Perfluoroalkyl Substituted Phthalocyanines

Cyclotetramerisation of the dinitrile 83b in a melt with hydroquinone (180 °C, 18 h) leads to the free-base [H2Pc (CF3)8] (78 %). 

The structure of the free-base 84b determined by single X-ray diffraction study [68] has revealed the strong saddle-type distortion of the macrocycle due to steric repulsion of the CF3 groups in the adjacent isoindole units (see Fig. 5). 

Complexation of [H2Pc (CF3)8] with FeCU affords the Fe complex containing two coordinated pyridine molecules [Py2FePc (CF3)8] [67], It is oxidized in an acidic medium to Fe complex isolated as p-oxo dimeric species p-0[FePc (CF3)8]2 Its X-Ray crystal structure (see Fig. 6) evidence that severe saddle-type distortion of the macrocycles due to interaction of a-CF3 groups leads to almost linear r-(FeOFe) bridge [68], The p-oxo species exhibit catalytic activity in epoxidation of olefins with iodosyl benzene to stabilize the Fe =0 (ferryl) intermediate by electron-accepting CF3 groups [67], 

The Sn complexes 100a,b were obtained from the dinitriles 96a,b and SnCl2 in 1-chloronaphthalene (reflnx 4 h), while diiminoimides 97a,b were used for preparation of the Ge complexes 99a,b (refluxing with GeCLt in quinoline, 4 h) and the free bases 98a,b (refluxing in dimethylaminoethanol, 7 h). The TP complex [0=TiPc (CF3)8] (lOlb)was obtained [70] by heating of the dinitrile with Ti(OBu)4 and urea in n-octanol (190 °C, 6 h, 32 %). 

Spectral data on perfluoroalkyl substituted phthalocyanines and their Cu complexes are presented in Table 5. It can be noticed that introduction of electron-withdrawing perfluoroalkyl group in a- or fl-position of each benzene ring results in a hypsochromic shift of the Q-band maximum, which indicates stabilization of HOMO in respect to LUMO. Eight CFj groups in p-positions have a similar effect, but in the case of octa-a-substituted species an opposite bathochromic shift of the Q-band is observed. This is evidently connected with the distortion of the planarity of the macrocycle due to steric interaction of CF3 groups in a-positions of the adjacent isoindole units (Fig. 5) which destabilize HOMO. 

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