Containing Wide-Bite. Angle Bisphosphines

Catalysts Containing Wide-Bite-Angle Bisphosphines 

The structure of H (CO)(BISBI)(PPh3) determined by X-ray diffraction demonstrated for the first time the unequivocal diequatorial coordination of a bidentate diphosphine. The 124° bite angle measured for BISBI is similar to the calculated natural bite angle of 112°. When HRh(CO)(BISBl)(PPh3) was placed imder 1 atm of CO, PPhj was replaced by CO to give HRh(CO)2(BISBl), which was shown by NMR and IR spectroscopy to possess a structure in which the two phosphorus atoms reside in the equatorial plane, and the hydrogen atom resides in an apical position. 

PhgP PPhj PPhg PPha PPhg PPhg PhgP P 

Relationship between several ligand bite angles and n i selectivity for propene hydroformylation. 

In contrast, deuterioformylation of 1-hexene with catalysts containing dppe and other bisphosphines under these mild conditions formed products containing deuterium only in the p-positions of the aldehdydes. This observation shows that formation of both n- and f-alkylrhodium complexes was irreversible with these less selective catalysts. 

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Catalysts Containing Wide-Bite-Angle Bisphosphines... 

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