Long, Directional Interactions in Cofacial Silicon Phthalocyanine Oligomers

Abstract

Single crystal structures have been determined for the three cofacial, oxygen-bridged, silicon phthalocyanine oligomers, [((CH(3))(3)SiO)(2)(CH(3))SiO](SiPcO)(2-4)[Si(CH(3))(OSi(CH(3))(3))(2)], and for the corresponding monomer. The data for the oligomers give structural parameters for a matching set of three cofacial, oxygen-bridged silicon phthalocyanine oligomers for the first time. The staggering angles between the six adjacent cofacial ring pairs in the three oligomers are not in a random distribution nor in a cluster at the intuitively expected angle of 45° but rather are in two clusters, one at an angle of 15° and the other at an angle of 41°. These two clusters lead to the conclusion that long, directional interactions (LDI) exist between the adjacent ring pairs. An understanding of these interactions is provided by atoms-in-molecules (AIM) and reduced-density-gradient (RDG) studies. A survey of the staggering angles in other single-atom-bridged, cofacial phthalocyanine oligomers provides further evidence for the existence of LDI between cofacial phthalocyanine ring pairs in single-atom-bridged phthalocyanine oligomers.

Silicon phthalocyanines: synthesis and resurgent applications

“…The properties of these polymers were investigated in both solid and solvent phases and some of these derivatives were even processed into thin polymeric films. [45][46][47][48][49][50] Attempts to react 1 with alternate ligand functionalities such as carboxylic acids were successful and expanded the domain of axial functionalization of SiPcs (Scheme 4). 27 Esterification reactions of 1 occurred under reflux conditions in polar solvents such as 2-methoxyethyl ether (~160 °C), diglyme (~160 °C) or 1,4-dioxane (~100 °C), DMF (~160 °C) to produce various SiPc esters, 5.…”

Optical Absorption and Visible Photoluminescence from Thin Films of Silicon Phthalocyanine Derivatives

“…In Pcs, as well as other planar cyclic molecules, π electron delocalization is the main responsible for the semiconducting properties [63]. The molecular organization in our compounds is probable to be similar to the sheet arrangement proposed by Yang [32]. The bidentate ligands used to synthesize the compounds promote a better conformation of the sheet arrangement, but SiPcs are the most responsible of the electronic properties of the final new materials.…”

“…They show electronic properties that make them suitable in diverse applications, from sensors [10] to organic light-emitting devices [11]. Moreover, Pcs and metal Pcs (MPcs) have been extensively studied in their optical, electrical, and structural properties [8,9,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32]. …”

Preparation and Structural Characterization of Metallophthalocyanine Particles Embedded in a Polymer Matrix

“…Optical absorption measurements are widely used to characterize the electronic properties of the thin films through the determination of parameters describing the electronic transitions, such as the band gap [11]. Additionally, the absorption spectra of different polymorphs of some Pc compounds show significant differences among each other [7,12].…”