19 research outputs found
Determination of the Structural Parameters of Heteronuclear (Phthalocyaninato)bis(crownphthalocyaninato)lanthanide(III) Triple-Deckers in Solution by Simultaneous Analysis of NMR and Single-Crystal Xâray Data
Application of a
general and convenient approach to the synthesis of heteronuclear
crown-substituted triple-decker phthalocyaninates afforded two series
of complexes containing one dia- and one paramagnetic LnÂ(III) ion
(for Y and almost the whole lanthanide family), [(15C5)<sub>4</sub>Pc]ÂM*Â[(15C5)<sub>4</sub>Pc]ÂMÂ(Pc) (or [M*,M] for brevity sake), where
(15C5) is 15-crown-5; (Pc<sup>2â</sup>) is phthalocyaninato
dianion; and M â M* = Y, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb. This
approach consists of using LaPc<sub>2</sub> as an efficient Pc<sup>2â</sup> source. The solid-state structures of two complexes
([Tm*,Y] and [Yb*,Y]) were studied by single-crystal X-ray diffraction
analysis, providing therefore a structural model for the assignment
and analysis of <sup>1</sup>H NMR spectra of the complexes, which
is strongly affected by the presence of paramagnetic lanthanide ions.
Model validation was performed on complexes containing two different
paramagnetic ionsî¸[Dy*,Gd] and [Gd*,Dy] as well as [Tb*,Tm]
and [Tm*,Tb]î¸synthesized by the above-mentioned method
A Molecular Chameleon: Reversible pH- and Cation-Induced Control of the Optical Properties of Phthalocyanine-Based Complexes in the Visible and Near-Infrared Spectral Ranges
A series
of novel nonperipherally substituted tetra-15-crown-5-dibutoxyoxanthrenocyanines
(H<sub>2</sub>, Mg, Zn), acting as chameleons with the unique properties
of switchable absorption and emission in the near-infrared (NIR) spectral
range have been synthesized and characterized by X-ray diffraction.
The attachment of 15-crown-5-Îą-dibutoxyoxanthreno moieties to
phthalocyanine is responsible for the high solubility of the resulting
molecules and the red shift of the Q band to the NIR region and offers
a unique possibility for postsynthetic modification of the optical
properties of the molecules. Both aggregation of phthalocyanine and
its participation in an acidâbase equilibrium strongly alter
their optical properties. For example, the absorption of complexes
can be reversibly tuned from 686 up to 1028 nm because of the cation-induced
formation of supramolecular dimers or subsequent protonation of <i>meso</i>-N atoms orf macrocycle, in contrast to peripherally
substituted tetra-15-crown-5-phthalocyanines without oxanthrene moieties.
The reversibility of these processes can be controlled by the addition
of [2.2.2]Âcryptand or amines. All investigated compounds exhibit fluorescence
with moderate quantum yield, which can also be switched between the
ON and OFF states by the action of similar agents
Determination of the Structural Parameters of Heteronuclear (Phthalocyaninato)bis(crownphthalocyaninato)lanthanide(III) Triple-Deckers in Solution by Simultaneous Analysis of NMR and Single-Crystal Xâray Data
Application of a
general and convenient approach to the synthesis of heteronuclear
crown-substituted triple-decker phthalocyaninates afforded two series
of complexes containing one dia- and one paramagnetic LnÂ(III) ion
(for Y and almost the whole lanthanide family), [(15C5)<sub>4</sub>Pc]ÂM*Â[(15C5)<sub>4</sub>Pc]ÂMÂ(Pc) (or [M*,M] for brevity sake), where
(15C5) is 15-crown-5; (Pc<sup>2â</sup>) is phthalocyaninato
dianion; and M â M* = Y, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb. This
approach consists of using LaPc<sub>2</sub> as an efficient Pc<sup>2â</sup> source. The solid-state structures of two complexes
([Tm*,Y] and [Yb*,Y]) were studied by single-crystal X-ray diffraction
analysis, providing therefore a structural model for the assignment
and analysis of <sup>1</sup>H NMR spectra of the complexes, which
is strongly affected by the presence of paramagnetic lanthanide ions.
Model validation was performed on complexes containing two different
paramagnetic ionsî¸[Dy*,Gd] and [Gd*,Dy] as well as [Tb*,Tm]
and [Tm*,Tb]î¸synthesized by the above-mentioned method
Determination of the Structural Parameters of Heteronuclear (Phthalocyaninato)bis(crownphthalocyaninato)lanthanide(III) Triple-Deckers in Solution by Simultaneous Analysis of NMR and Single-Crystal Xâray Data
Application of a
general and convenient approach to the synthesis of heteronuclear
crown-substituted triple-decker phthalocyaninates afforded two series
of complexes containing one dia- and one paramagnetic LnÂ(III) ion
(for Y and almost the whole lanthanide family), [(15C5)<sub>4</sub>Pc]ÂM*Â[(15C5)<sub>4</sub>Pc]ÂMÂ(Pc) (or [M*,M] for brevity sake), where
(15C5) is 15-crown-5; (Pc<sup>2â</sup>) is phthalocyaninato
dianion; and M â M* = Y, Nd, Eu, Tb, Dy, Ho, Er, Tm, Yb. This
approach consists of using LaPc<sub>2</sub> as an efficient Pc<sup>2â</sup> source. The solid-state structures of two complexes
([Tm*,Y] and [Yb*,Y]) were studied by single-crystal X-ray diffraction
analysis, providing therefore a structural model for the assignment
and analysis of <sup>1</sup>H NMR spectra of the complexes, which
is strongly affected by the presence of paramagnetic lanthanide ions.
Model validation was performed on complexes containing two different
paramagnetic ionsî¸[Dy*,Gd] and [Gd*,Dy] as well as [Tb*,Tm]
and [Tm*,Tb]î¸synthesized by the above-mentioned method
A Molecular Chameleon: Reversible pH- and Cation-Induced Control of the Optical Properties of Phthalocyanine-Based Complexes in the Visible and Near-Infrared Spectral Ranges
A series
of novel nonperipherally substituted tetra-15-crown-5-dibutoxyoxanthrenocyanines
(H<sub>2</sub>, Mg, Zn), acting as chameleons with the unique properties
of switchable absorption and emission in the near-infrared (NIR) spectral
range have been synthesized and characterized by X-ray diffraction.
The attachment of 15-crown-5-Îą-dibutoxyoxanthreno moieties to
phthalocyanine is responsible for the high solubility of the resulting
molecules and the red shift of the Q band to the NIR region and offers
a unique possibility for postsynthetic modification of the optical
properties of the molecules. Both aggregation of phthalocyanine and
its participation in an acidâbase equilibrium strongly alter
their optical properties. For example, the absorption of complexes
can be reversibly tuned from 686 up to 1028 nm because of the cation-induced
formation of supramolecular dimers or subsequent protonation of <i>meso</i>-N atoms orf macrocycle, in contrast to peripherally
substituted tetra-15-crown-5-phthalocyanines without oxanthrene moieties.
The reversibility of these processes can be controlled by the addition
of [2.2.2]Âcryptand or amines. All investigated compounds exhibit fluorescence
with moderate quantum yield, which can also be switched between the
ON and OFF states by the action of similar agents
A Molecular Chameleon: Reversible pH- and Cation-Induced Control of the Optical Properties of Phthalocyanine-Based Complexes in the Visible and Near-Infrared Spectral Ranges
A series
of novel nonperipherally substituted tetra-15-crown-5-dibutoxyoxanthrenocyanines
(H<sub>2</sub>, Mg, Zn), acting as chameleons with the unique properties
of switchable absorption and emission in the near-infrared (NIR) spectral
range have been synthesized and characterized by X-ray diffraction.
The attachment of 15-crown-5-Îą-dibutoxyoxanthreno moieties to
phthalocyanine is responsible for the high solubility of the resulting
molecules and the red shift of the Q band to the NIR region and offers
a unique possibility for postsynthetic modification of the optical
properties of the molecules. Both aggregation of phthalocyanine and
its participation in an acidâbase equilibrium strongly alter
their optical properties. For example, the absorption of complexes
can be reversibly tuned from 686 up to 1028 nm because of the cation-induced
formation of supramolecular dimers or subsequent protonation of <i>meso</i>-N atoms orf macrocycle, in contrast to peripherally
substituted tetra-15-crown-5-phthalocyanines without oxanthrene moieties.
The reversibility of these processes can be controlled by the addition
of [2.2.2]Âcryptand or amines. All investigated compounds exhibit fluorescence
with moderate quantum yield, which can also be switched between the
ON and OFF states by the action of similar agents
Cation-Induced Dimerization of Crown-Substituted Phthalocyanines by Complexation with Rubidium Nicotinate As Revealed by Xâray Structural Data
The
supramolecular dimeric complex [(Îź-oxo)ÂbisÂ(tetra-15-crown-5-phthalocyaninato)Â(nicotinato)ÂaluminumÂ(III)]ÂtetraÂ(rubidium)
bisÂ(nicotinate) was prepared by addition of an excess of a methanol
solution of rubidium nicotinate to a chloroform solution of the aluminum
crown-phthalocyaninate, [(HO)ÂAlÂ(15C5)<sub>4</sub>Pc]. A single-crystal
X-ray diffraction study of {[Rb<sub>4</sub>(NicAlÂ(15C5)<sub>4</sub>Pc)<sub>2</sub>(Îź-O)]<sup>2+</sup>(Nic<sup>â</sup>)<sub>2</sub>}¡2.36HNic¡11H<sub>2</sub>O demonstrated that two
molecules of the aluminum crown-phthalocyaninate nicotinate are connected
through an AlâOâAl bridge supported by sandwiching of
crown ether moieties by Rb<sup>+</sup> cations
Phosphorus(V) Porphyrin-Based Molecular Turnstiles
A new cationic molecular
turnstile based on a PÂ(V) porphyrin backbone bearing two pyridyl interaction
sites, one at the meso position of the porphyrin and the other on
the handle connected to the porphyrin through PâO bonds, was
designed and synthesized. The dynamic behavior of the turnstile <b>2</b>, investigated by 1D and 2D <sup>1</sup>H NMR techniques,
showed that in the absence of an effector, the turnstile is in its
open state and undergoes a free rotation of the rotor (the handle)
around the stator (the porphyrin backbone). In the presence of an
external effector such as Ag<sup>+</sup> cation or H<sup>+</sup>,
the turnstile is switched to its closed states <b>2</b>-Ag<sup>+</sup> and <b>2</b>-H<sup>+</sup>, respectively. The locking/unlocking
process is reversible and may be achieved by precipitation of AgBr
upon addition of Et<sub>4</sub>NBr in the case of the silver-locked
turnstile or by addition of Et<sub>3</sub>N in the case of the proton-locked
turnstile
Phosphorus(V) Porphyrin-Based Molecular Turnstiles
A new cationic molecular
turnstile based on a PÂ(V) porphyrin backbone bearing two pyridyl interaction
sites, one at the meso position of the porphyrin and the other on
the handle connected to the porphyrin through PâO bonds, was
designed and synthesized. The dynamic behavior of the turnstile <b>2</b>, investigated by 1D and 2D <sup>1</sup>H NMR techniques,
showed that in the absence of an effector, the turnstile is in its
open state and undergoes a free rotation of the rotor (the handle)
around the stator (the porphyrin backbone). In the presence of an
external effector such as Ag<sup>+</sup> cation or H<sup>+</sup>,
the turnstile is switched to its closed states <b>2</b>-Ag<sup>+</sup> and <b>2</b>-H<sup>+</sup>, respectively. The locking/unlocking
process is reversible and may be achieved by precipitation of AgBr
upon addition of Et<sub>4</sub>NBr in the case of the silver-locked
turnstile or by addition of Et<sub>3</sub>N in the case of the proton-locked
turnstile
Phosphorus(V) Porphyrin-Based Molecular Turnstiles
A new cationic molecular
turnstile based on a PÂ(V) porphyrin backbone bearing two pyridyl interaction
sites, one at the meso position of the porphyrin and the other on
the handle connected to the porphyrin through PâO bonds, was
designed and synthesized. The dynamic behavior of the turnstile <b>2</b>, investigated by 1D and 2D <sup>1</sup>H NMR techniques,
showed that in the absence of an effector, the turnstile is in its
open state and undergoes a free rotation of the rotor (the handle)
around the stator (the porphyrin backbone). In the presence of an
external effector such as Ag<sup>+</sup> cation or H<sup>+</sup>,
the turnstile is switched to its closed states <b>2</b>-Ag<sup>+</sup> and <b>2</b>-H<sup>+</sup>, respectively. The locking/unlocking
process is reversible and may be achieved by precipitation of AgBr
upon addition of Et<sub>4</sub>NBr in the case of the silver-locked
turnstile or by addition of Et<sub>3</sub>N in the case of the proton-locked
turnstile