Polyphosphines, ligands

The complex consists of a bis(diphosphinomethanide) ligand binding a lithium atom at each end in an t/2-PP coordination mode [Li-P = 2.542(6) and 2.559(6) A]. The lithium atoms achieve four-coordination through the coordination of two molecules of THF each. Hydrolysis of this complex is an excellent route to the otherwise inaccessible tetraphosphine (Ph2P)2CHCH2 2, a potentially useful polyphosphine ligand analogous to two linked bis(diphenylphosphino)-methane (dppm) moieties. 

The phosphorus macrocycles are made via template condensation of coordinated polyphosphine ligands and a dibromoalkane (equation 8).60 A more recently reported method involves a template-assisted single-stage ring closure (equation 9).61 The arsenic donor macrocycles are synthesized by reacting lithiated polyarsanes with a dichloroalkane (equation 10).62... 

By using a combination of known reactions, synthetic chemistry, and electrochemistry, new catalysts for the electrochemical reduction of CO2 have been developed. Consideration of the electrochemical properties of a variety of transition metal complexes containing polyphosphine ligands led to a more detailed study of metal complexes of the type [M(PP2)(PR3)HbF )2 (where M is Ni, Pd, and Pt ... 

More recent work on the hydrogenation of thiophenic molecules catalyzed by water-soluble metal complexes is pursuing the use of polyphosphine ligands (cf. Section 3.2.2). These studies follow the success obtained with the tridentate phosphine MeC (CH2PPh2)3 (TRIPHOS), which forms rhodium and iridium catalysts for the hydrogenation, hydrogenolysis, and desulfurization of various thiophenic... 

Polyphospha macrocycles can be made via template condensations of coordinated polyphosphine ligands and dibromoalkanes (Scheme 6). ... 

Structure and Reactivity Patterns of Polyphosphine Ligands and Their Complexes of Rhodium and Cobalt(I)... 

This paper is concerned with all these five aspects of polyphosphines. In addition, the methods for synthesizing polyphosphine ligands are discussed briefly. 

Flexible polyphosphine ligands (e.g., 5-9), which contain either ethylene or trimethylene linkages, have been used to form mononuclear... 

Whereas many tri- and tetra-dentate combinations of nitrogen, oxygen, and sulfur donors have been accomplished via the template effect for two decades, syntheses of polyphosphine ligands via a template synthesis... 

In a particularly interesting application of the radical- and base-catalyzed synthesis of polyphosphine ligands (Section 3.2.2), Keiter have prepared all five possible nonchelated triphosphine complexes of W(CO)5 (35-39). 

Polyphosphine ligands form complexes of the type (shown below) whieh undergo faeile substitution at the vacant trigonal-bipyramidal site [92],... 

The polyphosphine ligands are used in ehiral hydrogenation [93,94], Most important of such chiral complex of rhodium is shown below -... 

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