1,1′-Bifunctional Aminophosphane Complexes via N–H Bond Insertions of a Li/Cl Phosphinidenoid Complex and First Studies on N/P Mono Functionalizations

Access to ligand-stabilized PH-containing phosphenium complexes

While the chemistry of phosphenium compounds, including metal complexes thereof, is very well established, few derivatives having a P-H bond have been described, yet. This work describes rational access to donor-stabilised phosphenium metal complexes possessing a P-H bond using protonation reactions of stable phosphinidene complex adducts. While most Brønsted-Lowry acids yield formal 1,1-addition products at the phosphorus centre under the loss of the donor, super-strong acids having weakly coordinating anions enable access to donor-stabilised P-H phosphenium complex salts. The latter possess N-methylimidazole as a donor (to phosphorus) and the N-P interaction has been studied theoretically.

Metal-Free N-H Bond Activation by Phospha-Wittig Reagents

N-containing molecules are mostly derived from ammonia (NH3 ). Ammonia activation has been demonstrated for single transition metal centers as well as for low-valent main group species. Phosphinidenes, mono-valent phosphorus species, can be stabilized by phosphines, giving so-called phosphanylidenephosphoranes of the type RP(PR'3 ). We demonstrate the facile, metal-free NH3 activation using ArP(PMe3 ), affording for the first time isolable secondary aminophosphines ArP(H)NH2 . DFT studies reveal that two molecules of NH3 act in concert to facilitate an NH3 for PMe3 exchange. Furthermore, H2 NR and HNR2 activation is demonstrated.

Regioselective N- versus P-Deprotonation of Aminophosphane Tungsten(0) Complexes

1,2-Bifunctional ligands are rare, in general, which holds especially for those with a P-N linkage. Herein, we report on the synthesis of P-tert-butyl substituted aminophosphane W(CO)5 complexes 3a-f (a: R = R’ = H; b: R = H, R = Me; c: R = H, R’ = ally; d: R = H, R’ = i-Pr; e: R = H, R’ = t-Bu; f: R = R’ = Me) obtained via formal N-H insertion reactions of Li/Cl phosphinidenoid complex 2 into NH bonds of ammonia and different amines. The 1,2-bifunctionality of 3b was addressed in targeted regioselective deprotonation reactions leading to amidophosphane complexes M-4b or M/N(H)Me phosphinidenoid complexes M-5b, respectively (M = Li, K). Remarkable was the observation that reactions of M-4b and M-5b with MeI as the electrophile resulted in the formation of the same product 7b. The constitution of all the compounds has been established by means of NMR and IR spectroscopy and mass spectrometry. Two possible reaction pathways were studied in detail using high-level DFT calculations.

Access and unprecedented reaction pathways of Li/Cl phosphinidenoid iron(0) complexes

Complexes [Fe(CO)₄(RPCl₂)] (2) (a: R = CPh₃, b: R = ^tBu) were used to generate the first examples of phosphinidenoid iron(0) complexes [Li(12-crown-4)(solv)_n][Fe(CO)₄(RPCl] (3a,b), characterized by NMR spectroscopy.