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We studied the optical properties of hybrid multilayer microspheres (HMMs). We prepared multilayer particles with alternating radial layers of gold nanoparticles (NPs) and poly(methyl methacrylate) and achieved control over particle size, the thickness of particle layers, and the surface coverage of gold NPs. We showed the ability to tune the spectral characteristics of the HMMs, which was based on frequency dispersion of the dielectric constant of polymer-metal NP structures. Good agreement between experimental and theoretical extinction properties of the HMMs was obtained. In comparison with multilayer structures synthesized solely from polymers, hybrid multilayer microspheres have a larger refractive layer contrast between adjacent layers, which is important for practical applications in optoelectronic devices. Key words: hybrid polymer-inorganic materials, polymer microspheres, gold nanoparticles, optical properties, extinction spectra. On a etudie les proprietes optiques de microspheres multicouches hybrides (MMH). On a prepare les particules a multicouches comportant des couches radiales alternantes de nanoparticules (NP) d'or et de poly(methacrylate de methyle) et on a pu controler la taille des particules des couches et la surface de la couverture des nanoparticules d'or. On a pu controler les caracteristiques spectrales des microspheres multicouches hybrides en ajustant la frequence de dispersion de la constante de dielectrique des structures des nanoparticules polymere-metal. On a obtenu un bon accord entre les proprietes d'extinction experiinentales et theoriques des microspheres multicouches hybrides. Par comparaison avec les structures multicouches synthetisees uniquement a partir de polymeres, les microspheres multicouches hybrides possedent un plus grand contraste de refraction par couche entre les couches, propriete importante pour les applications pratiques dans les appareils optoelectroniques. Mots-cles : materiaux hybrides polymere-inorganique, microspheres de polymere, nanoparticules d'or, proprietes optiques, spectres d'extinction. [Traduit par la Redaction] doi: 10.1139/V09-172, Introduction Polymer microspheres with a multilayer onion-like structure possess optical properties that are useful in photonic crystals, (1-2) optical data storage, (3-4) biometrics, (5,6) and, sensing and single-particle optical limiting. [...]

A process for the gram scale synthesis of the oxygen bridged dimer of boron subphthalocyanine, μ-oxo-(BsubPc)2, has been developed. During the development it was found that a wide range of reaction pathways under diverse conditions lead to μ-oxo-(BsubPc)2 formation. However, obtaining μ-oxo-(BsubPc)2 as the main reaction product in appreciable yields and its subsequent isolation were extremely challenging. The best balance of purity, yield and conversion was achieved with a time controlled reaction of an equimolar reaction of HO-BsubPc with Br-BsubPc in the presence of K3PO4. The purification involved sequentially Soxhlet extraction, Kauffman column chromatography and train sublimation. We have repeated the process and yields ranged from 27 to 30% of pure, doubly-sublimed μ-oxo-(BsubPc)2. This process also enabled the synthesis of unsymmetric μ-oxo-(BsubPc)2s by reaction of HO-BsubPc with Br-F12BsubPc, Cl-Cl6BsubPc and Cl-Cl12BsubPc. After synthesis the solution-state properties of the unsymmetric μ-oxo-(BsubPc)2s were investigated, and compared to the symmetric μ-oxo-(BsubPc)2 and more broadly to other BsubPcs. The electronic properties of μ-oxo-(BsubPc)2 were found to differ from its unsymmetric counterparts, but were found to be similar to halo-BsubPcs. Furthermore, the photophysical properties of μ-oxo-(BsubPc)2, both symmetric and unsymmetric, differed greatly from all other known BsubPcs. [ABSTRACT FROM AUTHOR]

The ability to control the solid-statestructure of organic electronicmaterials can have a large effect on the quality of the devices towhich they are applied. In this paper, we describe the use of π–πinteractions to direct the crystal structure/solid-state arrangementof boron subphthalocyanine (BsubPc) derivatives by taking advantageof the π-electron-deficiency (π-acidity) of the BsubPcmolecular fragment. First, we outline why BsubPc is a π-acidby looking at its chemical characteristics and the structure of crystalsformed with other π-acidic moieties. Then we show how the solid-statearrangement of BsubPc can be purposefully altered by adding π-basicsubstituents. We found that adding a naphthoxy substituent providesan interaction that is strong enough to direct BsubPc into a novelsolid-state arrangement made up of ribbons (or catemers) of moleculeslinked through π-stacking interactions between the naphthoxyand neighboring BsubPc molecular fragments. A similar effect was alsoseen when the naphthoxy fragment was added to the stronger π-acidperfluoro-BsubPc (F12BsubPc). [ABSTRACT FROM AUTHOR]

Boronsubphthalocyanine (BsubPc) derivativesare materialsthat have recently seen an increase in attention, particularily forapplication as colorants and functional materials in organic electronicdevices. However, the solubilities of most BsubPcderivativesare too low to utilize solution-based processing techniques. Wherethere are derivatives that are soluble, they rely on the additionof large alkyl chains for solubilization the result of which is anincrease in the molecular weight and a decrease of the specific absorptivityof the BsubPc. In this paper we disclose the identityof two mass-efficient, highly soluble BsubPcderivatives:3-methylphenoxy-BsubPcand 3,4-dimethylphenoxy-BsubPc. We compare their solubilities and crystal packingstructures to previously known BsubPcderivatives. Weput forward a symmetry-based argument for the reason for their surprisinglyhigh solubility wherein we treat the molecules as two separate fragments:the phenoxy group and the BsubPcgroup. The symmetry-basedargument suggests that by ignoring the BsubPcfragmentcommon to each derivative a better estimate of the relative solubilitiescan be estimated through previously established empirical formulas. [ABSTRACT FROM AUTHOR]

We report the synthesis and systematic description of a series of five para-substituted phenoxy-BsubPcsincluding their characterization in the crystal state. The nature of the substituents on the phenoxy molecular fragment was chosen so as to vary both the size and electronegativity: specifically with increasingly bulky para-alkyl groups from hydrogen to tert-octyl and a single electronegative substitute (F). Examination of the arrangement of the phenoxy-BsubPcswithin single crystals allows us to place each into one of the two categories. The first, which contains all but one of the derivatives, has a repeating motif which is made up of dimers of the BsubPcmolecular fragments. The second, containing only the derivative possessing the large tert-octyl substituent, is characterized by the formation of ribbons instead of dimers of the BsubPcfragment. Regardless of motif the arrangement of the BsubPcmolecular fragments was found to be convace–concave. [ABSTRACT FROM AUTHOR]

With the knowledge that the dominant photodynamic therapy (PDT) mechanism of 1a (WST09) switched from type 2 to type 1 for 1b (WST11) upon taurine-driven E-ring opening, we hypothesized that taurine-driven E-ring opening of bacteriochlorophyll derivatives and net-charge variations would modulate reactive oxygen species (ROS) photogeneration. Eight bacteriochlorophyll a derivatives were synthesized with varying charges that either contained the E ring (2a-5a) or were synthesized by taurine-driven E-ring opening (2b-5b). Time-dependent density functional theory (TDDFT) modeling showed that all derivatives would be type 2 PDT-active, and ROS-activated fluorescent probes were used to investigate the photogeneration of a combination of type 1 and type 2 PDT ROS in organic- and aqueous-based solutions. These investigations validated our predictive modeling calculations and showed that taurine-driven E-ring opening and increasing negative charge generally enhanced ROS photogeneration in aqueous solutions. We propose that these structure-activity relationships may provide simple strategies for designing bacteriochlorins that efficiently generate ROS upon photoirradiation.

In the title compound, C(32)H(19)BN(6)O(2), the B atom adopts a BON(3) tetra-hedral coordination geometry. In the crystal, pairs of mol-ecules are associated through aromatic π-π stacking inter-actions between the concave faces of the boronsubphthalocyanine fragments at a centroid-centroid distance of 3.4951 (19) Å and a weaker inter-action of the same type between the convex faces of the same group [centroid-centroid separation = 3.5669 (18) Å] also occurs.