Monte Carlo study of 13C nuclear spin—lattice relaxation in aliphatic chains bound to a macromolecule

Proton and Carbon-13 Spin-Lattice Relaxation Times Investigation of the Segmental Motion of Poly(4-vinylpridinium bromide) in Methanol Solution

“…8) of type (CHgCHgNfCONHPhDn directly from l-(N-phenylcarbamoyl)aziridine (NPCA). 2 The polymer showed significant specificities in the absorption of a variety of S=0 or P=0 compounds. 3 The specificity in absorption is probably assisted by the conformational change of the poly(NPCA) in the presence of the guest molecules, when considered the properties of related polymers of type (CH2CH2N(COR)),i studied by several research groups.…”

Nuclear magnetic spin relaxation of a spin-pair undergoing reorientations by jumping among unequivalent sites

“…Levine [11], and Yasukawa et al [12][13][14] have discussed the latter case, assuming jumps among three conformations (t, g+, and g-) by a Monte Carlo technique using a computer for a multiple bond system. However, it is possible to obtain the expressions for the relaxation quantities such as the spin-lattice and the spin-spin relaxation times and the nuclear Overhauser enhancement in explicit form by assuming a simplified model of the internal rotation.…”

Carbon-13 Nuclear Magnetic Relaxation in Macromolecules with Side Chains Undergoing Multiple Internal Rotations. Effects of the Distribution of Correlation Times and Overall Anisotropic Motion

“…The interpretation of the relaxation data in terms of molecular dynamics requires a thorough knowledge of the effects of overall and internal motions which have been subjected to many investigations in the last few years. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The basic theory for the effects of internal rotation on nuclear relaxation has been provided first by Woessner,17 and then extended to molecules undergoing multiple internal motions.6,18 '19 The two models of Woessner are the rotational jump among three equivalent sites and the unrestricted rotational diffusion.17 However, it happens generally that the different rotamers about a given bond are not equally populated and that the diffusion is limited to a restricted angular range. Such problems have been treated by London and Avitabile, 5 Tsutsumi,20 and Gronski and Murayama.…”

“…This model is a noticeable improvement over previous treatments, where all internal rotations are assumed to be independent or uncoupled from each other, although such an attempt has already been made by use of the Monte-Carlo method. [13][14][15]24 In this work, we have extended our previous model of internal rotations,20 which has been used for a molecule with one internal bond, to systems with multiple internal rotations as in macromolecules having side chains and examined the effects of the anisotropic motion and of the distribution of correlation times of the main chain on the side chain relaxation. Although our treatment is limited within the framework of independent internal rotations, it develops the previous treatments in this field and is considered to have further potentialities for investigating the dynamics of chain molecules.…”