Metal complexes of planar PR2 ligands: Examining the carbene analogy

Chemistry of CS2- and SCNPh-adducts of the pyramidal phosphinidene-bridged complex [Mo2Cp(μ–κ1:κ1,η5-PC5H4)(CO)2(η6-HMes*)(PMe3)]

“…Their IR spectra display in each case two CO stretches with a pattern comparable to that of the parent complex 1, characteristic of transoid M(CO) 2 oscillators, 15 (C1Mo1C2 = 106.7(1) o for 2a in the crystal), and their 31 P NMR spectra display quite shielded resonances for the bridging ligand at 21.6 and 22.6 ppm respectively, consistent with retention in solution of a phosphanyl-like pyramidal environment at a P atom bound to a single metal and bearing a lone electron pair. 16 We note that these shifts are comparable to the one measured for the molybdenum phosphanyl complex [MoCp(PPh 2 )(CO) 2 (PMe 3 )] ( P 31.9 ppm). 17 The cumulene C …”

Anionic phosph(in)ito (“phosphoryl”) ligands: Non-classical “actor” phosphane-type ligands in coordination chemistry

“…The ability of 4 to interconvert between N-heterocyclic phosphanide, NHP -, and N-heterocyclic phosphenium, NHP + , configurations was experimentally and theoretically demonstrated and is related to oxidation/reduction reaction and ligand coordination/dissociation processes [57]. It was proposed that, in the presence of the nucleophilic Cl − anion, initial oxidative addition of ROH (R= Me, Et) to the neutral N-heterocyclic phosphenium/phosphanido diphosphane complex 4 leads to Pt-hydride amidophosphite species 5.…”

Sterically Controlled Synthesis and Nucleophilic Substitution Reactions of Di‐ and Trimeric N‐Heterocyclic Phosphenium Metal(0) Halides

“…Cyclic diaminophosphenium ions1,2 (also known as N‐heterocyclic phosphenium ions, NHP) have a long history in coordination chemistry because of their ability to act as σ‐donor/π‐acceptor ligands in transition‐metal complexes 3,4. A particularly interesting sub‐class are complexes with group 10 metal atoms (M = Ni, Pd, Pt) of the general type [MX(NHP)(L) 2 ] ( I )5,6 and [MX(NHP)] 2 ( II ;7,8 L = phosphane, X = halide), which exhibit notable structural diversity and raise some scientifically interesting electron‐counting difficulties (Scheme ) 8. Thus, complexes I exist as two structural varieties in which the phosphorus atom in the NHP unit exists either in a trigonal‐planar coordination sphere with a short P–M bond or in a pyramidal coordination with a lengthened P–M bond.…”