Bite angles

Role of the bite angle (DA-M-DA angle, where DA is donor atom andD is metal atom) in catalytic properties of catalysts with xanthene-based bis-phosphine ligands 99PAC1443. 

Table 3. N-M-N Bite angle in di(pyridyl) ligand systems...

The catalytic hydroformylation of alkenes has been extensively studied. The selective formation of linear versus branched aldehydes is of capital relevance, and this selectivity is influenced by many factors such as the configuration of the ligands in the metallic catalysts, i.e., its bite angle, flexibility, and electronic properties [152,153]. A series of phosphinous amide ligands have been developed for influencing the direction of approach of the substrate to the active catalyst and, therefore, on the selectivity of the reaction. The use of Rh(I) catalysts bearing the ligands in Scheme 34, that is the phosphinous amides 37 (R ... 

Much progress has been made on regioselective hydroformylation of terminal alkenes in favor of the linear product. In particular bidentate phosphine or phosphite ligands, which have a natural bite angle 9 of about 110°, will favor the linear product. The most successful ligand types are BISBI [49, 50], BIPHEPHOS [51,52], and XANTPHOS systems (Scheme 8) [53]. 

Various mixed tridentate ligands with P,N,0/S/N donor sets have been explored in Ni11 chemistry. For example, condensation of 2-(diphenylphosphino)aniline with substituted (5-chloro-, 5-nitro, 5-bromo-, 5-methoxy-, and 3-methoxy-) salicylaldehydes yields (253).697 The deprotonated ligand coordinates through its P,N,0 donor set in a square planar geometry with some distortion, which is probably due to the bulk of the phosphine group and to the bite angle of the P,N chelate. 

The Ni—N bond distances, N—N bite distances, and N—M—N bite angles of Ni11 macrocyclic complexes depend on the coordination number of the metal ion and the type of macrocycle. These... 

Dppm has been used widely in coordination chemistry. Silver(I)-dppm complexes have been reported in several ratios and they present different structural frameworks. Due to the bite angle... 

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