe]3, (1) is a benzene-like iminoalane with a planar hexagonal (Al-N)3 core. The aluminum centers are highly Lewis acidic due to the low delocalization of nitrogen lone pairs. We examined the alumazene ability to form acid-base adducts with triphenylphosphine oxide. Both monoadduct, 1(OPPh3), (2) and bisadduct 1(OPPh3)2, (3) were prepared, isolated, and spectroscopically characterized. Their molecular structures were determined by the single-crystal X-ray diffraction method. The monoadduct 2 displays a boat conformation of the central ring with very short Al[sbnd]N bonds (1.779, 1.769(2) A). The bisadduct 3 features the expected trans geometry in contrast to the previously reported bisadduct cis-1[OP(OMe)3]2. A different behavior of 2 and 3 in solution was observed by NMR spectroscopy. The monoadduct 2 is stable to dissociation while 3 shows signal broadening by chemical exchange because of the weakening of the second coordination Al[sbnd]O bond and/or internal rotation. |
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