Room-Temperature Organic-Based Magnet (T_c ≈ 50 ℃) Containing Tetracyanobenzene and Hexacarbonylvanadate(-I)

摘要

The discovery of the first organic-based magnet, [Fe(C5Me5)2].+[TCNE].- (TCNE=tetracyanoethylene),[1] led to the development of several new families of magnetically ordered materials based on unpaired electron spins residing in p orbitals. These include [MnII(hfac)2(NITR)] (hfac=hexafluoroacetylactonate; NITR=2-R-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxy-3-oxide)[2] and [MnIII(porphyrin)]+[TCNE].- [3] based ferrimagnets as well as -p-NO2C6H4NIT,[4] [tetrakis(dimethylamino)ethylene][C60],[5] and NCC6F4CS2N2,[6] among others.[3b], [7] The reaction of V(C6H6)2[8a] and V(CO)6,[8b] albeit by different mechanisms, formed V[TCNE]xz CH2Cl2 (x2; z0.5), a disordered room-temperature organic magnet with Tc400 K.[3b] Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) studies reveal that the vanadium is divalent and surrounded by six nitrogen centers at 2.084(5) ?, Figure 1.