Monomere und dimere Chrom(III)-Phthalocyanine: Synthese und Eigenschaften von Hydroxopyridinophthalocyaninatochrom(III) und μ-Oxodi(pyridinophthalocyaninatochrom(III))

Monomeric and Dimeric Chromium(III) Phthalocyanines: Synthesis and Properties of Hydroxopyridinophthalocyaninatochromium(III) and μ-Oxodi(pyridinophthalocyaninatochromium(III)) Heating of ?Cr(OH)Pc^2?]”? in pyridine (Py) gives the paramagnetic (T = 273 K) complexes Cr(OH)(Py)Pc^2?] (μ_Cr = 3.84 μ_B) and (Cr(Py)Pc^2?)₂O] (μ_Cr = 1.24 μ_B) by consecutive substitution and condensation reactions. The UV-VIS spectra are characterized by the typical B, Q, and N regions of the Pc^2? ligand being shifted hypsochromically for the dimer with respect to the monomer due to excitonic coupling (1.5 kK). Regions of weak absorbance between 8 and 13 resp. 19 kK are assigned to trip-quartet transitions for both complexes. A weak band at 870 cm^?1 in the FIR/MIR spectra is assigned to v_as(Cr? O? Cr). In the resonance Raman(RR) spectra v(Cr? O) at 514 cm^?1 resp. v_s(Cr? O? Cr) at 426 cm^?1 is selectively enhanced. Further strong RR-lines of the μ-Oxo dimer at 110 and 631 cm^?1 are assigned to a (Py? Cr? O)- resp. internal pyridine deformation of a_1g symmetry. An assignment as 2v_as(Cr? O? Cr) is proposed for the remarkable RR line at 1740 cm^?1.