Ring Expansion Alkyne Metathesis Polymerization.

Authors :: Beauchamp AM
Chakraborty J
Ghiviriga I
Abboud KA
Lester DW
Veige AS
Source :: Journal of the American Chemical Society [J Am Chem Soc] 2023 Oct 18; Vol. 145 (41), pp. 22796-22802. Date of Electronic Publication: 2023 Oct 09.
Publication Year :: 2023
Abstract: The synthesis, characterization, and preliminary activity of an unprecedented tethered alkylidyne tungsten complex for ring expansion alkyne metathesis polymerization (REAMP) are reported. The tethered alkylidyne 7 is generated rapidly by combining alkylidyne W(C <superscript> t </superscript> Bu)(CH <subscript>2</subscript> <superscript> t </superscript> Bu)(O-2,6- i - Pr <subscript>2</subscript> C <subscript>6</subscript> H <subscript>3</subscript> ) <subscript>2</subscript> ( 6 ) with 1 equiv of an yne-ol proligand ( 5 ). Characterized by NMR studies and nuclear Overhauser effect spectroscopy, complex 7 is a dimer. Each metal center contains a tungsten-carbon triple bond tethered to the metal center via an alkoxide ligand. The polymerization of the strained cycloalkyne 3,8-didodecyloxy-5,6-dihydro-11,12-didehydrodibenzo[ a , e ]-[8]annulene, 8 , to generate cyclic polymers was demonstrated. Size exclusion chromatography (SEC) and intrinsic viscosity (η) measurements confirm the polymer's cyclic topology.