Tunable J-type aggregation of silicon phthalocyanines in a surface-anchored metal–organic framework thin film

Chen, Hongye; Martín‐Gomis, Luis; Zhao, Xu; Fischer, Johannes; Howard, Ian A.; Herrero, David; Sobrino-Bastan, Victor; Sastre‐Santos, Ángela; Haldar, Ritesh; Wöll, Christof

doi:10.1039/d3cp01865b

“…Meanwhile, it has been established that the inclusion of sterically demanding groups at the chromophore's core inhibits the otherwise inherent capability of preorganized π-conjugated molecules to stack in a cofacial H-type fashion, thereby enabling J-type excitonic coupling. [12] This has been widely observed for multiple types of chromophores, including perylene [13] and naphthalene diimides, [14] porphyrins, [15] chlorophylls, [16] phthalocyanines, [17] oligophenyleneethynylenes, [18] diketopyrrolopyrroles, [19] hydroazaacene dicarboximides [20] and BODIPY dyes, [21,22] which are the focus of this study.…”

Section: Introductionmentioning

confidence: 99%

Sterically Allowed H‐type Supramolecular Polymerizations

Manha Veedu,

Niemeyer,

Bäumer

et al. 2023

Angew Chem Int Ed

7

0

View full text Add to dashboard Cite

The functionalization of pi‐conjugated scaffolds with sterically demanding substituents is a widely used tactic to suppress cofacial (H‐type) stacking interactions, which may even inhibit self‐assembly. Contrary to expectations, we demonstrate herein that increasing steric effects can result in an enhanced thermodynamic stability of H‐type supramolecular polymers. In our approach, we have investigated two boron dipyrromethene (BODIPY) dyes with bulky phenyl (2) and mesityl (3) meso‐substituents and compared their self‐assembly in nonpolar media with that of a parent meso‐methyl BODIPY 1 lacking bulky groups. While the enhanced steric demand induces pathway complexity, the superior thermodynamic stability of the H‐type pathways can be rationalized in terms of additional enthalpic gain arising from intermolecular C‐H···F‐B interactions of the orthogonally arranged aromatic substituents, which overrule their inherent steric demand. Our findings underline the importance of balancing competing non‐covalent interactions in self‐assembly.

show abstract

Sterisch erlaubte Supramolekulare Polymerisationen des H‐Typs

Manha Veedu,

Niemeyer,

Bäumer

et al. 2023

Angewandte Chemie

0

View full text Add to dashboard Cite

The functionalization of pi‐conjugated scaffolds with sterically demanding substituents is a widely used tactic to suppress cofacial (H‐type) stacking interactions, which may even inhibit self‐assembly. Contrary to expectations, we demonstrate herein that increasing steric effects can result in an enhanced thermodynamic stability of H‐type supramolecular polymers. In our approach, we have investigated two boron dipyrromethene (BODIPY) dyes with bulky phenyl (2) and mesityl (3) meso‐substituents and compared their self‐assembly in nonpolar media with that of a parent meso‐methyl BODIPY 1 lacking bulky groups. While the enhanced steric demand induces pathway complexity, the superior thermodynamic stability of the H‐type pathways can be rationalized in terms of additional enthalpic gain arising from intermolecular C‐H···F‐B interactions of the orthogonally arranged aromatic substituents, which overrule their inherent steric demand. Our findings underline the importance of balancing competing non‐covalent interactions in self‐assembly.

show abstract

First principles study of electronic structure of x-form phthalocyanine crystals doped with one-dimensional iodine atomic chains

Inaoka

2024

AIP Advances

0

View full text Add to dashboard Cite

The x-form phthalocyanine (Pc) crystal is composed of a square-lattice arrangement of one-dimensional and double-period molecular chains with molecular planes normal to the stacking direction, and doped iodine (I) atomic chains between these molecular chains are known to induce the insulator-metal transition. Using the van der Waals density functional method, we investigate the electronic structure of a single x-form silicon Pc (x-SiPc) chain and the x-SiPc crystal undoped and doped with I atomic chains in a comparative manner. Although a SiPc molecule has a Si pz derived orbital just above the LUMO, the aligned Si atoms in x-crystals, each of which is at the center of the molecular plane, dimerize in the stacking direction, which prevents formation of a Si metallic band. In a single SiPc chain, two molecules in each primitive unit cell are stacked face-to-face with a staggering angle of 45°. However, when these molecular chains aggregate to create x-crystals, the staggering angle deviates from 45° to about 40° to form H–H bonding orbitals like H2 molecules between neighboring molecular planes in the lateral direction. Doping of the I atomic chains converts half-filling of the doubly degenerate bands to a lower band occupancy, which corresponds to the insulator-metal transition observed experimentally. The equally spaced I atomic chains create a metallic band due to pz-orbital overlapping with an effective-mass ratio of 0.15. Although the SiPc chains operate to create equally spaced I atomic chains, the effect of I atoms trying to trimerize is larger. This trimerization prevents pz orbitals of I atoms from making a metallic band.

show abstract

Tunable J-type aggregation of silicon phthalocyanines in a surface-anchored metal–organic framework thin film

Abstract: Organic chromophores and semiconductors, like anthracene, pentacene, perylene, and porphyrin, are prone to aggregation, and their packing in the solid state is often hard to predict and difficult to control....

Cited by 3 publications

References 44 publications

Sterically Allowed H‐type Supramolecular Polymerizations

Sterically Allowed H‐type Supramolecular Polymerizations

Sterisch erlaubte Supramolekulare Polymerisationen des H‐Typs

First principles study of electronic structure of x-form phthalocyanine crystals doped with one-dimensional iodine atomic chains

Contact Info

Product

Resources

About