Terpyridine-metal complexes: effects of different substituents on their physico-chemical properties and density functional theory studies

Abstract

A series of different substituted terpyridine (tpy)-based ligands have been synthesized by Kröhnke method. Their binding behaviour was evaluated by complexing them with Co(II), Fe(II) and Zn(II) ions, which resulted in interesting coordination compounds with formulae, [Zn(tpy) 2 ]PF 6 , [Co(tpy) 2 ](PF 6 ) 2 , [Fe(tpy) 2 ](PF 6 ) 2 and interesting spectroscopic properties. Their absorption and emission behaviours in dilute solutions were investigated in order to explain structure–property associations and demonstrate the impact of different aryl substituents on the terpyridine scaffold as well as the role of the metal on the complexes. Photo-luminescence analysis of the complexes in acetonitrile solution revealed a transition from hypsochromic to bathochromic shift. All the compounds displayed remarkable photo-luminescent properties and various maximum emission peaks owing to the different nature of the functional groups. Furthermore, the anti-microbial potential of ligands and complexes was evaluated with docking analyses carried out to investigate the binding affinity of terpyridine-based ligands along with corresponding proteins (shikimate dehydrogenase and penicillin-binding protein) binding sites. To obtain further insight into molecular orbital distributions and spectroscopic properties, density functional theory calculations were performed for representative complexes. The photophysical activity and interactions between chromophore structure and properties were both investigated experimentally as well as theoretically.

Fine-Tuning Metal and Ligand-Centered Redox Potentials of Homoleptic Bis-Terpyridine Complexes with 4′-Aryl Substituents

“…The characterization of L = 2-OMe , 3-OMe , 4-OMe , 3,5-OMe , 3,4,5-OMe , 2,4-OMe , 2,4,6-OMe , 3,4,5-F , 2-CF3 , 3-CF3 , 4-CF3 , 3,5-F , 3,5-CF3 , 3-Br , and 3,5-Br is consistent with that previously reported. To the best of our knowledge, 2,6-F and 3-CF3,4-OMe have not been reported previously.…”

“…With the exception of [Co­( 3,4,5-OMe ) 2 ] 2+ , [Co­( 3-CF3 ) 2 ] 2+ , [Co­( 4-OMe ) 2 ] 2+ , and [Co­( 2-CF3 ) 2 ] 2+ , [Co­( 3-CF3 ) 2 ] 2+ , [Co­( 4-CF3 ) 2 ] 2+ , all cobalt complexes presented here, are new and were synthesized according to the general metalation procedure described below. , Complexes of Mn, Fe, Ni, and Zn were also synthesized according to the general metalation procedure. All [M­( L ) 2 ] 2+ complexes are new, with the exceptions of [Ni­( 4-CF3 ) 2 ] 2+ , [Ni­( 4-OMe ) 2 ] 2+ , [Mn­( 4-OMe ) 2 ] 2+ , [Zn­( 4-OMe ) 2 ] 2+ , [Fe­( 4-OMe ) 2 ] 2+ , and [Fe­( 3-CF3 ) 2 ] 2+ . ,,,,,, …”

Electronic and structural data of 4’-substituted bis(2,2’;6’2’’-terpyridine)manganese in mono-, bis-, tris- and tetra-cationic states from DFT calculations

“… This data gives experimental chemists insight into the expected stability and reactivity of mono -, bis -, tris - and tetra -cationic states of [Mn(tpy) 2 ] n+ complexes, that go through different oxidation states during catalytic cycles and electrochemical oxidation and reduction processes [5] . Transition metal-terpyridine complexes exhibit anti-microbial potential, are used in biomedical applications, and have unique optical, photo-luminescence-, catalytic-, photovoltaic-, sensitizers and sensor properties [6] , [7] , [8] , [9] . This data provides the geometry of the basic structure of the ground states of mono -, bis -, tris - and tetra -cationic states of [Mn(tpy) 2 ] n+ complexes, that include broken symmetry, constrained octahedral and compression Jahn-Teller geometries.…”

Photocatalytic Carbon Dioxide Reduction and Density Functional Theory Investigation of 2,6-(Pyridin-2-yl)-1,3,5-triazine-2,4-diamine and Its Cobalt and Nickel Complexes

“…23−26 played important roles in our understanding of the kinetics and thermodynamics of complexation of metal ions and the physicochemical properties of metal complexes. 27,28 As a tridentate (tpy) metal-binding ligand, it has been extensively used as a scaffold in supramolecular and metallosupramolecular chemistry. 29,30 The most common coordination behavior of tpy is the one in which nitrogen atoms are bonded to the same metal center.…”

“…tpy is an oligopyridine ligand which is one of the most commonly used and easily identified ligands in coordination chemistry. − Coordination compounds with tpy have played important roles in our understanding of the kinetics and thermodynamics of complexation of metal ions and the physicochemical properties of metal complexes. , As a tridentate ( tpy ) metal-binding ligand, it has been extensively used as a scaffold in supramolecular and metallosupramolecular chemistry. , The most common coordination behavior of tpy is the one in which nitrogen atoms are bonded to the same metal center. According to the stoichiometry employed, it is possible to form the compounds [M­( tpy ) m ] x+ (m = 1 or 2 and M = metal ion).…”