title: Charge-transfer complexes of 4-methylpiperidine with σ- and π-acceptors.
abstract: The solid charge-transfer (CT) molecular complexes formed in the reaction of the electron donor 4-methylpiperidine (4MP) with the σ-electron acceptor iodine and π-acceptors 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD) have been investigated spectrophotometrically in chloroform at 25 °C. These were characterized through electronic and infrared spectra as well as elemental and thermal analysis. The obtained results showed that the formed solid CT-complexes have the formulas [(4MP) I](+)I(-)3, [(4MP)(DDQ)2] and [(4MP)(TBCHD)] and with TCNQ the adduct [TCMPQDM] is obtained through N-substitution reaction in full agreement with the known reaction stoichiometries in solution as well as the elemental measurements. The formation constant KCT, molar extinction coefficient εCT, free energy change ΔG(0), CT energy ECT and the ionization potential Ip have been calculated for the CT-complexes [(4MP) I](+)I(-)3, [(4MP)(DDQ)2] and [(4MP)(TBCHD)].
authors.affiliation: Department of Chemistry and Earth Sciences, College of Arts and Sciences, Qatar University, P.O. Box 2713, Doha, Qatar. Electronic address: siham@qu.edu.qa.
authors.forename: Siham Y
authors.initials: SY
authors.lastname: AlQaradawi
authors.affiliation: Department of Chemistry, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar.
authors.forename: Adel
authors.initials: A
authors.lastname: Mostafa
authors.affiliation: Department of Chemistry, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar.
authors.forename: Hassan S
authors.initials: HS
authors.lastname: Bazzi
mesh_terms: D065966:Absorption, Physicochemical; D016227:Benzoquinones / Q000737:chemistry; D004583:Electrons; D009570:Nitriles / Q000737:chemistry; D010880:Piperidines / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D013816:Thermodynamics; D017186:Titrimetry
chemical_list: D016227:Benzoquinones; D009570:Nitriles; D010880:Piperidines; D012997:Solvents; C013703:tetracyanoquinodimethane; C000928:dichlorodicyanobenzoquinone; C032727:piperidine; C000598710:4-methylpiperidine
keywords: 4-Methylpiperidine; DDQ; Iodine; Spectra; TBCHD