Phthalocyanine electronic absorption spectra

Arsenic phthalocyanine electronic absorption spectra, 7 69 preparation of, 7 50 Arsenic trichloride, 16 49 preparation of, 7 15... 

Cadmium nitrate, preparation of, 6 135 Cadmium phthalocyanine electronic absorption spectra of, 7 68 preparation of, 7 41 Cadmium selenocyanates, 17 337 Cadmium sulfoxide complexes, 24 167-168... 

Perylenediimides represent another class of photoactive dyes which are characterized by their strong fluorescence emission and facile electrochemical reduction. Recently, a supramolecular bis(phthalocyanine)-perylenediimide hetero-triad (compound 42) has been assembled through axial coordination [47]. Treatment of perylenediimide 43, which has two 4-pyridyl substituents at the imido positions, with 2.5 equiv. of ruthenium(II) phthalocyanine 44 in chloroform affords 42 in 68% yield (Scheme 3). This array shows remarkable stability in solution due to the robustness of the ruthenium-pyridyl bond. Its electronic absorption spectrum is essentially the sum of the spectra of its molecular components 43 and 44 in... 

The complex [Cu(Pc)] is an important commercial pigment and its electronic absorption spectrum is shown in Fig. 20.40. The absorption spectrum represented by the green line in Fig. 20.40 arises from another metal(II) phthalocyanine complex, [M(Pc)]. (a) Suggest how the ligand H2PC binds... 

Fig. 20.40 The electronic absorption spectrum of copper(II) phthalocyanine, [Cu(Pc)], (red trace) and an absorption spectrum of a different metal(II) phthalocyanine, [M(Pc)] (green trace). [Based on Figure 4 in P. Gregory in Comprehensive Coordination Chemistry II, 2004, Elsevier, Chapter 9.12, p. 549.].

In addition, only mild changes in the calculated absorption spectrum are seen. This suggests that, in this case, adapting the solute to the solvated situation obtained with ab initio dynamics essentially corrects the limitations of the classical force field. However, a more complex situation may arise. In the case of free base phthalocyanine the average and the distribution results obtained from a BOMD for the bond distances, bond angles and torsion angles were used to reparametrize the GROMOS53a6 [139] force field. Preliminary results for the electronic absorption spectrum [140, 141] well reproduced the data from the BOMD for free base phthalocyanine [142]. 

Moreover, supra-molecular systems involving crown ethers, fullerene and k-extended systems have been achieved that can mimic the photosynthetic process [9-14]. The fullerene Qo has been used successfully as an electron acceptor in the construction of model photosynthetic systems [9], the r-extended systems, such as porphyrins [12], phthalocyanines [13], r-extended tetrathiafulvalene (w -exTTF) derivatives [9,10], which are utilized as electron donors, while the crown ethers act as a bridge between the electron donor and acceptor. In the absorption spectrum of the complexes, the absorption maxima are associated experimentally and theoretically with the formation of charge-transfer states [14-16]. Consequently, these supramolecular systems have potential for applications in photonic, photocatalytic, and molecular optoelectronic gates and devices [9-14]. As a result, the study of the conformations and the complexation behavior of crown ethers and their derivatives are motivated both by scientific curiosity regarding the specificity of their binding and by potential technological applications. 

Uranyl phthalocyanine 31) has a linear 0—U—O bond system whose asymmetric stretching frequency occurs at 920 cm-1. A band observed at 278 cm-1 in the far infrared is assigned to the 0—U—O bending vibration. The electronic spectrum of uranyl phthalocyanine in 1-chloronaphthalene is unique in having no absorption in the 500-800 mju region. All other phthalocyanines exhibit bands in this region (see Section V,B). The complex may be purified by sublimation, but is demetallated in sulfuric acid. 

Fla. 6. Electron spin resonance spectrum of o-chloranil doped phthalocyanine. Curve represents the first derivative of absorption. 

They are not soluble in common organic solvents and hence it is difficult to determine the molecular weights of the polymers by the usual methods. UV-vis spectra were used by some authors to determine the degree of polymerization [70]. An increase of conjugation length (TT-electron delocalisation) is expected to increase the extinction coefficient and cause a red shift in Q band absorption. UV-vis absorption spectra of polymeric phthalocyanine are comparable to those of low molecular-weight phthalocyanines and show blue shifts at 2 > 350 nm (Q and B bands) The IR spectrum... 

The electronic spectrum in DMF solution had absorption bands at 634 and 660 nm. The polymer contained 4.0 mol% Fe(III)-Pc rings that were covalently bonded to polystyrene. If the amount of Fe(III)-Pc attached to the polymer was less than 4 mol%, the polymer was soluble in DMF or benzene. A Fe(III)-Pc-containing film was obtained by casting from a benzene solution. Co(II), Ni(II), and Cu(II)-phthalocyanine were bonded covalently to polystyrene in a similar way. 

---