Oligophosphan-Liganden, XXXVIII / Oligophosphine Ligands, XXXVIII

Abstract

Intermolecular activation of carbon-hydrogen bonds has been accomplished by reduction with sodium amalgam of (sip3)(Me3P)RuCl2, 1, [“sip3” = MeSi(CH2PMe)2)3] in aromatic hydrocarbons, such as benzene and substituted derivatives thereof. In these reactions, the 16e equivalent (sip3XMe3P)Ru(O) thus generated exhibits a preference for insertion across the unhindered metaand para-C-H bonds to produce complexes of composition (sip3)(Me3P)RuH(C6H3RR′) [R = R′ = H, 2; R = H, R′ = CH3, 3; R = R′ = CH3 (3,4-xylyl), 4; R = R′ = CH3 (3,5-xylyl), 5; R = H, R′ = CF3, 6], of which 3, 4, and 6 were isolated as mixtures of meta/para-isomers and Ru-aryl rotamers, respectively. Reaction of the phenyl hydride 2 with 4-MeC6H4NCE (E = O, S) leads to insertion of the heteroallenes into the Ru-Η bond to give (sip3)(Me3P)Ru[N(C6H4Me-4)C(O)H]C6H5, 8, and (sip3)(Me3P)Ru[SC(=NC6H4Me-4)H]C6H5, 10, as the primary products. While the latter forms (sip3), 11, by loss of PMe3, the former reacts with another molecule of isocyanate to afford the acyl compound (sip3)9, as the ultimate product. Treatment of 2 with CO2 results in the formation of a carbonato derivative, (sip3)(Me3P)Ru(O2CO), 7.•

Stereochemical Control of Transition Metal Complexes by Polyphosphine Ligands

“…For example with Fe(BF4)2 the borohy-Scheme 25 When the apical carbon atom in these podands is replaced by the larger silicon atom as in MeSi(CH2-PMe2)3, the resultant metal complexes can metalate certain substrates. 149 The larger stereochemical control of the ligand and the added electron density on the metal atom, contribute to electron rich coordination sites for the type of intermolecular metalation (Scheme 26). The formation of the carbonate complex 92 is Scheme 26 92 "O unusual and only occurs under pressure.…”

Group 8 Transition Metal Complexes of the Tripodal Triphosphino Ligands PhSi(CH2PR2)3 (R = Ph, iPr)

“…These latter neutral tridentate tripodal phosphine ligands were previously employed to stabilize highly reactive iron(0) complexes for vicinal dichlorine elimination at dichloroalkenes6,7 or heterodinuclear trihydride complexes of rhodium and iron for hydrogenations and C–H activation reactions 8. For ruthenium, they have also been used in mechanistic studies of C–C and C–H bond activations 9–11. In this contribution we report new triphosphines PhSi(CH 2 PPh 2 ) 3 ( 1a ) and PhSi(CH 2 P i Pr 2 ) 3 ( 1b ).…”

Direct Preparation of [Ru(η2‐O2CO)(η6‐arene)(L)] Carbonate Complexes (L = Phosphane, Carbene) and Their Use as Precursors of [RuH2(p‐cymene)(PCy3)] and [Ru(η6‐arene)(L)(MeCN)2][BF4]2: X‐ray Crystal Structure Determination of [Ru(η2‐O2CO)(p‐cymene)(PCy3)]·1/2CH2Cl2 and [Ru(η2‐O2CO)(η6‐C6Me6Demerseman1, Mbaye2, Sémeril3 et al. 2006Eur J Inorg Chem465370View full textAdd to dashboardCite

“…Their formation has been observed during the course of various processes, including metathetical exchange between an alkali [ metal carbonate and a ruthenium halide or cationic ruthenium precursor, [8][9][10][11] reaction of carbon dioxide with an oxaruthenacyclobutane, [8] hydrolysis of carbamato ligands, [12] oxidation of coordinated carbon monoxide, [13][14][15][16][17][18] and reactions involving a formal reduction of carbon dioxide (2 CO 2 + 2e -Ǟ CO + CO 3 2-). [19,20] From a structural point of view, mononuclear carbonatoruthenium() complexes contain an Ru(η 2 -O 2 CO) fragment, whereas the carbonate dianion is a bridging ligand in the dinuclear [Ru 2 (µ-O 2 CO) 4 ] 3-anion [21][22][23] and in polynuclear, heteroleptic ruthenium complexes. [9,24,25] The involvement of carbonatoruthenium complexes in organometallic synthesis is still uncommon but, remarkably, the carbonato complex [Ru(η 2 No reaction was detected under similar conditions starting from [RuCl 2 (p-cymene)(PR 3 )] precursors 1b,c (b: R = Ph; c: R = Me) without the addition of a small amount of water to the reaction mixture (ca.…”