Synthesis and Crystal Structure of Cis [Pd {Ph2PCH2C (O) Ph} 2]-[BF4][B2F7]. Unexpected Formation and First Structural Characterisation of the Heptafluorodiborate Anion B2F7

Abstract

The reaction of cis-[Pd{Ph2PCH-C(O)Ph}2] (1) with HBF4/H2O instantly leads to the formation of the cationic complex cis-[Pd{Ph2PCH-C(O)Ph}2][BF4]2. When 1 was treated with commercial BF3·Et2O, containing HBF4 as an impurity, the related compound cis-[Pd{Ph2PCH-C(O)Ph}2][BF4][B2F7](2) was formed. The structure of 2 was determined by an X-ray diffraction study. The compound ctystallizes in the orthorhombic system, P212121 space group, Z=4, cell dimensions: a=16.474(4), b=19.007(5), c=12.932(4) Å, V=4049.3 Å3, final R=0.030. The two chelating phosphines define puckered five membered metallocycles characterised by PCH2 carbon atoms lying significantly out of the metal coordination plane (−0.617(7) Å for C1 and +0.779(7) Å for C21). This study establishes the first structural data for the B2F7− anion: the value of the BFbridgeB angle is 128.1(7)°. The values of the BFbridge bond lengths (1.50(1) and 1.51(1) Å are significantly longer than the other BF bonds (1.34–1.39 Å).

Publisher

Elsevier

Publication Date

1-1-1992

Publication Title

Inorganica Chimica Acta

Department

Chemistry and Biochemistry

Document Type

Article

DOI

10.1016/S0020-1693(00)82656-0

Language

English

Format

text

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