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1.
Chem Sci ; 6(10): 5571-5577, 2015 Oct 01.
Article in English | MEDLINE | ID: mdl-29861894

ABSTRACT

Unsymmetrical subphthalocyanine fused dimers have been prepared from appropriate ortho-dinitrile SubPc precursors. In particular, either electron-donating or electron-accepting substituents have been introduced on each SubPc constituent unit, resulting in unprecedented push-pull π-extended curved aromatic macrocycles. From fluorescence experiments in solvents of different polarity we conclude a dual fluorescence, namely a delocalized singlet excited state (1.73 eV) and a polarized charge transfer state (<1.7 eV). Pump probe experiments corroborate the dual nature of the fluorescence. On one hand, the delocalized singlet excited state gives rise to a several nanosecond lasting intersystem crossing yielding the corresponding triplet excited state. On the other hand, the polarized charge transfer state deactivates within a few picosesonds. Visualization of the charge transfer state was accomplished by means of molecular modeling with a slight polarization of the HOMO towards the electron donor and of the LUMO towards the electron acceptor.

3.
Chemistry ; 20(7): 2016-21, 2014 Feb 10.
Article in English | MEDLINE | ID: mdl-24443172

ABSTRACT

A series of subphthalocyanines (SubPcs) bearing a carboxylic acid group either at the peripheral or axial position have been designed and synthesized to investigate the influence of the COOH group positions on the dye-sensitized solar cell (DSSC) performance. The DSSC devices based on SubPcs with axially substituted carboxylic acid groups showed low photovoltaic performance, whereas peripherally substituted one exhibited higher power conversion efficiency owing to improved injection from LUMO of SubPcs to the TiO2 conduction band.

4.
J Am Chem Soc ; 135(28): 10503-11, 2013 Jul 17.
Article in English | MEDLINE | ID: mdl-23763242

ABSTRACT

Four new subphthalocyanine-based capsules have been synthesized and characterized. These supramolecular systems have been successfully employed for the encapsulation of fullerenes and probed by a wide range of characterization methods, including NMR, UV-vis and fluorescence spectroscopy, electrospray ionization mass spectrometry, and electrochemistry. Furthermore, the binding constants of the host guest complexes were estimated. Finally, the photophysical properties revealed that the subphthalocyanines undergo a transduction of singlet excited-state energy to the fullerene inside the cavity upon photoexcitation.


Subject(s)
Indoles/chemistry , Organometallic Compounds/chemistry , Isoindoles , Macromolecular Substances/chemistry , Models, Molecular , Molecular Structure , Photochemical Processes
5.
Chem Commun (Camb) ; 48(41): 4953-5, 2012 May 21.
Article in English | MEDLINE | ID: mdl-22511005

ABSTRACT

One carbon atom is too many. Two subphthalocyanine-extended TTF electron donor-acceptor conjugates were synthesized and characterized. Their photophysical properties prompt the remarkable impact that one extra carbon between the two constitutents exerts on photoinduced processes, that is, charge recombination dynamics in the normal versus inverted region.

6.
Org Lett ; 13(18): 4918-21, 2011 Sep 16.
Article in English | MEDLINE | ID: mdl-21863793

ABSTRACT

The synthesis of a new subphthalocyanine is reported. Its structural and photophysical properties are ideal for probing the accessibility of arrays of silica nanochannels.


Subject(s)
Indoles/chemical synthesis , Luminescent Agents/chemical synthesis , Nanostructures/chemistry , Silicon Dioxide/chemistry , Indoles/chemistry , Isoindoles , Luminescent Agents/chemistry , Models, Molecular , Molecular Structure , Particle Size , Stereoisomerism , Surface Properties
7.
Chem Commun (Camb) ; 47(36): 9986-8, 2011 Sep 28.
Article in English | MEDLINE | ID: mdl-21573275

ABSTRACT

Ultra high vacuum scanning tunnelling microscopy revealed chlorosubphthalocyanine to self-organize into discrete well-defined bilayer and trilayer triangular nanocrystallites when evaporated onto a Cu(111) surface.

8.
Chem Commun (Camb) ; (47): 6378-80, 2008 Dec 21.
Article in English | MEDLINE | ID: mdl-19048161

ABSTRACT

A kinetic mixture of self-assembled subphthalocyanine-based capsules was shown to gradually reorganize into its more stable symmetrical components by electrospray mass spectrometry.

9.
Chem Commun (Camb) ; (15): 1759-61, 2008 Apr 21.
Article in English | MEDLINE | ID: mdl-18379684

ABSTRACT

We have designed, synthesized and probed a dodecafluoro-subphthalocyaninato boron(III) unit, which bears a triphenylamine moiety in its axial position, as a novel electron donor-acceptor system.


Subject(s)
Aniline Compounds/chemistry , Indoles/chemistry , Isoindoles , Spectrum Analysis/methods
10.
Chem Rec ; 8(2): 75-97, 2008.
Article in English | MEDLINE | ID: mdl-18366105

ABSTRACT

This review paper gives a brief overview on how the outstanding chemical and physical properties of phthalocyanines and phthalocyanine derivatives are being studied and employed in order to construct state-of-the-art technological devices. In a first instance, a short account on how the nature of the phthalocyanine structure and its organization in condensed phases play an important role in their conducting and ultraviolet-visible absorption properties is presented. Consequently, these basic electronic and photophysical features of phthalocyanines allow us to explain why phthalocyanine-based multicomponent covalent or noncovalent donor-acceptor systems may give rise to very interesting photophysical properties, in particular in terms of their ability to generate very long-lived photoinduced charge-separated states. A concise survey on the organization of these multifunctional systems shows how a profound understanding of the morphology at the nanometer-scale of these phthalocyanine-based molecular materials is needed in order to control their physical properties in condensed phases. All the previously mentioned chemical and physical features combined together led us to the description of the latest attempts at incorporating phthalocyanines into photovoltaic devices for solar energy conversion and onto quantum dots for photodynamic therapy or quantum computing.

11.
Chemistry ; 14(4): 1342-50, 2008.
Article in English | MEDLINE | ID: mdl-18165956

ABSTRACT

A new and general synthetic method for the preparation of fluoro-substituted subazaporphyrins is reported that involves the treatment of the corresponding chloro- or aryloxy-substituted subazaporphyrins (SubAPs) with BF(3).OEt(2). The strategy has been applied to both subphthalocyanines (SubPcs) and subporphyrazines (SubPzs). The yields were high for the latter, although low yields were obtained for the benzo derivatives. In contrast to the corresponding chloro derivatives, fluorosubazaporphyrins are quite robust towards hydrolysis. All of the new compounds were characterized by several spectroscopic techniques, which included (1)H, (13)C, (19)F, (15)N, and (11)B NMR spectroscopy, IR spectroscopy, UV/Vis spectrophotometry, and mass spectrometry (both high and low resolution). In addition, DFT calculations provided theoretical NMR spectroscopy values that are in good agreement with the experimental ones. The high dipole moments exhibited by the fluorosubazaporphyrins as a result of the presence of a fluorine atom in an axial position are responsible for the spontaneous and singular supramolecular aggregation of the macrocycles in the crystalline state. The molecular and crystal structures of two one-dimensional fluorine SubAPs, namely, a SubPc and a SubPz, are discussed. Molecules of the same class stack in alternating configurations along the c axis, which gives rise to columns that contain large numbers of monomers. SubPz 3 c forms aggregates with the macrocycles arranged in a parallel fashion with the B-F bonds perfectly aligned within a column, whereas with SubPc 3 b the neighboring columns cause a commensurate sinusoidal distortion along the columns in the c direction, which prevents the alignment of the B-F bonds. However, the most remarkable feature, common to both crystalline architectures, is the extremely short and unusual intermolecular F...N distances of the contiguous molecules, which are shorter than the sum of the corresponding van der Waals radii. Theoretical calculations have shown that these short distances can be explained by the existence of a cooperativity effect as the number of monomers included in the cluster increases.


Subject(s)
Porphyrins/chemistry , Porphyrins/chemical synthesis , Crystallography, X-Ray , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Structure
12.
Org Lett ; 9(26): 5381-4, 2007 Dec 20.
Article in English | MEDLINE | ID: mdl-18047353

ABSTRACT

A subphthalocyanine trimer built around a dehydro[18]annulene core was prepared. The synthesis was achieved through direct homocoupling of an ortho-diethynyl-functionalized subphthalocyanine, obtained by palladium-catalyzed cross-coupling of the corresponding diiodo-subphthalocyanine with an ethynyl derivative. The lower analogue dehydro[12]annulene did not form in these homocoupling conditions. The trimers were fully characterized and their electrochemical properties investigated.

13.
Chem Commun (Camb) ; (20): 2000-15, 2007 May 28.
Article in English | MEDLINE | ID: mdl-17713062

ABSTRACT

Phthalocyanines are versatile building blocks for fabricating materials at the nanometer scale. These colored macrocycles exhibit fascinating physical properties which arise from their delocalized pi-electronic structure. This article describes why these molecules are targets for different scientific purposes and technological applications.

14.
J Org Chem ; 72(8): 2967-77, 2007 Apr 13.
Article in English | MEDLINE | ID: mdl-17358079

ABSTRACT

Subphthalocyanine (SubPc)-fused dimers and trimers bearing fluorine, iodine, and thioether peripheral substituents were synthesized and characterized. Absorption spectroscopy and electrochemical studies revealed (i) that the substituents have a strong effect on the electronic properties of the macrocycles and (ii) that there is good communication between the subphthalocyaninic moieties within the oligomeric structures. Theoretical calculations at DFT/6-31G(d,p) computational level and electron density studies support the experimental findings. The frontier orbitals in the dimers and trimers were also shown to be significantly altered with respect to those of SubPcs as a consequence of the extension of the conjugation associated with symmetry breaking. Time-dependent density functional theory calculations reproduced the differences observed in the UV-vis spectra of the fused dimers and the monomeric SubPcs.

15.
Chemistry ; 11(13): 3881-93, 2005 Jun 20.
Article in English | MEDLINE | ID: mdl-15827986

ABSTRACT

A series of subphthalocyanine-phthalocyanine dyads has been prepared by means of palladium-catalyzed cross-coupling reactions between a monoalkynylphthalocyanine and different monoiodosubphthalocyanines. Electronic coupling between the two photoactive units is ensured by a rigid and pi-conjugated alkynyl spacer. In addition, the electronic characteristics of the subphthalocyanine moiety were modulated by the introduction of different peripheral substituents. Cyclic and Osteryoung square-wave voltammetry experiments revealed that the reduction potential of this subunit can be decreased by about 400 mV on going from thioether or no substituents to nitro groups. As a consequence, the energy level of the charge-transfer state could be fine-tuned so as to gain control over the fate of the photoexcitation energy in each subunit. The diverse steady-state and time-resolved photophysical techniques employed demonstrated that, when the charge-transfer state lies high in energy, a quantitative singlet-singlet energy-transfer mechanism from the excited subphthalocyanine to the phthalocyanine takes place. On the contrary, stabilization of the radical pair by lowering the redox gap between electron donor and acceptor results in a highly efficient photoinduced electron-transfer process, even in solvents of low polarity such as toluene (Phi(ET) approximately 0.9). These features, together with the extraordinary absorptive cross section that these molecular ensembles display across the whole UV/Vis spectrum, make them model candidates for application in situations where broadband light sources are needed.


Subject(s)
Indoles/chemistry , Electrochemistry , Electrons , Indoles/radiation effects , Isoindoles , Molecular Structure , Oxidation-Reduction , Photochemistry , Pyridines/chemistry , Spectrophotometry , Toluene/chemistry
16.
Chem Commun (Camb) ; (16): 2113-5, 2005 Apr 28.
Article in English | MEDLINE | ID: mdl-15846417

ABSTRACT

Photophysical studies of a newly synthesized fused subphthalocyanine dimer-C60 revealed a complex cascade of energy transfer events to succeed the initial SubPc dimer photoexcitation.


Subject(s)
Boron Compounds/chemical synthesis , Fullerenes/chemistry , Indoles/chemistry , Boron Compounds/chemistry , Dimerization , Isoindoles , Molecular Structure , Photochemistry
17.
J Phys Chem B ; 109(9): 3800-6, 2005 Mar 10.
Article in English | MEDLINE | ID: mdl-16851428

ABSTRACT

Second order nonlinear optical properties of a series of trinitrosubphthalocyanine (SubPc) isomers were studied experimentally by electric field induced second harmonic (EFISH) generation and hyper Rayleigh scattering (HRS). These experimental values were compared to the ones obtained theoretically employing both sum over states (SOS) and finite field (FF) methods. From these studies, it was shown that the dipolar contributions to the beta tensor are very much dependent on the substitution pattern at the periphery of the subphthalocyanine macrocycle, whereas the octupolar contributions remain mostly unchanged. Consequently, it was deduced that SubPc is extremely well suited for the decoupling of octupolar and dipolar contribution to the NLO response.

18.
Chem Commun (Camb) ; (11): 1298-9, 2004 Jun 07.
Article in English | MEDLINE | ID: mdl-15154045
19.
J Am Chem Soc ; 124(49): 14522-3, 2002 Dec 11.
Article in English | MEDLINE | ID: mdl-12465947

ABSTRACT

A tris(3-pyridyl)-substituted C3 symmetric subphthalocyanine (SubPc) was dimerized into a M3L2 cage in the presence of a stoichiometric amount of (en)Pd(NO3)2. NMR studies demonstrated the recognition event to be accompanied by chiral self-discrimination between the two enantiomers of the SubPc. Moreover, the specificity is such that only one of four possible isomers was detected in solution.

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