Unsymmetrical Phthalocyanines Research Articles

Synthesis of Nickel Phthalocyanines with One Aldehyde Group and Preparation of a Bisvinylene-Phenylene-Bridged Bisphthalocyanine

The synthesis and characterization of two soluble, unsymmetrical nickel phthalocyanines with one aldehyde group in the α- (10b) and β-position (10a), respectively, is reported. The β-functionalized phthalocyanine (Pc) (10a) was used in a Wittig reaction to afford the first "real" bisvinylene-phenylene-bridged bisphthalocyanine 11. The properties of the new Pcs are compared with those of the corresponding tribenzonaphthoporphyrazino (TBNP) nickel analogues 1 and 3.

1999 Alfred Bader Award Lecture From early developments in multi-step organic synthesis on solid phases to multi-nuclear phthalocyanines

Early developments in solid phase organic synthesis are traced. Particular emphasis is placed on the use of cross-linked polystyrene in the first general method of monoblocking symmetrical difunctional compounds. The monoprotected polymer-bound symmetrical starting materials were then used in multi-step syntheses of a variety of compounds, particularly insect pheromones. Asymmetric synthesis on polymer supports was demonstrated. Diels-Alder and 1,3-dipolar additions on polymer supports proceeded readily as did macrocyclic formation of porphyrins and phthalocyanines. All of these reactions clearly showed that most organic chemical reactions could be performed on solid phases and laid the basis for the development of combinatorial chemistry. The first unsymmetrical phthalocyanine was prepared using the solid phase method and this led eventually to solution phase methods of preparing bi-, tri-, tetra-, and even a dendritic-like pentanuclear phthalocyanine.Key Words: solid phase organic synthesis (SPOS), phthalocyanines.

New approach to the synthesis of phthalocyanines containing strong accepting and donating groups

The mixed condensation of 3,6-didecyloxyphthalodinitrile and 4-nitrophthalimide in the presence of copper acetate, urea and ammonium molybdate gives new unsymmetrical phthalocyanines containing both alkoxy and nitro groups.

Synthesis, Spectroscopy, and Molecular Orbital Calculations of Subazaporphyrins, Subphthalocyanines, Subnaphthalocyanines, and Compounds Derived Therefrom by Ring Expansion1

A subazaporphyrin (SubAP), tert-butylated and crowned subphthalocyanines (tBSubPc and SubCRPc), a μ-oxo dimer of tert-butylated SubPc {(tBSubPc)2O}, a subnaphthalocyanine (SubNc), and monosubstituted type unsymmetrical phthalocyanine (Pc) and naphthalocyanine (Nc) analogues have been synthesized. In particular, unsymmetrical Pc's and Nc's have been prepared in moderate yields by the ring expansion reaction of structurally distorted SubPc's and SubNc's with isoindolediimine derivatives in dimethyl sulfoxide−chloronaphthalene (or chlorobenzenes or aromatic hydrocarbons such as toluene and xylene) mixtures. The compounds have been characterized by electronic absorption, magnetic circular dichroism (MCD), fluorescence emission, and nuclear magnetic resonance spectroscopy. Both the Soret bands and Q-bands shift to longer wavelength and gain intensity in the order SubAP, SubPc, and SubNc. Fluorescence quantum yields and lifetimes generally decrease with decreasing molecular symmetry. Circular dichroism and NMR spectroscopy have revealed that a SubPc with three 15-crown-5 ether voids having a phenyl group as an axial ligand (SubCRPc) forms inclusion complexes with 2,6-dimethyl-β-cyclodextrin in acetonitrile or water−acetonitrile mixtures, while the electronic absorption spectroscopy suggests that it is not dimerized by the addition of cations such as K+, Rb+, Ce+, i.e., cations which are effective in dimerizing Pc's with 15-crown-5 ether voids. Molecular orbital (MO) calculations within the framework of the Pariser−Parr−Pople approximation have succeeded in reproducing the optical absorption experimental data of not only the parent subazamacrocycles but also Pc derivatives with lower symmetry obtained by the ring expansion reaction. The correspondence between MO calculations and experiments suggests strongly that, in the metal-free unsymmetrical Pc's, two pyrrole hydrogen atoms are bound to the nitrogens along the short axis. Comparison of formation, bonding, and donation energies between SubPc and typical Pc, i.e., MgPc by natural bond orbital analysis, suggests that the distortion energy is not the major reason for the ring expansion reactivity of SubPc, and that the lack of donor−acceptor stabilization in B−N(pyrrole) bonds destabilizes SubPc. Band deconvolution of the electronic absorption and MCD spectra of SubPc with the same set of bands (with the same centers and width) experimentally identified that the excited state of the Q-band of SubPc is orbitally degenerate, with three degenerate transitions located in the 250−450-nm region. In particular, the transition at 359 nm corresponds to a shoulder seen on the red side of the Soret band tail. Time-resolved EPR analysis has shown that the size of the π-system of SubPc is, indeed, smaller than that of Pc's.

Synthesis of Highly Unsymmetrical Phthalocyanines

The synthesis of unsymmetrical sub-phthalocyanines and their ring enlargement to yield the highly unsymmetrical phthalocyanines is reported.

Synthesis of Alkynyl-Linked Phthalocyanine Dyads: Push-Pull Homo- and Heterodimetallic Bisphthalocyaninato Complexes

Metallophthalocyanine dimers linked by butadiynyl and ethynyl bridges 3a - c and 5 a -c , respectively, have been synthesized by metal-mediated coupling methodologies. The key to the synthesis of these chromophores was the ready availability of appropriately functionalized unsymmetrical phthalocyanines 2a - c that bear a terminal ethynyl group. Following the same methodology, push - pull homo- and heterodimetallic ethynyl-bridged bisphthalocyaninato complexes 10 a - c, that contain electron-donor and electron-acceptor substituents in each of the two phthalocyanine subunits, have been also prepared.

Synthesis and Diels–Alder Reactions of Some New (Phthalocyanine)nickel Complexes

The octasubstituted (phthalocyanine)nickel complexes 4a,b, soluble in common organic solvents, bearing four dienophilic functionalities were synthesized from the corresponding phthalodinitriles 3a,b and nickel(II) acetate. Reaction of 4a with tetracyclone 5 led to the phthalocyanine–tetracyclone adduct 6 which is a precursor for an intermediate phthalocyanine 7 containing four isobenzofuran moieties. The capability of 7 to react as tetrakis(diene) was demonstrated by its reaction with naphthoquinone. Furthermore, the unsymmetrical phthalocyanines 13 and 16a,b,c containing one dienophilic functionality were synthesized using a statistical approach. Their tetracyclone adducts 17, 18a,b,c can be used for the synthesis of ladder-type phthalocyanine dimers. The dimer 22 was synthesized from 18c and p-benzoquinone via the isobenzofuran intermediate 19 and the benzoquinone adduct 21. For dehydration experiments the naphthoquinone monoadduct 23 was synthesized from 18c. Dehydration of 22 and 23 was carried out successfully with p-toluenesulfonic acid. The Diels–Alder reactions are discussed with respect to the occurring exo/endo ratio.

Synthesis of Highly Unsymmetrical Phthalocyanines

The synthesis of unsymmetrical sub-phthalocyanines and their ring enlargement to yield the highly unsymmetrical phthalocyanines is reported.

Phthalocyanine-containing polystyrenes

An unsymmetrical phthalocyanine derivative containing a single styrene unit, prepared using a mixed phthalonitrile cyclotetramerisation, can undergo free radical polymerisation to give well-defined polystyrenes in which the macrocyclic components aggregate even in dilute solution.

Synthesis of unsymmetrically substituted dodecakis(trifluoroethoxy)‐phthalocyaninato vanadyl complexes

AbstractThree novel unsymmetrical vanadyl dodecakis(2,2,2‐trifluoroethoxy)phthalocyaninates with nitro, amino or with no substitution were synthesized by a statistical condensation of 3,4,5,6‐tetrakis(2,2,2‐trifluoroethoxy)phthalonitrile with 4‐nitro, 4‐amino or 4‐unsubstituted phthalonitrile, and separated by common column chromatography. These highly soluble phthalocyanines were characterized by elemental analysis, ir and 1H‐nmr, uv‐visible and fast‐atom‐bombardment mass spectroscopy. Their uv‐visible absorption spectra in solution and in doped poly(methyl methacrylate) films showed that they were less aggregated unsymmetrical phthalocyanines.

Low Symmetrical Phthalocyanine Analogues Substituted with Three Crown Ether Voids and Their Cation-Induced Supermolecules

Unsymmetrical phthalocyanine analogues with three 15-crown-5 ether voids at the 3,4-positions (MtNIL, MtBZ, MtNAP) (Mt = Zn, Cu) have been synthesized and characterized. Their dimerization is induced by addition of some cations, particularly Rb2+ and K+. Cofacial dimer formation in the presence of these cations proceeds in a two-step three-stage process, as indicated by absorption and emission spectroscopy. These cofacial species have a highly specific C2v eclipsed configuration providing well-defined dimeric species for spectroscopic analysis. The ESR spectra of the cation-induced dimeric copper derivatives show axial symmetry and may be analyzed in terms of interplanar separation of 4.2 A. CuNAP alone forms a cofacial dimer even in the presence of Na+ or Cs+, and the estimated interplanar distances are 4.1−4.2 A without depending on the size of cations. The 1H NMR spectra of zinc dimers are consistent with a cofacial configuration. Magnetic circular dichroism (MCD) spectra of C2v type monomers can be in...

Synthesis of Novel Unsymmetrically Substituted Push-Pull Phthalocyanines

The synthesis and characterization of novel non-centrosymmetrically push-pull substituted metal-free phthalocyanines 3−9 are described. The compounds have different donor (dialkoxy, tert-butyl, methyl, p-tolylthio) and/or attractor (p-tolylsulfinyl, p-tolylsulfonyl, nitro) functional groups, are soluble in organic solvents, and are especially designed to study their second- and third-order nonlinear optical properties. Compounds 7−9 are mixtures of the four corresponding regioisomers. For preparing the unsymmetrical phthalocyanines 7−9, the effectiveness of the subphthalocyanine route, using different substituted diiminoisoindolines as reagents, has been tested. Furthermore, a comparison between this method versus the statistical one has been done. The results obtained show that the ring enlargement reaction of subphthalocyanines to obtain unsymmetrically substituted phthalocyanines is not a selective reaction but a multistep process, which depends dramatically on the nature of the substituents on the sub...

Hexakis(alkylthio)‐Substituted Unsymmetrical Phthalocyanines

Cyclotrimerization of 4,5‐bis(hexylthio)phthalodinitrile (1) in 1‐chloronaphthalene in the presence of BCl3 leads to the subphthalocyanine 4. Unsymmetrical phthalocyanines (5, 6) with six alkylthio substituents on three of the benzenoid units are synthesized by the reaction of 4 with an diiminoisoindoline derivative (R′ = H or NO2). These extremely soluble compounds are characterized by IR, 1H‐ and 13C‐NMR as well as UV/Vis spectra.

Phthalocyanine-modified silica gels and their application in the purification of unsymmetrical phthalocyanines

Five species of phthalocyanine-modified silica gels were prepared. The loadings of phthalocyanine on these silica gels were determined by acidic hydrolysis. The concept of using the aggregation phenomenon to advantage to aid chromatographic separation of unsymmetrical phthalocyanines was investigated by employing these modified silica gels as chromatographic media to purify unsymmetrical phthalocyanines. Four groups of phthalocyanine mixtures were prepared by mixed condensation. One of the desired unsymmetrical phthalocyanines was successfully purified by conventional column chromatography while others were separated by the new method described herein.

Theoretical characterization of the electronic properties of unsymmetrical phthalocyanine analogues

The electronic structure of unsymmetrical phthalocyanine-based compounds is investigated using the nonempirical valence effective Hamiltonian (VEH) method. The VEH results predict a slight but continuous destabilization of the HOMO level and a monotonous narrowing of the HOMO-LUMO energy gap as the size of the system increases. The theoretical trends are found to agree with optical absorption experimental data and show that the optical properties of phthalocyanine can be monitored by adjusting the size of the π-conjugated macrocycle.

Unsymmetrical phthalocyanines with a single macrocyclic substituent

AbstractUnsymmetrical phthalocanines (5–7) with a single macrocyclic substituent are synthesized by the reaction of the boron complex of phthalonitrile (1) with the iminoisoindoline derivatives 2–4 of macrocyclic compounds, i.e. 15‐crown‐5, monoaza‐15‐crown‐5, and tetraazacyclotetradecane. The monomacrocycle‐substituted phthalocyanines are less soluble than the tetra‐substituted one.

Preparation of unsymmetrical phthalocyanine by means of a ring expansion of subphthalocyanine

Preparation of unsymmetrical phthalocyanine by means of a ring expansion of subphthalocyanine

New route to unsymmetrical phthalocyanine analogs by the use of structurally distorted subphthalocyanines

In addition to traditional uses as dyes and in photocopying devices, phthalocyanines (Pcs) are now rapidly growing in importance in many fields such as chemical sensors, electrochromism, batteries, photodynamic cancer therapy, molecular metals, photochemical hole burning, and liquid crystals. In this communication, the authors present a completely new method for the preparation of monosubstituted type unsymmetrical Pcs and Pc analogues, which utilizes the so-called subphthalocyanines (SubPcs).

The synthesis of a soluble, unsymmetrical phthalocyanine on a polymer support

A 1% crosslinked divinylbenzene-styrene copolymer was used in the preparation of the unsymmetrical 2-(6'-hydroxyhexoxy)-9,16,23-triisopropoxyphthalocyanine, soluble in common organic solvents.