346001-77-2Relevant academic research and scientific papers
Calix[4]arene-derived diphosphines, diphosphinites and diphosphites as chelating ligands for transition metal ions. Encapsulation of silver(I) in a calix-crown diphosphite
Jeunesse, Catherine,Dieleman, Cedric,Steyer, Stephane,Matt, Dominique
, p. 881 - 882 (2007/10/03)
A series of lower rim-functionalised calix[4]arenes bearing 1,3-positioned phosphorus(III) ligands L1-L9 have been synthesized and their coordinative properties examined. L1 and L2 {5,11,17,23-tetra-tert-butyl-25,27-bis[2-(diphenylphosphino) ethoxy]- and -25,27-bis(diphenylphosphinomethoxy)-26,28-bis(3-oxabutyloxy)calix[4]arene} react with [Rh(nbd)(THF)2]BF4 (nbd = 1,5-norbornadiene; THF = tetrahydrofuran) to afford in high yield the complexes [Rh(nbd)L 1]BF4 and [Rh(nbd)L2]BF4, respectively, where the calixarene behaves as a P,P′ chelator. Both complexes catalyse hydroformylation of styrene at comparable rates, the linear:branched aldehyde ratio being 5:95. The presence of the ether side groups did not exert a noticeable effect on the selectivity nor the catalytic activity. Reaction of L1-L8 with [Pd(η3- C3H4Me)(THF)2]BF4 gave the corresponding cationic chelate complexes [Pd(η3-C 3H4Me)Li]BF4 that are active in the catalytic alkylation of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate. Owing to the presence of a non-planar Pd-allyl fragment, the achiral calixarene subunits of some of these complexes are no longer C2v-symmetrical, as evidenced by the 1H and 13C NMR spectra that show non-equivalent side groups. Selective chelation via the two phosphorus atoms was also observed in the complexes [RuCl(p-MeC6H4Pr i)Li]BF4 (Li = L3 or L4) obtained by reaction of the amide phosphines Li with [RuCl(p-MeC6H4Pri)(THF)2]BF 4 [L3 = 5,11,17,23-tetratert-butyl-25,27- bis(diethylcarbamoylmethoxy)-26,28-bis(diphenylphosphinomethoxy)- and L 4 = 5,11,17,23-tetratert-butyl-25,27-bis(diphenylphosphinomethoxy)- 26,28-bis{(1-(R)-phenylethyl)carbamoylmethoxy}-calix[4]arene]. Reaction of L3 or L4 with neutral [RuCl2(p-MeC 6H4Pri)]2 afforded the bimetallic complexes [{RuCl(p-MeC6H4Pri)}2-Li] where the calixarene acts as a P,P′ bridging ligand. Reaction of AgBF4 with calix-crown L9 {25,27-bis(diethoxyphosphinoxy)-26,28-(3,6,9- trioxaundecane-1,11-dioxy)calix[4]arene} resulted in quantitative formation of the complex [AgL9]BF4 in which the silver(I) ion lies inside the cavity constituted by the crown ether fragment and the two phosphorus arms. As revealed by a single crystal X-ray diffraction study, the Ag + ion has a trigonal P2O coordination environment with a P-Ag-P angle of 134.74(4)°. The Royal Society of Chemistry 2001.
