Synthesis of azadiphosphiridine complexes. Theoretical studies on ring formation, the P-to-P' metal shift and the resulting nitrogen geometry.

A set of azadiphosphiridine complexes 3a and 4b,c were synthesized in high selectivity using N-H and P-H deprotonation as key steps and RPCl as substrates (R = NPr (), -Bu (), Ph ()). While complex 3a (-NPr) retained the P-W linkage of the starting material W(CO){PhCP(H)NH}, complexes 4b (-Bu) and 4c (-Ph) revealed that a P-to-P' haptotropic shift of the W(CO) group has occurred. Remarkably, complex 3a, bearing an unligated -NPr unit, displays a planar ring N geometry while 4b,c showed a pyramidal geometry of the ring nitrogen atom.

A homonuclear π-system with a singlet carbene-type α and a nucleophilic β phosphorus - the first use in P-heterocyclic synthesis.

A μ-(η,η)-dinuclear diphosphene complex having two W(CO) groups with dimethyl acetylenedicarboxylate, 4-phenyl-1,2,4-triazoline-3,5-dione and diethyl azodicarboxylate was applied to P-heterocyclic synthesis, , using a singlet carbene-type reactivity of a homonuclear π-system assisted by a haptotropic shift thus rendering a more nucleophilic β phosphorus and, hence, a subsequent ring expansion.

M/X Phosphinidenoid Metal Complex Chemistry.

ConspectusLike singlet carbenes and silylenes, transient electrophilic terminal phosphinidene complexes enabled highly selective synthetic transformations, but the required multistep synthetic protocols precluded widespread use of these P building blocks. By contrast, nucleophilic M/Cl phosphinidenoid complexes can be easily accessed in one step from [M(CO)(RPCl)] complexes. This advantage and the mild reaction conditions opened broad synthetic applicability that enabled access to a variety of novel compounds.

Molecular 1,1'-bifunctional mixed-valence P-P compounds, enabled through metal complexation.

Mixed-valence compounds feature the same atoms but in different formal oxidation states. This research field is largely dominated by metal-based solid-state chemistry and has been intensively studied in recent years. By contrast, the situation is different for molecular main group element compounds and to establish 1,1'-bifunctional groups remained a particular challenge.

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. The bonding situation of 3 was analyzed for a P-Me model complex using DFT calculations. Complex 3a (R = CPh3) reacted with H2O and MeOH to give selectively O-H bond insertion products 5 and 7; for the case of H2O, a multistep electrophilic reaction is supported by detailed DFT calculations.

Synthesis and Deprotonation of Aminophosphane Complexes: First K/N(H)R Phosphinidenoid Complexes and Access to a Complex with a P N-Ring Ligand.

Synthesis of 1,1'-bifunctional aminophosphane complexes 3 a-e was achieved by the reaction of Li/Cl phosphinidenoid complex 2 with various primary amines (R=Me, iPr, tBu, Cy, Ph). Deprotonation of complex 3 a (R=Me) with potassium hexamethyldisilazide yielded a mixture of K/NHMe phosphinidenoid complex 4 a and potassium phosphanylamido complex 4 a'. Treatment of complex 3 c (R=tBu) and e (R=Ph) with KHMDS afforded the first examples of K/NHR phosphinidenoid complexes 4 c and e.

Amide-Substituted Titanocenes in Hydrogen-Atom Transfer Catalysis.

Two new catalytic systems for hydrogen-atom transfer (HAT) catalysis involving the N-H bonds of titanocene(III) complexes with pendant amide ligands are reported. In a monometallic system, a bifunctional catalyst for radical generation and reduction through HAT catalysis depending on the coordination of the amide ligand is employed. The pendant amide ligand is used to activate Crabtree's catalyst to yield an efficient bimetallic system for radical generation and HAT catalysis.