Construction of optically active multimetallic systems of rhodium(I), palladium(II), and ruthenium(II) with a P-chiral tetraphosphine ligand

Chiral Octapalladium Chains Supported by Enantiopure P-Stereogenic Linear Tetraphosphines, (R,R)- and (S,S)-Ph2PCH2P(Ph)CH2P(Ph)CH2PPh2

“…In the present study, we have intended to establish optical resolution of rac -dpmppm, with an aim of creating chiral octapalladium chains supported by enantiopure dpmppm ligands, and found an effective synthetic route via a cyclic tetranuclear Pd­(II) complex with a chiral bisisocyanide, 1,1′-binaphthyl-2,2′-bisisocyanide (Binac), in which chirality of dpmppm and Binac ligands is sorted as ( R*,R* ) and ( R* ). It is worth noting that chiral polyphosphines have almost exclusively been limited to two-atom or ethylene-bridged linear polyphosphines (RR′P­(CH 2 ­CH 2 ­PR) 2 n ­CH 2 ­CH 2 ­PRR′, n = 0–3, 5; R, R′ = Ph, t Bu, Me) which are capable of chelating to metal ions and could be resolved mainly through their borane adducts. − Some chiral tetraphosphines with ethylene linkers were also synthesized by making diastereomeric Pd­(II) complexes containing another chiral CN -chelating ligand, [1-(dimethylamino)-2-C 6 H 4 ]­ethane. , In contrast, monoatom-bridged chiral polyphosphines that are likely to induce metal–metal direct interaction have been restricted only to dppm (bis­(diphenylphosphino)­methane) and dppa (bis­(diphenylphosphino)­amine) archetypal diphosphines. − We wish to report herein synthesis and characterization of cyclic tetranuclear complexes, [{M 2 X 2 ( rac -dpmppm)­( rac -Binac)} 2 ]­(OTf) 4 (M = Pd, X = Cl ( 5 ), Br ( 6 ), I ( 7 ); M = Pt, X = Cl ( 8 )) and optical resolution of rac -dpmppm by utilizing enantiopure [{Pd 2 Cl 2 (( R*,R* )-dpmppm)­(( R* )-Binac)} 2 ]­(OTf) 4 ( 5 RR/R and 5 SS/S ). Finally, chiral Pd 8 chains, [Pd 8 (( R*,R* )-dpmppm) 4 ­(NCCH 3 ) 2 ]­(BF 4 ) 4 ( 2 RR and 2 SS ), were successfully isolated, and the absolute configuration was determined by X-ray crystallography.…”

Cyclic Trinuclear Rh2M Complexes (M = Rh, Pt, Pd, Ni) Supported by meso-1,3-Bis[(diphenylphosphinomethyl)phenylphosphino]propane

“…However, tetraphosphine ligands, in contrast to di- and triphosphines, have still been limited due to their synthetic difficulty and complicated stereoisomerism. The linearly ordered tetraphosphines bis[((2-diphenylphosphino)ethyl)phenylphosphino]methane (tetraphos-2,1,2), 1,2-bis[((2-diphenylphosphino)ethyl)phenylphosphino]ethane (tetraphos-2,2,2), and 1,3-bis[((2-diphenylphosphino)ethyl)phenylphosphino]propane (tetraphos-2,3,2) and their derivatives have been known to form mono- and dinuclear systems; however, multinuclear structures containing more than three metal ions supported by these linear tetraphosphines are limited to a few examples with Au 4 , Re 4 , Pt 2 Pd, and PdRu 2 centers . Recently, we have synthesized a methylene-bridged linear tetraphosphine ligand, meso -bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm, tetraphos-1,1,1), which has proven very effective in assembling linearly ordered tetrametallic chains of group 11 metal ions.…”

Synthesis of unsymmetrical P-stereogenic oligophosphines and chemoselective cleavage of phosphine-borane coordinate bonds

“…Wild and co-workers reported the syntheses and coordination behaviors of optically active P-stereogenic tetraphosphines and hexaphosphines, which were obtained by separating a mixture of stereoisomers by column chromatography and successive complexation with chiral palladium complexes. [17][18][19][20][21][22][23] Our group [14][15][16] and Imamoto's group [24][25][26][27][28][29] independently succeeded in synthesizing optically active P-stereogenic tetraphosphines ( Figure 1) through different synthetic routes. Imamoto et al 28 prepared their transition metal complexes, and the obtained complexes were used as chiral catalysts for transition metal-catalyzed asymmetric hydrogenations.…”