Red manganese phthalocyanines from highly hindered hexadecaalkoxyphthalocyanines

Abstract

Dediated to Bdau Jam6 on the occasion of his 70tb birthday. AbstractHighly hindered magnesium and metal-free green 1,2,3,4,8,9,10,1 l,l5,l6,l7,l 8,22,23,24,25'hexadecaneop€ntoxyphthalocyanine and t,Z,:,1,A,S,f0,tt,15,16,11,18,22,23,24,25-hexadeca(cyclohexylmethylor.y)phthalocyanine were prepared via magnesium l-octanolate and 3,4,5,6+etraneopentoxyphthalonitrile or 33,5,6-tetra(cyclohexylmethyloxy) The inertness ofPcs is well known [3], but their classical use as dyes [3] is now overshadowed by other applications taking advantage of the inlense absorption of the Q-band' normally between 670 and 730 nrn. Highly red-shifted anatogs of Pcs,-having additional benzo groups attached to the Pc benzo groups (the naphthalocyanines and even anthracenocyanines [4] are usually difficult to prepare, highly insoluble, and prone to decomposition [5]. It has long been known that Pcs containing electron-donating substituents at the 1,4,8,! 1,15,18,22,25 substituents) show some red-shifts of the Pc chromophore, but that only minor shifts occur due to substituents placed at the 2, 3,9,10,16,17,23,24 positions (the peripheral substituents) [6][7][8]. On the other hand some hexadecaalkoxysubstituted Pc nickel cornpounds exhibited enhanced red shifts, showing a Q-band shifted to as long a wavelength as 745 nm [9]. It appears that the substituents at the peripheral positions buttress the substituents at the non-peripheral posilions effeotively making the non-peripheral substituents bulkier.In this spirit, in previous res€arch in the Lezno Further reduction at -1.6V versus Fc*/Fc (Fig. 3) yiolds a spectrum consistent with expectation for a Pc(3-) radical anion t2l-241 Curiously, the absorption bands in the 700 nm region for this species are closely similar to those of the Mnl! precursor. There is growth ol a weak band near 900 nm. The electrochemical data shown in Fig. 4 Spectroelectrochem.istry, discussed below, shows that peak I (Fig. 4) (Fig. 4! ihe nature of the second species was not further studied.Oxidation at peak VI yielded a spectrum (Fig. 9) typical P2-24,26) of tn-e radical cation phthalocyanino(l-) species, and hence the formation of [NeoPdl-)Mnlv absorption between 500 and 600 nm to which we return in Section 3.5. The Mn(II)Pc(3-) spectra are also targely similar with three peaks in the visible region and a weak absorption around 900 nrn. This provides a means to change the counter axial anion by simply changing the acid used. The counter-ion does, as expected, have a small but noticeable eflect on the spectrum. Table I Variation of axial counter-ion

Synthesis and electrochemical properties of benzyl-mercapto and dodecyl-mercapto tetrasubstituted manganese phthalocyanine complexes

“…Both complexes showed the C O bands of the acetate ion at 1743 and 1765 cm −1 , respectively. MALDI-TOF spectra showed the complexes without the acetate residue though the reason could not be ascertained but similar observation has been reported before [19]. Elemental analysis of both complexes gave satisfactory results corresponding to the Mn(OAc)Pcs.…”

“…All methods showed satisfactory results. Both complexes are deep red in colour due to absorption in the 400-500 nm region and the red shift of the Q band, typical of Mn III Pc complexes [13], [14] and [19], Fig. 2.…”

Electrochemical Characterization of Self‐Assembled Monolayer of a Novel Manganese Tetrabenzylthio‐Substituted Phthalocyanine and Its Use in Nitrite Oxidation

“…The UV-visible spectra of the complex in DMF displayed bands at 764, 681, 511 and 360 nm. The UV-visible bands at 360 and 511 nm give complex MnPc(SPh) 4 its deep red color [26]. The relatively large red shift of the Q-band (764 nm), typical of Mn III Pc complexes [4,15,26,27], is enhanced by the electron donating properties of sulfur.…”

Syntheses and characterization of phthalonitriles and phthalocyanines substituted with adamantane moieties

“…It has been postulated that sterically bulky substituents at the peripheral positions around the Pc exert influence upon the nonperipheral positions, thereby effectively increasing the steric bulk of the nonperipheral substituents and further promoting a shifting of the Q band. Various metallated and nonmetallated Pcs bearing sterically bulky alkoxy moieties have been reported, including both neopentoxy and cyclohexylmethoxy groups (6,7). In addition to the effect that these substitutions appear to have on the absorption spectra of the resulting Pcs, a disruption of the n stacking among the aromatic macrocycles increases (5) in the presence of a base to generate 4,5-di-(1-adamantyloxy)-3,6-difluorophthalonitrile (6), 4,5-di-(1-adamantylamino)-3,6-difluorophthalonitrile (7), 4-(l -adamantylamino)-3,5,6-trifluorophthalonitrile (8), 3,4,5,6-retra-(l-adamantylmethoxy)phthalonitrile (9), or 3,4,5,6-tetra-f2-(l-adamantyl)ethoxy]phthalonitrile (10 Synthesis of 4,5-di-(1-adamantylamino)-3,6-difluorophthalonitrile (7) l-Adamantylamine (3, 1.52 g, 10.1 mmol, 2 equiv.)…”

“…Various metallated and nonmetallated Pcs bearing sterically bulky alkoxy moieties have been reported, including both neopentoxy and cyclohexylmethoxy groups (6,7). In addition to the effect that these substitutions appear to have on the absorption spectra of the resulting Pcs, a disruption of the n stacking among the aromatic macrocycles increases (5) in the presence of a base to generate 4,5-di-(1-adamantyloxy)-3,6-difluorophthalonitrile (6), 4,5-di-(1-adamantylamino)-3,6-difluorophthalonitrile (7), 4-(l -adamantylamino)-3,5,6-trifluorophthalonitrile (8), 3,4,5,6-retra-(l-adamantylmethoxy)phthalonitrile (9), or 3,4,5,6-tetra-f2-(l-adamantyl)ethoxy]phthalonitrile (10 Synthesis of 4,5-di-(1-adamantylamino)-3,6-difluorophthalonitrile (7) l-Adamantylamine (3, 1.52 g, 10.1 mmol, 2 equiv.) was dissolved in 15 Synthesis of 4-(1-adamantylamino)-3,5,6-trifluorophthalonitrile (8) l-Adamantylamine (3, 0.76 g, 5.0 mmol, 1 equiv.)…”