2,4,6-Triphenylphosphinine and 2,4,6-triphenylposphabarrelene revisited: synthesis, reactivity and coordination chemistry

Abstract

The synthesis of 2,4,6-triphenylphosphinine has been revisited and a general protocol for the preparation of such low-coordinate phosphorus compounds in good to excellent yields could be established. This allows to investigate several aspects of the chemistry of 2,4,6-triarylphosphinine, such as the reaction with in situ generated benzyne to give 2,4,6-triphenylphosphabarrelene. The corresponding 2,4,6-triphenylphosphabarrelene-selenide could be characterized crystallographically for the first time and the structural and electronic properties of this cage-compound in comparison to classical triarylphosphines could be evaluated. Moreover, [(L)W(CO)5)] complexes of both 2,4,6-triphenylphosphinine and 2,4,6-triphenylphosphabarrelene were prepared and characterized by means of X-ray crystallography. This allowed for the first time a direct structural comparison of these related phosphorus compounds, coordinated to the same metal fragment.

Expanding the phosphorus–carbon analogy: formation of an unprecedented 5-phosphasemibullvalene derivative

“…Alternatively, we found that 12 can also be obtained quantitatively from the corresponding phosphabarrelene-selenide 13, as this compound was converted to 12 within 1.5 h upon irradiation with UV light. 17 The transformations described above are summarized in Scheme 2.…”

“…The relevant IR-spectroscopic data (ñ A 1 ) of this series of Ni(0) complexes are summarized in Table 1, with Ph 3 PNi(CO) 3 (17) as the reference compound. As expected, the aromatic 2,4,6-triphenylphosphinine 7 is the best p-acceptor with the lowest net-donor capability, while phosphabarrelene 6 is a somewhat better s-donor.…”

“…It is thus interesting to note that the here described results apparently demonstrate also a striking analogy between formally sp 3 -hybridized phosphorus and carbon centers. 16) and triphenylphosphine (17).…”

“…Fig. 5 Ni(CO) 3 complexes of 5-phosphasemibullvalene (14), phosphabarrelene (15), 2,4,6-triphenylphosphinine (16) and triphenylphosphine(17).…”

Buchwald–Hartwig Amination of Phosphinines and the Effect of Amine Substituents on Optoelectronic Properties of the Resulting Coupling Products

“…For instance, Mathey and co-workers have demonstrated the synthesis of 2-(2-pyridyl)­phosphinines and their coordination chemistry toward Group 9 and 10 metals . Muller’s group has synthesized λ 3 -phosphinines that bears a 2-pyridyl group via the corresponding pyrylium salt, and their unique emission behavior has also been disclosed . In addition, the transformation into λ 5 -phosphinines and their photophysical properties have been reported .…”