Nitridocyanometalates of CrV, MnV, and MnVI

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  • Bendix, Jesper
  • Karsten Meyer
  • Thomas Weyhermüller
  • Eckhard Bill
  • Nils Metzler-Nolte
  • Karl Wieghardt

Reaction of [CrV(N)(salen)]·CH3NO2 and [MnV(N)(salen)] in dimethylformamide or a methanol/water mixture with an aqueous solution of NaCN and CsCl or [N(CH3)4]Cl at elevated temperatures affords in good yields, respectively, yellow microcrystalline compounds of Cs2Na[CrV(N)(CN)5] (1); [N(CH3)4]2Na[CrV(N)(CN) 5]·H2O (1a) and pink-violet crystals of Cs2Na[MnV(N)(CN)5] (4); and [N(CH3)4]2Na[MnV(N)(CN) 5]·H2O (4a). These six-coordinate nitridopentacyanometalates contain a terminal M≡N unit and a labile cyano group in trans position. Recrystallization from water and addition of [PPh4]Cl yields the five-coordinate species [PPh4]2[M(N)(CN)4]· 2H2O (M = CrV (2), MnV (5)). From pyridine solutions of 2 and 5 the six-coordinate species [PPh4]2[M(N)-(CN)4(py)]·H 2O· py (M = CrV (3), MnV (6)) crystallize. Complexes 1, 1a, 2, and 3 are paramagnetic (1.8 ± 0.1 μB at 298 K; d1) whereas 4, 4a, 5, and 6 have a low-spin d2 ground state. Electrochemically, 5 can be reversibly one-electron-oxidized in CH3CN with formation of a relatively stable [MnVI(N)(CN)4]- anion. Complexes 3, 5, and 6 have been characterized by single-crystal X-ray crystallography: 3 and 6 are isostructural and crystallize in the orthorhombic space group Pnma with a = 17.336(3) (17.254(3)) Å , b = 23.019(4) (22.873(4)) Å, c = 13.563(2) (13.490(2)) Å, V = 5412(2) (5324(2)) Å3, and Z = 4 (4) (values in parentheses refer to 6); 5 crystallizes in the triclinic space group P1̄ with a = 12.050(1), b= 12.310(1), c = 16.685(2) Å, α = 97.88(2)°, β = 109.33(2)°, γ = 90.55(2)°, V = 2309.4(4) Å3, and Z=2. The complexes have been characterized by 13C and 15N NMR, UV-vis, EPR, IR/Raman, and MCD spectroscopies.

Original languageEnglish
JournalInorganic Chemistry
Volume37
Issue number8
Pages (from-to)1767-1775
Number of pages9
ISSN0020-1669
Publication statusPublished - 1 Dec 1998

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