NITRIDOCYANOMETALATES OF CR-V, MN-V, AND MN-VI

Reaction of [Cr-V(N)(salen)]. CH3NO2 and [Mn-V(N)(salen)] in dimethylf ormamide or a methanol/water mixture with an aqueous solution of NaCN and CsCl or [N(CH3)(4)]Cl at elevated temperatures affords in good yie lds, respectively, yellow microcrystalline compounds of Cs2Na[Cr-V(N)( CN)(5)] (1); [N(CH3)(4)](2)Na[Cr-V(N) (CN)(5)]. H2O (la) and pink-viol et crystals of Cs2Na[Mn-V(N)(CN)(5)] (4); and [N(CH3)(4)](2)Na[Mn-V(N) (CN)(5)]. H2O (4a). These six-coordinate nitridopentacyanometalates co ntain a terminal M drop N unit and a labile cyano group in trans posit ion. Recrystallization from water and addition of [PPk(4)]Cl yields th e five-coordinate species [PPh4](2)[M(N)(CN)(4)]. 2H(2)O (M = Cr-V (2) , Mn-V (5)). From pyridine solutions of 2 and 5 the six-coordinate spe cies [PPh4](2)[M(N)(CN)4(py)l ]H2O . py (M = Cr-V (3), Mn-V (6)) cryst allize. Complexes 1, 1a, 2, and 3 are paramagnetic (1.8 +/- 0.1 mu B a t 298 K; d(1)) whereas 4, 4a, 5, and 6 have a low-spin d(2) ground sta te. Electrochemically, 5 can be reversibly one-electron-oxidized in CH 3CN with formation of a relatively stable [Mn-VI(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 orth orhombic space group Pnma with a = 17.336(3) (17.254(3)) Angstrom, b = 23.019(4) (22.873(4)) Angstrom, c = 13.563(2) (13.490(2)) Angstrom, V = 5412(2) (5324(2)) Angstrom(3), and Z = 4 (4) (values in parentheses refer to 6); 5 crystallizes in the triclinic space group P (1) over b ar with a = 12.050(1), b = 12.310(1), c 16.685(2) Angstrom, alpha = 97 .88(2)degrees, beta 109.33(2)degrees, gamma = 90.55(7)degrees, V = 230 9.4(4) Angstrom(3), and Z = 2. The complexes have been characterized b y C-13 and N-15 NMR, UV-vis, EPR, IR/Raman, and MCD spectroscopies.