Polymorphism in Sn(IV)-Tetrapyridyl Porphyrins with a Halogenated Axial Ligand: Structural, Photophysical, and Morphological Study

Rani, Jyoti; Raveendran, Anju; Sushila,; Chaudhary, Arvind; Panda, Manas K.; Patra, Ranjan

doi:10.1021/acs.cgd.7b01357

Cited by 12 publications

(17 citation statements)

References 52 publications

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“…The UV–visible spectra of compound 5 , 6 , 7 , and 8 showed an intense Soret band at around 420 nm and two Q bands at 553 and 591 nm, respectively, as shown in Figure A. These absorption bands can be assigned to the π–π* transition of the macrocycle core of the porphyrin monomer. − The photochemical behaviors of all the complexes were studied by steady state fluorescence measurements. Upon excitation at 560 nm, all the compounds showed two emission bands at 607 and 657 nm (Figure B) in dichloromethane (DCM).…”

Section: Resultsmentioning

confidence: 99%

Wheel and Axle Topology Driven Halogen Bonds for the Construction of Molecular Arrays in Hexacoordinated Sn(IV)Porphyrins: A Structural and Theoretical Investigation

Sushila

Venugopalan

Kataria

et al. 2019

Crystal Growth & Design

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The present study illustrates how halogen bonds (XB) in conjunction with judiciously selected molecular scaffolds can be used for the construction of molecular arrays (ladder, one-dimensional (1D), and two-dimensional (2D) frameworks) in a series of Sn(IV)-porphyrin derivatives, which topologically resemble a “wheel–axle” duo. In all the complexes investigated here, the wheel is constructed with Sn(IV)-5,10,15,20-meso-tetrakis(4-bromophenyl)porphyrin [Sn(L)2-TBrPP], which is relatively rigid, and the two pairs of diametrically opposite Br atoms can get involved in various kind of halogen bond interactions, depending upon the complementary atom(s) present at the axle. Detailed single crystal X-ray structural studies of these complexes reveal the diverse occurrence of Br···O, Br···Br, Br···π halogen bonds, and these XBs are not only restricted between the wheel···axle alone, but also can occur among themselves (i.e., wheel···wheel and axle···axle). Different types of XB directed molecular associations are observed; for example, ladder type supramolecular associations occur in 1 and 2, interlinked 1D framework in 4, molecular chains in 7, 2D-framework in 8, etc. Complementary theoretical studies with Hirshfeld surface analysis show the definite role of Br···Br interactions in the overall stability and mapping of electrostatic potential isosurfaces with the aid of density functional theory in 8 definitely shows the presence of a σ-hole, a requisite feature to show XBs in the crystalline state. The detailed structural and theoretical studies presented here clearly vouch for the use of wheel and axle topology driven halogen bonds for the construction of molecular arrays in hexa-coordinated Sn(IV)-porphyrin derivatives. Photophysical studies show that the variation of axial ligands has a minimal effect on fluorescence as well as the excited state lifetime in these complexes.

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Section: Resultsmentioning

confidence: 99%

Wheel and Axle Topology Driven Halogen Bonds for the Construction of Molecular Arrays in Hexacoordinated Sn(IV)Porphyrins: A Structural and Theoretical Investigation

Sushila

Venugopalan

Kataria

et al. 2019

Crystal Growth & Design

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“…In the structure with the CSD code CERWEE 98 (Figure S12), the Cl•••N contact exhibits the A•••M geometry, involving a chlorine atom in the axial position and a nitrogen atom of a pyridine ring located in the meso position. This interaction is characterized by an angle of 122°, which prevents it from being classified as a halogen bond to either the nitrogen sp 2 lone pair of electrons or the π-system.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Database Investigation of Halogen Bonding and Halogen···Halogen Interactions between Porphyrins: Emergence of Robust Supramolecular Motifs and Frameworks

Spilfogel

Titi

Friščić

2021

Crystal Growth & Design

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We provide a Cambridge Structural Database (CSD) analysis of the role of halogen bonds and halogen···halogen interactions in the solid-state structures of porphyrins. This survey provides a detailed view of halogens in porphyrin self-assembly, highlighting interaction motifs beyond the often considered iodine-based halogen bonds. Particularly notable are the observations of self-assembly through β-positioned substituents, the role of the pyrrole π-system as a halogen bond acceptor, and an abundance of chlorine-based halogen···halogen and halogen-bonding motifs. This overview enabled the observation and systematic classification of complex, multipoint recognition motifs in halogen-based architectures. Similarly to synthons in hydrogen-bonded crystal engineering, these motifs appear in discrete molecular assemblies and can also underlie the formation of two- and three-dimensional frameworks. The systematic categorization of these robust motifs provides a foundation for the design of complex halogen-based supramolecular architectures.

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“…This nanoscale-and molecular-level insight into the presence of disordered and ordered phases and vibrational excitons confined to few-nanometer domains can provide critical understanding for the design of functional materials. Both crystalline and amorphous phases may occur in devices made with porphyrins or other molecular materials, and tradeoffs exist between benefits of crystalline phases with typically higher charge carrier mobility and exciton diffusion length versus amorphous phases that may exhibit improved interfacial miscibility and improved charge separation (48)(49)(50)(51). The spatial organization of domains remains poorly understood across multiple length scales and is often only characterized by ensemble-averaged measurements due to the combined challenge of short length scales and low-energy scales of interaction.…”

Section: Discussionmentioning

confidence: 99%

Vibrational exciton nanoimaging of phases and domains in porphyrin nanocrystals

Muller

Gray

Zhou

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Much of the electronic transport, photophysical, or biological functions of molecular materials emerge from intermolecular interactions and associated nanoscale structure and morphology. However, competing phases, defects, and disorder give rise to confinement and many-body localization of the associated wavefunction, disturbing the performance of the material. Here, we employ vibrational excitons as a sensitive local probe of intermolecular coupling in hyperspectral infrared scattering scanning near-field optical microscopy (IR s-SNOM) with complementary small-angle X-ray scattering to map multiscale structure from molecular coupling to long-range order. In the model organic electronic material octaethyl porphyrin ruthenium(II) carbonyl (RuOEP), we observe the evolution of competing ordered and disordered phases, in nucleation, growth, and ripening of porphyrin nanocrystals. From measurement of vibrational exciton delocalization, we identify coexistence of ordered and disordered phases in RuOEP that extend down to the molecular scale. Even when reaching a high degree of macroscopic crystallinity, identify significant local disorder with correlation lengths of only a few nanometers. This minimally invasive approach of vibrational exciton nanospectroscopy and -imaging is generally applicable to provide the molecular-level insight into photoresponse and energy transport in organic photovoltaics, electronics, or proteins. infrared spectroscopy | molecular vibrations | scattering-scanning near-field optical microscopy (s-SNOM) | vibrational exciton | molecular energy transport

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Polymorphism in Sn(IV)-Tetrapyridyl Porphyrins with a Halogenated Axial Ligand: Structural, Photophysical, and Morphological Study

Cited by 12 publications

References 52 publications

Wheel and Axle Topology Driven Halogen Bonds for the Construction of Molecular Arrays in Hexacoordinated Sn(IV)Porphyrins: A Structural and Theoretical Investigation

Wheel and Axle Topology Driven Halogen Bonds for the Construction of Molecular Arrays in Hexacoordinated Sn(IV)Porphyrins: A Structural and Theoretical Investigation

Database Investigation of Halogen Bonding and Halogen···Halogen Interactions between Porphyrins: Emergence of Robust Supramolecular Motifs and Frameworks

Vibrational exciton nanoimaging of phases and domains in porphyrin nanocrystals

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