| Abstract
| - The crystal structures of diamagnetic dichloro(2-aza-2-methyl-5,10,15,20-tetraphenyl-21-carbaporphyrinato-N,N′,N′′)-tin(IV) methanol solvate [Sn(2-NCH3NCTPP)Cl2·2(0.2MeOH); 6·2(0.2MeOH)] and paramagnetic bromo(2-aza-2-methyl-5,10,15,20-tetraphenyl-21-carbaporphyrinato-N,N′,N′′)-manganese(III) [Mn(2-NCH3NCTPP)Br; 5] were determined. The coordination sphere around Sn4+ in 6·2(0.2MeOH) is described as six-coordinate octahedron (OC-6) in which the apical site is occupied by two transoid Cl− ligands, whereas for the Mn3+ ion in 5, it is a five-coordinate square pyramid (SPY-5) in which the unidentate Br− ligand occupies the axial site. The g value of 9.19 (or 10.4) measured from the parallel polarization (or perpendicular polarization) of X-band EPR spectra at 4 K is consistent with a high spin mononuclear manganese(III) (S = 2) in 5. The magnitude of axial (D) and rhombic (E) zero-field splitting (ZFS) for the mononuclear Mn(III) in 5 were determined approximately as −2.4 cm−1 and −0.0013 cm−1, respectively, by paramagnetic susceptibility measurements and conventional EPR spectroscopy. Owing to weak C(45)−H(45A)···Br(1) hydrogen bonds, the mononuclear Mn(III) neutral molecules of 5 are arranged in a one-dimensional network. A weak Mn(III)···Mn(III) ferromagnetic interaction (J = 0.56 cm−1) operates via a [Mn(1)−C(2)−C(1)−N(4)−C(45)−H(45A)···Br(1)−Mn(1)] superexchange pathway in complex 5.
- This work reports X-ray crystals of two new inverted N-methylated porphyrin complexes, that is, a paramagnetic Mn(2-NCH3NCTPP)Br (5) and a diamagnetic Sn(2-NCH3NCTPP)Cl2(6). The ESR and magnetic susceptibility study of 5 has yielded actual structural information in terms of the parameters of D and E in 5.
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