Photophysical Behavior and Computational Investigation of Novel 1,4-Bis(2-(2-Phenylpyrimido[1,2-a]Benzimidazol-4-Yl)Phenoxy)Butan (BPPB) Macromolecule

Tamer S Saleh; Mahmoud A Hussein; Osman I Osman; Khalid A Alamry; Ahmed E M Mekky; Abdullah M Asiri; Samy A El-Daly

doi:10.1007/s10895-016-1884-2

Photophysical Behavior and Computational Investigation of Novel 1,4-Bis(2-(2-Phenylpyrimido[1,2-a]Benzimidazol-4-Yl)Phenoxy)Butan (BPPB) Macromolecule

J Fluoresc. 2016 Sep;26(5):1895-904. doi: 10.1007/s10895-016-1884-2. Epub 2016 Jul 30.

Authors

Tamer S Saleh^{1

2}, Mahmoud A Hussein^{3

4}, Osman I Osman^{3

5}, Khalid A Alamry^{1

3}, Ahmed E M Mekky^{1

6}, Abdullah M Asiri^{3

7}, Samy A El-Daly⁸

Affiliations

¹ Chemistry Department, Faculty of Science, Jeddah University, Jeddah, 80327, Saudi Arabia.
² Green Chemistry Department, National Research Centre, Dokki, Cairo, 12622, Egypt.
³ Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia.
⁴ Chemistry Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
⁵ Chemistry Department, Faculty of Science, Khartoum University, P.O. Box 321, 11111, Khartoum, Sudan.
⁶ Chemistry Department, Faculty of Science, Cairo University, Giza, 12613, Egypt.
⁷ Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, Jeddah, 21589, P.O. Box 80203, Saudi Arabia.
⁸ Chemistry Department, Faculty of Science, Tanta University, Tanta, 2173, Egypt. samyeldaly@yahoo.com.

PMID: 27476069
DOI: 10.1007/s10895-016-1884-2

Abstract

A new macromolecule pyrimido[l,2-a]benzimidazole derivative named 1,4-bis(2-(2-phenylpyrimido[1,2-a]benzimidazol-4-yl)phenoxy)butan (BPPB) has been synthesized in accepted yield using microwave assistance. The new compound BPPB has been formed by the interaction of 3,3'-((butane-1,4-diylbis(oxy))bis(2,1-phenylene))bis(1-phenylprop-2-en-1-one) (3) with 2- aminobenzimidazole (4) in the presence of potassium hydroxide as a basic catalyst in dimethylformamide (DMF) under microwave radiation for 20 min. The chemical structure of this novel compound was elucidated by elemental and spectral techniques including: FT-IR, (1)H-NMR, (13)C-NMR and mass spectra. The electronic absorption and emission spectra of BPPB were measured in different solvents. BPPB displayed a solvatochromic effect of the emission spectrum that is reflected by red shifts of its fluorescence emission maxima on increasing the solvent polarity, indicating a change of electronic charge distribution upon excitation. BPPB crystalline solids gave excimer-like emission at 535 nm with a bandwidth of ca. 60 nm. Ground and excited states electronic geometry optimizations using density functional theory (DFT) and time-dependent density functional theory (TD-DFT), respectively, complemented these spectral findings. The intramolecular charge transfer was investigated by natural bond orbital (NBO) technique.

Keywords: 1,4-bis(2-(2-phenylpyrimido[1,2-a]benzimidazol-4-yl)phenoxy)butan (BPPB); DFT studies; Effect of solvent; Photoluminescence; Photostability.