NMR study of phthalide‐type poly(phenylene)s. Symmetry and additivity

Abstract

All H and C NMR signals of the four poly(phenylenephthalides): polydiphenylenephthalide (P(DPh)-1), polyterphenylenephthalide (P(TPh)-2) and two sequentially ordered polymers with different ratios of alternating diphenylenephthalide and terphenylenephthalide units (P(DTPh)-3, P(DDTPh)-4) were assigned unequivocally with two-dimensional NMR techniques ( H- H COSY and NOESY; H- C HSQC and HMBC). There are four types of polyphenylene fragments: not symmetrical end, symmetrical inner, symmetrical pre-end and formally symmetric pre-end. The equivalent carbon atoms in these fragments have different chemical shifts. A full additivity of the chemical shifts for the side phthalide and polyphenylene carbon atoms was revealed. A new structure of diads with a mirror symmetry plane, passing through the middle of aromatic moieties, is proposed. Copyright © 2017 John Wiley & Sons, Ltd.

Structure-Property Relationship on the Example of Gas Separation Characteristics of Poly(Arylene Ether Ketone)s and Poly(Diphenylene Phtalide)

“…Chemical structures of C1-C4 polymers were confirmed using 1 H NMR, 13 C NMR and 19 F NMR spectra. Spectra for C1 and C3 were previously reported in [56], spectra for C4 were previously reported in [60].…”

NMR study of dyadic and triadic splitting in copoly(arylene)phthalides based on diphenyl oxide and diphenyl sulfide

“…In a previous work, [ 13 ] studying the synthesis of polyarylenephthalides of the polyphenylene series using 13 C NMR spectroscopy, we found that aromatic fragments of the skeletal chain of the resulting polymers (diphenylene and terphenylene) can be separated by a symmetry plane passing through the center of the polyphenylene fragment into two halves, each of which is associated with the phthalide cycle adjacent to it. In turn, each phthalide cycle is associated with adjoining halves of two adjacent aromatic fragments.…”

“…A lot of physical and chemical properties of polycondensation copolymers, like all copolymers, in general, depend not only on their composition but also on the compositional heterogeneity (microheterogeneity), determined by the microstructure of macromolecules, which characterizes the distribution of monomer units along the polymer chain. The main method for studying the microstructure of polycondensation copolymers is high resolution NMR in its various modifications and, first of all, 1 H and 13 C NMR spectroscopy. The aliphatic-aromatic copolyesters obtained on the basis of iso-and terephthalic acids were studied in most detail by the 1 H NMR method.…”

“…[2,3] The same authors, using mixed solvent systems using the 1 H NMR method, were also able to determine longer tetrad and pentadic sequences in four-component copolymers of this series. [4] To study the distribution of monomer units in the copolyesters, a combination of 1 H and 13 C NMR methods was also used. [9,10] However, for most polycondensation copolymers, as described above, [5][6][7] as well as for copolymers of other classes (polysulfones and polyamides), [8,11] due to the small difference in the chemical shifts of the protons of aromatic rings, complex overlapping multiplets are observed.…”

“…Therefore, the main method for determining the structure of macromolecules is 13 C NMR spectroscopy of polyheteroarylenes [12] . For the same reason, 13C NMR spectroscopy remains the only method for studying the microheterogeneity polyarylenephthalides, in general, and copolyarylenephthalides, in particular [13] .…”