Influence of Jahn−Teller Coupling on the Magnetic Properties of Transition Metal Complexes with Orbital Triplet Ground Terms:  Magnetization and Electronic Raman Studies of the Titanium(III) Hexa-Aqua Cation

2001 ◽  
Vol 40 (22) ◽  
pp. 5497-5506 ◽  
Author(s):  
P. L. W. Tregenna-Piggott ◽  
Hans-Ueli Güdel
Keyword(s):  
Magnetic Properties ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Jahn Teller

scholarly journals A New Twist on an ‘Old’ Ligand: A [Mn16] Double Square Wheel and a [Mn10] Contorted Wheel

2020 ◽  
Author(s):  
Euan Brechin ◽  
Constantinos J. Milios ◽  
Thomais Tziotzi ◽  
Marco Coletta ◽  
Mark Gray ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Direct Current ◽  
Coordination Compounds ◽  
Exchange Interactions ◽  
Ligand Design ◽  
Jahn Teller

Ligand design remains key to the synthesis of coordination compounds possessing specific topologies, nuclearities and symmetries that direct targeted physical properties. N,O-chelates based on ethanolamine have been particularly prolific in constructing a variety of paramagnetic 3d transition metal complexes with fascinating magnetic properties. Here, we show that combining three ethanolamine moieties within the same organic framework in the form of the ligand 1,3,5-tri(2-hydroxyethyl)-1,3,5-triazacyclohexane (LH3) leads to the formation of two highly unusual Mn wheels. Reaction of Mn(NO3)2·6H2O with LH3 in basic methanolic solutions leads to the formation of [MnIII 12MnII 4(µ3-O)6(µ-OH)4(µ3-OMe)2(µOMe)2(L)4(LH)2(H2O)10](NO3)6(OH)2 (1) and [MnIII 10(µ3-O)4(µ-OH)4(µ-OMe)4(L)4(H2O)4](NO3)2 (2); the only difference in the synthesis being the ratio of metal:ligand employed. The structure of the former describes two offset [MnIII 6MnII 2] square wheels, linked through a common centre, and the latter a single [MnIII 10] wheel twisted at its centre, such that the top half is orientated perpendicular to the bottom half. In both cases the L 3- /LH2- ligands dictate the orientation of the Jahn-Teller axes of the MnIII ions which lie perpendicular to the triazacyclohexane plane. Direct current magnetic susceptibility and magnetisation data reveal the presence of competing exchange interactions in 1 and strong antiferromagnetic interactions in 2. Given the simplicity of the reactions employed and the paucity of previous work, the formation of these two compounds suggests that LH3 will prove to be a profitable ligand for the synthesis of a multitude of novel 3d transition metal complexes

scholarly journals A New Twist on an ‘Old’ Ligand: A [Mn16] Double Square Wheel and a [Mn10] Contorted Wheel

2020 ◽  
Author(s):  
Euan Brechin ◽  
Constantinos J. Milios ◽  
Thomais Tziotzi ◽  
Marco Coletta ◽  
Mark Gray ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Direct Current ◽  
Coordination Compounds ◽  
Exchange Interactions ◽  
Ligand Design ◽  
Jahn Teller

Ligand design remains key to the synthesis of coordination compounds possessing specific topologies, nuclearities and symmetries that direct targeted physical properties. N,O-chelates based on ethanolamine have been particularly prolific in constructing a variety of paramagnetic 3d transition metal complexes with fascinating magnetic properties. Here, we show that combining three ethanolamine moieties within the same organic framework in the form of the ligand 1,3,5-tri(2-hydroxyethyl)-1,3,5-triazacyclohexane (LH3) leads to the formation of two highly unusual Mn wheels. Reaction of Mn(NO3)2·6H2O with LH3 in basic methanolic solutions leads to the formation of [MnIII 12MnII 4(µ3-O)6(µ-OH)4(µ3-OMe)2(µOMe)2(L)4(LH)2(H2O)10](NO3)6(OH)2 (1) and [MnIII 10(µ3-O)4(µ-OH)4(µ-OMe)4(L)4(H2O)4](NO3)2 (2); the only difference in the synthesis being the ratio of metal:ligand employed. The structure of the former describes two offset [MnIII 6MnII 2] square wheels, linked through a common centre, and the latter a single [MnIII 10] wheel twisted at its centre, such that the top half is orientated perpendicular to the bottom half. In both cases the L 3- /LH2- ligands dictate the orientation of the Jahn-Teller axes of the MnIII ions which lie perpendicular to the triazacyclohexane plane. Direct current magnetic susceptibility and magnetisation data reveal the presence of competing exchange interactions in 1 and strong antiferromagnetic interactions in 2. Given the simplicity of the reactions employed and the paucity of previous work, the formation of these two compounds suggests that LH3 will prove to be a profitable ligand for the synthesis of a multitude of novel 3d transition metal complexes

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