1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 z Electro, Physical & Theoretical Chemistry Synthesis of New Porphyrin Complexes: Evaluations on Optical, Electrochemical, Electronic Properties and Application as an Optical Sensor Jihed Brahmi,* [a] Soumaya Nasri, [b, c] Hamza Saidi, [d] Habib Nasri, [b] and Kaiss Aouadi [a, e] This work reports on the synthesis, characterization and application as an optical sensor of two new porphyrin complexes namely :(Hexamethylenetetramine)(meso-tetratri- fluoromethylphenylporphyrinato) zinc(II) [Zn(TFMPP)(HMTA)] and (Hexamethylenetetramine)(meso-tetra-tert-butylphenylphe- nylporphyrinato) Zinc(II) [Zn(TtBuPP)(HMTA)]. The chemical structures of these species were defined by 1 HNMR and FT-IR spectroscopic analysis. The optical properties of these π- conjugated systems were investigated by UV-visible, absorption and photoluminescence spectroscopy. The UV-visible titrations show that the Soret and Q bands of the new complexes are red-shifted compared to those of the starting material species [Zn(TFMPP)] and [Zn(TtBuPP)] and the association constants (K as ) was found to be depending on the withdrawing-donating effects of the substituents on the phenyls ring of the meso- porphyrins. The electrochemical behavior was also investigated and the optical and electrochemical energy gaps were determinate. The electronic properties of the ITO/Pi/Al have been defined by I–V characteristics and impedance spectro- scopy measurements. 1. Introduction Owing to their optical and electronic properties, porphyrins and metalloporphyrins have recently attracted significant attention of both chemists and physicists. The unusual physicochemical properties of these compounds such as high thermal and chemical stability and strong absorption in the visible region make porphyrins extremely useful molecules in various fields. Indeed, porphyrins and metalloporphyrins have been used in photodynamic therapy. [1,2] They have also been used as semiconductors, [3] chemical and biological sensors, [4–6] organic light-emitting diodes, [7,8] dye-sensitized solar cells (DSSCs) [9–12] and photovoltaic materials. [13] Molecular systems based on metalloporphyrin are also of interest in the field of molecular electronic equipments such as optoelectronic mem- ory devices. [14] We herein, describe the synthesis of two new zinc(II) porphyrin complexes: The (Hexamethylenetetramine)(meso- tetratrifluoromethylphenylporphyrinato) zinc(II) [Zn(TFMPP) (HMTA)] (3) and the (Hexamethylenetetramine)(meso-tetra-tert- butylphenylphenylporphyrinato) zinc(II) [Zn(TtBuPP)(HMTA)] (4). Their structures are shown in Scheme 1. UV-visible spectroscopy, Fourier Transform Infrared Spectro- scopy (FT-IR), Proton nuclear magnetic resonance ( 1 HNMR), Cyclic Voltammetry and Photoluminescence spectroscopy are used firstly to confirm the synthesis of the new porphyrin complexes secondly, to study the optical and electrochemical properties of these compounds. We have also investigated the electronic properties of these species using the ITO/Pi/Al structure (Pi refers to the zinc(II) metalloporphyrins). This [a] Dr. J. Brahmi, Prof. K. Aouadi University of Monastir, Laboratoire de Chimie Hétérocyclique, Produits Naturels et Réactivités, Faculté des Sciences de Monastir, Avenue de l’Environnement, 5019 Monastir, Tunisie E-mail: jihedbrahmi85@live.fr [b] Dr. S. Nasri, Prof. H. Nasri University of Monastir, Laboratoire de Physico-chimie des Matériaux, Fa- culté des Sciences de Monastir, Avenue de l’environnement, 5019 Mon- astir, Tunisie [c] Dr. S. Nasri University Center for Girls, Study, Premedical Department, Faculty of Sciences, King Khalid University, Abha, P.O. 3340, Kingdom of Saudi Arabia [d] Dr. H. Saidi University of Monastir, Laboratoire de la Matière Condensée et des Na- nosciences, Faculté des Sciences Monastir, Avenue de l’Environnement, 5019, Monastir, Tunisie [e] Prof. K. Aouadi Qassim University-College of Science, Department of Chemistry, Buraidah 51452, Saudi Arabia Supporting information for this article is available on the WWW under https://doi.org/10.1002/slct.201803676 Scheme 1. Synthesis of the new porphyrin complexes (3, 4). Full Papers DOI: 10.1002/slct.201803676 1350 ChemistrySelect 2019, 4, 1350 – 1359 © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim