The coordination behaviour of large natural bite angle diphosphine ligands towards methyl and 4-cyanophenylpalladium(ii) complexes

Zuideveld, Martin A.; Swennenhuis, Bert H. G.; Boele, Maarten D. K.; Guari, Yannick; Strijdonck, Gino P. F. van; Reek, Joost N. H.; Kamer, Paul C. J.; Goubitz, K.; Fraanje, Jan; Lutz, Martin; Spek, Anthony L.; Leeuwen, Piet W. N. M. van

doi:10.1039/b111596k

Cited by 147 publications

(132 citation statements)

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“…The trans coordination in square-planar palladium complexes with xanthene-based diphosphine ligands has been reported before by van Leeuwen and co-workers 13 and independently by Yin and Buchwald. 24 In both cases, bite angles of around 150Њ were found in the solid state structures with Pd-O backbone distances of around 2.6 Å, which might point to a weak bonding interaction, and consequently to a square pyrimidal coordination around the palladium atom.…”

Section: 23supporting

confidence: 64%

Coordination chemistry and X-ray studies with novel sterically constrained diphosphonite ligands

et al. 2003

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The coordination of two novel, sterically constrained diphosphonite ligands towards different palladium, platinum and rhodium precursors has been studied. Complexes of this hitherto unexplored class of diphosphonites, based on rigid xanthene backbones, have been characterized by X-ray crystallography as well as by NMR and IR spectroscopy. A short and concise overview is given on the scarce literature on phosphonite related chemistry. Structural differences in the complexes obtained due to steric influences of the ligands are discussed. Ligand 1, bearing 2-tert-butylphenolate groups, led to orthometallated complexes cis-[MCl{1-κ 3 C,P,P}] (M = Pd, Pt) and to trans- [RhCl(CO) (1)]. These complexes were compared with those formed with ligand 2, bearing 2,2Ј-dioxo-3,3Ј-di-tert-butyl-5,5Ј-dimethoxy-1,1Ј-biphenyl groups, preventing orthometallation. The complexes trans-{PdCl 2 (2)], cis-[PtCl 2 (2)] and trans-[RhCl(CO)(2)] were structurally characterized. Valuable data were collected on chemical shifts, Pt-P coupling constants, as well as CO stretch frequencies of Rh-CO complexes as important tools for structural characterization of such complexes. IntroductionProgress and development of homogeneous catalysis is very much related and dependent on the synthesis and availability of ligands. In recent years a number of powerful new ligand classes have emerged, most of which are chelating phosphorusbased compounds 1 such as phosphines 2 or phosphites.3 Phosphonites however have been widely neglected and only very recently a few examples were reported. Reetz et al. used several backbones, amongst others ferrocene, to prepare chelating diphosphonites and used them in asymmetric Rh-catalyzed hydrogenations of the typical benchmark substrates 4 as well as in conjugate addition of aryl boronic acids.5 ZanottiGerosa et al. also described diphosphonites but they used the para-cyclophane backbone and performed hydrogenation reactions.6 Pringle andco-workers used binaphthol-derived mono-and bidentate phosphonites for conjugate additions of diethyl zinc to enones. 7 The same monophosphonites were used by Claver and Pringle in asymmetric hydrogenations.8 Scharf and co-workers used the monodentate phosphonites based on TADDOL as the chiral auxiliary for the rhodum-catalyzed hydrosilylation of ketones.9 Börner and co-workers have published on the use of both monodentate and bidentate phosphonite ligands in the hydroformylation of alkenes, with varying results.10 Finally the Reetz group, in line with their earlier work, prepared phosphite-phosphonite bidentate ligands but no applications in catalysis were reported so far. 11During recent years xanthene-based chelating ligands have been introduced and extensively used in transition metal catalyzed C-C bond forming reactions.12 These backbones provide a unique combination of rigidity and P-P distance in such a way, that specific, large bite-angle coordination modes are supported. Additionally interaction of the central oxygen atom in the backbone with a metal atom coordinated is possible...

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Section: 23supporting

confidence: 64%

Coordination chemistry and X-ray studies with novel sterically constrained diphosphonite ligands

et al. 2003

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“…Concerning the diphosphine derivative, the typical P À M À P angle in a cis palladium complex is 104.68 [Pd(7)A C H T U N G T R E N N U N G (TECN)] [19] while for [PtCl 2 (7)] the angle is 99.178. [20] However, it is known that the weak interaction with the bridgehead oxygen atom can give rise to pseudo-terdentate coordination and hence to very large bite angles.…”

Section: X-ray Crystal Structures Of Co(6)cl 2 and Co(7)clmentioning

confidence: 99%

Highly Selective Cobalt‐Catalyzed Hydrovinylation of Styrene

et al. 2009

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Phosphine complexes of cobalt halide salts activated by diethylaluminum chloride are shown to yield highly active catalysts in the hydrovinylation of styrene, with unprecedented high selectivity to the desired product 3-phenyl-1-butene (3P1B). Doublebond isomerization, a common problem in codimerization reactions, only occurs after full conversion with these catalyst systems, even at elevated temperature. The most active catalysts are based on cobalt halide species combined with either C 1 -or C 2 -bridged diphosphines, heterodonor P,N or P,O ligands, flexible bidentate phosphine ligands or monodentate phosphine ligands. Kinetic investigations show an order > 1 in catalyst, which indicates either the involvement of dinuclear species in the catalytic cycle or partial catalyst decomposition via a bimolecular pathway.

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“…[19] Compared with crystal structures of Pd complexes known for xanthene diphosphane ligands, the bite angle of 100°for ligand 1 is unusually small. For instance, we previously reported on trans-coordinated diphosphonites [16] and both van Leeuwen et al [20] and Buchwald et al [21] reported on trans-Pd(Xantphos) complexes. Only in the case of Pd 0 complexes or with cationic palladium species has cis-coordination of Xantphos been ob- (1)]; displacement ellipsoids are drawn at the 50% probability level; all hydrogen atoms and solvent molecules are omitted for clarity; PdϪP 1 2.2449(9); PdϪP 2 2.2532(9); PdϪCl 1 2.3412(10); PdϪCl 2 2.3442 (9); P 1 ϪO served by X-ray crystallography.…”

mentioning

confidence: 92%

“…Only in the case of Pd 0 complexes or with cationic palladium species has cis-coordination of Xantphos been ob- (1)]; displacement ellipsoids are drawn at the 50% probability level; all hydrogen atoms and solvent molecules are omitted for clarity; PdϪP 1 2.2449(9); PdϪP 2 2.2532(9); PdϪCl 1 2.3412(10); PdϪCl 2 2.3442 (9); P 1 ϪO served by X-ray crystallography. [20,22] , indicating that the palladium is actually positioned outside the plane defined by the backbone and the phosphorus atoms, as illustrated in This is quite unusual for cis-Pd-diphosphorus complexes. A similar structural disposition of the metal atom, together with a small ligand bite angle, was found for an unexpected ortho- Figure 4.…”

mentioning

confidence: 92%