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Role of donor‐acceptor functional groups in N 3 P 3 cyclic‐triphosphazene backbone. Unraveling bonding characteristics from natural orbitals within an extended transition state‐natural orbital for the chemical valence scheme
Author(s) -
LinaresFlores Cristian,
RamirezTagle Rodrigo,
RojasPoblete Macarena,
ArratiaPerez Ramiro,
MuñozCastro Alvaro,
GuajardoMaturana Raul
Publication year - 2020
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.26057
Subject(s) - chemistry , phosphazene , substituent , atomic orbital , crystallography , ring (chemistry) , homo/lumo , acceptor , density functional theory , valence (chemistry) , stereochemistry , ligand (biochemistry) , computational chemistry , electron , molecule , organic chemistry , physics , biochemistry , polymer , receptor , quantum mechanics , condensed matter physics
The formation of cyclophosphazenes containing several ligands or substituent groups gives rise to an attractive derivative set, for development of novel applications, with variable properties. Here, it is possible to unravel the role of different functional groups attached to the N 3 P 3 backbone, to reach a better understanding of the bonding character in the cyclic [─P─N─] skeleton. We employed the extended transition state‐natural orbital for the chemical valence scheme to unravel the σ and π orbital kernels that are involved in the assembling of such structures, by varying the acceptor‐donor characteristics of the ─CF 3 , ─NO 2 , ─COOH, ─CN, ─NH 2 , ─OH, and ─OCH 3 groups, where ─NO 2 behaves as a stronger electron‐withdrawing substituent rather than ─CF 3 , ─COOH, and ─CN, denoting that the nature of the ligand‐phosphazene interaction contributes to some degree to the bond strength of the cyclic [─P─N─] backbone. Our results reveal that the electron‐withdrawing ─NO 2 group leads to higher σ and π [─P─N─] orbital‐energy contributions, which is reflected in a shortening of the [─P─N─] distance, contrasting with the case of electron‐donating groups such as ─NH 2 , ─OH, and ─OCH 3 within the phosphazene set. These insights allow further variation and modulation of the bonding in the [─P─N─] ring.