Rhodium(I) carbonyl complexes containing bidentate X, O-Bid [S,O-BdiPT or N,O-ox; S,O-BdiPTH = N-benzoyl-N′,N′-(diphenyl)thiourea; N,O-oxH = 8-hydroxyquinoline] ligands of the form [Rh(X,O-Bid)(CO)(PR 1 R 2 R 3 )] (R 1 , R 2 , R 3 = Ph or Cy) bearing different phosphine ligands, were investigated, the structural characterization of four example complexes is described and an extensive spectroscopic kinetic-mechanistic study of the oxidative addition of iodomethane thereto is discussed. Reaction with iodomethane led to Rh III -acyl species as secondary (final) products, whereas the primary Rh III -alkyl complexes, although rapidly formed, were only observed as intermediates, in small quantities for S,O-BdiPT (large S-Rh-O bite angle of 90-91°) but in significant amounts for N,O-ox complexes (less [a]

An automated control system was developed for the bench-scale evaluation of continuous catalytic regeneration (CCR) naphtha reforming catalysts. Deactivation of these catalysts is too rapid for fixed bed operation, and regenerating the catalyst continually is not feasible on bench scale. To emulate the commercial process, a solution was required which would allow catalyst evaluation at a constant research octane number (iso-RON). Because changes are too fast for manual adjustment (especially when using Fischer–Tropsch naphtha), automated adjustment of process conditions was required. This was achieved through the use of simple matrix algebra, semiautomated gas chromatography and on-line near-infrared (NIR) analyses. Commercial catalysts with very small activity and reformate yield differences, could be compared and their RON versus yield correlations determined. Product samples large enough for engine research octane number (RON) analyses could also be collected at steady state. Through the use of multidisciplinary analytical and advanced process control techniques, substantial improvement of bench-scale piloting methodology in naphtha reforming was obtained.

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Source of materialTo a cold DMF solution (5 mL) of [Rh(m-Cl)(CO) 2 ] 2 (30 mg, 0.1028 mmol) 2 equivalents of N-benzoyl-N'-(4-hydroxy-2-methylphenyl)thiourea were added [9]. After 4 minutes of stirring, ice-cold water was added to precipitate a dark-red solid. After isolating the solid, it was taken up in diethyl ether and treated with 4 equivalents of triphenylphosphine. The solvent was allowed to evaporate slowly, yielding the title compound as bright orange crystals. DiscussionIn our ongoing research in bidentate ligand systems, we have investigated the use of thiourea (tu) ligands for the synthesis of rhodium complexes, amongst others [1][2][3][4]. These ligands show exceptional coordination behaviour, being able to coordinate through their sulfur atom alone as a neutral monodentate ligand [5,6], through their sulfur and oxygen atoms as a monoanionic bidentate ligand [7], and as a monoanionic bidentate ligand through its sulfur and one of its nitrogen atoms (this work). This four-membered chelate ring has a very small bite angle of 63.06 (4)°, whereas the bite angle of the S,O-coordination mode is much closer to the preferred 90°for square planar coordination to rhodium(I) [8]. The coordination in the title compound can be described as distorted trigonal bipyrimidal, with the two triphenylphosphine ligands in the apical positions. Alternatively, the N,S-thioureato ligand can be considered as one donating moiety, in which case the complex can be described as distorted square planar. The rhodium-ligand bond lengths are all within expected ranges; the Rh-S and Rh-N bond lengths are 2.623(1) and 2.278(2) Å, respectively. The C-O bond length within the carbonyl ligand is 1.158(2) Å, while it is coordinated in an almost linear fashion, with a Rh1-C01-O1 angle of 176.9(2)°. The solid state structure is stabilized by both intra-and intermolecular hydrogen bonds. The intramolecular bond is between the N1 hydrogen and O2 (1.88(2) Å), whereas the intermolecular ones link two molecules together in a dimeric fashion from the phenolic hydrogen to the benzoyl oxygen (O2-H2···O3, 1.99 Å).