Abstract

It has come to the attention of the authors that Figure 6, the values of effective magnetic moments for complexes 1 and 2, giso, E/D values in Abstract section and in the Magnetic properties sections, giso and E/D values in Table 1, and D value for complex 2 in Conclusions section were changed mistakenly in the final stage of manuscript preparation. The data published in Figure 6 reveal the results obtained for older measurement on different batches of the complexes. The correct values, corresponding to the results obtained for the same batches of complexes for which the DC and AC magnetic measurements were done, are presented below. These mistakes do not affect the integrity of the research and overall conclusions of the published paper. The corrected Figure 6 and corresponding text are given below. Magnetic properties. Investigation of the magnetic features of complexes 1 and 2 proceeded using a PPMS device on which the temperature (1.9–300 K) and field (0–9 T) dependent magnetic data were obtained (Figure 6). Figure 6 Temperature dependence of the effective magnetic moment (inset: temperature dependence of the molar magnetic susceptibility) for complexes 1 and 2 (Left). The isothermal magnetizations measured in the range of B=0–9 T and at T=2, 5 and 10 K (Right). The magnetic properties of the complexes are primarily due to the presence of central tetrahedral CoII ion since octahedral LS-CoIII ions are diamagnetic. The value of effective magnetic moment (μeff) of complex 1 at 300 K is 3.5 μB, slightly lower than the spin-only value of 3.9 μB for S=3/2, g=2.0. Thereafter upon cooling the μeff value raises slightly up to ca 75 K and then, it drops sharply to a minimum at 1.9 K, where it adopts the value of 3.2 μB. In the case of complex 2, the μeff value at 300 K is 5.0 μB which is again much higher that the calculated value for isotropic S=3/2 spin. It decreases gradually upon cooling up to ca 50 K and then, it declines sharply to a minimum at 4.4 K reaching the value of 4.2 μB. The high μeff value at 300 K indicates considerable contribution of a spin-orbit coupling to the ground state in the complex 2. Isothermal magnetization experiments (Figure 6) for 1 and 2 in the applied field range of B=0–9 T at different constant temperatures T=2, 5 and 10 K reveal that the magnetization does not show saturation suggesting the presence of magnetic anisotropy. To extract the parameters affected by magnetic anisotropy arising from crystal field effects (g, D), both the susceptibility and magnetization data were fitted simultaneously. The best fit parameters were calculated using the PHI program package[26] for S=3/2 and they are as follows: giso=2.05, D=−23.6 cm−1, E/D=0, zJ/hc=0 cm−1, χTIP=−13.0×10−4 cm3 mol−1 for 1 and giso=2.61, D=−24.3 cm−1, E/D=0.01, zJ/hc=0.05 cm−1, χTIP=2.0×10−4 cm3 mol−1 for 2. The presence of temperature-independent paramagnetism (TIP) term accounts for the four surrounding CoIII ions. The observed D values for 1 and 2 are relatively close compared to those (−31.31 cm−1 and −21.88 cm−1) obtained in our previous investigations with complexes having similar molecular structures.[10] The authors wish to emphasize that with these corrections, the reported ZFS parameters relevant for the discussion of single molecule magnetism (i.e. the D values) did not change at all and the overall conclusions published in the original version of the article are not affected.

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