Asymmetric Cationic Phosphines: Synthesis, Coordination Chemistry, and Reactivity

Abstract

A single enantiomer of a cationic phosphine, [α-CgPAmHMe]BF, containing two asymmetric subunits, an amidinium group (AmH) and a phosphacycle (CgP), has been synthesized and isolated. The ligand, which is of an extremely rare class, has been coordinated to Rh(I), Au(I), Ag(I), Cu(I), and Pt(0) to enable an empirical assessment of its donor properties. Analysis of the IR stretching frequency of the carbonyl ligand in trans-[Rh(α-CgPAmHMe)(CO)Cl](BF) coupled with metric data obtained from crystal-state molecular structures of pertinent complexes confirms the strong π-accepting properties of the ligand. The integrity of the N-P bond is compromised upon addition of base to both [Cu(α-CgPAmHMe)Cl]BF and [Ag(α-CgPAmHMe)(OTf)]BF where, instead of isolating anticipated chelating and/or bridging forms of the neutral, deprotonated α-CgPAmMe derivative, decomposition products were obtained containing a phosphacycle fragment and/or amidine ligands. The fragility of the N-P bond is also evident in uncoordinated [α-CgPAmHMe]BF as treatment with aqueous base releases a neutral amidine fragment and generates the P-P dimer [α,α-CgPP(O)Cg]. These fortuitous observations show [α-CgPAmHMe]BF to be a very useful synthon for the potential production of novel asymmetric phosphines.

Transition metal complexes of the PPO/POP ligand: variable coordination chemistry and photo-luminescence properties

“…The POP ligand R 2 P-O-PR 2 was thereby formed in situ from the dehydration of two secondary phosphine oxide molecules. 23 Other reactions leading to PPO/POP-based transition metal complexes via metal promoted rearrangements are based on P-N, [28][29][30][31][32][33][34][35] P-O [36][37][38][39][40][41][42][43][44] or P-H 22 bond scissions and subsequent reactions (often in the presence of water) with transition metal precursors. Reviewing the literature more closely, it becomes obvious that almost all of these reported transition metal complexes comprise the POP form of the ligand with only a very few PPO complexes being described.…”

Welcoming Neighbour or Inhospitable Host? Selective Second Metal Binding in 5- and 6-Phospha-Substituted Bpy Ligands

“…Although not directly comparable, the Rh–P bond length of 2.3176(8) Å observed for 5L Re,Rh is shorter than the 2.3205(7) Å and 2.3245 (av.) seen in related [Rh(L) 2 CO(Cl)] complexes [ 44 , 46 ]. The Re–N bond lengths are equivalent, reflecting both a lack of steric impedance and little electronic influence of the 5-phospha/rhodium unit.…”

Adamantane-type clusters: compounds with a ubiquitous architecture but a wide variety of compositions and unexpected materials properties

“…[µ4-O{Cu(MeOH)}4Cl6] (737) / DMF Q [394] [µ4-O{Cu(3-nonyl-8-fluoroimidazo[1,5-a]pyridine)}4Cl6] (757) [µ4-O{Cu(MeCN)}4Cl6] (707), 3-nonyl-8-fluoroimidazo[1,5-a]pyridine / MeCN, 100 °C, 10 min Q [440] [µ4-O{Cu(Amt)}4Cl6] (758) [Cu(α-CgPAmtHMe)(Cl)][BF4], KHMDS / THF J [441] [µ4-O{Cu(nmp)}3(CuOH2)Cl6] (759) CuCl, O2 / nmp, H2O F [442] [µ4-O{Cu(Me2NH)}3{Cu(dmso)}Cl6] (760)…”