Silver(I)-mediated isomerisation of trans-[RuCl2(P-P)(2)] (P-P = four-membered ring chelate diphosphine ligand) to cis-[{Ru(P-P)(2)(mu-Cl)(2)}(n)Ag](+) species, and applications in stereoselective syntheses of cis- and trans-[RuCl(L)(P-P)(2)](+) (L = neutral ligand)
Sj. Higgins et al., Silver(I)-mediated isomerisation of trans-[RuCl2(P-P)(2)] (P-P = four-membered ring chelate diphosphine ligand) to cis-[{Ru(P-P)(2)(mu-Cl)(2)}(n)Ag](+) species, and applications in stereoselective syntheses of cis- and trans-[RuCl(L)(P-P)(2)](+) (L = neutral ligand), J CHEM S DA, (6), 2001, pp. 902-910
Citations number
47
Categorie Soggetti
Inorganic & Nuclear Chemistry
Journal title
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
When complexes trans-[RuCl2(diphos)(2)] (diphos=(Ph2P)(2)C=CH2, Ph2PCH2PPh2
or Ph2PNHPPh2) were treated with silver salts of poorly coordinating anion
s (e.g. AgBF4, AgO3SCF3) in 1,2-dichloroethane halide abstraction was slow,
even at reflux, and the reaction proceeded by an interesting mechanism inv
olving a trans to cis isomerisation. At room temperature, a complex, charac
terized as [RuCl(diphos)(2)(mu -Cl)Ag](+), forms. When heated to reflux for
5-10 min this reacts to give a mixture, which includes cis-[RuCl2(diphos)(
2)], and species of the type [{Ru(diphos)(2)(mu -Cl)(2)}(n)Ag](+) (n=1 or 2
) in which the exact coordination geometry at Ag-I is unknown. The reaction
s have been followed by P-31-{H-1} NMR spectroscopy, and electronic spectro
scopy results also support the isomerisation. The ruthenium and silver K-ed
ge EXAFS spectra of the solid isolated from the reaction of trans-[RuCl2(dp
pm)(2)] and AgO3SCF3 lend support to this formulation; in particular, the b
est fit for the silver(I) environment includes coordination to one oxygen (
from the -O3SCF3; Ru-O 2.43 Angstrom), two Cl (2.79 Angstrom) and between o
ne and two Ru (3.94 Angstrom). Over 30-40 min at reflux, AgCl precipitates,
the signals due to cis-[RuCl2(diphos)(2)] disappear from the P-31-{H-1} NM
R spectra, those due to the [{Ru(diphos)(2)(mu -Cl)(2)}(n)Ag](+) mixture di
minish, and new resonances, attributed to five-coordinate [RuCl(diphos)(2)]
(+), appear. This reaction has been investigated for stereoselective ligand
substitution. Treatment of trans-[RuCl2(diphos)(2)] with AgBF4 or AgO3SCF3
in DCE in the presence of CH3CN or CO yields exclusively trans-[RuCl(L)(di
phos)(2)](+) (L=CH3CN or CO), but treatment of trans-[RuCl2(diphos)(2)] wit
h AgBF4 or AgO3SCF3 in DCE, followed by treatment with L, usually gave excl
usively cis-[RuCl(L)(diphos)(2)](+) (L=CH3CN or CO).