Potential hydrogen storage complexes: Short-time microwave-assisted synthesis, characterization, thermodynamic, and international relations

Abstract

This work included preparing and characterizing new platinum complexes with the ligand 3,4,5-trimethoxybenzoic acid (TMB). The reactions were carried out using an autoclave in microwave within 3 min only in an alkali medium of triethylamine, where two moles of TMB reacted with one mole of platinum ion and two moles of PPh₃, or with one mole of diphosphines (Bis(diphenylphosphino)x; x = methane (dppm), ethane (dppe), propane (dppp), ferrocene (dppf)). The prepared complexes were characterized by measuring melting points and by the techniques of (C.H.N), molar electrical conductivity, FT-IR and ¹H NMR. The characterization results demonstrated that the TMB ligand behaves as a bidentate ligand through the oxygen atom of the carboxylic groups, and its geometric shape is a square planar around the platinum ion. The complex formed with high yield ([Pt(TMB)₂(dppf)]) was used in hydrogen storage application. The storage isotherm showed that the complex has a high storage capacity of about 4.2 wt% at 61 bar under low temperature (77 K). The study showed that the thermodynamic functions were − 0.67KJ/mol and − 3.6 J/mol H₂ for enthalpy and entropy, indicating the occurrence of physical hydrogen storage.