A Stable Structurally Characterized Phosphorus‐Bound Isocyanide and Its Thermal and Catalyzed Isomerization to the Corresponding Cyanide

3/2-Order Chain Kinetics Involving a Postulated Dicationic Intermediate in the Isomerization of a P−Isocyano to a P−Cyano Azaphosphatrane Monocation

“…6 Here we report a detailed kinetic study of the isomerization of 1 in which we postulate an unusual dicationic intermediate in a chain mechanism.…”

Formation of a Dicyanotriorganophosphorane from the Reaction of Triphenylphosphane with Phenylselenocyanate

“…[4,5] This species is only stable for a few hours in acetone, and after 48 h the only major resonance present in the 31 P{ 1 H} NMR spectrum is that observed at d = 29.1 ppm, along with a few minor species. A similar situation was observed when the reaction was followed in [D 8 ]toluene and [D 10 ]diethyl ether, although the reaction occurs at a slower rate, with Ph 3 P persisting in the mixture over several days.…”

“…[4] Recent work by Verkade and co-workers has shown that Me 3 SiCN converts [(Me 2 N) 3 PBr]Br into [(Me 2 N) 3 PCN]Br, whilst the same reaction with similar azaphosphatrane systems results in the isolation of both cyano (PÀCN) and isocyano (PÀNC) compounds. [5] In contrast, covalent dicyanotriorganophosphoranes (R 3 P(CN) 2 ) are much more elusive with only three examples known (R 3 = Ph 2 Me, PhMe 2 , and (Et 2 N) 3 ), each obtained from the reaction of [R 3 PCN]I with a second equivalent of ICN, although the products were not extensively characterized. [3] Herein, we report the remarkably facile formation of the dicyanotriorganophosphorane Ph 3 P(CN) 2 by the reaction of triphenylphosphane with phenylselenocyanate.…”

“…[17] In Ph 3 P(CN) 2 , the NC-P-CN bond angle is essentially linear (C19-P1-C20: 178.85 (16)8) and displays none of the distortions from regular trigonal-bipyramidal geometry observed for Ph 3 PCl 2 . [7] The P À C bonds to the cyano groups (P1-C19: 1.941(3), P1-C20: 1.929(3) ) are substantially longer than those to the phenyl rings (P1-C1: 1.801(3), P1-C7: 1.776(4), P1-C13: 1.801(3) ) and are considerably longer than in ionic [{2,4,6-(MeO) 3 C 6 H 2 } 3 PCN]I (P-CN: 1.78 (2) ) [4] and the cyano phosphatrane [N(CH 2 CH 2 NiBu) 3 PCN]Br (P-CN: 1.854(2) ); [5] however, these P À CN bonds are closer to the axial PÀCN bond length of 1.915(5) in the [P(CN) 3 Cl] À ion. [18] The CN bond lengths (C19-N1: 1.148(5), C20-N2: 1.147(5) ) are, however, very similar to the CN bond length of 1.148 (3) in [N(CH 2 CH 2 NiBu) 3 PCN]Br, [5] but rather shorter than that of 1.19(5) observed for [{2,4,6-(MeO) 3 C 6 H 2 } 3 PCN]I.…”

“…[7] The P À C bonds to the cyano groups (P1-C19: 1.941(3), P1-C20: 1.929(3) ) are substantially longer than those to the phenyl rings (P1-C1: 1.801(3), P1-C7: 1.776(4), P1-C13: 1.801(3) ) and are considerably longer than in ionic [{2,4,6-(MeO) 3 C 6 H 2 } 3 PCN]I (P-CN: 1.78 (2) ) [4] and the cyano phosphatrane [N(CH 2 CH 2 NiBu) 3 PCN]Br (P-CN: 1.854(2) ); [5] however, these P À CN bonds are closer to the axial PÀCN bond length of 1.915(5) in the [P(CN) 3 Cl] À ion. [18] The CN bond lengths (C19-N1: 1.148(5), C20-N2: 1.147(5) ) are, however, very similar to the CN bond length of 1.148 (3) in [N(CH 2 CH 2 NiBu) 3 PCN]Br, [5] but rather shorter than that of 1.19(5) observed for [{2,4,6-(MeO) 3 C 6 H 2 } 3 PCN]I. [4] The formation of Ph 3 P(CN) 2 in this reaction was unanticipated and is in contrast to the analogous reactions of "PhSeI" (a centrosymmetric dimer (Ph 2 Se 2 I 2 ) 2 in the solid state) [19] with tertiary phosphanes, which result in cleavage of the weak SeÀSe bond and formation of either charge-transfer R 3 PSe(Ph)I compounds [20] or ionic [R 3 PSePh]I salts, [21] depending on the basicity of the phosphane.…”