An-Najah Staff

1-hTrans-dichloro-piperazine-bis(ether-phosphine)ruthenium(II) complex of general formula Cl2Ru(Ph2PCH2CH2OCH3)2(C4H10N2) 2 was made available in good yield through treating equimolar amounts of O)2 complex 1 with piperazine as co-ligand. The hemilability ring open reaction of ether-phosphine inÇCl2Ru(Pcomplex 1 to prepare complex 2 was monitored by 31P-NMR. The structure of complex 2 was confirmed by elemental analysis, IR, 31P-NMR 1H-NMR,13C-NMR, FAB-MS and UV-visible spectroscopy.

Trans-dichloro-piperazine-bis(ether-phosphine)ruthenium(II) complex of general  formula Cl₂Ru(h¹-Ph₂PCH₂CH₂OCH₃)₂(C₄H₁₀N₂) 2 was made available in good yield through treating equimolar amounts of Cl₂Ru(P^ÇO)₂ complex 1 with piperazine as co-ligand. The hemilability ring open reaction of ether-phosphine in complex 1 to prepare complex 2 was monitored by ³¹P-NMR. The structure of complex 2 was confirmed byelemental analysis, IR, ³¹P-NMR ¹H-NMR,¹³C-NMR, FAB-MS and UV-visible spectroscopy.

Diamineruthenium(II) complexes containing the hemilabile methoxyethyldimethylphosphine ligand, [Cl2Ru(Ln)(η1-Me2PCH2CH2OMe)2] (2Ln) (n = 1-12, Scheme 1), have been synthesized from the starting materials Me2PCH2CH2OMe, [Ru(COD)Cl2]n, and the respective diamines L1-L12. The structure of complex 2L5 reveals that two chlorides are in trans position, while in complex 2L11 the two chlorides favor a cis configuration. Most of the complexes are highly catalytic active in the hydrogen transfer reduction of acetophenone. The experimental study indicates that the replacement of phenyl groups for methyl functions in the ether-phosphine ruthenium(II) complexes resulted in a switch of the hydrogenation mechanism from direct hydrogenation to transfer hydrogenation. The reason is attributed to the better donor ability of methyl groups compared to phenyl substitutents. Thus the metal center becomes more electron-rich and inhibits the binding of dihydrogen to the ruthenium(II) complex fragment.

The novel trans-[Cl2Ru(II)(PPh3)2(3,4-diaminophenyl)(phenyl)methanone] complex was obtained by reacting RuCl2(PPh3)3 with equimolar amounts of (3,4-diaminophenyl)(phenyl)methanone as diamine co-ligand in CH2Cl2. One of the PPh3 ligand was quantitatively exchanged by (3,4-diaminophenyl)(phenyl)methanone, even when excess diamine was added. The trans-RuCl2 desired complex was characterized on the basis of elemental analysis, elemental analysis, FAB-MS, IR, UV-vis, 1H, 13C and 31P{1H}NMR.

The ligands exchange of the ether-phosphine (Ph2PCH2CH2OCH3) on the diamine(ether-phosphine)ruthenium(II) with 1,3-bis(diphenylphosphino)propane as a bidentate chelate ligand successfully occurs to produce diamine[1,3-bis(diphenylphosphino)propane]ruthenium(II) complexes in a good yields under vigorous stirring for one week in an inert atmosphere using dichloromethane as solvent. Several ether-phosphine-RuC12 complexes with different types of diamine have been tested to confirm the substitution method. In order to collect more information about the system 31P{1H} NMR and 13C{1H} NMR as well as FAB- Mass spectroscopy have been investigated in parallel way to control and support the ligands exchange reaction processes.

C33H40Cl2N2P2Ru, triclinic, P1 (no. 2), a = 9.870(1) Å, b = 13.044(1) Å, c = 14.446(3) Å, + = 110.86(1)°, * = 100.55(1)°, & = 107.657(9)°, V = 1565.2 Å3, Z = 2, Rgt(F) = 0.028, wRref(F2) = 0.067, T = 173 K.

Trans-dichloro-2,3-naphthalenediamine bis[(2-methoxyethyl)¬(diphenyl)¬phos¬phine]¬¬ruthenium(II) complex Cl2Ru(h1-Ph2PCH2CH2OCH3)2(C10H10N2) has been obtained by reaction of equimolar amounts of Cl2Ru(PÇO)2 complex 2 with one equivalent of 2,3-naphthalenediamine as co-ligand in very good yield. The structure of this new complex 3 was confirmed by elemental analysis, IR, 31P-NMR 1H-NMR, 13C-NMR, UV-visible spectroscopy and FAB-MS.

The novel diamine–bis(ether–phosphine)ruthenium(II) complexes Cl2Ru(η1-Ph2PCH2 CH2OCH3)2(diamine)2(3L1–3L11) have been obtained by reaction of equimolar amounts of Cl2Ru(P∩O)2 (2) with the respective diamines L1–L11 in good yields. X-ray structural investigations of 3L2 and 3L8 show monoclinic unit cells with the space group P21/c. The octahedrally coordinated ruthenium atoms have each two trans-chlorides and cis-phosphines which is in agreement with NMR studies in solution. With the exception of 3L4 all mentioned ruthenium complexes are highly catalytically active in the hydrogenation of the α,β-unsaturated ketone trans-4-phenyl-3-butene-2-one. In most cases the conversions and selectivities toward the formation of the unsaturated alcohol trans-4-phenyl-3-butene-2-ol were 100% with high turnover frequencies under mild conditions. Novel diamine–bis(ether–phosphine)ruthenium(II) complexes have been prepared and characterized. X-ray structural investigations of 3L2 and 3L8 show monoclinic unit cells with the space group P21/c. These complexes are highly catalytically active in the hydrogenation of an α,β-unsaturated ketone, with excellent conversions and selectivities under mild conditions.

The novel diamine(dppp)ruthenium(II) complexes 3L1–3L12 have been obtained by reaction of equimolar amounts of Cl2Ru(dppp)2 (2) with the diamines L1–L12 in excellent yields. Within a few minutes one of the diphosphine ligands was quantitatively exchanged by the corresponding diamine. X-ray structural investigations of 3L1, 3L2, and 3L8 show triclinic unit cells with the space groups PView the MathML source (3L1, 3L2) and P 1 (3L8). Whereas in solution all these complexes prefer a trans-RuCl2 configuration, in the solid state cis-(3L1, 3L2) and trans-isomers (3L8) were observed. With the exception of 3L5, 3L6, and 3L12 all mentioned ruthenium complexes are highly catalytically active in the hydrogenation of the α,β-unsaturated ketone trans-4-phenyl-3-butene-2-one. In most cases the conversions and selectivities toward the formation of the unsaturated alcohol trans-4-phenyl-3-butene-2-ol were >99% with high turnover frequencies (TOFs) under mild conditions.

Treatment of RuCl2(η1-Ph2PCH2CH2OCH3)2(diamine) (1L1–1L7) with one equivalent of AgX (X=OTf, BF4) in CH2Cl2 results in the formation of the monocationic ruthenium(II) complexes [RuCl(η1-Ph2PCH2CH2OCH3)(η2-Ph2PCH2CH2OCH3)(diamine)]+X− (2L1–2L7). These complexes were characterized by NMR, and mass spectroscopy as well as by elemental analyses, 2L1 additionally by an X-ray structural analysis. Complex 2L1 crystallizes in the monoclinic space group C2/c with Z=8. The monocationic and neutral complexes were applied as catalysts in the selective hydrogenation of trans-4-phenyl-3-butene-2-one. With the exception of 1L3/1L7 and 2L3/2L7 all catalysts showed high activities and selectivities toward the hydrogenation of the carbonyl group under mild conditions. However, the activity of the cationic catalysts is only half of that of their neutral congeners.