Crystal structure of triphenylphosphine oxide

Isomeric Dithienophosphepines: The Impact of Ring Fusion on Electronic and Structural Properties

“…Owing to the nonplanar seven‐membered rings, all derivatives adopt butterfly shaped structures with an average dihedral angle of 145° between the thiophene moieties, whereby 1β has the most bent structure (134°) and 5β the most flattened one (156°). Regarding the environment of the phosphorus center, the sum of C‐P‐C bond angles (Σ C‐P‐C ) ranges from 303.9° ( 1β ) to 319.1° ( 5α ), which is similar to the pyramidalizations of PPh 3 (Σ C‐P‐C =308.4°) and PPh 3 O (Σ C‐P‐C =318.6°) . Whereas the P−C phenyl bond lengths of the DTP derivatives (P−C phenyl 1.80–1.84 Å) lie in the same range as the P−C bond lengths of PPh 3 O (1.80 Å) and PPh 3 (1.83 Å), the P−C ring bonds are found to be slightly shorter with an average length of 1.789 Å throughout the series.…”

“…Regarding the environment of the phosphorus center, the sum of C‐P‐C bond angles (Σ C‐P‐C ) ranges from 303.9° ( 1β ) to 319.1° ( 5α ), which is similar to the pyramidalizations of PPh 3 (Σ C‐P‐C =308.4°) and PPh 3 O (Σ C‐P‐C =318.6°) . Whereas the P−C phenyl bond lengths of the DTP derivatives (P−C phenyl 1.80–1.84 Å) lie in the same range as the P−C bond lengths of PPh 3 O (1.80 Å) and PPh 3 (1.83 Å), the P−C ring bonds are found to be slightly shorter with an average length of 1.789 Å throughout the series. In this connection, it is worth mentioning that the P−C ring bonds in the α‐isomers are on average slightly shorter by 0.016 Å than in the β‐derivatives (Table S1, Supporting Information).…”

Theoretical studies of 31P NMR spectral properties of phosphanes and related compounds in solution

“…46,5c At this level of theory two different minima are identified for phosphane oxide 2 (C 3 vs. C 1 symmetry; the latter structure is also found in solid-state X-ray studies). 47 Only a single minimum with C 3 symmetry can be found for phosphane 1. This is in agreement with results from solid state X-ray studies, gas phase electron diffraction measurements and earlier ab initio calculations.…”

Bis[(dialkylamino)cyclopropenimine]‐Stabilized PIII‐ and PV‐Centered Dications

“…The NP bond lengths (average 1.688(2) Å) are shorter than those in 12 (average 1.726(2) Å), indicating a stronger donation from the nitrogen atoms to the highly oxidized P V ‐center. Moreover, the P1O1 distance in 25 (1.468(1) Å) is slightly shorter than the one reported for triphenylphosphine oxide (1.479 Å); this could be explained by the stronger back‐donation from the oxygen to the phosphorus induced by the two positive charges 16. The employment of peracids to oxidize cationic phosphines was already known; however, this is the first time that this procedure has been used to oxidize dicationic ones 17.…”