Double Bonds Between Phosphorus and Carbon

Chemistry of Diphosphinidenecyclobutenes

“…The two protecting Mes* groups are tilted by 78.2° and 91.9° from the plane. The total shape of this diphospha [4]radialene 25 is highly symmetric in contrast to the octaphenyl [4]radialene reported by Iyoda et al 23 The UV/Vis spectrum of 25 showed a red-shift compared to that of 23. The absorption peaks due to 2T-2r* transition appeared at 243-244 nm with almost equal intensities, while the absorption at 298 nm due to the conjugated double bonds associated with phosphorus atom(s) for 23 shifted to a longer wavelength at 327 nm by about 30 nm with a slightly increasing intensity for 25.…”

“…The absorption peaks due to 2T-2r* transition appeared at 243-244 nm with almost equal intensities, while the absorption at 298 nm due to the conjugated double bonds associated with phosphorus atom(s) for 23 shifted to a longer wavelength at 327 nm by about 30 nm with a slightly increasing intensity for 25. Moreover, a featureless band longer than 400 nm appeared in the spectrum of 25, indicating a very extended conjugated system,23 suggesting that this diphospha [4]radialene is a new interesting 2r-system in terms of electrochemistry and photochemistry as well as coordination chemistry. 4 It is of interest to note that the ligand (E,E)-20c (= 4) on the group-6 metal(0) tetracarbonyl complexes 30 undergoes oxidation reaction with molecular oxygen upon exposure to light to give [2,3- dibenzoy1-1,4-bis(2,4,6-tri-t-butylpheny1)-1,4-diphospha-1,3-butadiene]metal (0) complexes (31) On the other hand, we have developed several protecting groups other than the Mes* group32 and found that the 2,4-di-t-butyl-6-methylphenyl (abbreviated to Dbt) group is also useful for the stabilization of the diphosphinidenecyclobutene system.…”

“…Moreover, a featureless band longer than 400 nm appeared in the spectrum of 25, indicating a very extended conjugated system,23 suggesting that this diphospha [4]radialene is a new interesting 2r-system in terms of electrochemistry and photochemistry as well as coordination chemistry. 4 It is of interest to note that the ligand (E,E)-20c (= 4) on the group-6 metal(0) tetracarbonyl complexes 30 undergoes oxidation reaction with molecular oxygen upon exposure to light to give [2,3- dibenzoy1-1,4-bis(2,4,6-tri-t-butylpheny1)-1,4-diphospha-1,3-butadiene]metal (0) complexes (31) On the other hand, we have developed several protecting groups other than the Mes* group32 and found that the 2,4-di-t-butyl-6-methylphenyl (abbreviated to Dbt) group is also useful for the stabilization of the diphosphinidenecyclobutene system. Interestingly, the Dbt group exhibited conformational isomerism due to the restricted rotation around the two P-Dbt bonds at the edges of the system.…”

1‐Heteroakylation of tris(trimethylsilyl)phosphine

“…Tris(dimethylaminomethyl)phosphine (2). A mixture of 6 g of tris(trimethylsilyl)phosphine 1, 8 g of No.…”

“…Tris(trimethylsilyl)phosphine containing three highly reactive P Si bonds was a well-known key substance for the synthesis of the low coordinated organophosphorus compounds, e.g., the phosphaalkenes and phosphaalkynes [1,2]. In the present paper, we developed convenient methods for the synthesis of tris(heteromethyl)phosphines and several phosphaethylenes, which were of great interest as chelating ligands for the preparation of various metal complexes and the promising precursors in organophosphorus chemistry.…”