Controlling the Nature of Mixed (Phthalocyaninato)(porphyrinato) Rare‐Earth(III) Double‐Decker Complexes: The Effects of Nonperipheral Alkoxy Substitution of the Phthalocyanine Ligand

Abstract

The half-sandwich rare-earth complexes [M(III)(acac)(TClPP)] (M = Sm, Eu, Y; TClPP = meso-tetrakis(4-chlorophenyl)porphyrinate; acac = acetylacetonate), generated in situ from [M(acac)3] x n H2O and H2(TClPP), were treated with 1,8,15,22-tetrakis(3-pentyloxy)phthalocyanine [H2{Pc(alpha-OC5H11)4}] (Pc = phthalocyaninate) under reflux in n-octanol to yield both the neutral nonprotonated and protonated (phthalocyaninato)(porphyrinato) rare-earth double-decker complexes, [M(III){Pc(alpha-OC5H11)4}(TClPP)] (1-3) and [M(III)H{Pc(alpha-OC5H11)4}(TClPP)] (4-6), respectively. In contrast, reaction of [Y(III)(acac)(TClPP)] with 1,4,8,11,15,18,22,25-octakis(1-butyloxy)phthalocyanine [H2Pc(alpha-OC4H9)8] gave only the protonated double-decker complex [Y(III)H{Pc(alpha-OC4H9)8}(TClPP)] (7). These observations clearly show the importance of the number and positions of substituents on the phthalocyanine ligand in controlling the nature of the (phthalocyaninato)(porphyrinato) rare-earth double-deckers obtained. In particular, alpha-alkoxylation of the phthalocyanine ligand is found to stabilize the protonated form, a fact supported by molecular-orbital calculations. A combination of mass spectrometry, NMR, UV-visible, near-IR, MCD, and IR spectroscopy, and X-ray diffraction analyses, facilitated the differentiation of the newly prepared neutral nonprotonated and protonated double-decker complexes. The crystal structure of the protonated form has been determined for the first time.

Toward panchromatic organic functional molecules: Density functional theory study on the nature of the broad UV–Vis–NIR spectra of substituted tetra(azulene)porphyrins

“…Combination of the present result with previous investigations [22][23][24][25][26][27][28][29][30][58][59][60][61][62][63][64][65][99][100][101], the following points appear to be useful in the design of general panchromatic tetrapyrrole organic functional molecules, Scheme 2.…”

“…Introduction of electron-withdrawing or electron-donating groups onto the periphery of TAzP skeleton further tunes the HOMO-LUMO gap, inducing obvious red/blue-shift of the NIR electronic absorption bands of H 2 [␣-(NH 2 ) 4 TAzP]/H 2 [-(NH 2 ) 4 TAnP] into the range of 1000-2500 nm. Moreover, in combination with the previous results [22,[25][26][27][28][29][30][58][59][60][61][62][63][64][65], general rule regarding the design of panchromatic organic functional molecules is also proposed.…”

“…This in turn will induce remarkably red-shifted broad Q bands into the NIR region, resulting in complicated electron absorption spectrum of tetra(azulene)porphyrins (TAzPs) relative to most general porphyrins (Pors) [41][42][43], tetraazaporphyrins (TAPs) [43], phthalocyanines (Pcs) [43][44][45][46], naphthalocyanines (Ncs) [47,48], and even many core-modified porphyrins [49][50][51][52][53][54][55][56][57]. In addition, the absorption spectra of some sandwich-type multi(tetarpyrrole) metal multiple-decker complexes can also cover such a broad NIR region [58][59][60][61][62][63][64][65]. However, their absorption intensity in this region is much weaker than TAzPs.…”

Metal-cation-mediated nanocrystal arrays of sandwich-type (phthalocyaninato) [tetrakis(4-pyridyl)porphyrinato] cerium complex formed at the water–chloroform interface

“…It is worth noting that the intense band appears at approximately 1592 cm −1 for the bulk double-decker molecules due to the C=N band vibration (ν C=N ) of pyridyl substituents attached at the double-decker molecules, which shifts to 1602 cm −1 as a weak band in Hg-[Ce(Pc)(TPyP)] nanowires, indicating the formation of coordination bonds between N atoms of the pyridyl substituents of Ce(Pc)(TPyP) and Hg 2+ cations. The intense band at 1330 cm −1 observed for both bulk double-decker com- pound and Hg-mediated double-decker nanowires is the marker band of the phthalocyanine dianion [55,56].…”

The nonlinear absorption in new lanthanide double decker pyridine-based phthalocyanines in solution and thin films

“…The peaks beyond the Q band (around 900 nm) are typical of bisphthalocyanines containing Pc(1-) rings, and they are due to transitions from the semi-occupied orbital to the degenerate highest unoccupied molecular orbital (LUMO) [36]. A shoulder in the 400-500 nm region of the absorption spectrum characteristically designates a radical phthalocyanine anion [37,38].…”