Trimerization and cyclization of reactive P-functionalities confined within OCO pincers.

In order to stabilize a 10-P-3 species with symmetry and two lone pairs on the central phosphorus atom, a specialized ligand is required. Using an NCN pincer, previous efforts to enforce this planarized geometry at P resulted in the formation of a -symmetric, 10π-electron benzazaphosphole that existed as a dynamic "bell-clapper" in solution. Here, OCO pincers 1 and 2 were synthesized, operating under the hypothesis that the more electron-withdrawing oxygen donors would better stabilize the 3-center, 4-electron O-P-O bond of the 10-P-3 target and the sp-hybridized benzylic carbon atoms would prevent the formation of aromatic P-heterocycles.

P-Alkynyl functionalized benzazaphospholes as transmetalating agents.

Exposure of 10π-electron benzazaphosphole 1 to HCl, followed by nucleophilic substitution with the Grignard reagent BrMgCCPh afforded alkynyl functionalized 3 featuring an exocyclic -C[triple bond, length as m-dash]C-Ph group with an elongated P-C bond (1.7932(19) Å). Stoichiometric experiments revealed that treatment of trans-Pd(PEt3)2(Ar)(i) (Ar = p-Me (C) or p-F (D)) with 3 generated trans-Pd(PEt3)2(Ar)(CCPh) (Ar = p-Me (E) or p-F (F)), 5, which is the result of ligand exchange between P-I byproduct 4 and C/D, and the reductively eliminated product (Ar-C[triple bond, length as m-dash]C-Ph).

-Selective Synthesis and Coordination Chemistry of Pyridine-Phosphaalkenes: Five Ligands Produce Four Distinct Types of Ru(II) Complexes.

Pyridine-phosphaalkene (PN) ligands were prepared in an -selective fashion using phospha-Wittig methodology. Treatment of these five ligands, varying only in their 6-substituent with RuCl(PPh), produced four distinct types of coordination complexes: pyridine-phosphaalkene-derived , cyclized , and six-coordinate and . Prolonged heating of in THF resulted in C-H activation of the Mes* group and cyclization to give featuring a bidentate pyridine-phospholane ligand bound to the metal center.

Diastereoselective Coordination of P-Stereogenic Secondary Phosphines in Copper(I) Chiral Bis(phosphine) Complexes: Structure, Dynamics, and Generation of Phosphido Complexes.

Diastereoselective coordination of racemic secondary phosphines (PHRR') to Cu(I) precursors containing chiral bis(phosphines) (diphos*) was explored as a potential route to P-stereogenic phosphido complexes. Reaction of [Cu(NCMe)][PF] with chiral bis(phospholanes) gave [Cu(diphos*)][PF] (diphos* = ( R, R)-Me-DuPhos (1), ( R, R)-Et-DuPhos (2), or ( R, R)-Me-FerroLANE) (3)) or the mono(chelates) [Cu(diphos*)(NCMe) ][PF] (diphos* = ( R, R)- i-Pr-DuPhos, n = 2 (4); diphos* = ( R, R)-Me-FerroLANE, n = 1 (5)). Treatment of [Cu(NCMe)][PF] with diphos* and PHMe(Is) (Is = 2,4,6-( i-Pr)CH) gave mixtures of diastereomers of [Cu(( R, R)- i-Pr-DuPhos)(PHMe(Is))(NCMe)][PF] (6) and [Cu(( R, R)-Me-FerroLANE)(PHMe(Is))][PF] (7); two of the three expected isomers of the bis(secondary phosphine) complexes [Cu(( R, R)- i-Pr-DuPhos)(PhHP(CH) PHPh)][PF] ( n = 2 (8); n = 3 (9)) were formed preferentially in related reactions.

A Masked Phosphinidene Trapped in a Fluxional NCN Pincer.

The trapping of a phosphinidene (R-P) in an NCN pincer is presented. Stabilized phosphinidene 1 was characterized by P{ H}, H, and C{ H} NMR spectroscopy, exhibiting an averaged C symmetry in solution between -60 and 60 °C. In the solid state, the phosphinidene is coordinated by one adjacent N atom featuring a formal P-N bond (1.

Synthesis of a TREN in which the aryl substituents are part of a 45 atom macrocycle.

A substituted TREN has been prepared in which the aryl groups in (ArylNHCH2CH2)3N are substituted at the 3- and 5-positions with a total of six OCH2(CH2)nCH═CH2 groups (n = 1, 2, 3). Molybdenum nitride complexes, [(ArylNCH2CH2)3N]Mo(N), have been isolated as adducts that contain B(C6F5)3 bound to the nitride. Two of these [(ArylNCH2CH2)3N]Mo(NB(C6F5)3) complexes (n = 1 and 3) were crystallographically characterized.

Synthesis and structure of intermediates in copper-catalyzed alkylation of diphenylphosphine.

Cu(I) catalysts for alkylation of diphenylphosphine were developed. Treatment of [Cu(NCMe)(4)][PF(6)] (1) with chelating ligands gave [CuL(NCMe)][PF(6)] (2; L = MeC(CH(2)PPh(2))(3) (triphos), 3; L = 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (XantPhos)). These complexes catalyzed the alkylation of PHPh(2) with PhCH(2)Br in the presence of the base NaOSiMe(3) to yield PPh(2)CH(2)Ph (4).