Manganese(II/II/II) and manganese(III/II/III) trinuclear compounds. Structure and solid and solution behavior

Two mixed-valence (MnMnII)-Mn-III complexes and a home-valence Mn-II trinuclear manganese complex of stoichiometry (MnMnMnIII)-Mn-III-Mn-II(5-Cl-Hsaladhp)(2)(AcO)(4)(MeOH)(2) . 4CH(3)OH (1a), (MnMnMnIII)-Mn-III-Mn-II (Hsaladhp)(2)(AcO)(2)(5-Cl-Sal)(2)-(thf)(2) (3a) and (MnMnMnII)-Mn-II-Mn-II (AcO)(6)(pybim)(2) (1b) where H(3)saladhp is a tridentate Schiff base ligand and pybim a neutral bidentate donor ligand, have been structurally characterized by using X-ray crystallography. The structurally characterized mixed-valence complexes have strictly 180 degrees Mn-III-Mn-II-Mn-III angles as required by crystallographic inversion symmetry. The complexes are valence trapped with two terminal Mn-III ions showing Jahn-Teller distortion along the acetate or salicylate-Mn-III-X axis. The Mn ... Mn separation is 3.511 Angstrom and 3.507 Angstrom respectively. The mixed-valence complexes have S = 3/2 ground state and the homovalence complex S = 5/2, With Small antiferromagnetic exchange J couplings, -5.6 and -1.8 cm(-1), respectively, while the powder ESR spectra at 4 K show a broad low field signal with g approximate to 4.3 for (MnMnMnIII)-Mn-III-Mn-II and a broad temperature-dependent signal at g = 2 for (MnMnMnII)-Mn-II-Mn-II. Crystal data for 1a: [C36H60O20N2Cl2Mn3], triclinic, space group P (1) over bar, a = 9.272(7) Angstrom, b = 11.046(8) Angstrom, c = 12.635(9) Angstrom, alpha = 76.78(2)degrees, beta = 81.84(2)degrees, gamma = 85.90(2)degrees, Z = 1. Crystal data for 3a: [C48H56O18N2Cl2Mn3], monoclinic, space group P2(1)/n, a = 8.776(3) Angstrom, b = 22.182(7) Angstrom, c = 13.575(4) Angstrom, beta = 94.44(1)degrees, Z = 2. Crystal data for 1b: [C36H36O12N6Mn3], triclinic, space group P (1) over bar, a = 13.345(6) Angstrom, b = 8.514(4) Angstrom, c = 9.494(4) Angstrom, alpha = 75.48(1)degrees, beta = 75.83(1)degrees, gamma = 76.42(1)degrees, Z = 1.