Phosphanide cluster

Scheme 3.6-7. Synthesis of the sodium (fluorosilyl)phosphanide clusters 22 and 23.

Fig. 3.6-7. Core structure of the lithium phosphanide cluster 28. Small dark circles lithium atoms, big dark circles phosphorus atoms.

Compound 14 is diamagnetic and represents the first tetrasodium-dication cluster that is stabilized by two sterically congested silyKflu-orosilyl)phosphanide counterions (see Section II,D). It has been also independently synthesized through sodium consumption of 13 in the presence of styrene as catalyst in 24% yield. The electron reservoir of the Na) cluster can serve for reduction processes, that is, it reduces Me3SiCl to hexamethyldisilane (see Section II,F). The fact that 14 is intensely yellow, and not red or blue as observed for Na-loaded zeolites (28), suggests that the residual metal electrons are probably much less delocalized. 

The Na-Na distances of 3.076(3) (Nal-Na2) and 3.202(3) A (Nal-Nal ) reflect Na-Na bonds (3.82 A in elemental Na), whereas the Nal-Na2 distance of 3.530(3) A suggested less attractive interactions. The Na4-dication cluster is embedded between two silyl(fluoro-silyl)phosphanide counterions. The relatively low-coordinated Na centers are remarkably stabilized by the -fluorine atoms and by... 

The first Ca/Sn-mixed phosphandiide cluster 43 has been prepared by reaction of the calcium phosphanide 44 with Sn[N(SiMe3)2]2 in THF... 

The Ca/Sn-mixed metalated phosphanide-phosphandiide cluster 43 crystallizes in the triclinic space group PI (71). It consists of a trigonal Ca2SnP2 bipyramid, where the phosphandiide P centers serve as ju -bridging centers to the metals. The two phosphanide ligands, however, are. -bridging between two Ca and Ca/Sn centers (Fig. 32). Both Ca ions are octahedrally coordinated. 

Fig. 3.6-6. Molecular structures of the mixed lithium phosphanide-LiCI cluster 20 and the anionic cluster core in 21.

Scheme 3.6-13. Synthesis of heterobimetallic phosphanide-phosphandiide clusters.

Scheme 3.6-14. Structural variety in group 2 metal and tin(+2) phosphanide (arsanide)-phosphandiide (arsandiide) cluster chemistry.

Driess, M. Pritzkow, H. Skipinski, M. Winkler, U. Intriguing tetrasodium dication cluster NaJ stabilized between two silyl(fluorosilyl)phosphanide shells. J. Am. Chem. Soc. 1998,120, 10774. 

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