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Ligand‐stabilized Nickel and Palladium Boride Colloids
Author(s) -
Schmid G.,
Schöps E.,
Malm J.O.,
Bovin J.O.
Publication year - 1994
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19946200707
Subject(s) - colloid , palladium , boride , ligand (biochemistry) , nickel , amorphous solid , particle size , analytical chemistry (journal) , transmission electron microscopy , metal , chemistry , toluene , materials science , crystallography , inorganic chemistry , organic chemistry , catalysis , nanotechnology , biochemistry , receptor
A route to the first ligand stabilized nickel and palladium boride colloids with core diameters of 1.4 and 1.6 nm is described. The particles are formed by reaction of the metal complexes Cl 2 M(PR 3 ) 2 (M = Ni, Pd, PR 3 = PPr 3 , PBu 3 ) with B 2 H 6 in toluene at room temperature with 40–70% yield. The characterization of the pyrophoric brown powders occurred by elementary analyses, resulting in smallest formula units, which then could be extended to averaged molecular formulas by mass determinations, using an analytical ultracentrifuge: [Ni 6 B 10 Cl 1.5 (PPr 3 )] 12.5 ( 1 ), [Ni 6 B 10 Cl 1.5 (PBu 3 )] 8.5 ( 2 ), [Pd 4 B 6 Cl(PPr 3 )] 16.5 ( 3 ), and [Pd 4 B 6 Cl(PBu 3 )] 16.5 ( 4 ). From the masses of the colloid cores and their roughly calculated densities the size of the boride particles could be estimated. The diameters of 1.6 nm for 1, 3 , and 4 are identical within the experimental error. Only 2 seems to have a slightly reduced diameter of 1.4 nm. 1–4 can be dispersed in inert organic solvents in any concentration. To confirm these relatively uncertain values high resolution transmission electron microscopy has been used. Investigations of 1 and 3 show indeed an averaged particle size of 1.6 ± 0.3 nm in agreement with the data derived from the mass determinations. Surprisingly most of the observed particles appear to have amorphous structure. This finding is supported by X‐ray powder diffraction experiments, as no significant reflex data could be registered. 31 P and 11 B NMR measurements have been performed too, however, do not contribute to further characterization.