[(η⁵-C₅H₅)Ru(PPh₃)(CNBu^t)(η-²-H₂)]PF₆: a cationic molecular hydrogen complex from protonation of a monohydride precursor

Abstract

Protonation of [(q5-C5H,)Ru(PPh3)(CNBut)H] with HPF6 gives the title complex, a cationic molecular hydrogen complex.Recently reported molecular hydrogen complexes fall into two classes: neutral complexes formed by reaction of molecular dihydrogen with co-ordinatively unsaturated precursors,1 and cationic complexes containing both metal hydride and metal-(q2-H2) ligands, formed by protonation of metal polyhydrides,2J or by reaction of molecular dihydrogen with a cationic monohydride.4 We now report the preparation of a cationic complex containing only a metal-(y2-H2) ligand from protonation of a neutral monohydride precursor.The monohydride, [ (+C5H5)Ru(PPh3)(CNBut)H] (1) was prepared by the reaction of LiA1H4 on [(q5-C5H5)Ru(PPh3)(CNBut)C1]5 as sand coloured crystals in 94% yield. The compound was characterised by elemental analyses and i.r. [CH2C12, vmax,: 2049, (CN); 1974, (Ru-H) cm-11 and 1H n.m.r. spectroscopy [C6D6, 6: -11.4 (d, JpH 34 Hz,Reaction of (1) with aqueous HPF6 in dichloromethane solution at 0 "C caused an immediate colour change and from the orange solution the pale yellow cationic complex, [(y5-

Characterization of transition-metal molecular hydrogen complexes by solid-state proton NMR

“…zraru-Stilbene formation with C6H5IO was found to be BLM-independent; the ratio was therefore omitted. including m-stilbene oxide and benzaldehyde.5 Exclusion of dioxygen had little effect on the production of m-stilbene oxide, in accord with the hypothesis that 02 plays no direct role in the formation of this product in exogenous oxidant-supported reactions.511 In contrast, in all cases the yield of benzaldehyde was (6) Oxidants employed included H202, NaI04, C6H5IO, and cumene hydroperoxide. In a typical experiment, 15 mL of an aqueous solution of preformed 9.1 mM Fe'"-BLM was added to a solution composed of 150 yL of 100 mM cii-stilbene in methanol and 285 uL of 8:2 methanol/water.…”

S–H Bond cleavage versus thiol co-ordination in half-sandwich ruthenium complexes †

“…13 The relevance of this reaction is striking, given the reluctance of d 6 ruthenium() complexes to undergo oxidative addition. 4 However we failed in identifying any species resulting from the interaction of organic thiols such as HSPh with either [RuCp*-Cl(PEt 3 ) 2 ] or [RuCpCl(PEt 3 ) 2 ]. We now show that the systems [RuCp*Cl(dippe)] and [RuCpCl(dippe)] (dippe = 1,2-bis-(diisopropylphosphino)ethane) exhibit a behaviour towards H 2 S quite similar to that of their PEt 3 counterparts, and it has been possible to prepare the new hydridometallothiol derivative † Supplementary data available: ].…”

Coordination of molecular hydrogen and nitrogen to coordinatively unsaturated tungsten carbonyls in the gas phase

“…Since the first isolable molecular hydrogen complex, M(CO)3(PR3)2(t;2-H2) (M = Mo, W;R = Cy, f-Pr), was characterized by X-ray and neutron diffraction and IR and NMR spectroscopies,9 several molecular dihydrogen complexes have been reported. [10][11][12][13][14][15][16][17][18][19][20] Dihydrogen complexes of the group 6 metal carbonyls of the form M(CO)x(H2)^( M = Cr, Mo, W) have been of special significance as models in theoretical studies of H-H bond activation on metal centers.2 •21•22 They are presumed to be intermediates in both hydrogenation reactions1 and the water-gas shift reaction. 23 The structure of Cr(CO)5(H2) has been confirmed by the characteristic IR band associated with H-H stretching at 3030 cm-1.…”