Supported Organometallic Complexes. XXXVIII [1] Bis(methoxyethyldimethylphosphine)ruthenium(II) Complexes as Transfer Hydrogenation Catalysts

Abstract

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.

A simple molecule with a complex crystal structure: interplay of 31P solid‐state NMR spectroscopy and single‐crystal x‐ray diffraction in the structure determination of a ruthenium diphosphine diamine complex

“…For example, variations of the nature of the diamine in complexes such as 1 causes variations in υ( 31 P of the order of ca 10 ppm, 3,6,7,14 and it appears that the difference in υ( 31 P between the cis-P isomer (cct) and the trans-P isomer (tcc) is a shift to lower frequencies by about 10 ppm in the latter isomer. 15 16 The principal components of the CS tensor can be easily extracted from the points of inflection and the singularity of the powder pattern.…”

Synthesis, characterization, crystal structure and chemical behavior of [1,1-bis(diphenylphosphinomethyl)ethene]ruthenium(II) complex toward primary alkylamine addition

“…The phosphorus chemical shifts [11][12][13][14][15][16] suggest that the diphosphine ligands are trans to the amine (9) Ru(1)-Cl(1A) 2.4158 (9) Ru(1)-P(1) 2.4192 (10) Ru (1) co-ligands in complexes 3-5; the chlorides must be mutually trans in all of these complexes. The 13 C{ 1 H} NMR spectra also corroborate the structures given in Scheme 1.…”

“…Our ongoing research interest is to synthesize supported and non-supported phosphine Ru(II) complexes and to examine their activity for catalytic hydrogenation of unsaturated carbonyl compounds in homogenous and heterogeneous phase [11][12][13][14][15][16][17][18][19]. In this article, we describe the synthesis and characterization of mixed ligand ruthenium(II) complexes containing substitute dppme as primary ligand and RNH 2 as secondary ligands.…”

“…These functionalized phosphine ligands have important industrial applications such as water-soluble and asymmetric phosphines [9,10]. Metal complexes containing phosphorus ligands have always been important due to their possible catalytic activity, and a variety of them have been reported [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Several sixcoordinated complexes of ruthenium(II) of the general formula [RuX 2 (diphosphine) 2 ] have been reported in the last few years [3][4][5][6][7][8].…”

The Synthesis and Structure of Hexakis(dimethylphenylphosphonite)ruthenium(II) bis[tetraphenylborate(–1)]

“…The 13 C spectrum of 3 in DMSO gave a series of lines in the region 122–136 ppm, which were assigned to the aromatic carbon atoms of the phenyl rings, while the presence of methoxy carbon atoms were observed as a single line at δ = 57.22 ppm. The 31 P{ 1 H} NMR spectrum of 3 is a singlet at δ = 154.81 ppm, which indicates that all the phosphorus atoms in the complex are chemically equivalent 14. The 31 P chemical shift of free P(OMe) 2 Ph has been reported at δ +165.09 ppm 15.…”