Biomimetic self-assembling acylphthalocyanines

Abstract

We synthesized a series of biomimetic self-assembling phthalocyanines equipped with carbonyl groups as recognition motifs, a central zinc atom and diverse solubilizing alkyl chains mimicking for the first time with these robust pigments the natural chlorosomal bacteriochlorophylls. Upon self-assembly a very broad and red-shifted Q-band absorption extending to over 900 nm is put into evidence.

Lesson from Nature: Biomimetic Self-Assembling Phthalocyanines for High-Efficient Photothermal Therapy within the Biological Transparent Window

“…Bio-ZnPc was synthesized according to our previous protocol. 58 As a control, one common free-base H 2 Pc and its metallated ZnPc (Figure 1c) were also prepared and characterized (Scheme S1 and Figures S3 and S4). The biomimetic self-assembly capacity and mechanism of Bio-ZnPc have been well documented; 58 herein, we further studied the self-assembly phenomenon.…”

“…58 As a control, one common free-base H 2 Pc and its metallated ZnPc (Figure 1c) were also prepared and characterized (Scheme S1 and Figures S3 and S4). The biomimetic self-assembly capacity and mechanism of Bio-ZnPc have been well documented; 58 herein, we further studied the self-assembly phenomenon. In chloroform-D, Bio-ZnPc exhibited obvious broad and red-shifted absorption up to 900 nm because of the biomimetic selfassembly initiated by the recognition effect of the peripheral carbonyl groups and the central zinc atom (Figure S5).…”

“…55−58 Of note is that upon self-assembly, the biomimetic Pcs exhibit a broad and red-shifted Q-band absorption up to 900 nm, which was in the biological transparent window. 58 With these considerations in mind, in the present work, inspired by nature, we developed biomimetic self-assembling tetrahexanoyl ZnPc (Bio-ZnPc) (Figure 1b) as a PTA for PTT. Remarkable in vitro/in vivo PTT results were demonstrated, which were attributed to the excellent photothermal conversion efficiency of Bio-ZnPc within the biological transparent window (808 nm was selected).…”

“…In polar solvents, the monomeric species have a strong and sharp Q y -band at ∼670 nm. When the self-assembly is operated, this band maximum red-shifted to ∼740–750 nm as well as its full width at half-maximum increased by up to five times mainly because of inhomogeneous broadening. , This self-assembly algorithm has been successfully mimicked and extended by the group of Balaban, via incorporating different recognition and solubilizing groups onto porphyrinoids, and the obtained mimics could self-assemble utilizing the similar way as that of natural BChls. − Of note is that upon self-assembly, the biomimetic Pcs exhibit a broad and red-shifted Q-band absorption up to 900 nm, which was in the biological transparent window …”

Bottom-Up Hierarchical Self-Assembly of Chiral Porphyrins through Coordination and Hydrogen Bonds

“…To understand the role of metal ions and self-organization of porphyrins, enzymes and light-harvesting systems mimicking the natural pigments have been synthesized and studied, confirming the importance of the supramolecular structure on the light harvesting ability. [8][9][10][11][12] Self-assembled chiral systems based on synthetic porphyrins present a broad range of potential applications in areas such as photovoltaic cells, 13 sensors, 14 optoelectronics 15 and nanoelectronic devices 16 and also non-linear optical materials. 17 The number and position of the stereogenic centers in molecules united by covalent or non-covalent bonds directly affect the chiral transfer from the molecular level up to the supramolecular aggregates that they form in solution and consequently their optical activity can be modified.…”