Kenneth S. MacFarlane

The reactivity of five-coordinate Ru(II) (1,4-bis(diphenylphosphino)butane) complexes with the N-donor ligands: ammonia, pyridine, 4-substituted pyridines, 2,2′-bipyridine, bis(o-pyridyl)amine, 1,10-phenanthroline, 4,7-diphenylphenanthroline and ethylenediamine

Abstract A series of Ru(II)(1,4-bis(diphenylphosphino)butane)(L)2 complexes was synthesized from [RuCl2(dppb) l2 (μ-dppb) or RuCl2 (dppb)- (PPh3); dppb = Ph2P(CH2)4PPH2, L = NH3, pyridine (py), 4-aminopyridine (4-NH2py), 4-cyanopyridine (4-CNpy), 4-dimethylaminopyridine (4-Me2Npy), 4-methylpyridine (4-Mepy), 4-phenylpyridine (4-Phpy), 4-vinylpyridine (4-Phy) and N-methylimidazole (Melm) and L2 = 2,2′-bipyridine (bipy), bis(o-pyridyl)amine (bpa), 1,10-phenanthroline (phen), 4,7-diphenylphenanthroline (or bathophenanthroline, batho) and ethylenediamine (en). The complexes were characterized by elemental analysis, cyclic voltametry, UV-Vis, NMR and IR spectroscopies. The structures of trans-RuCl2(dppb) (py)2 (3), cis-RuCl2(dppb)(bipy) (4) and cis-RuCl2(dppb) (phen) (5) were established by X-ray crystallographic analyses. Crystals of trans-3, cis-4-CH2Cl2 and cis-5-solvate are all monoclinic, space group P21/c, with Z=4; a = 12.946 (2), b = 14.204(3), c = 18.439(4) A , β = 90.08(2)° for trans-3; a=10.694(6), b=18.485(6), c=18.632(7) A , β = 90.26(3)° for cis-4·CH2Cl2; a = 17.094 (1), b = 9.923(2), c = 21.905(2) A , β = 98.883 (6)° for cis-5 solvate. The structures were solved by the heavy atom Patterson method and were refined by full-matrix least-squares procedures to R=0.069, 0.071 and 0.036 (Rw = 0.069, 0.076 and 0.039) for 1957, 4165 and 4824 reflections with l ≥ 3σ (l), respectively.

Kinetics and mechanism of H2-hydrogenation of styrene catalyzed by [RuCl(dppb) (μ-Cl)]2 (dppb = 1,4-bis(dipphenylphosphino)butane). Evidence for hydrogen transfer from a dinuclear molecular hydrogen species

Abstract Kinetic studies on the H 2 -hydrogenation of styrene catalyzed by [RuCl(dppb)(μ-Cl)] 2 (dppb = Ph 2 P(CH 2 ) 4 PPh 2 ) in N,N-dimethylacetamide solution, near ambient conditions have revealed a first-order dependence on Ru, and dependences on H 2 and on styrene that are first-order at lower concentrations and decrease with increasing concentration. Considered along with NMR and tensiometric data, the findings are interpreted in terms of a basic hydride route in which an initially formed, dinuclear, molecular hydrogen complex ( η 2 -H 2 )Ru(dppb)( μ -Cl) 3 RuCl(dppb) transfersboth hydrogens to the styrene.

Triply-bridged diruthenium(II) 1,4-bis(diphenylphosphino)butane (dppb) and (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (binap) complexes, including structural characterisation of [(dppb) ClRu(μ-D2O)-(μ-Cl)2RuCl(dppb)], [(η2-H2) (dppb)Ru(μ-Cl)3RuCl(dppb)] and the [(dppb)ClRu(μ-Cl)3RuCl(dppb)]− anion

Abstract Several triply-bridged diruthenium(II)(1,4-bis(diphenylphosphino)butane) complexes were synthesised and characterised by elemental analysis, UV-Vis, NMR and IR spectroscopies. The solid-state structures of [(dppb)ClRu(μ-D2O)(μ-Cl)2RuCl(dppb)] (1), [(η2-H2) (dppb)Ru(μ-Cl)3RuCl(dppb)] (2) and [Tmp][(dppb)ClRu(μ-Cl)3RuCl(dppb)] (3) were established by X-ray crystallographic analyses (TMP = 1,1,3-trimethyl-2,3-dihydroperimidinium; dppb = Ph2P(CH2)4PPh2). Crystals of 1·1.5C6D6, 2·1.5C7D8 and 3·2Me2CO·2H2O are all monoclinic, space groups P21/c, P21/n and C2/c, respectively, with Z = 4; a = 16.8681(6), b = 13.3542(4), c = 26.4966(7) A, β = 91.877(1)° for 1·1.5C6D6; a = 19.8123(1), b = 14.5246(2), c = 22.1803(1) A, β = 106.58(1)° for 2·1.5C7D8; a = 21.596(2), b = 16.019(2), c = 22.317(2) A, β= 106.15(1)° for 3·2Me2CO·2H2O. The structures of 1 and 2 were solved by direct methods while 3 was solved by heavy atom methods and all were refined by full-matrix least-squares procedures to R1 = 0.0433, 0.0612 and R = 0.039 (wR2 = 0.0709 (1), 0.1178 (2)) for 7751, 6757 and 5237 reflections with I ≥ 2σ(I) for 1 and 2 and I ≥ 3σ(I) for 3, respectively. Complex 1 was also studied in the solid-state by 31P CP/MAS NMR spectroscopy. The bromo- and iodo-analogues of 1 were prepared, and these three species were screened as catalysts for hydrogenation of aldimines. The complexes [H2NR2][{RuCl(P-P)}2(μ-Cl)3] were synthesised by the addition of NR3 or [H2NR2]Cl to RuCl2(P-P) (PPh3), where P-P = dppb or (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (binap) and R - Et, n-Bu or n-Oct. The syntheses of [(DMA)2H][(PPh3)2ClRu(μ-Cl)3RuCl(PPh3)2], [(py)(dppb)Ru(μ-Cl)3RuCl(dppb)] and [(C2H4) (dppb)Ru(μ-Cl)3RuCl(dppb)] were also accomplished (DMA = N,N-dimethylacetamide; py = pyridine).

Homogeneous hydrogenation of nitriles: effective ruthenium-phosphine catalysts

Abstract Di- and trinuclear ruthenium(II) complexes containing one Ph 2 P-(CH 2 ) 4 PPh 2 ligand (dppb) per Ru are effective precursor catalysts for the selective, homogeneous H 2 -hydrogenation of benzonitrile to benzylamine, the imine PhCH 2 N=CHPh, or dibenzylamine, depending on reaction conditions.

The co-crystallization of Ru((R)-binap)(η3-Me-allyl)2 and binap dioxide, and synthesis of Ru(Ph2P(CH2)4PPh2)(η3-Me-allyl)2

Abstract The molecular structure of the 2-methylallyl species Ru(( R )-binap)( η 3 -Me-allyl) 2 ( 3 ) was established by X-ray crystallography of a crystal of 3a , the asymmetric unit of which is composed of half of a molecule of 3 and half of a ( R )-(+)-2,2′-bis(diphenylphosphinoyl)-1,1′-binaphthyl(binap dioxide) molecule, co-crystallized with two disordered deuterobenzenes; crystals of 3a are tetragonal, space group I 422, with Z =8, a =21.344(1) A and c =36.453(2) A. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R =0.034 and R w =0.032 for 3431 reflections with I ≥3 σ ( I ). The 1,4-bis(diphenylphosphino)butane (dppb) analogue ( 2 ) of 3 was also prepared and characterized by 1 H and 31 P{ 1 H}-NMR spectroscopy and elemental analysis, and the reactivities of 2 and 3 toward halogen acids are discussed.

Intramolecular proton transfer from a cation to the associated,structurally characterised, hydride-containing anion[(PPh3)2(H)Ru(µ-H)(µ-Cl)2Ru(H)(PPh3)2]- to give anη2-H2 complex

The previously unknown, dinuclear, ionic ruthenium(II) species [Hdma][(PPh 3 ) 2 (H)Ru(µ-H)(µ-Cl) 2 Ru( H)-(PPh 3 ) 2 ]·dma 1 (dma = N,N-dimethylacetamide) is characterised by X-ray crystallography; in solution, intramolecular proton transfer from the cation to the anion gives the known molecular hydrogen complex [(PPh 3 ) 2 (η 2 -H 2 )Ru(µ-H) (µ-Cl) 2 Ru(H)(PPh 3 ) 2 ] 2.