10 research outputs found
Design of Triads for Probing the Direct Through Space Energy Transfers in Closely Spaced Assemblies
Using a selective
stepwise Suzuki cross-coupling reaction, two trimers built on three
different chromophores were prepared. These trimers exhibit a <b>D<sup>∧</sup>A</b><sub><b>1</b></sub>-<b>A</b><sub><b>2</b></sub> structure where the donor <b>D</b> (octa-β-alkyl zincÂ(II)Âporphyrin either as diethylhexamethyl, <b>10a</b>, or tetraethyltetramethyl, <b>10b</b>, derivatives)
through space transfers the S<sub>1</sub> energy to two different
acceptors, diÂ(4-ethylbenzene) zincÂ(II)Âporphyrin (<b>A</b><sub><b>1</b></sub>; acceptor 1) placed cofacial with <b>D</b>, and the corresponding free base (<b>A</b><sub><b>2</b></sub>; acceptor 2), which is <i>meso–meso</i>-linked
with <b>A</b><sub><b>1</b></sub>. This structure design
allows for the possibility of comparing two series of assemblies, <b>9a,b</b> (<b>D<sup>∧</sup>A</b><sub><b>1</b></sub>) with <b>10a,b</b> (<b>D<sup>∧</sup>A</b><b>̂</b><sub><b>1</b></sub>-<b>A</b><sub><b>2</b></sub>), for the evaluation of the S<sub>1</sub> energy
transfer for the global process <b>D</b>*→<b>A</b><sub><b>2</b></sub> in the trimers. From the comparison of
the decays of the fluorescence of <b>D</b>, the rates for through
space energy transfer, <i>k</i><sub>ET</sub> for <b>10a,b</b> (<i>k</i><sub>ET</sub> ≈ 6.4 × 10<sup>9</sup> (<b>10a</b>), 5.9 × 10<sup>9</sup> s<sup>–1</sup> (<b>10b</b>)), and those for the corresponding cofacial <b>D</b><b><sup>∧</sup>A</b><sub><b>1</b></sub> systems, <b>9a,b</b>, (<i>k</i><sub>ET</sub> ≈
5.0 × 10<sup>9</sup> (<b>9a</b>), 4.7 × 10<sup>9</sup> s<sup>–1</sup> (<b>9b</b>)), provide an estimate for
k<sub>ET</sub> for the direct through space <b>D</b>*→<b>A</b><sub><b>2</b></sub> process (i.e., <i>k</i><sub>ET</sub>(<b>D<sup>∧</sup>A</b><sub><b>1</b></sub>-<b>A</b><sub><b>2</b></sub>) – <i>k</i><sub>ET</sub>(<b>D<sup>∧</sup>A</b><sub><b>1</b></sub>) = <i>k</i><sub>ET</sub>(<b>D</b>*→<b>A</b><sub><b>2</b></sub>) ∼ 1 × 10<sup>9</sup> s<sup>–1</sup>). This channel of relaxation represents ∼15%
of <i>k</i><sub>ET</sub> for <b>D</b>*→<b>A</b><sub><b>1</b></sub>
Colorimetric Hg<sup>2+</sup> Sensing in Water: From Molecules toward Low-Cost Solid Devices
A new colorimetric molecular sensor allowing for cheap, fast, sensitive, and highly selective naked-eye detection of Hg<sup>2+</sup> in water is described. This molecule combines a 1,8-diaminoanthraquinone signaling subunit and phosphonic acid esters that confer the water solubility to the dye (R = H). A ready-to-use colorimetric solid sensor was obtained by incorporating an amphiphilic analog (R = OC<sub>12</sub>H<sub>25</sub>) exhibiting similar binding properties and optical responses in an agarose film
Colorimetric Hg<sup>2+</sup> Sensing in Water: From Molecules toward Low-Cost Solid Devices
A new colorimetric molecular sensor allowing for cheap, fast, sensitive, and highly selective naked-eye detection of Hg<sup>2+</sup> in water is described. This molecule combines a 1,8-diaminoanthraquinone signaling subunit and phosphonic acid esters that confer the water solubility to the dye (R = H). A ready-to-use colorimetric solid sensor was obtained by incorporating an amphiphilic analog (R = OC<sub>12</sub>H<sub>25</sub>) exhibiting similar binding properties and optical responses in an agarose film
Gallium(III) and Indium(III) Complexes with <i>meso</i>-Monophosphorylated Porphyrins: Synthesis and Structure. A First Example of Dimers Formed by the Self-Assembly of <i>meso</i>-Porphyrinylphosphonic Acid Monoester
The synthesis and
structural characterization, both in solution by means of <sup>1</sup>H and <sup>31</sup>P NMR and UV–vis spectroscopies and in
the solid state by X-ray diffraction on single crystal, of a series
of galliumÂ(III) and indiumÂ(III) <i>meso</i>-monoÂ(diethoxyphosphoryl)Âporphyrins
bearing different peripheral substituents as well as the corresponding
monoesters and phosphonic acids are reported. This work describes
the first example of the X-ray structure of a self-assembled dimer
formed via strong binding between the oxygen atom of the phosphonate
substituent and the galliumÂ(III) cations of adjacent porphyrin molecules
[Ga–O = 1.9708(13) Å]
Gallium(III) and Indium(III) Complexes with <i>meso</i>-Monophosphorylated Porphyrins: Synthesis and Structure. A First Example of Dimers Formed by the Self-Assembly of <i>meso</i>-Porphyrinylphosphonic Acid Monoester
The synthesis and
structural characterization, both in solution by means of <sup>1</sup>H and <sup>31</sup>P NMR and UV–vis spectroscopies and in
the solid state by X-ray diffraction on single crystal, of a series
of galliumÂ(III) and indiumÂ(III) <i>meso</i>-monoÂ(diethoxyphosphoryl)Âporphyrins
bearing different peripheral substituents as well as the corresponding
monoesters and phosphonic acids are reported. This work describes
the first example of the X-ray structure of a self-assembled dimer
formed via strong binding between the oxygen atom of the phosphonate
substituent and the galliumÂ(III) cations of adjacent porphyrin molecules
[Ga–O = 1.9708(13) Å]
Gallium(III) and Indium(III) Complexes with <i>meso</i>-Monophosphorylated Porphyrins: Synthesis and Structure. A First Example of Dimers Formed by the Self-Assembly of <i>meso</i>-Porphyrinylphosphonic Acid Monoester
The synthesis and
structural characterization, both in solution by means of <sup>1</sup>H and <sup>31</sup>P NMR and UV–vis spectroscopies and in
the solid state by X-ray diffraction on single crystal, of a series
of galliumÂ(III) and indiumÂ(III) <i>meso</i>-monoÂ(diethoxyphosphoryl)Âporphyrins
bearing different peripheral substituents as well as the corresponding
monoesters and phosphonic acids are reported. This work describes
the first example of the X-ray structure of a self-assembled dimer
formed via strong binding between the oxygen atom of the phosphonate
substituent and the galliumÂ(III) cations of adjacent porphyrin molecules
[Ga–O = 1.9708(13) Å]
Unusual Formation of a Stable 2D Copper Porphyrin Network
CopperÂ(II) 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
was obtained and characterized by means of cyclic voltammetry, electron
paramagnetic resonance, Fourier transform infrared, and UV–visible
spectroscopy. Three crystalline forms were grown and studied by means
of X-ray diffraction methods (single crystal and powder). The highly
electron-withdrawing effect of phosphoryl groups attached directly
to the porphyrin macrocycle results in a self-assembling process,
with formation of a stable 2D coordination network, which is unusual
for copperÂ(II) porphyrins. The resulting 2D structure is a rare example
of an assembly based on copperÂ(II) porphyrins where the copperÂ(II)
central metal ion is six-coordinated because of a weak interaction
with two phosphoryl groups of adjacent porphyrins. The other polymorph
of copperÂ(II) 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
contains individual (isolated) porphyrin molecules with four-coordinated
copperÂ(II) in a distorted porphyrin core. This polymorph can be obtained
only by slow diffusion of a copper acetate/methanol solution into
solutions of free base 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
in chloroform. It converts to the 2D structure after dissolution in
chloroform followed by consecutive crystallizations, using slow diffusion
of hexane. A six-coordinated copperÂ(II) porphyrin containing two axially
coordinated dioxane molecules was also obtained and characterized
by X-ray diffraction crystallography. The association of copperÂ(II)
5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin in solution was
also studied
Unusual Formation of a Stable 2D Copper Porphyrin Network
CopperÂ(II) 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
was obtained and characterized by means of cyclic voltammetry, electron
paramagnetic resonance, Fourier transform infrared, and UV–visible
spectroscopy. Three crystalline forms were grown and studied by means
of X-ray diffraction methods (single crystal and powder). The highly
electron-withdrawing effect of phosphoryl groups attached directly
to the porphyrin macrocycle results in a self-assembling process,
with formation of a stable 2D coordination network, which is unusual
for copperÂ(II) porphyrins. The resulting 2D structure is a rare example
of an assembly based on copperÂ(II) porphyrins where the copperÂ(II)
central metal ion is six-coordinated because of a weak interaction
with two phosphoryl groups of adjacent porphyrins. The other polymorph
of copperÂ(II) 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
contains individual (isolated) porphyrin molecules with four-coordinated
copperÂ(II) in a distorted porphyrin core. This polymorph can be obtained
only by slow diffusion of a copper acetate/methanol solution into
solutions of free base 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
in chloroform. It converts to the 2D structure after dissolution in
chloroform followed by consecutive crystallizations, using slow diffusion
of hexane. A six-coordinated copperÂ(II) porphyrin containing two axially
coordinated dioxane molecules was also obtained and characterized
by X-ray diffraction crystallography. The association of copperÂ(II)
5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin in solution was
also studied
Unusual Formation of a Stable 2D Copper Porphyrin Network
CopperÂ(II) 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
was obtained and characterized by means of cyclic voltammetry, electron
paramagnetic resonance, Fourier transform infrared, and UV–visible
spectroscopy. Three crystalline forms were grown and studied by means
of X-ray diffraction methods (single crystal and powder). The highly
electron-withdrawing effect of phosphoryl groups attached directly
to the porphyrin macrocycle results in a self-assembling process,
with formation of a stable 2D coordination network, which is unusual
for copperÂ(II) porphyrins. The resulting 2D structure is a rare example
of an assembly based on copperÂ(II) porphyrins where the copperÂ(II)
central metal ion is six-coordinated because of a weak interaction
with two phosphoryl groups of adjacent porphyrins. The other polymorph
of copperÂ(II) 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
contains individual (isolated) porphyrin molecules with four-coordinated
copperÂ(II) in a distorted porphyrin core. This polymorph can be obtained
only by slow diffusion of a copper acetate/methanol solution into
solutions of free base 5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin
in chloroform. It converts to the 2D structure after dissolution in
chloroform followed by consecutive crystallizations, using slow diffusion
of hexane. A six-coordinated copperÂ(II) porphyrin containing two axially
coordinated dioxane molecules was also obtained and characterized
by X-ray diffraction crystallography. The association of copperÂ(II)
5,15-bisÂ(diethoxyphosphoryl)-10,20-diphenylporphyrin in solution was
also studied
Supramolecular Assembly of Organophosphonate Diesters Using Paddle-Wheel Complexes: First Examples in Porphyrin Series
The reactions of dicopper tetrapivalate
complex Cu<sub>2</sub>(μ-OOC-<i>t-</i>Bu)<sub>4</sub>Â(NCMe)<sub>2</sub> (<b>1</b>) with triphenylphosphine
oxide and diethyl phosphite allow paddle-wheel
(PW) copperÂ(II) complexes with phosphorus-containing axial ligands
(<b>2</b>, <b>3</b>) to be obtained. When <i>meso</i>-bisÂ(diethoxyphosphoryl)Âporphyrins <b>4M</b> were employed
in this ligand exchange reaction, a series of one-dimensional (1D)
homo- and heterometallic coordination polymers <b>5M</b> composed
of PW subunits and organophosphonate diesters were prepared and characterized
by means of single crystal X-ray analysis. Planar porphyrinate <b>4Pd</b> and nonplanar metalloporphyrinates <b>4Cu</b> and <b>4Ni</b> proved to be appropriate molecular structural blocks for
assembly of coordination polymers. The structural parameters of the
tetrapyrrolic macrocycles incorporated into the polymer chain are
determined by the nature of the metal center of the porphyrin moiety.
While the geometry of palladiumÂ(II) and nickelÂ(II) porphyrinates <b>4Pd</b> and <b>4Ni</b> does not change significantly in
the polymer chain, saddle-shaped CuÂ(II) porphyrinate <b>4Cu</b> exhibits a nearly planar core configuration, being coordinated to
the copper centers of PW fragments by two peripheral phosphoryl groups
in the polymer chain. The geometry of the tetrapyrrolic core is a
key parameter influencing the structural properties of the polymeric
materials. For <b>5Pd</b> and for isostructural <b>5Cu</b>, all metal centers of the polymeric chain are aligned. The planar
macrocycles of adjacent chains are parallel and are shifted one to
another in such a way that the angle between the Pd···P
and Pd···Pd directions is 40.4°, and the distance
between the nearest palladiumÂ(II) atoms of neighboring chains is 11.668
Ã…. There is no free volume in these crystals. In the crystals
of <b>5Ni</b>, formed by nonplanar porphyrinates, only copper
atoms of the PW pivalate moiety are located in one plane, and zigzag
chains are formed so that two adjacent tetrapyrrolic macrocycles are
located in alternating positions with respect to this plane, the nickel
atoms being displaced from this plane by 1.548 Ã…. This arrangement
naturally leads to the formation of regular pores. The resulting channels
have an effective cross-section of about 10 × 12 Å and represent
ca. 18% of the volume of the crystal. The exchange reaction between
the free-base porphyrin <b>4H</b><sub><b>2</b></sub> and
an excess of copperÂ(II) pivalate complex <b>1</b> is accompanied
by the metalation of the porphyrin core affording the polymer <b>5Cu</b>. Moreover, self-assembly of metalloporphyrinate <b>4Zn</b> is observed under studied experimental conditions, which
interferes with the formation of the target mixed coordination polymers