Magnetic property of 1:2 mixture of Co(p-tolsal)2; p-tolsal = N-p-tolylsalicylideniminato, and cyclic pentacarbene–pyridine with S = 10/2 in dilute frozen solution

A cyclic pentadiazo-pyridine ligand, cD5py, was prepared and its photoproduct, cC5py, in a frozen solution was confirmed to be a high-spin polycarbene with S = 10/2. The magnetic property of the 1:2 mixture of Co(p-tolsal)2; p-tolsal = N-p-tolylsalicylideniminato, and cD5py in a dilute frozen solution after irradiation was investigated by SQUID magneto/susceptometry. In the ac magnetic susceptibility measurements, the in-phase and out-of-phase components (χ′ and χ″, respectively) with frequency dependence were observed, indicating that the 1:2 complex, Co(p-tolsal)2-(cC5py)2, had slow magnetic relaxation characteristic of the single-molecule magnet (SMM). From the χ″ versus T plots with various frequencies, the values of activation barrier, Ueff, for the reverse of the magnetism was estimated to be 72 K. In the dc magnetic susceptibility measurements, the magnetic hysteresis loops were observed below 3 K. The value of the coercive force, Hc, depends on the temperature and increases on cooling. The hysteresis loop with Hc = 7.1 kOe was observed at 1.9 K.

A cyclic pentadiazo-pyridine derivative, cD5py, was prepared. The 1:2 complex of Co(p-tolsal)2 with cD5py in frozen solution after irradiation functions as the single-molecule magnet with Ueff = 72 K and τ0 = 2.0 × 10−9 s. A hysteresis loop with Hc = 7.1 kOe at 1.9 K was also observed.Figure optionsDownload as PowerPoint slide