Structural modulation of pi-conjugated linkers in D-pi-A dyes based on triphenylamine dicyanovinylene framework to explore the NLO properties

Author(s)

Khalid, Muhammad ^[1] ; Khan, Muhammad Usman ^[2] ; Shafiq, Iqra ^[1] ; Hussain, Riaz ^[2] ; Ali, Akbar ^[3] ; Imran, Muhammad ^[4] ; Braga, Ataualpa A. C. ^[5] ; Rehman, Muhammad Fayyaz Ur ^[3] ; Akram, Muhammad Safwan ^{[6, 7]}

Affiliation

^[1] Khawaja Fareed Univ Engn & Informat Technol, Dept Chem, Rahim Yar Khan 64200 - Pakistan

^[2] Univ Okara, Dept Chem, Okara 56300 - Pakistan

^[3] Univ Sargodha, Inst Chem, Sargodha 40100 - Pakistan

^[4] King Khalid Univ, Fac Sci, Dept Chem, POB 9004, Abha 61413 - Saudi Arabia

^[5] Univ Sao Paulo, Dept Quim Fundamental, Inst Quim, Ave Prof LineuPrestes 748, BR-05508000 Sao Paulo - Brazil

^[6] Teesside Univ, Sch Hlth & Life Sci, Middlesbrough TS1 3BA, Cleveland - England

^[7] Teesside Univ, Natl Horizons Ctr, Darlington DL1 1HG, Durham - England

• Document type: Journal article
• Source: ROYAL SOCIETY OPEN SCIENCE; v. 8, n. 8 AUG 4 2021.
• Web of Science Citations: 0

Abstract

A donor-pi-acceptor type series of Triphenylamine-dicyanovinylene-based chromophores (DPMN1-DPMN11) was designed theoretically by the structural tailoring of pi-linkers of experimentally synthesized molecules DTTh and DTTz to exploit changes in the optical properties and their nonlinear optical materials (NLO) behaviour. Density functional theory (DFT) computations were employed to understand the electronic structures, absorption spectra, charge transfer phenomena and the influence of these structural modifications on NLO properties. Interestingly, all investigated chromophores exhibited lower band gap (2.22-2.60 eV) with broad absorption spectra in the visible region, reflecting the remarkable NLO response. Furthermore, natural bond orbital (NBO) findings revealed a strong push-pull mechanism in DPMN1-DPMN11 as donor and pi-conjugates exhibited positive, while all acceptors showed negative values. Examination of electronic transitions from donor to acceptor moieties via pi-conjugated linkers revealed greater linear (<alpha > = 526.536-641.756 a.u.) and nonlinear (beta(tot) = 51 313.8-314 412.661 a.u.) response. It was noted that the chromophores containing imidazole in the second p-linker expressed greater hyperpolarizability when compared with the ones containing pyrrole. This study reveals that by controlling the type of pi-spacers, interesting metal-free NLO materials can be designed, which can be valuable for the hi-tech NLO applications. (AU)

• FAPESP's process: 14/25770-6 - New frontiers in cross-coupling reactions promoted by palladium: combining enantioselective catalysis, C-H activations, new materials and in flux reactions aiming at high efficiency and sustainability in synthetic processes
• Grantee: Carlos Roque Duarte Correia
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/01491-3 - Theoretical study of cross-coupling reactions: homogeneous and heterogeneous catalysis
• Grantee: Ataualpa Albert Carmo Braga
• Support Opportunities: Regular Research Grants