Tetraphosphorus ligand

Scheme I. The tetraphosphorus ligands rac-L and meso-L, and the hydroformylation active dirhodium complex rac-1.

Yan Y, Zhang X, Zhang X (2006) A tetraphosphorus ligand for highly regioselective isomerization-hydroformylation of internal olefins. J Am Chem Soc 128 16058-16061... 

Zhang and coworkers investigated the reaction of 1,5-hexadiene with a Rh complex containing a tetraphosphorus ligand and obtained pimelaldehyde with up to 98% selectivity (Scheme 4.16) [89, 90]. 

Transition metal complexes with cyclo-triphosphorus (r)3-P3) and tetrahedro-tetraphosphorus (fi -P-t) ligands. M. Di Vaira and L. Sacconi, Angew. Chem., Int. Ed. Engl., 1982, 21,330-342 (40). 

Other complexes whose crystal structures have been determined include the tetraphosphorus complex (21),191 and the dinitrogen complex (22).182 The latter complex was originally believed to contain a sideways-on dinitrogen ligand 183 however, once corrections were made for disorder and anisotropy of the dinitrogen ligand, the more usual end-on coordination was proposed.182... 

Noticeably, all the new fefra/zedro-tetraphosphorus complexes, apart from 8, are unstable in solution at room temperature and decompose between -40°C (9) and 0°C (5). They were characterized by 31P NMR spectroscopy in solution and, for complex 5 only, by X-ray crystallography (Fig. 1). In all cases the unquestionable presence of an rf- P4 ligand was ascertained. 

As the cleavage of the first P-P bond to yield P4-butterfly complexes has extensively been discussed in the previous sessions, we will now skip to illustrate those polyphosphorus ligands formed via rupture of a second bond in the tetraphosphorus tetrahedron. 

DelDonno TA, Rosen W (1978) Studies of a 15-membered tetraphosphorus macrocyclic ligand. Inorg Chem 17 3714—3716... 

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