Ligands bite angle

The structure of tris(l,l,l,5,5,5-hexafluoro-2,4-pentanedionato)chromium(III) has been determined by gas-phase electron diffraction.767 A most interesting feature of this study was that the normalized ligand bite angle [(O—O/M—O) 30.1°] was very close to the value found in the solid state by X-ray diffraction (30.8°) but quite different to the value predicted by Kepert s model,768 The results of this and related work on vapour phase structures are summarized in Table 80. 

Figure 6.14 Bar graph comparing the analysis All calculations were performed on a 2.5 GHz capacity, in number of ligands bite angles and desktop computer (analysis capacity will flexibility ranges calculated per hour, using improve with better computers and software, topological descriptors (2D), and 3D descriptors but the 2D/3D cost-effectiveness ratio will based on MM force fields, semi-empirical remain constant).

Note Selectivity issues in phosphane rhodium catalyst hydroformylation reactions are often discussed in terms of the ligand bite angle [109-111 ]. This feature is entirely absent in the monodentate NHC ligands discussed here. 

Ditertiary phosphines such as (86), (92), and (98) (100) (Scheme 6) have found important uses as ligands for metal-catalyzed transformations, including e.g., palladium-catalyzed Grignard cross couplings,194,205 rhodium-catalyzed Michael additions,2 hydrocyanations,206 copolymerizations,20 and palladium-catalyzed animations.208 Rhodium complexes of (86) are catalysts for the carbonylation of methanol.188 More recently the ligand bite angle of ditertiary phosphines such as (100) has been shown to influence catalytic activity/selectivity in several important catalytic processes.209-213... 

The effect of the ligand bite angle on the enantioselectivity in the copper(n) catalyzed Diels-Alder reaction of cyclopentadiene with A-acryloyl-l,3-oxazoUdin-2-one was studied using spiro bis(oxazolidine) based complexes 431a-d (Table The data... 

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