Distortions of the coordination polyhedron in high-spin manganese(III) complexes. 3. Crystal and molecular structure of .gamma.-tris(acetylacetonato)manganese(III): a tetragonally elongated octahedral form

Sensitivity enhancement, assignment, and distance measurement in 13C solid-state NMR spectroscopy for paramagnetic systems under fast magic angle spinning

“…Hence, we consider that three and two CH 3 signals are overlapping at the former two positions. These results suggest that the existence of three non-equivalent ligand molecules in Mn(acac) 3 , which is consistent with recent X-ray crystallography results [65]. In the present spectra, the cross-peak for 13 CO at 517 ppm was too weak to be properly analyzed.…”

“…These values reasonably agree with 71% and 128% obtained for CH and CH 3 of L-Ala, respectively. The sidebands due to paramagnetic dipolar shifts observed for CH 3 groups are fewer; this is consistent with the X-ray structures, in which the CH 3 groups are more remotely located from Mn(III) (R C-Mn = 4.4 Å ) than CO (3.0 Å ) or CH (3.3 Å ) groups [65]. The two CH signals at (x H , x C ) = (5 ppm, 350 ppm) and (9 ppm, 346 ppm) have an intensity ratio 1:2; hence it is likely that signals for two CH groups are overlapping at (9 ppm, 346 ppm).…”

Jahn-Teller distortion in tris[4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionato]manganese(III) isomers: An X-ray and computational study

“…Crystal structures of different tris(β-diketonato)manganese(III) complexes exhibit elongation JahnTeller distortion [2,3,4] or compression Jahn-Teller distortion [5,6,7]. Reported structures of [Mn(acetylacetonato) 3 ] include three different crystalline forms: namely a β form obtained at room temperature, which exhibited a moderate compression (TC) of the metal-ligand bonds along the zaxis of about 0.05 Å [5]; secondly, a γ form, also obtained at room temperature (RT), which showed a significant elongation (TE) of the metal-ligand bonds along the z-axis of about 0.18 Å [2]; and thirdly, a δ form, obtained at low temperature (LT) (100K), exhibiting a Jahn-Teller orthorhombic distortion [8].…”

“…Reported structures of [Mn(acetylacetonato) 3 ] include three different crystalline forms: namely a β form obtained at room temperature, which exhibited a moderate compression (TC) of the metal-ligand bonds along the zaxis of about 0.05 Å [5]; secondly, a γ form, also obtained at room temperature (RT), which showed a significant elongation (TE) of the metal-ligand bonds along the z-axis of about 0.18 Å [2]; and thirdly, a δ form, obtained at low temperature (LT) (100K), exhibiting a Jahn-Teller orthorhombic distortion [8]. This result encouraged us to similarly determine the crystal structure of another [Mn(β-diketonato) 3 ] complex, at both RT and LT.…”

I–V Characteristics of tris(2,4-pentanedionato)manganese(III) thin films

“…Acac: [CH 3 COCHCOCH 3 ] À ) [7,8] by strong metal-ligand dative covalent bonds. In the solid state, these complex molecules are arranged forming three different crystalline structures: orthorhombic (a), monoclinic (b), and monoclinic (c) [9,10]. The phase of the powder used in the present investigation was the bphase, which has a monoclinic structure (P2 1 /c) of a = 0.14013 nm, b = 0.76 nm, c = 0.16373 nm, and b = 99.33° [9].…”