An Original Calix[4]arene‐Containing Oligomer/Polymer Catalyst for Homogeneous Hydroformylation

Abstract

The title compound (10) was prepared from the calix[4]arene precursor (11) to form the ligand 5,11‐bis(methyl(diphenylphosphino))‐25,26,27,28‐tetra‐n‐propoxy calix[4]arene (12), which was reacted with [Rh(COD)Cl]2 (COD = 1,5‐cyclooctadienyl) and TlPF6 as chloride scavenger, in 31% overall chemical yield. The dimer structure in solution was demonstrated by the measurements of the 31P NMR spin‐lattice relaxation time (T1) in comparison with the ligand itself. Computer modeling shows that the dimer macrocycle exhibits many possible conformers, including some with obvious steric hindrance about the Rh atom, but no apparent ring stress. 10 was tested for the catalytic homogeneous hydroformylation of hex‐1‐ene and compared with other closely related analogue systems recently reported in the literature.magnified image

Inorganic and organometallic polymers

“…A rhodium(I) containing polymer bearing a diphosphine-functionalized calix [4]arene has been employed as a catalyst for homogeneous hydrogenation. 148 The hemilabile pincer ligand, 1,4-C 6 H 4 (N(CH 2 CH 2 PPh 2 ) 2 ) 2 , containing P-and N-donor atoms was studied as a precursor to oligomers and polymers containing palladium, platinum or silver atoms in the main chain. 149 Interesting thiophene-substituted Schiff-base complexes of vanadium, nickel or copper in the main chain have been electropolymerized in microgravity.…”

How Do Positions of Phosphito Units on a Calix[4]Arene Platform Affect the Enantioselectivity of a Catalytic Reaction?

“…Among these, phosphorus-based ligands are often used in transition metal chemistry in particular for catalytic applications [10,11]. The phosphorus atom(s) can be specifically grafted on the upper [12][13][14][15][16][17][18][19][20] or lower [21][22][23][24][25][26][27][28][29][30] rim of the calix [4]arene.…”