The tris-bidentate ligand 1,3,5-tris(5‘-tert-butyl-3‘,4‘-dihydroxyphenyl)benzene ((TBCat)3Ph) was synthesized. The reaction of this molecule in basic solution with two paramagnetic acceptors, i.e., a nickel(II)−tetraazamacrocyclic ligand complex (Ni(CTH)) (CTH = dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) and manganese(II)−hydrotris[3-(4‘-cumenyl)-5-methylpyrazolyl]borate (Mn(TpCum,Me)), yielded two complexes whose analytical formulas are consistent with those of trinuclear complexes. Spectroscopic and magnetic measurements suggest that these derivatives contain divalent metal ions coordinated to the tris(semiquinone) form of the ligand. Analysis of the magnetic data shows that the π-connectivity of the ligand enforces ferromagnetic coupling between the three semiquinone units of the molecule, giving rise to complexes with S = 9/2 (M = NiII) and S = 6 (M = MnII) ground states. The coupling within the tris(semiquinone) unit is quite large (J = −26 cm-1 for the nickel(II) derivative and J = −40 cm-1 for the manganese(II) one, using the general exchange Hamiltonian H = ∑JijSiSj), and it is of the same order of magnitude as that observed in an analogous series of bis(semiquinone) complexes that we recently reported.

High-Spin Metal Complexes Containing a Ferromagnetically-Coupled Tris(Semiquinone) Ligand / Caneschi, Andrea; Dei, Andrea; Mussari, C. P.; Shultz, D. A.; Sorace, Lorenzo; Vostrikova, K.. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - STAMPA. - 41:(2002), pp. 1086-1092. [10.1021/ic0106322]

High-Spin Metal Complexes Containing a Ferromagnetically-Coupled Tris(Semiquinone) Ligand

CANESCHI, ANDREA;DEI, ANDREA;SORACE, LORENZO;
2002

Abstract

The tris-bidentate ligand 1,3,5-tris(5‘-tert-butyl-3‘,4‘-dihydroxyphenyl)benzene ((TBCat)3Ph) was synthesized. The reaction of this molecule in basic solution with two paramagnetic acceptors, i.e., a nickel(II)−tetraazamacrocyclic ligand complex (Ni(CTH)) (CTH = dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) and manganese(II)−hydrotris[3-(4‘-cumenyl)-5-methylpyrazolyl]borate (Mn(TpCum,Me)), yielded two complexes whose analytical formulas are consistent with those of trinuclear complexes. Spectroscopic and magnetic measurements suggest that these derivatives contain divalent metal ions coordinated to the tris(semiquinone) form of the ligand. Analysis of the magnetic data shows that the π-connectivity of the ligand enforces ferromagnetic coupling between the three semiquinone units of the molecule, giving rise to complexes with S = 9/2 (M = NiII) and S = 6 (M = MnII) ground states. The coupling within the tris(semiquinone) unit is quite large (J = −26 cm-1 for the nickel(II) derivative and J = −40 cm-1 for the manganese(II) one, using the general exchange Hamiltonian H = ∑JijSiSj), and it is of the same order of magnitude as that observed in an analogous series of bis(semiquinone) complexes that we recently reported.
2002
41
1086
1092
Caneschi, Andrea; Dei, Andrea; Mussari, C. P.; Shultz, D. A.; Sorace, Lorenzo; Vostrikova, K.
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/204986
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