TY - JOUR

T1 - Fluorescent nano-sized aggregates of halogen bonded complexes formed using perfluoropropyl iodides: a systematic comparison between two isomeric halogen bond acceptors, aniline and 4-methyl pyridine

AU - Fan, Haiyan

AU - Nurtay, Lazzat

AU - Daniyeva, Nurgul

AU - Benassi, Enrico

N1 - HF is thankful for the Nazarbayev University small grants 110119FD4542 and 11022021FD2928. Computational resources were kindly provided by Shabyt HPC at Nazarbayev University. The authors thank the facilities and technicians in the Core facilities at Nazarbayev University, and Dr Timur Atabaev and Ms Kamila Zhumanova for their help with the quantum yield measurements.

PY - 2023/6/28

Y1 - 2023/6/28

N2 - The halogen bonds (XB) formed by the two isomers 4-methyl pyridine (MePy) and aniline (ANL) with heptafluoro-1-propyl iodide (n-C3F7I) and heptafluoro-2-propyl iodide (iso-C3F7I) were investigated using vibrational (FT-IR and Raman) spectroscopy and quantum mechanical calculations. While these two isomers indicated a distinctive impact on the ring related vibrations, molecular electrostatic potential, frontier molecular orbitals, intermolecular electron density delocalisation and consequential charge transfer upon halogen bonding with n-C3F7I and iso-C3F7I, the dramatic intermolecular charge transfer (CT) occurring on the MePy involved XB systems demonstrated an ion-pair like aggregation. Such aggregation, after 72 h and longer after mixing, leads to an emission of fluorescence for both [MePy·C3F7I] systems. The resulting nano-sized aggregates were characterised using UV-Vis absorption and fluorescence spectroscopy along with scanning and transmittance electron microscopy (SEM and TEM), wherein, the XB complex with iso-C3F7I showed a faster and more severe aggregation due to a stronger CT than that with n-C3F7I. The present work is the first case of aggregation induced emission (AIE) due to aggregation of XB complexes formed by small neutral molecules.

AB - The halogen bonds (XB) formed by the two isomers 4-methyl pyridine (MePy) and aniline (ANL) with heptafluoro-1-propyl iodide (n-C3F7I) and heptafluoro-2-propyl iodide (iso-C3F7I) were investigated using vibrational (FT-IR and Raman) spectroscopy and quantum mechanical calculations. While these two isomers indicated a distinctive impact on the ring related vibrations, molecular electrostatic potential, frontier molecular orbitals, intermolecular electron density delocalisation and consequential charge transfer upon halogen bonding with n-C3F7I and iso-C3F7I, the dramatic intermolecular charge transfer (CT) occurring on the MePy involved XB systems demonstrated an ion-pair like aggregation. Such aggregation, after 72 h and longer after mixing, leads to an emission of fluorescence for both [MePy·C3F7I] systems. The resulting nano-sized aggregates were characterised using UV-Vis absorption and fluorescence spectroscopy along with scanning and transmittance electron microscopy (SEM and TEM), wherein, the XB complex with iso-C3F7I showed a faster and more severe aggregation due to a stronger CT than that with n-C3F7I. The present work is the first case of aggregation induced emission (AIE) due to aggregation of XB complexes formed by small neutral molecules.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85163418843&origin=inward&txGid=cc02e5453d889d8b6d3c3fe07a9dbd8b

UR - https://www.mendeley.com/catalogue/f921c464-5494-34bc-88a3-dab904883a24/

U2 - 10.1039/d3cp01225e

DO - 10.1039/d3cp01225e

M3 - Article

C2 - 37326502

VL - 25

SP - 16938

EP - 16951

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 25

ER -