Dicarbonyl­{3,3′-di-tert-butyl-5,5′-di­meth­oxy-2,2′-bis­[(4,4,5,5-tetra­phenyl-1,3,2-dioxa­phospho­lan-2-yl)­oxy-κP]biphen­yl}hydridorhodium(I) diethyl ether monosolvate

In the title compound, [Rh(C74H68O8P2)H(CO)2]·C4H10O, the C2HP2 coordination set at the RhI ion is arranged in a distorted trigonal–planar geometry with one P atom of the diphosphite mol­ecule and the H atom adopting the axial coordination sites

{2-[Bis(2,4-di-tert-butyl­phen­oxy)phosphan­yloxy-κP]-3,5-di-tert-butyl­phenyl-κC 1}[(1,2,5,6-η)-cyclo­octa-1,5-diene]rhodium(I) toluene monosolvate

The reaction of (η3-all­yl)[(1,2,5,6-η)-cyclo­octa-1,5-diene]rhodium(I) with tris­(2,4-di-tert-butyl­phen­yl)phosphite in toluene produces the title compound, [Rh(C42H62O3P)(C8H12)]·C7H8, by spontaneous metallation at one of the nonsubstituted phenyl ortho-C atoms of the phosphite mol­ecule. The coordination geometry at the RhI ion is distorted square-planar. The toluene solvent mol­ecule is disordered over two different orientations, with site-occupation factors of 0.810 (2) and 0.190 (2)

Effects of substitution pattern in phosphite ligands used in rhodium-catalyzed hydroformylation on reactivity and hydrolysis stability

The stability of homogeneous catalytic systems is an industrially crucial topic, which, however, receives comparatively little attention from academic research. Phosphites are among the most frequently used ligands in industrial, rhodium-catalyzed n-regioselective hydroformylation. However, they are particularly vulnerable to hydrolysis. Since the decomposition of ligands should be dependent on the substitution patterns, phenyl, tert-butyl and condensed ring systems of benzopinacolphosphites were evaluated concerning their activity, regioselectivity and hydrolysis stability. A series of twelve strongly related phosphites were synthesized, tested in the hydroformylation of isomeric n-octenes, and studied in hydrolysis experiments using in situ NMR spectroscopy. Our results show that substituents in the ortho-position, especially tert-butyl substituents, enhance hydrolysis stability while maintaining compelling activity and regioselectivity. In contrast, substituents in the para-position may destabilize the phosphite. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Synthesis of C2-Symmetric Diphosphormonoamidites and Their Use as Ligands in Rh-Catalyzed Hydroformylation: Relationships between Activity and Hydrolysis Stability

A series of diphosphoramidites has been synthetized with a piperazine, homopiperazine, and an acyclic 1,2-diamine unit in the backbone. New compounds were tested alongside related N-acyl phosphoramidites as ligands in the Rh-catalyzed hydroformylation of n-octenes to investigate their influence on the activity and regioselectivity. A subsequent study of their hydrolysis stability revealed that the most stable ligands induced the highest activity in the catalytic reaction

Carbonyl{3,3′-di-tert-butyl-5,5′-dimethoxy-2,2′-bis[(4,4,5,5-tetramethyl-1,3,2-dioxaphospholan-2-yl)oxy]biphenyl-κ2P,P′}hydrido(triphenylphosphane-κP)rhodium(I) diethyl ether trisolvate

In the title compound, [RhH(C74H68O8P2)(C18H15P)(CO)]·3C4H10O, the CHP3 coordination set at the RhI ion is arranged in a distorted trigonal–bipyramidal geometry with the P atoms adopting equatorial coordination sites and the C atom of the carbonyl ligand as well as the H atom adopting the axial sites. The asymmetric unit contains two very similar molecules of the rhodium complex, two half-occupied diethyl ether molecules and further diethyl ether solvent molecules which could not be modelled successfully. Therefore contributions of the latter were removed from the diffraction data using the SQUEEZE procedure in PLATON [Spek (2009). Acta Cryst. D65, 148–155]

Tetrakis(μ-benzoato-κ2O:O′)bis[(piperidine-κN)rhodium]

The title compound, [Rh2(C7H5O2)4(C5H11N)2], an adduct of dimeric rhodium(II) benzoate with piperidine, was prepared. The complex lies across an inversion centre with the unique RhII ion in a slightly distorted octahedral coordination environment

{2-[Bis(2,4-di-tert-butylphenoxy)phosphanyloxy-κP]-3,5-di-tert-butylphenyl-κC1}{3,3′-di-tert-butyl-5,5′-dimethoxy-2,2′-bis[(1,1,2,2-tetraphenylethane-1,2-dioxy)phosphanyloxy-κP]biphenyl}rhodium(I) toluene-d8 2.7-solvate

The molecule of the title compound, [Rh(C42H62O3P)(C74H68O4P2]·2.7C7D8, consists of two phospharhodacyclic substructures sharing the Rh atom, which are formed by coordination/ortho-metallation of a triaryl phosphite, and by the coordination of a rigid bisphosphite, respectively. The metal displays a tetrahedrally distorted square-planar coordination geometry. A tert-butyl group shows rotational disorder over two positions with refined site occupancy of 0.561 (3):0.439 (3). Two partial-occupancy toluene solvent molecules are disordered over two orientations with site occupancies of 0.5:0.3 and 0.5:0.4, respectively. Intramolecular C—H...O hydrogen bonds are observed. In the crystal, complex molecules and toluene solvent molecules pack as alternating layers parallel to the ac plane

Effects of Substitution Pattern in Phosphite Ligands Used in Rhodium-Catalyzed Hydroformylation on Reactivity and Hydrolysis Stability

The stability of homogeneous catalytic systems is an industrially crucial topic, which, however, receives comparatively little attention from academic research. Phosphites are among the most frequently used ligands in industrial, rhodium-catalyzed n-regioselective hydroformylation. However, they are particularly vulnerable to hydrolysis. Since the decomposition of ligands should be dependent on the substitution patterns, phenyl, tert-butyl and condensed ring systems of benzopinacolphosphites were evaluated concerning their activity, regioselectivity and hydrolysis stability. A series of twelve strongly related phosphites were synthesized, tested in the hydroformylation of isomeric n-octenes, and studied in hydrolysis experiments using in situ NMR spectroscopy. Our results show that substituents in the ortho-position, especially tert-butyl substituents, enhance hydrolysis stability while maintaining compelling activity and regioselectivity. In contrast, substituents in the para-position may destabilize the phosphite