Packing of DPDP [254] (Scheme 6) changed by the swelling of SA with DMSO
[255]. DPDP was intercalated into SA film with various loading amounts from 0.033
to 49.7 meq/100 g (from 0.05 to 75%CEC). At the loading from 0.033 to 26.5 meq/
100 g, the emission of the monomer at 482 nm decreased, while new emission at
588 nm of excimer appeared by the increase of the concentration. The gallery height
of the hybrid increased from 0.48 to 0.93 nm by the swelling of SA with DMSO and
the excimer emission enhanced, suggesting that the swollen SA provides the
interlayer expansion large enough for the π-π stacking of DPDP.
4.2.3 Energy and Electron Transfer Between Molecules Adsorbed
on Clays
The construction of photocatalyst by energy transfer in the interlayer space is a topic
of interest [256–262]. Adsorption on layered materials is a way to concentrate dyes
and to control the proximity, which resulted in efficient energy [19, 263–269] and
electron transfer [18, 31, 270, 271]. Expected effects of hybridization of dyes and
layered materials are (1) efficient quenching of the excited state of the dyes for
photostabilization, (2) separation of the photosensitizer from photocatalyst to avoid
the photocatalytic decomposition of sensitizer, and (3) directional energy and electron transfer by locational and orientational design.
A possible way to improve the photostability is quenching the photoexcited state
by energy transfer as discussed in Sect. 4.1. The stability of herbicides [272–274],
bioresmethrin [275], and norflurazon [276] was improved by energy or electron
transfers to methyl green co-adsorbed on montmorillonite and to thioflavin T on
SWy-1. The separation of the photosensitizer from the photocatalyst (anatase particle) by smectite nanosheet induced durability of the photosensitizer. The
photocatalytic oxidation of benzene to phenol was done in an aqueous suspension
of anatase with the tris(2,2-bipyridine)ruthenium(II) (designated as [Ru(bpy) 3 ]
2+ )synthetic saponite, resulting in a high yield of benzene decomposition and selectivity
of phenol. The hybrid was processed as a film to be used as the photocatalyst layer to
obtain a photocatalytic flow reactor [277, 278].
The fluorescence of [Ru(bpy) 3 ]
2+ was quenched by SO 2 gas [107] suggesting a
possible gas sensor application. The fluorescence of [Ru(bpy) 3 ]
2+ was quenched by
the MV
2+ co-adsorbed on smectites, and the quenching efficiency was higher when
smectites with larger particle sizes (e.g., TSM) was used if compared with those on
clays with smaller particle sizes (e.g., SA and LP-XLG) [279]. Such quenchers as
cyanine, MV
2+ , and anthraquinone derivatives were co-adsorbed with cyanine dyes
on laponite RDS (Southern Clay Products, Inc.) to quench the fluorescence of the
J-aggregate of the cyanine [280].
MV
2+ (Scheme 7) in the interlayer space of smectites acted as an electron
acceptor [232, 233, 281–284]. It was reported the photoinduced electron transfer
from TPP (Scheme 5) to MV
2+ under visible light irradiation to form the TPP radical
cation and MV
+ radical cation [281]. The color of MV
2+ intercalated in a hectoritelike layered silicate changed by the adsorption of N,N-dimethylaniline and
270
T. Yamaguchi et al.
[255]. DPDP was intercalated into SA film with various loading amounts from 0.033
to 49.7 meq/100 g (from 0.05 to 75%CEC). At the loading from 0.033 to 26.5 meq/
100 g, the emission of the monomer at 482 nm decreased, while new emission at
588 nm of excimer appeared by the increase of the concentration. The gallery height
of the hybrid increased from 0.48 to 0.93 nm by the swelling of SA with DMSO and
the excimer emission enhanced, suggesting that the swollen SA provides the
interlayer expansion large enough for the π-π stacking of DPDP.
4.2.3 Energy and Electron Transfer Between Molecules Adsorbed
on Clays
The construction of photocatalyst by energy transfer in the interlayer space is a topic
of interest [256–262]. Adsorption on layered materials is a way to concentrate dyes
and to control the proximity, which resulted in efficient energy [19, 263–269] and
electron transfer [18, 31, 270, 271]. Expected effects of hybridization of dyes and
layered materials are (1) efficient quenching of the excited state of the dyes for
photostabilization, (2) separation of the photosensitizer from photocatalyst to avoid
the photocatalytic decomposition of sensitizer, and (3) directional energy and electron transfer by locational and orientational design.
A possible way to improve the photostability is quenching the photoexcited state
by energy transfer as discussed in Sect. 4.1. The stability of herbicides [272–274],
bioresmethrin [275], and norflurazon [276] was improved by energy or electron
transfers to methyl green co-adsorbed on montmorillonite and to thioflavin T on
SWy-1. The separation of the photosensitizer from the photocatalyst (anatase particle) by smectite nanosheet induced durability of the photosensitizer. The
photocatalytic oxidation of benzene to phenol was done in an aqueous suspension
of anatase with the tris(2,2-bipyridine)ruthenium(II) (designated as [Ru(bpy) 3 ]
2+ )synthetic saponite, resulting in a high yield of benzene decomposition and selectivity
of phenol. The hybrid was processed as a film to be used as the photocatalyst layer to
obtain a photocatalytic flow reactor [277, 278].
The fluorescence of [Ru(bpy) 3 ]
2+ was quenched by SO 2 gas [107] suggesting a
possible gas sensor application. The fluorescence of [Ru(bpy) 3 ]
2+ was quenched by
the MV
2+ co-adsorbed on smectites, and the quenching efficiency was higher when
smectites with larger particle sizes (e.g., TSM) was used if compared with those on
clays with smaller particle sizes (e.g., SA and LP-XLG) [279]. Such quenchers as
cyanine, MV
2+ , and anthraquinone derivatives were co-adsorbed with cyanine dyes
on laponite RDS (Southern Clay Products, Inc.) to quench the fluorescence of the
J-aggregate of the cyanine [280].
MV
2+ (Scheme 7) in the interlayer space of smectites acted as an electron
acceptor [232, 233, 281–284]. It was reported the photoinduced electron transfer
from TPP (Scheme 5) to MV
2+ under visible light irradiation to form the TPP radical
cation and MV
+ radical cation [281]. The color of MV
2+ intercalated in a hectoritelike layered silicate changed by the adsorption of N,N-dimethylaniline and
270
T. Yamaguchi et al.