Conformational Analysis of Poly(trimethylene imine) and Poly(N-methyltrimethylene imine) by the Rotational Isomeric State Scheme with up to Fourth-Order Intramolecular Interactions

Abstract

An inversional-rotational isomeric state (IRIS) scheme including first-order to fourth-order intramolecular interactions has been developed and applied to conformational analysis of poly(trimethylene imine) (PTMI) and poly(N-methyltrimethylene imine) (PMTMI). Bond conformations and conformational energies of PTMI and PMTMI were evaluated from ab initio molecular orbital calculations at the MP2/6-311++G(3df, 3pd)//HF/6-31G(d) level and 1H and 13C NMR experiments for the monomeric model compounds, CH3NR1CH2CH2CH2NR2CH3 (R1 = R2 = H; R1 = H and R2 = CH3; R1 = R2 = CH3). The IRIS analysis yielded the following data on the polymers at 25 °C: the characteristic ratio for the infinite chain, 3.5 (PTMI) and 4.2 (PMTMI); trans fractions of the C−C and C−N bonds, respectively, 0.29 and 0.77 (PTMI) and 0.40 and 0.65 (PMTMI); the meso-diad probability, 0.44 (PTMI) and 0.48 (PMTMI). Intramolecular hydrogen bonds were found in the polyimines: PTMI, N−H···N (the interaction energy, −0.83 kcal mol-1) and C−H···N (−0.15 kcal mol-1); PMTMI, C−H···N (−0.40 kcal mol-1). The chain dimension, stereochemical configuration, and bond conformations of the polyimines are sensitive to the first-order interaction energy around the C−C bond and the hydrogen-bond energies. Polar solvents weaken the hydrogen bonds to increase the chain dimension and randomize the configuration.

Conformational Characteristics of Poly(trimethylene sulfide) and Structure−Property Relationships of Representative Polysulfides and Polyethers

“…The vicinal 13 Table 3. The trans fractions are somewhat larger than those of case I but closer to the MO calculations; therefore, the p t CS data of case II have been adopted here.…”

Modular chemical geometry and symbolic calculation

“…Recent work includes x‐ray crystallography of trimethylene imine, oxetane, and thietane by Esteban et al 30 and in many studies of silaheterocycles by Weidenbruch, e.g., Ref. 31 Nuclear magnetic resonance (NMR) of caryophyllenes by Clericuzlo et al 32 and trimethylene imine in relation to its polymers 33 Electron diffraction of 1,1Me 2 silaCB by Novikov et al 34 Infrared (IR) spectra of 1,1F 2 CB by Lesarri et al 35, oxetane by Moruzzi et al 36, thietane and seletane by Pousa et al 37, and complexes of oxetane and thietane with HCl by Rode and Dobrowolski 38 Raman spectra in Ref. 37 Using the puckering of a cyclobutane ring to drive the synthesis of the tricyclic structure of the naturally occurring guanacastepenes, by Shipe and Sorensen 39 …”

“…Nuclear magnetic resonance (NMR) of caryophyllenes by Clericuzlo et al 32 and trimethylene imine in relation to its polymers 33…”

Study of cis–trans stereochemistry of 2-(2-chlorobenzylideneamino)phenol and 2-(2-chlorophenyl imino)methyl)phenol (Schiff bases) by GC and GC-MS spectrometry

“…Influence of protonation on the photoisomerization of imine has also been studied [9]. On the other hand, there are major interests for spectroscopic and theoretical investigation of the Schiff bases configuration [10][11][12]. Thus, the effects of UV radiation and temperature on the cis-trans conversion of imine have been reported [12].…”