Synthesis, Structure, Spectroscopic Properties, and Electrochemistry of (1,8,15,22-Tetrasubstituted phthalocyaninato)lead Complexes

Abstract

Three (1,8,15,22-tetrasubstituted phthalocyaninato)lead complexes Pb[Pc(alpha-OR)(4)] [H(2)Pc(alpha-OC(5)H(11))(4) = 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine; H(2)Pc(alpha-OC(7)H(15))(4) = 1,8,15,22-tetrakis(2,4-dimethyl-3-pentyloxy)phthalocyanine; H(2)Pc(alpha-OC(10)H(7))(4) = 1,8,15,22-tetrakis(2-naphthyloxy)phthalocyanine] (1-3) have been prepared as racemic mixtures by treating the corresponding metal-free phthalocyanines H(2)Pc(alpha-OR)(4) (4-6) with Pb(OAc)(2).3H(2)O in refluxing n-pentanol. The molecular structure of Pb[Pc(alpha-OC(5)H(11))(4)] (1) in the solid state has been determined by single-crystal X-ray diffraction analysis. This compound, having a nonplanar structure, crystallizes in the monoclinic system with a P2(1)/c space group. Each unit cell contains two pairs of enantiomeric molecules, which are linked by weak coordination of the Pb atom of one molecule with an aza nitrogen atom and its neighboring oxygen atom from the alkoxy substituent of another molecule, forming a pseudo-double-decker supramolecular structure in the crystals with a short ring-to-ring separation, 2.726 A, and thus a strong ring-ring pi-pi interaction. The decreased molecular symmetry for these complexes has also been revealed by the NMR spectra of 1 and 2. The methyl protons of the 3-pentyloxy and 2,4-dimethyl-3-pentyloxy side chains of 1 and 2, respectively, are chemically inequivalent. In addition to the elemental analysis and various spectroscopic characterizations, these compounds have also been electrochemically studied. Two one-electron oxidations and up to five one-electron reductions have been revealed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods.

Synthesis, spectroscopic properties and electrochemistry of (2,9,16,23-tetrasubstituted phthalocyaninato) erbium complexes

“…The weak absorption at 450 nm for 3 is common for alkoxysubstituted phthalocyanines, which may be attributed to an nep* transition [9]. A simplified molecular orbital diagram of [Er{Pc (b-OC 5 H 11 ) 4 } 2 ] and [Er{Pc(b-C 4 H 9 ) 4 } 2 ] constructed from the a 1u and e g orbitals of the two ligands is given in Fig.…”

Spectroelectrochemical characterization and controlled potential chronocoulometric demetallation of tetra- and octa-substituted lead phthalocyanines

“…Since the metal sits outside of the phthalocyanine ring, the complex shows a tendency to demetallation in the redox reactions [24]. Compared to more intensely studied transition metal-phthalocyanines, papers on the synthesis [25][26][27] and electrochemical and spectroelectrochemical properties [24,28] of lead-phthalocyanines (PbPc) are not many in number. Therefore to reach more detailed information about the redox behavior of the relevant complexes, in this study, we examine and compare the electrochemical and spectroelectrochemical properties of new PbPcs, tetra(dihexoxymalonyl)-tetrahexhylthio phthalocyaninato lead (II) (1), tetra(dihexoxymalonyl)-tetrachloro phthalocyaninato lead (II) (2), and tetra(dihexoxymalonyl) phthalocyaninato lead (II) (3) (Fig.…”

Morphology Controlled Nanostructures Self‐Assembled from Phthalocyanine Derivatives Bearing Alkylthio Moieties: Effect of Sulfur–Sulfur and Metal–Ligand Coordination on Intermolecular Stacking

“…In the wide-angle range, the (001) plane also shows its series of higher order diffraction peaks at 0.62 (003), 0.47 (004), 0.37 (005), and 0.32 nm (006), respectively. As revealed by the single crystal X-ray diffraction analysis of phthalocyaninato lead compounds, [22,29] the divalent lead ion cannot be situated in the central hole of the phthalocyanine ring, but sits atop it, above the N(isoindole) 4 plane due to the larger ionic size. This, in combination with the electronic absorption and IR spectroscopic results, indicates that a Pb-connected pseudo-doubledecker supramolecular structure exists as dimeric building block in the self-assembled nanostructures ( Figure 5).…”

“…The last two are attributed to the PbÀS metal-ligand coordination bond length between the central lead ion of the phthalocyaninato lead molecule and the sulfur atom of the adjacent molecule and the distance between the central lead ion and the phthalocyanine N(isoindole) 4 plane ( Figure 5), respectively, and correspond well with those revealed in single crystals of similar compounds. [22,29,30] The remaining sharp diffraction peak at 0.42 nm is assigned to the stacking distance between the (N isoindole ) 4 plane of neighboring Pb-connected pseudo-doubledeckers.…”