Synthesis and X-ray structure of the MnIICl2 and MnIIIF2 complexes of N,N'-dimethyl-2,11-diaza[3,3](2,6)pyridinophane. High-field electron paramagnetic resonance and density functional theory studies of the MnIII complex. Evidence for a low-lying spin triplet state.
Two manganese complexes, (py2(NMe)2)MnIICl2 (1) and [(py2(NMe)2)MnIIIF2]+ (2), are here described with the macrocyclic ligand py2(NMe)2 (py2(NMe)2 = N,N'-dimethyl-2,11-diaza[3,3](2,6)pyridinophane). For both, the crystal structure is reported. The UV-visible spectrum of 2 exhibits a very broad near-infrared (NIR) band corresponding to the transition between the two e(g)-type orbitals split by the Jahn-Teller effect. A negative D value of ca. -4 cm(-1) was estimated by high-field and high-frequency electron paramagnetic resonance (HF-EPR) spectroscopy, which was consistent with symmetry considerations. Density functional theory (DFT) calculations on 2 support the 5B1 electronic ground state predicted from the X-ray structure. Moreover, to explain the large value of the D parameter, a spin triplet first excited spin state was postulated to occur at low energy. This was confirmed by the DFT calculations.
Albela
Belén
B
Laboratoire de Chimie Inorganique, UMR 8613, UMR 8124, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Sud, France.
Carina
Riccardo
R
Policar
Clotilde
C
Poussereau
Sandrine
S
Cano
Joan
J
Guilhem
Jean
J
Tchertanov
Luba
L
Blondin
Geneviève
G
Delroisse
Michel
M
Girerd
Jean-Jacques
JJ
D001372:Aza Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D008345:Manganese; D017895:Manganese Compounds / Q000737:chemistry*; D008958:Models, Molecular; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry*; D014961:X-Ray Diffraction
D001372:Aza Compounds; D002712:Chlorides; D017895:Manganese Compounds; C511913:N,N'-dimethyl-2,11-diaza(3,3)(2,6)pyridinophane; D011725:Pyridines; D008345:Manganese; C025340:manganese chloride