Spectroscopic investigations of novel host-guest compounds based on microporous SiO2 frameworks and inorganic guest species

Wirnsberger, Gernot; Fritzer, Harald P.; Goor, Gianpietro van de; Pillep, B.; Behrens, Peter; Popitsch, Alois

doi:10.1016/s0022-2860(96)09678-0

Cited by 11 publications

(23 citation statements)

References 13 publications

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“…Furthermore, the iodineiodine interaction might play a role. UV/VIS absorption spectra taken by Wirnsberger et al 40,47 show that the B state potential energy is shifted by Ϫ700 cm Ϫ1 . Raman spectra taken by the same authors yielded a shift of the vibrational levels of the ground state by 13 cm Ϫ1 .…”

Section: Potential Energy Shift Of Iodine In Tonmentioning

confidence: 99%

“…25 These properties made zeolites an interesting matrix system for optical spectroscopy, especially over the past few years. [27][28][29][30][31][32][33][34][35][36][37][38][39][40] The spectroscopy of cations of organic molecules was of special interest in many experimental investigations. The zeolite pores are used as reactors for the control of the photochemical behavior of a͒ organic molecules in order to produce long-lived radical cations from the neutral molecules.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, first experimental results were published on the spectroscopy of iodine molecules in zeolites. 40 For the spectroscopic characterization of the molecules enclosed into channels and cages of zeolites mostly nontime-resolved methods were utilized, like Raman spectroscopy. 38,40 Time-resolved spectroscopy was virtually exclusively performed on a nanosecond or longer time scale.…”

Section: Introductionmentioning

confidence: 99%

“…40 For the spectroscopic characterization of the molecules enclosed into channels and cages of zeolites mostly nontime-resolved methods were utilized, like Raman spectroscopy. 38,40 Time-resolved spectroscopy was virtually exclusively performed on a nanosecond or longer time scale. 32 Theoretical investigations in most cases deal with the kinetics of molecular diffusion between the different zeolite pores.…”

Section: Introductionmentioning

confidence: 99%

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The elementary steps of the photodissociation and recombination reactions of iodine molecules enclosed in cages and channels of zeolite crystals: A femtosecond time-resolved study of the geometry effect

Flachenecker

Materny

2004

The Journal of Chemical Physics

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We present femtosecond time-resolved pump-probe experiments on iodine molecules enclosed into well-defined cages and channels of different crystalline SiO2 modifications of zeolites. The new experimental results obtained from iodine in TON (Silica-ZSM-22), FER (Silica-Ferrierit), and MFI (Silicalit-1) porosils are compared with data published earlier on the iodine/DDR (Decadodecasil 3R) porosil system [Flachenecker et al., Phys. Chem. Chem. Phys. 5, 865 (2003)]. A summary of all findings is given. The processes analyzed by means of the ultrafast spectroscopy are the vibrational relaxation as well as the dissociation and recombination reactions, which are caused by the interaction of the photo-excited iodine molecules with the cavity walls of the porosils. A clear dependence of the observed dynamics on the geometry of the surrounding lattice structure can be seen. These measurements are supported by temperature-dependent experiments. Making use of a theoretical model which is based on the classical Langevin equation, an analysis of the geometry-reaction relation is performed. The Brownian dynamics simulations show that in contrast to the vibrational relaxation the predissociation dynamics are independent of the frequency of collisions with the surroundings. From the results obtained in the different surroundings, we conclude that mainly local fields are responsible for the crossing from the bound B state to the repulsive a/a' states of the iodine molecules.

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Section: Potential Energy Shift Of Iodine In Tonmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The elementary steps of the photodissociation and recombination reactions of iodine molecules enclosed in cages and channels of zeolite crystals: A femtosecond time-resolved study of the geometry effect

Flachenecker

Materny

2004

The Journal of Chemical Physics

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“…Molecular iodine is an interesting Raman laser material, as it has a narrow Raman line width [16] and large output wavelength spectrum [17], and highly efficient I 2 Raman laser was also reported [18]. There are several reports on the inclusion of iodine in the channels of zeolite [19][20][21][22]. I 2 molecules that stabilized in the channels of zeolite have the perspective to realize Raman laser.…”

Section: Introductionmentioning

confidence: 99%

Incorporation of iodine into the channels of AlPO4-5 crystals

Jiang

Liu

2007

Journal of Physics and Chemistry of Solids

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Probing the Limit of Weak Host–Guest Interactions: Insertion Compounds of Mercury(II) Halides with Microporous SiO2 Hosts

et al. 2002

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Mercury(II) halides HgX2 (X=Cl, Br, I) were inserted into the voids of the crystalline microporous SiO2 modifications deca‐dodecasil 3R (short term: DDR), silica‐theta‐1 (TON), silica‐ferrierite (FER) and silicalite‐1 (MFI) by vapour phase loading. The properties of the occluded guest species were studied by X‐ray absorption spectroscopy (X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) analysis), UV/Vis spectroscopy, and IR and Raman spectroscopy. The methods reveal the presence of HgX2 molecules in the insertion compounds. The interactions between these electroneutral guest molecules and the electroneutral surrounding SiO2 framework are weak. In addition, no indication of any significant guest–guest interaction between the embedded molecules was found, in contrast to the analogous iodine insertion compounds, where these become more important with increasing pore dimensionality (G. Wirnsberger et al., Angew. Chem. 1996, 108, 2951–2953; Angew. Chem. Int. Ed. Engl. 1996, 35, 2777). Analysis of the HgL3 EXAFS confirms a coordination number of two for Hg and gives HgX bond lengths of 2.26±0.02, 2.38±0.02 and 2.57±0.02 Å for the trapped HgCl2, HgBr2 and HgI2 molecules, respectively. These values are very close to those of the corresponding molecules in the vapour phase and are the shortest determined for HgX2 molecules in solid‐state compounds to date (a comparably short distance only appears in the recently reported [Cu(2‐pyrazinecarboxylato)2HgI2]⋅HgI2 with d(HgI)=2.577(2) Å; Dong et al., Angew. Chem. 2000, 112, 4441–4443; Angew. Chem. Int. Ed. 2000, 39, 4271). Thus, there emerges a picture of almost unperturbed HgX2 molecules, similar to those in the vapour phase or in non‐coordinating solvents, in a solid crystalline matrix of high temperature stability, a very unusual state of matter. Despite the weakness of the host–guest interactions, investigations on small crystallites of the HgX2–TON composites using a Raman microscope show a strong polarization dependence, providing evidence for an orientational alignment of the HgX2 molecules inside the one‐dimensional pore system of this host. For these reasons, the host matrices used in this study can be viewed as orienting solid solvents, coordinating only very weakly to the inserted HgX2 guest molecules, but exhibiting a strong geometrical template function for their alignment. The concept of using electroneutral SiO2 modifications as host components for a modular construction of new host–guest compounds thus allows the designed construction of ordered guest assemblies, with the pore systems of the rigid host matrices acting as space‐confining and ordering templates for the guest components.

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Spectroscopic investigations of novel host-guest compounds based on microporous SiO2 frameworks and inorganic guest species

Cited by 11 publications

References 13 publications

The elementary steps of the photodissociation and recombination reactions of iodine molecules enclosed in cages and channels of zeolite crystals: A femtosecond time-resolved study of the geometry effect

The elementary steps of the photodissociation and recombination reactions of iodine molecules enclosed in cages and channels of zeolite crystals: A femtosecond time-resolved study of the geometry effect

Incorporation of iodine into the channels of AlPO4-5 crystals

Probing the Limit of Weak Host–Guest Interactions: Insertion Compounds of Mercury(II) Halides with Microporous SiO2 Hosts

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