Polar inclusion compounds of perhydrotriphenylene (phtp) and efficient nonlinear optical molecules**

Hulliger, Jürg; König, Olaf; Hoss, Ralf

doi:10.1002/adma.19950070807

Cited by 83 publications

(55 citation statements)

References 12 publications

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“…where c, which depends on the ratio between the acceptor and the critical concentrations, can be written for our system as c 4(p/3) 3=2 (R 0 /d) 3 x, where d is the interchannel distance. In Fig.…”

Section: Discussionmentioning

confidence: 99%

“…This approach has attracted considerable interest since it demonstrates the possibility to manifest macroscopic physical properties based on embedded microscopic structures. The potentiality of these host±guest systems is clear in the ®eld of non-linear optics as parallel arrays of polar molecules exhibiting a macroscopic polarization (and therefore a macroscopic second-order response) can be fabricated [3]. Energy transfer (ET) in organic semiconductors has been used to funnel the excitation produced by photon absorption onto properly chosen dopant which acts as the emitting species.…”

Section: Introductionmentioning

confidence: 99%

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Energy transfer in nanostructured oligothiophene inclusion compounds

Bongiovanni

Botta

Silvestro

et al. 2001

Chemical Physics Letters

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Resonant energy transfers from terthiophene (T3) to quinquethiophene (T5) oligomers embedded in the nanochannels of perhydrotriphenylene (PHTP) crystals are studied by cw and femtosecond spectroscopy. The stringent geometry imposed by the host results in a very peculiar supramolecular organization of the guest molecules consisting of parallel linear arrays of chromophores. This provides a unique opportunity to make a quantitative analysis of the energy transfer phenomena and in particular to distinguish between heterotransfers and homotransfers. The experimental data ®tted by a suitable theoretical analysis indicate that homotransfers become important in the long time dynamics and that the heterotransfer rate is satisfactorily described by the analytical solution obtained by assuming a continuous intermolecular spacing. Ó

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Energy transfer in nanostructured oligothiophene inclusion compounds

Bongiovanni

Botta

Silvestro

et al. 2001

Chemical Physics Letters

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“…The melting points of these systems were above that of pure PHTP (125.2 'C). Oscillation photographs show a system of diffuse layer lines perpendicular to the channel axis [14]. From this data.…”

Section: Methodsmentioning

confidence: 99%

“…Of the large number of NLO compounds [I -41 only the 20 D-x-A systems described herein were available to us. The crystallizations by controlled isothermal evaporation of2-butanone or paraldehyde were performed as described [14,19]. When solid starting materials were employed, the first step was grinding with a mortar and pestle.…”

Section: Methodsmentioning

confidence: 99%

Crystallization of Supramolecular Materials: Perhydrotriphenylene (PHTP) Inclusion Compounds with Nonlinear Optical Properties

Hoss¹,

König²,

Kramer‐Hoss³

et al. 1996

Angew. Chem. Int. Ed. Engl.

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A prerequisite for the design and synthesis of materials with nonlinear optical (NLO) properties is a molecular building block that can be incorporated into a solid in an appropriately functionalized and oriented manner. To obtain new, single-crystal materials that exhibit electrooptical (EO) effects more pronounced than those of the currently known organic NLO crystals,[' -41 stable molecules showing hyperpolarizabilities B, of up to 10000 x m 4 V 1 and. having dipole moments that can be aligned in a parallel manner within the solid are required. While a large number of target compounds can be envisioned based on these known criteria,I3. ' 1 the probability is low that during the crystallization of pure NLO compounds a crystal structure with a parallel arrangement of the b, axes is realized (about 25% for an acentric space group, less than 5 % for a nearly parallel Hence, the question of alternatives for the formation of crystalline and structurally optimized EO materials arises. In this study it is shown that perhydrophenylene (PHTP)I6] forms inclusion compounds with electronically optimized NLO species, in which the guest molecules can attain a parallel arrangement; materials with polar properties on a macroscopic level are formed about 90% of the time.

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“…Vector property formation is particularly interesting in the case of molecular crystals, constituted by prolate shaped dipolar molecules. After an extensive experimental [9][10][11][12] and theoretical [3,[13][14][15][16][17][18][19][20][21][22][23] analysis starting in 1995, we are about to conclude that any dipolar molecule crystallizing into a crystal structure described on average by a non-polar point group undergoes (to some extent) sector-wise dissymetrization, leading to sectors showing polar properties. Growth-induced polarity formation leads to non-classical twinning, i.e.…”

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confidence: 99%

Dissymetrization of molecular crystals: a driving force for property formation

Hulliger¹,

Batagiannis

2008

Cryst. Res. Technol.

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Phenomena of dissymetrization of molecular crystals are reviewed which lead to sector wise polar properties. Orientational disorder of prolate-type dipolar molecules taking place at attachment sites can produce partial polar alignment of dipoles in corresponding growth sectors of molecular crystals nucleating into topologically centric packings. As a result bi-polar crystals are obtained. In case of native polar groups, Monte Carlo simulations predict a basic behaviour for pyroelectric molecular crystals: the dipoles belonging to sectors of either the plus or minus direction of the unique axis show a non-vanishing probability to be gradually reversed. Domain reversal may start upon a single orientational defect developing into complete sector reversal. Basic features of growth induced stochastic polarity formation are confirmed by scanning pyroelectric microscopy, phase sensitive second harmonic generation microscopy and x-ray scattering. Real systems comprise channel-type inclusion compounds, single component molecular crystals, solid solutions and long chain proteins in natural tissues. Neumann's principle gives thought to physical properties of bulk crystals [2], although building blocks undergo attachment to surfaces confined to 2D point groups. For growth induced properties, Neumann's principle may thus be restated as follows [3]: The symmetry elements of a physical property of a growth sector include all symmetry elements of the point group of the growth sector. Properties resulting explicitly from processes at the crystal-nutrient interface are those, which in principle should disappear if thermalization of the bulk structure far off the surface has reached the minimum of free energy. Growth processes leading to the dissymmetrization of crystals are known for a long time [4][5][6] and were mainly discussed for minerals [7]. For a review discussing also molecular crystals featuring optical anomalies [8]. Recently, we have reviewed the impact of surface symmetry on growth-induced properties emerging from corresponding families of faces of the 32 point groups. Explicitly, a symmetry analysis for a vector property, i.e. pyroelectricity was performed [3].Here, we shall understand dissymetrization as a constructive phenomenon for physical property formation. Vector property formation is particularly interesting in the case of molecular crystals, constituted by prolate shaped dipolar molecules. After an extensive experimental [9][10][11][12] and theoretical [3,[13][14][15][16][17][18][19][20][21][22][23] analysis starting in 1995, we are about to conclude that any dipolar molecule crystallizing into a crystal structure described on average by a non-polar point group undergoes (to some extent) sector-wise dissymetrization, leading to sectors showing polar properties. Growth-induced polarity formation leads to non-classical twinning, i.e. bi-polar states of molecular crystals.The basic phenomenon behind growth induced polarity formation is symmetry breaking at the crystalnutrient interface. The probabilities of att...

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Polar inclusion compounds of perhydrotriphenylene (phtp) and efficient nonlinear optical molecules**

Cited by 83 publications

References 12 publications

Energy transfer in nanostructured oligothiophene inclusion compounds

Energy transfer in nanostructured oligothiophene inclusion compounds

Crystallization of Supramolecular Materials: Perhydrotriphenylene (PHTP) Inclusion Compounds with Nonlinear Optical Properties

Dissymetrization of molecular crystals: a driving force for property formation

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