Tandem <scp>ROMP</scp>/Vinyl‐Addition Polymerization of Norbornene Catalyzed by a Ru/Ni Heterobimetallic Complex

ABSTRACT The new compound (1S,4S)‐ N ‐(4‐iodophenyl)bicyclo[2.2.1]hept‐5‐en‐2‐carboxamide ( NBE–amide‐I ) was synthesized using 4‐iodoaniline and 5‐norbornene‐2‐carboxylic acid. NBE–amide‐I was then used in an oxidative addition reaction with [Ni(PPh 3 ) 4 ] to obtain the new complex [NiI(NBE–amide)(PPh 3 ) 2 ] ( Ni–NBE ). The complexes [Ni(NBE–amide)(PPh 3 )(Schiff–cyclohexane)] (mono‐Schiff–Ni) and [{RuCl 2 (η 6 ‐ p ‐cymene)}μ{(Schiff‐pip)Ni(aryl–NBE)(PPh 3 )}] ( Ru–Ni–NBE ) were synthesized via a one‐pot reaction using Ni–NBE, salicylaldehyde, and 4‐(aminomethyl)piperidine or [RuCl 2 (η 6 ‐ p ‐cymene)(piperidine‐(4‐aminomethyl))] (mono‐RuPip), respectively, in dichloromethane for 16 h. The mono‐Ni–Schiff and Ru–Ni–NBE complexes were fully characterized using FTIR, UV–Vis, 1 H and 31 P{ 1 H} NMR, MALDI–TOF, EPR, and cyclic voltammetry. These complexes were then evaluated as precatalysts for the vinyl‐addition polymerization of norbornene (NBE), achieving yields of 91% and 71%, respectively, using methylaluminoxane (MAO) as the cocatalyst (Al/[Ni] = 2000). Ru–Ni–NBE was also shown to be active in the ring‐opening metathesis polymerization (ROMP) of NBE, achieving yields of up to 50% in the presence of 10 equivalents of (trimethylsilyl)diazomethane (TMSDM) as the carbene source. The one‐pot synthesis of a copolymer based on assisted‐tandem catalysis, combining ROMP and vinyl‐addition polymerization of NBE using Ru–Ni–NBE , was conducted through the sequential addition of TMSDM and MAO under previously optimized conditions. The copolymer was characterized by 1 H NMR, GPC, Raman scattering, and SEM.