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Magnesiation of Triisopropylsilylphosphane: Synthesis and Structures of New Mg 2 n P 2 m Polyhedra
Author(s) -
Westerhausen Matthias,
Schneiderbauer Stefan,
Knizek Jörg,
Nöth Heinrich,
Pfitzner Arno
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199912)1999:12<2215::aid-ejic2215>3.0.co;2-v
Subject(s) - chemistry , steric effects , cubane , tetrahydrofuran , crystallography , metalation , triangular prism , hexagonal prism , stereochemistry , moiety , ring strain , crystal structure , molecule , hexagonal crystal system , geometry , organic chemistry , mathematics , solvent
The magnesiation of triisopropylsilylphosphane with dibutylmagnesium in toluene yields the octanuclear complex [Mg 8 (PSi i Pr 3 ) 6 {P(H)Si i Pr 3 } 4 ] (1) which consists of MgPSi i Pr 3 units forming a hexagonal Mg 6 P 6 prism, with two opposite Mg 2 P 2 moieties capped by additional Mg[P(H)Si i Pr 3 ] 2 groups. If a small amount of THF is present during the metalation reaction [(THF) 4 Mg 6 (PSi i Pr 3 ) 6 ] (2) also containing a hexagonal Mg 6 P 6 prism can be isolated. The magnesiation of H 2 P–Si i Pr 3 in tetrahydrofuran leads to the formation of the tetrameric complex [(THF)MgPSi i Pr 3 ] 4 (3) with a slightly distorted Mg 4 P 4 cubane‐like structure.The structures depend strongly on the steric strain caused by the trialkylsilyl substituents and the neutral coligands at the magnesium center. The highest steric strain, which is induced by coordination to every magnesium atom, leads to the smallest Mg n P n polyhedron – the central Mg 4 P 4 heterocubane moiety. In compounds 1 and 2 the hexagonal Mg 6 P 6 prism is formed, however, with reduced steric strain as observed for 2 where the Mg–P bond lengths become more similar.