ESI-MS Characterization of Polymer Samples

The ESI-MS analyses were performed as previously described by Todea et al. [37 (link)]. About 1 mg of crude reaction mixture was dissolved in methanol/acetonitrile (1 mL) and formic acid (0.1% v/v) was added. The analyses were performed using an Esquire 4000 (Bruker) instrument in electrospray positive ionization mode by generating the ions in an acidic environment. The generated ions were positively charged with an m/z ratio that fell in the range of 200–1000. The medium molecular weights, numerical, Mn and gravimetric, Mw and dispersity values, $Đ$ were calculated by using the Equations (1)–(3), as previously reported [65 (link)]: $$M_n=\raisebox{1ex}{$\sum N_i\times M_i$}\!\left/ \!\raisebox{-1ex}{$\sum N_i$}\right.$$
$$M_w=\raisebox{1ex}{$\sum N_i\times M_i^2$}\!\left/ \!\raisebox{-1ex}{$\sum N_i\times M_i$}\right.$$
$$Đ=\raisebox{1ex}{$M_w$}\!\left/ \!\raisebox{-1ex}{$M_n$}\right.$$
where Ni is the abundance and Mi is the molecular weight.