Syntheses and Properties ofBis[1-(p-substituted phenyl)-1, 3-butanedionato]ma nganese(II) Complexes

Abstract

Bis[1-(p-substituted phenyl)-1, 3-butanedionato]manganese(n) complexes, MnL₂x H₂O(x=1, 2) and MnL₂ (L=p-XC₃H₄COCHCOCH₃, X = NO_, [1], COOCH₃ 21 Br [₃], Cl[4], H[5], NHCOCH₈ [6], C₂H₅ [7], CH, [8], OCH₃[9], OH[10]), were synthe sized, and their configuration and some properties were determined by the magnetic and spectral measurements.
[1a ], [3 a]-[10a] of the MnL₂.2 H₂O type were the mononuclear high spin complexes with an octahedral configuration. However, [2 a] of the MnI.21-120 type and [1b]-[10 b]of the MnL₂ type were the bi- and trinuclear octahedral complexes, respectively. In pyridine and DMSO, all the complexes were smoothly converted into the mononuclear octahedral ones, MnL₂.2 solv (solv=pyridine or DMSO). The reflectance and absorption bands of π→πtransition, charge transfer and 4T1g(G)←6A_1g(S) transition in solid state and in solvents were observed at (28-33) x108, (21-25) x108 and (17-20) x 108 cm^-1, respectively. From the shift of IR absorption bands arising from the metallic chelate ring and of the 4T_1g(G)←6A_1g(S) transition, it was concluded that an electron donating substituent increases the strength of Mn-O bond and the stability of complexes.