Protonation of some cyclic triphosphenium ions

Reaction of a cyclic triphosphenium ion with triflic acid and SnX2 (X = Br or Cl): A 31P NMR study

“…The formation of 4 from 3 necessarily involves a redox reaction, with SnX 2 as the reducing agent in the presence of HX, as shown in Scheme 1. This rationalizes the nonappearance of 4 in the t BuCl/AlCl 3 reaction, where there was no comparable reducing agent present [8].…”

“…We also found that decomposition of the seven-membered ring dication derived by t BuCl/AlCl 3 protonation of the cyclic triphosphenium ion from 1,4-bis-diphenylphosphinobutane (dppb) proceeded via ring opening to give a P P bonded species, with the end group assigned as a PHCl fragment. Unfortunately, we were unable to record the proton-coupled 31 P NMR spectrum of this intermediate, to confirm the P H bond, before further decomposition occurred, although the final reaction products are the diprotonated diphosphane [Ph 2 PH(CH 2 ) 4 PHPh 2 ] 2+ and probably polymeric phosphorus [8,9]. We now present conclusive evidence from 31 P NMR solution-state spectroscopy, including low-temperature studies, for a further intermediate dication formed by a redox reaction in the presence of SnX 2 (X = Br or Cl), with a terminal primary phosphane PH 2 group; this moiety is comparatively stable, although the final decomposition products are identical to those from the t BuCl AlCl 3 reaction.…”

“…In a recent paper, we have extended this work considerably, having protonated a wide variety of cyclic triphosphenium ions to the corresponding di-ium dications, using either [8]. The stabilities of the dications depended on ring size, with stability decreasing in the order 5 > 6 > 7-membered rings.…”

Homoleptic Pnictogen–Chalcogen Coordination Complexes

“…51 The one structurally characterized example (R = Ph) reveals short P -O bond lengths of 64,65 These molecular architectures have been represented with a variety of bonding models.…”

Preparation and Characterization of a Ligand‐Stabilized Trimethylphosphane Dication

“…Also summarized in Figure 1 are generic examples of donor-acceptor complexes that have been structurally characterized for monocations of type A, [2][3][4][5][6][7][8] B, [9][10][11][12][13] C, [1,[14][15][16][17][18] D, [19][20][21] E [22,23] and F. [24] Complexes of a phosphorus dication of type G have been proposed on the basis of spectroscopic and chemical analysis data, [25][26][27][28] but solid-state structures have been confirmed for only two examples. [6,14,18] There are no structural reports of complexes involving cations of the type H, I, J, K, L or M.…”