Salts of the bis(catecholato)borate anion with rhodium– and iridium–phosphine complex cations

Terminal versus Bridging Boryl Coordination in N-Heterocyclic Carbene Copper(I) Boryl Complexes: Syntheses, Structures, and Dynamic Behavior

The B-B bond activation of the diborane(4) derivatives B₂cat₂ with the copper(I) alkoxido complex [(SIDipp)Cu-O tBu] delivers, depending on the solvent, either the linear boryl complex [(SIDipp)Cu-Bcat] from PhMe or the μ-boryl complex [((SIDipp)Cu)₂Bcat][cat₂B] from THF. The relevant conversion of the linear boryl complex to the μ-boryl complex occurs in the polar solvent via formal boryl anion abstraction by the Lewis acid catB-O tBu, concomitantly formed during the B-B activation. With Lewis acids such as BPh₃ or [CPh₃][BArF] (reversible), boryl abstraction from the linear complexes [(SIDipp)Cu-Bcat] or [(SIDipp)Cu-Bdmab] occurs and results in the μ-boryl complexes [((SIDipp)Cu)₂Bcat/dmab][Ph₃B-Bcat/dmab] and [((SIDipp)Cu)₂Bcat][BArF]. The formation of [((SIDipp)Cu)₂Bcat][cat₂B] is generally accompanied by the concomitant formation of the μ-hydrido complex [((SIDipp)Cu)₂H][cat₂B]. The spiroborate [cat₂B]^- is formed from the initially formed Lewis acid/base adduct [catB-B(O tBu)cat]^- presumably in a process that involves the glass surface of the reaction vessel. All complexes are thoroughly characterized structurally as well as spectroscopically, in particular with respect to the dynamic behavior of the μ-boryl complexes in solution.

A chiral spiroborate anion from diphenyl-l-tartramide [B{l-Tar(NHPh)2}2]−applied to some challenging resolutions

A chiral spiroborate anion [B{l-Tar(NHPh)₂}₂]⁻is effective in challenging high yield, 1-pot resolutions, as for the S-2-phenylpropylammonium salt shown.

Hydroboration of carbon dioxide with catechol- and pinacolborane using an Ir–CNP* pincer complex. Water influence on the catalytic activity

Lutidine-derived CNP*–Ir complexes catalyze the hydroboration of CO₂ to methoxyborane and formoxyborane in the presence of small amounts of water.

Isolation and enantiostability of the B-chiral bis(salicylato)borate anions [BR(Sal)2] and [BS(Sal)2]

Both chiral hands of bis(salicylato)borate anion [B_S(Sal)₂] and [B_R(Sal)₂] are isolated and CD spectroscopy indicates they can be configurationally stable.

Bis(mandelato)borate: an effective, inexpensive spiroborate anion for chiral resolution

Bis(mandelato)borate [B(Man)2](-) (R- or S-) anions are simply prepared and appear widely effective for resolution of racemic cations. Three examples demonstrate their scope; the alkaloid tetrahydropalmatine (THP), 1,2-diaminopropane (1,2-dap) and the metal-organic complex [Co(phen)3](3+) are readily resolved, either by a facile one-pot procedure, or via counter-ion metathesis.

Synthesis and structures of the homoleptic cations [M(PMe3)5]+ (M = Rh, Ir)

The homoleptic cations [M(PMe(3))(5)](+) (M = Rh, Ir) are formed in high yield from reactions of 16 electron 4 coordinate precursors, such as [Rh(PMe(3))(4)](+), with excess neat PMe(3) at 80 degrees C.

Syntheses and reactions of the bis-boryloxide O(Bpin)2(pin = O2C2Me4)

The reaction of the phosphine oxides, OPEt31 and OPn-Bu32 with pinacolborane (HBpin) results in phosphine oxide reduction and the formation of O(Bpin)23. In contrast, the phosphine oxide OPn-Bu3 reacts with HB(C6F5)2 or B(C6F5)3 to give only the donor-acceptor adducts. Compound 3 reacts with HNPt-Bu3 to give the phosphinimonium borate salt, [t-Bu3PNH2][(Bpin(OBpin)2]6, while reaction with Cp2ZrMe2 affords the species Cp2Zr(OBpin)27.

Synthesis and characterization of iridium 1,3,5-triaza-7-phosphaadamantane (PTA) complexes. X-ray crystal and molecular structures of [Ir(PTA)4(CO)]Cl and [Ir(PTAH)3(PTAH2)(H)2]Cl6

The first 1,3,5-triaza-7-phosphaadamantane (PTA) ligated iridium compounds have been synthesized. The reaction of PTA with [Ir(COD)Cl]2 (COD = 1,5-cyclooctadiene) under a CO atmosphere produces an inseparable mixture of [Ir(PTA)3(CO)Cl] (1) and the PTA analogue of Vaska's compound, [Ir(PTA)2(CO)Cl] (2). Compound 1 and [Ir(PTA)4(CO)]Cl (3) were prepared via ligand substitution reactions of PTA with Vaska's compound, trans-Ir(PPh3)2(CO)Cl, in absolute and 95% ethanol, respectively. Complex 3 crystallizes in the orthorhombic space group Pbca with a = 20.3619(4) A, b = 14.0345(3) A, c = 24.1575(5) A, and Z = 8. Single-crystal X-ray diffraction studies show that 3 has a trigonal bipyramidal structure in which the CO occupies an axial position. This is the first crystallographically characterized [IrP4(CO)]+ complex in which the CO is axially ligated. Compound 1 was converted into 3 by ligand substitution with 1 equiv of PTA in water. Interestingly, the reaction of 3 with excess NaCl did not result in the production of 1, but instead the formation of the dichloro species, [Ir(PTAH)2(PTA)2Cl2]Cl3 (4) (PTAH = protonated PTA). Dissolution of 1 or 3 in dilute HCl produced 4 and a dihydrido species, [Ir(PTAH)4(H)2]Cl5 (5), which were readily separated by inspection due to their different crystal habits. Compound 5 crystallizes in the triclinic space group P1 with a = 12.4432(9) A, b = 12.5921(9) A, c = 16.3231(12) A, alpha = 76.004(1) degrees, beta = 71.605(1) degrees, gamma = 69.177(1) degrees, and Z = 2. Complex 5 exhibits a distorted octahedral geometry with two hydride ligands in a cis configuration. A rationale consistent with these reactions is presented by consideration of the steric and electronic properties of the PTA ligand.