The present report deals with the one electron oxidation and the one- and two-electron reduction of [Mn(tmtaa)L], [L=THF, 1a; L=none, 1b; tmtaa=dibenzotetramethyltetraaza[14]annulene]. The former class of reactions led to the formation of a variety of functionalised Mn(III) species, [(tmtaa)Mn-X] [X=I, 2; X=Cl, 3; X=NCS, 5], including the cationic derivatives [Mn(tmtaa)(L)(L')]BPh4 [L=L'=THF, 4a; L=L'=DME, 4b; L=Py, L'=none, 4c]. The magnetic properties of the Mn(III) derivatives are strongly dependent on the axial ligand. Reaction of 1a with NO gave [(tmtaa)Mn(NO)], 6, which takes up an axial pyridine leading to the diamagnetic [(tmtaa)Mn(NO)(Py)], 7. Complex 6 displays a peculiar magnetic behavior, which has been interpreted as a S=0 reversible arrow S=2 spin equilibrium with a Delta H-eff=4.0 kJ mol(-1) and a Delta S-eff=11.3 J mol(-1) K-1 associated to the spin transition process. Reaction of 1 with sodium metal in DME leads to [Mn-2(mu(2)-tmtaa)(2){Na .(DME)(2)}(2)], 8, while in THF [Mn-2(*tmtaa(2)*)Na-4.(THF)(6)], 9, is formed. Extended Huckel calculations have been performed for a better understanding of the magnetic and electronic properties of 6 and 9. The proposed structures have been supported by X-ray analyses of 3, 4b, 6, 8, and 9.

The Reactivity of Dibenzotetramethyltetraaza[14]annulene-Mn(II): Functionalisation of Manganese in a Macrocyclic Environment / F., Franceschi; J., Hesschenbrouck; E., Solari; C., Floriani; N., Re; Rizzoli, Corrado; A., Chiesi Villa. - In: DALTON. - ISSN 1470-479X. - ?:(2000), pp. 593-604. [10.1039/a908121f]

The Reactivity of Dibenzotetramethyltetraaza[14]annulene-Mn(II): Functionalisation of Manganese in a Macrocyclic Environment

RIZZOLI, Corrado;
2000

Abstract

The present report deals with the one electron oxidation and the one- and two-electron reduction of [Mn(tmtaa)L], [L=THF, 1a; L=none, 1b; tmtaa=dibenzotetramethyltetraaza[14]annulene]. The former class of reactions led to the formation of a variety of functionalised Mn(III) species, [(tmtaa)Mn-X] [X=I, 2; X=Cl, 3; X=NCS, 5], including the cationic derivatives [Mn(tmtaa)(L)(L')]BPh4 [L=L'=THF, 4a; L=L'=DME, 4b; L=Py, L'=none, 4c]. The magnetic properties of the Mn(III) derivatives are strongly dependent on the axial ligand. Reaction of 1a with NO gave [(tmtaa)Mn(NO)], 6, which takes up an axial pyridine leading to the diamagnetic [(tmtaa)Mn(NO)(Py)], 7. Complex 6 displays a peculiar magnetic behavior, which has been interpreted as a S=0 reversible arrow S=2 spin equilibrium with a Delta H-eff=4.0 kJ mol(-1) and a Delta S-eff=11.3 J mol(-1) K-1 associated to the spin transition process. Reaction of 1 with sodium metal in DME leads to [Mn-2(mu(2)-tmtaa)(2){Na .(DME)(2)}(2)], 8, while in THF [Mn-2(*tmtaa(2)*)Na-4.(THF)(6)], 9, is formed. Extended Huckel calculations have been performed for a better understanding of the magnetic and electronic properties of 6 and 9. The proposed structures have been supported by X-ray analyses of 3, 4b, 6, 8, and 9.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11381/1840825
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