Electron Paramagnetic Resonance of Mn(II) Complexes in Acetonitrile

Abstract

Electron paramagnetic resonance has been observed for the systems (a) Mn(ClO4)2–Et4NClO4, (b) MnCl2–Et4NCl, and (c) MnBr2–(n-C4H9)4NBr in acetonitrile. EPR intensity measurements, linewidths of the hyperfine components, electrical conductance, and optical spectra have been used to characterize the species exhibiting the paramagnetic resonance as [Mn(CH3CN)6]++, [MnCl4]=, and [MnBr4]=. The 〈g〉 values and hyperfine interaction constants 〈A〉 for these complexes were determined to be: 〈g〉|〈A〉|G [Mn(CH3CN)6]++ 2.003±0.00192±1 [MnCl4]= 2.007±0.00179±1 [MnBr4]= 2.008±0.00175±1.

Synthesis and Characterization of a “Turn-On” photoCORM for Trackable CO Delivery to Biological Targets

“…The Mn(II) center in such solution appears to exist as an acetonitrile complex, and the modest hyperfine broadening possibly arises from ligand exchange (Br − ) as reported by Chan and co-workers. 28 This is corroborated by the fact that a solution of MnSO 4 with equimolar KBr in acetonitrile−water (40:60, v/v) mixture also affords a very similar EPR spectrum (Figure 4 bottom). The close resemblance of these two EPR spectra suggests that upon photolysis the Mn(I) center of 1 undergoes oxidation to Mn(II) and remains as a solvated species in solution.…”

Structure and Properties of Tetracyanomanganate(II), [MnII(CN)4]2−, The First Paramagnetic Tetrahedral Cyanometalate Complex

“…[12] The room-temperature EPR spectrum of [Mn II (CN) 4 ] 2À in solution is typical of high-spin Mn II . [14] At concentrations less than or equal to 1 mm the expected six-line hyperfine structure for 55 Mn (I 5/2) is isotropic in solution and centered at g 2.003(1) with an average hyperfine coupling constant j A j 71 AE 1 G (Figure 2a).…”

Electron Spin Resonance of Manganese Nitrate in Diethylacetamide-Water Solution

“…A second group comprises several complexes with nitrogen con taining ligands. They mostly show normal g, and a less pronounced but obvious reduction of hyperfine splitting, 9.2 mT [12,13,16]. Among these, there is an example with decreased g (äs 1.998) in addition, which was ascribed to Mn(NCS)2(MeOH)4 [13].…”