Secondary Oxide Phosphines to Promote Tandem Acyl-Alkyl Coupling/Hydrogen Transfer to Afford (Hydroxyalkyl)rhodium Complexes. Theoretical and Experimental Studies.

Acyl(σ-norbornenyl)rhodium(III) dimer [Rh(μ-Cl)(CHNCO)(CH)L] (1) (CH = σ-norbornenyl; L = 4-picoline, isoquinoline) reacts with diphenylphosphine oxide (SPO) to undergo a one-pot reaction involving (i) cleavage of the chloride bridges and coordination of the phosphine, (ii) C-C bond coupling between acyl and norbornenyl in a 18e species, and (iii) ligand-assisted outer-sphere O(P)-to-O(C) hydrogen transfer, to afford mononuclear 16e species [RhCl{(CHNC(O)CH)(PhPO)H}(L)] (2) containing a quinolinyl-(norbornenylhydroxyalkyl) fragment hydrogen-bonded to a κ- P-phosphinite ligand. Pentacoordinated 2, which adopt a distorted trigonal bipyramidal structure, are kinetic reaction products that transform into the thermodynamic favored isomers 3. Structures 3 contain an unusual weak η-C anagostic interaction involving the rhodium atom and one carbon atom of the olefinic C-H bond of the norbornenyl substituent in the chelating quinolinyl-hydroxyalkyl moiety.

Stereoselective formation and catalytic activity of hydrido(acylphosphane)(chlorido)(pyrazole)rhodium(III) complexes. Experimental and DFT studies.

The reaction of [{RhCl(COD)}2] (COD = 1,5-cyclooctadiene) with L = pyrazole (Hpz), 3(5)-methylpyrazole (Hmpz) or 3,5-dimethylpyrazole (Hdmpz) and PPh2(o-C6H4CHO) (Rh : L : P = 1 : 2 : 1) gives hydridoacyl complexes [RhHCl{PPh2(o-C6H4CO)}(L)2] (). Stereoselective formation of and with pyrazoles trans to hydrido and phosphorus and hydrogen bond formation with O-acyl and chlorido occur. is a mixture of two linkage isomers in a 9 : 1 ratio, with two 5-methylpyrazole ligands or with one 3- and one 5-methylpyrazole ligand, respectively.

Reactions of hydridoirida-β-diketones with amines or with 2-aminopyridines: formation of hydridoirida-β-ketoimines, PCN terdentate ligands, and acyl decarbonylation.

The hydridoirida-β-diketone [IrHCl{(PPh(2)(o-C(6)H(4)CO))(2)H}] (1) reacts with benzylamine (C(6)H(5)CH(2)NH(2)) to give the hydridoirida-β-ketoimine [IrHCl{(PPh(2)(o-C(6)H(4)CO))(PPh(2)(o-C(6)H(4)CNCH(2)C(6)H(5)))H}] (2), stabilized by an intramolecular hydrogen bond. 2 reacts with water to undergo hydrolysis and amine coordination giving hydridodiacylamino [IrH(PPh(2)(o-C(6)H(4)CO))(2)(C(6)H(5)CH(2)NH(2))] (3). Cyclohexylamine or dimethylamine lead to hydridodiacylamino [IrH(PPh(2)(o-C(6)H(4)CO))(2)L] (4-5).

A hydridoirida-beta-diketone as an efficient and robust homogeneous catalyst for the hydrolysis of ammonia-borane or amine-borane adducts in air to produce hydrogen.

The first homogeneous metal-catalysed hydrolysis of ammonia-borane or amine-borane adducts for hydrogen generation, using a stable organometallic complex [IrHCl{(PPh(2)(o-C(6)H(4)CO))(2)H}], is reported.

New hydridoirida-beta-diketones derived from 8-quinoline-carbaldehyde and o-(diphenylphosphino)benzaldehyde.

8-Quinoline-carbaldehyde (C(9)H(6)NCHO) reacts in methanol with [IrCl(Cod)](2) (Cod = 1,5-cyclooctadiene) to give the acylhydrido complex [IrHCl(C(9)H(6)NCO)(Cod)] (1) or with [IrHCl{PPh(2)(o-C(6)H(4)CO)}(Cod)] to afford the hydridoirida-beta-diketone complex [IrHCl({PPh(2)(o-C(6)H(4)CO)}(C(9)H(6)NCO)H)] (2). Complex 2 reacts with silver perchlorate in the presence of pyridine to afford the cationic [IrH({PPh(2)(o-C(6)H(4)CO)}(C(9)H(6)NCO)H)(py)]ClO(4) (), which in solution transforms slowly into the cationic dinuclear complex [Ir{micro-PPh(2)(o-C(6)H(4)CO)}(C(9)H(6)NCO)(py)](2)(ClO(4))(2) (4) with two acylphosphine chelate-bridging ligands. The reaction of 2 with AgClO(4) in the presence of carbon monoxide affords [IrH({PPh(2)(o-C(6)H(4)CO)}(C(9)H(6)NCO)H)(CO)]ClO(4) (5), which in solution is in equilibrium with the deprotonated diacylhydrido complex [IrH{PPh(2)(o-C(6)H(4)CO)}(C(9)H(6)NCO)(CO)] (6).

Reactivity of hydridoirida-beta-diketones with bases: the selective formation of new di-mu-acyl-mu-hydridodiiridium(III) or dihydridoirida-beta-diketone complexes and heterometallic Ir(III)-Rh(I) derivatives.

The hydridoirida-beta-diketone [IrHCl{(PPh2(o-C6H4CO))2H}] (1a) reacts with bases such as KOH or NaHCO3 in methanol to undergo dehydrodechlorination and acyl-bridge formation affording [Ir2H2(PPh2(o-C6H4CO))2(mu-PPh2(o-C6H4CO))2] (2) with two acylphosphine chelate-bridging ligands, in a head-to-tail disposition, and terminal hydrides. The acyl bridges can be broken by pyridine, PPh3, CO or dimethylsulfoxide affording selectively mononuclear diacylhydrido neutral derivatives [IrH(PPh2(o-C6H4CO))2L] (3-6). la reacts with KOH or NaHCO3 in refluxing methanol to afford a novel dihydridoirida-beta-diketone [IrH2{(PPh2(o-C6H4CO))2H}](7), via dehydrodechlorination to afford 2, which then undergoes hydrogenation and protonation.

Novel hydridoirida-beta-diketones containing small molecules, CO, or ethylene: their behavior in coordinating solvents such as dimethylsulfoxide or acetonitrile.

New hydridoirida-beta-diketones [IrH[(PPh2(o-C6H4CO))2H](CO)]ClO4 2 and [IrH[(PPh2(o-C6H4CO))2H](olefin)]BF4 (olefin = C2H4, 5; 1-hexene, 10) have been prepared. These complexes may afford new diacylhydridoiridium(III) derivatives. In chloroform solution, complex 2 is in equilibrium with the deprotonated diacylhydride trans-[IrH(PPh2(o-C6H4CO))2(CO)] complex 3.