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Products from reactions of [Mn[sub 2]O[sub 2](O[sub 2]CCH[sub 3])(tpen)][sup 2+] in acidic and neutral aqueous media: [Mn[sub 2]([mu]-O)[sub 2]([mu]-O[sub 2]CCH[sub 3])(tpen)][sup 3+] and [[l brace]Mn[sub 3]([mu]-O)[sub 4](OH)(tpen)[r brace][sub 2]([mu]-tpen)][sup 6+]

Journal Article · · Inorganic Chemistry; (United States)
DOI:https://doi.org/10.1021/ic00052a017· OSTI ID:6717649
;  [1]
  1. Univ. of California, Berkeley (United States)

The mixed-valence compound [Mn[sub 2]([mu]-O)[sub 2]([mu]-O[sub 2]CCH[sub 3])(tpen)](ClO[sub 4])[sub 2][center dot]3H[sub 2]O (2[center dot]3H[sub 2]O) reacts to form [Mn[sub 2]([mu]-O)[sub 2]([mu]-O[sub 2]CCH[sub 3])(tpen)](ClO[sub 4])[sub 3] (3) is acidic aqueous solution and in contrast is converted to [[l brace]Mn[sub 3]([mu]-O)[sub 4](OH)(tpen)[r brace][sub 2]([mu]-tpen)](ClO[sub 4])[sub 6][center dot]4H[sub 2]O (4[center dot]4H[sub 2]O) in distilled water (tpen is N,N,N[prime],N[prime]-tetrakis(2-pyridylmethyl)-1,2-ethanediamine). Both reactions were carried out in the presence of a large excess of perchlorate counterion. Syntheses, structures, and selected properties of 3 and 4 are reported. Structural parameters for 3 are consistent with both manganese ions being in the 4+ oxidation state. The cyclic voltammogram of 3 in CH[sub 3]CN exhibits IV,IV/IV,III and IV,III/III,III reductions at +0.90 and [minus]0.13 V, respectively, vs SSCE. The cation in 4 resides on an inversion center. Bond distances and angles in 4 confirm that all Mn atoms are in the +4 oxidation state. The structure of 4 consists of two [l brace]Mn[sub 3]O[sub 4][r brace][sup 4+] units linked by one tpen moiety. The [l brace]Mn[sub 3]O[sub 4][r brace][sup 4+] cores in 4 are distorted in a manner that is reminiscent of [Mn[sub 3]O[sub 4](OH)(bpea)[sub 3]][sup 3+] (J. Am. Chem. Soc. 1992, 114, 6398-6406). The cyclic voltammogram of 4 in CH[sub 3]CN displays two irreversible reduction responses at +0.10 and [minus]0.27 V vs SSCE. The EPR spectrum of 4[center dot]4H[sub 2]O in frozen CH[sub 3]CN-C[sub 6]H[sub 5]CH[sub 3] is consistent with an S = 3/2 ground-state origin. Both 3 and 4[center dot]4H[sub 2]O were also characterized by infrared and electronic spectral measurements. 27 refs., 3 figs., 5 tabs.

OSTI ID:
6717649
Journal Information:
Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 31:26; ISSN 0020-1669; ISSN INOCAJ
Country of Publication:
United States
Language:
English