Soluble polymers of monosubstituted acetylenes with quaternary ammonium pendant groups: structure and morphology

Soluble conjugated polymers were obtained in the presence of Pd(II), Pt(II) and Rh(I) complexes from monosubstituted acetylene 3-dimethylamino-1-propyne (H-C equivalent to CCH(2)N(CH(3))(2), 1) and the corresponding hydrochloride (H-C equivalent to CCH(2)N(CH(3))2 center dot HCl, 2) and hydrobromide (H-C equivalent to CCH(2)N(CH(3))(2)center dot HBr, 3) derivatives. A series of reactions were performed to achieve the optimization of the polymerization conditions. The highest yields were found for polymers synthesized using Pd(II) bisacetylides specially prepared, i.e. trans-[Pd(PPh(3))(2)(C equivalent to CCH(2)N(CH(3))(2))(2)], trans-[Pd(PPh(3))(2)(C equivalent to CCH(2)N(CH(3))(2))(2)HCl] and trans-[Pd(PPh(3))(2)(C equivalent to CCH(2)N(CH(3))(2))(2)HBr], respectively. The dimension and size distribution of the polymers were investigated using dynamic light scattering. Polymers containing quaternary ammonium groups showed evidence of a hydrodynamic radius of about 300 nm if prepared with the Rh(I) catalyst and of 160 nm if prepared with the Pd(II) catalysts. Polymers obtained from 1 showed smaller hydrodynamic radius compared to polymers obtained from 2 and 3, regardless the polymerization catalyst. The ionic polymeric materials were soluble in organic solvents and, more interestingly, in water. The formation of nanoparticles with pearl-like morphology was achieved using a recently developed osmosis-based method, with dimensions varying from 60 nm up to micrometres. (C) 2011 Society of Chemical Industry