Intermediate-spin complexes, pure

METHODOLOGY TO OBTAIN PURE INTERMEDIATE-SPIN COMPLEXES... 

These results indicate that not only CIO4 but also the I and Br complexes adopt the nearly pure intermediate-spin state. The EPR data in Fe(OETPP)X are in sharp contrast to those in Fe(TPP)X since the latter complexes show the pure high-spin state regardless of the kind of the axial halides [26]. The results clearly demonstrate that the saddled deformation indeed stabilizes the intermediate-spin state as Cheng et al. pointed out [32]. 

Table 10.5 also lists the EPR g values of [Fe(T PrP)L2] and [Fe(TPP)L2]. The axial ligands are classified into two groups. The [Fe(TPrP)L2] complexes carrying pyridine N-oxide and substituted pyridine N-oxide exhibit the high-spin state while all the other ligands located below 4-CIPyNO in Table 10.5 show an essentially pure intermediate-spin state the Int (%) values are larger than 90%. In contrast, all the TPP complexes cept [Fe(TPP)(THF)2] adopt the high-spin state. These results clearly indicate that the ruffled deformation does stabilize the intermediate-spin state [15-18,26]. 

Pr and Pr at the meso positions, and L is a nitrogen base [59,60]. The spectroscopic data of the BuNC complexes are also included in Table 10.6 [60]. These data indicate that all the complies listed in Table 10.6 adopt either the 5=1/2 (d ground state. The results contrast to those of saddled [Fe(OETPP)L2]. where [Fe(OETPP)(4-CNPy)2] shows an essentially pure intermediate-spin state [15,45]. 

Luminescence from Cr + complexes, both in the solid state and in solution, is a widespread phenomenon. The great majority belong to type a) in Figure 1, where the luminescent state is 2E and the optical transitions are sharp. The well-known ruby emission is a prototype for this situation. In a weaker ligand field the situation b) in Figure 1 is approached, the T2 state becomes competitive with E as the luminescent state. The T emission, corresponding to a spin-allowed d-d transition, is vibronically broadened. Pure 2 luminescence from Cr + has been observed in halide and oxide coordinations (J ). Intermediate situations with both 2E and 2 emissions ar also known. 

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