Ambiphilic ligands featuring benzyl spacers

As presented in Section II, several PBs featuring unsaturated C2 linkers (-C=C—, trails or cis -CR=CR -) have been prepared. Here, only the structure of the ds-alkenyl bridged systems 22 will be discussed since these are the only systems prone to forming intramolecular P-B 

The simplest bonding situation conceivable upon coordination of an ambiphilic ligand to a transition metal is that involving the sole coordination of the Lewis base moiety, the Lewis acid fragment remaining pendant. Several examples of such complexes have been described in the recent years, most frequently upon coordination of preformed ambiphilic ligands. 

Subsequently, Landis studied the coordination of the ferrocene-based diphosphine-benzoxaborolidine ligands 53 with the aim of supporting secondary interactions between the pendant Lewis acid and an external Lewis base.63 Stable platinum complexes 63a-c were formed by reacting 

The structure of 73 was substantiated spectroscopically (5 nB = 82.5 ppm) and confirmed crystallographically. A centrosymmetric chloro-bridged dimeric structure with tricoordinate copper centers was observed. The pendant character of the borane is apparent from the rather long the B- Cu (3.05 A) and B- Cl (4.06 A) distances associated with a trigonal planar geometry around boron. Compared to related mononuclear palladium and rhodium complexes (see Section IV.B), the presence of the chloro-bridge disfavors the formation of Cl-B interactions (coordination mode F) in 73. 

Hereafter are described the few complexes featuring pendant borane moeities that have been obtained as rearranged- or side-products starting from phosphine-borates. 

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