4 4 isopropylidene diphenoxy bis phthalic anhydride 6hda

In this study, the following materials were used: 4,4′-isopropylidene-diphenoxy-bis(phthalic anhydride) (6HDA), which was purchased from Sigma-Aldrich, St. Louis, MO, USA; and 2,6-bis(3-aminophenoxy)benzonitrile (m-CN) and 4-[(4-cyanophenyl)diazenyl]phenol (AzoCN) synthesized in our laboratory using previously reported methods [33 ,34 (link),35 (link),36 ] at M.p. 136–138 and 200–202 °C, respectively. N,N-dimethylacetamide (HPLC grade), p-aminobenzonitrile, phenol (99%) and NaNO₂ (99.9%) were purchased from Merck KGaA, Darmstadt, Germany. All reagents and solvents were used as received.

The monomers used in this study, 4,4′-isopropylidene-diphenoxy-bis(phthalic anhydride) (6HDA), were purchased from Sigma-Aldrich, St. Louis, MO, USA, and 2,4-Bis(p-aminophenoxy)benzonitrile (o-CN) was synthesized in our laboratory by a previously reported method [47 ,48 (link),49 (link)]. N,N-Dimethylacetamide (HPLC grade), p-toluidine (97%), p-aminobenzonitrile, phenol (99%), and NaNO2 (99.9%) were purchased from Merck KGaA, Darmstadt, Germany. All reagents and solvents were used as received. 4-[(4-Methylphenyl)diazenyl]phenol (AzoCH3) and 4-[(4-cyanophenyl)diazenyl]phenol (AzoCN) was synthesized in our laboratory by a previously reported method [50 (link),51 ]. M.p. were 152–154 °C and 200–202 °C, respectively.