Synthesis and Antimicrobial Activity of New Phthalocyanine Complexes and Electrochemical and Spectroelectrochemical Behaviour of Cobaltphthalocyanine

A novel phthalocyanine bearing oxygen donor atoms on the peripheral positions has been synthesised by cyclotetramerisation of ( E)-4-(4-cinnamoylphenoxy) phthalonitrile and its nickel, zinc, cobalt, copper and lead derivatives prepared. The thermal stabilities of the phthalocyanine compounds have been determined and their possible biological activities (antibacterial, anticandidal and antifungal) studied. The effects of substituent on the electrochemical and in situ spectroelectrochemical behaviour of cobaltphthalocyanine have been investigated and an in situ electrocolorimetric method was applied to investigate the colour of the electrogenerated anionic and cationic forms of the complex.

Electrochemical and Adsorption Properties of Novel Phthalocyanines with Four 16-Membered Diazadithia Macrocycles

Cyclic voltammetric measurements of Cu (II) and Ni (II) phthalocyanines with four 16-membered diazadithia macrocycles (1 and 2) and pentanuclear Ni (II) phthalocyanine bearing four Cu (II) ions in diazadithia macrocycles at the peripheral positions (3) have been carried out on platinum in DMSO and in aqueous medium 3 showed strong adsorption properties in DMSO and especially in aqueous medium, possibly as a result of the interaction between the copper ions in the four macrocycles and the platinum working electrode. Interestingly, the oxidation peak of 3 was split into two waves in aqueous medium. This behaviour is discussed in terms of disaggregation of the mixed valence species produced by the oxidation of aggregated species. A mechanism for both the oxidation of the complex and the splitting of the oxidation peak into two waves is suggested.

Synthesis and characterization of novel metal-free and metallophthalocyanines peripherally fused to four 24-membered tetraoxatetraaza macrocycles

New metal-free 5 and metallophthalocyanines 6-11( M = Cu , Ni , Co , Pb , Zn ) fused in peripheral positions with four 24-membered tetraoxatetraaza macrocycles were prepared by cyclotetramerization of 24,25-dicyano-4,10,13,17-tetra(toluene-p-sulfonyl)-1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22-didicontinehydrobenzo[y][3,9,12,18]tetraaza[1,7,16,22]tetraoxatetradicontine in the presence of the corresponding metal salt or a strong organic base. While the N-tosylated derivatives of the phthalocyanines are soluble in common organic solvents, the detosylated derivative of copper phthalocyaninate is soluble in water. The aggregation properties of the phthalocyanines were also investigated as a function of concentration, solvent and oxidative medium. The new compounds are characterized by a combination of elemental analysis and 1 H NMR, 13 C NMR, IR, UV-vis and MS spectral data.

Synthesis and Properties of Copper(II) Phthalocyanines with Monoazacrown and Crown Ethers as Peripheral Substituents

Soluble and less soluble phthalocyaninatocopper(II) derivatives (4a and 4b) were prepared from the corresponding 7-[(4′-benzo-15-crown-5)oyl]-15, 16-dibromo-2,3,6,7,8,9,11,12-octahydro-5H-benzo[e]-[1,4,10,13,7] tetraoxaazacyclopentadecine (3a) and 7-(2′-tosylaminoethyl)-15, 16-dibromo-2,3,6,7,8,9,11, 12-octahydro-5H-benzo[e]-[1,4,10,13,7] tetraoxaazacyclopentadecine (3b) and CuCN in pyridine. A less soluble novel multifunctionalized scorpiand macrocycle-substituted phthalocyanine (4c) in which an NH 2 CH 2 CH 2— chain is appended to a monoazacrown ether ring was obtained by detosylation of 4b with concentrated sulfuric acid.

Synthesis, characterization and ESR spectroscopy of novel s-triazine bearing three oxygen-linked lutetium bisphthalocyanine sandwich complexes

The conversion of compound 1 [2,4,6-tris(2-oxaphthalonitrile)-s-triazine] into its isoindoline derivative of 2,4,6-tris[2-oxa(1,3-hexaimino isoindoline)]-s-triazine 2 was accomplished by bubbling ammonia gas through a solution in methanol in the presence of sodium methoxide. The cyclization of two different isoindoline derivatives namely, compound 2 and 4,5-bis(hexylthio)-1,2-diimino-isoindoline 3 with lutetium(III) acetate, [ Lu ( OAc )3] in refluxed DMF by the method of statistically mixed condensation gave trimeric trilutetium phthalocyanine [( LuOAc )3( Pc )3]4. [ Lu 3( Pc )6]5 has been synthesized in situ by the reaction of phthalocyanine 4 and three equivalents of dilithium octakis-hexylsulfanyl phthalocyanine in amyl alcohol.

Peripheral substitution of a near-IR-absorbing soluble phthalocyanine using "click" chemistry

A series of near-IR-absorbing soluble phthalocyanines (Pcs) with eight alkyne moieties as side chains of the chromophore have been synthesized. One of these Pcs has been used as a scaffold for functional group modification using alkyne-azide click chemistry with various azides. This led to a small library of Pcs with photo and thermal crosslinkable, dendritic, and hydrophilic moieties starting from a single Pc molecule. A patterned thin film was fabricated by photocrosslinking one of these Pc derivatives.

In Situ Monitoring of the Synthesis of a Pyranine-Substituted Phthalonitrile Derivative via the Steady-State Fluorescence Technique

A new approach based on fluorescence quenching of a chromophore, pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, trisodium salt, POH), was established for monitoring the synthesis of the pyranine-substituted phthalonitrile derivative POPht. 4-Nitrophthalonitrile binds to the POH through nitro elimination, by means of a nucleophilic aromatic substitution reaction in a basic medium, and forms phthalonitrile (Pht) bearing deprotonated POH units, Pht + POH --> POPht. This binding process results in a considerable blue shift (from 515 to 430 nm) in the fluorescence emission spectra of POH. Besides, the fluorescence intensities of unreacted pyranines and POPht molecules in the reacting mixture decrease as they are quenched by nitrite appearing as one of the byproducts. POH, therefore, acts as both an aromatic substituent for Pht and a fluorescence probe for monitoring the substitution reaction. Thus, the change in the fluorescence spectra introduces a novel method for in situ monitoring of the synthesis of the phthalonitrile derivative POPht. This new material may have a potential to synthesize the phthalocyanine having an enhanced fluorescence property and solubility in an aqua medium that would result in a desired candidate molecule in many applications of phthalocyanines.

Peripheral metal-ion binding to tris(thia-oxo crown) porphyrazines

We report the preparation and solution properties of metal-free [1b(H(2))] and cobalt [1c(Co)] porphyrazines (pz's), where three pyrroles are functionalized with a S(2)O(3) crown ether for metal-ion binding and the fourth pyrrole is appended with two long-chain alcohols (bis((11-hydroxyundecyl)thio)) for potential use as surface anchors. Compounds 1b(H(2) and 1c(Co) exhibit ion-specific optical changes in the presence of Ag(+) and Hg(2+). Binding of Ag(+) to 1b(H(2)) is described by a 1:1 binding isotherm, with K(D) approximately 147 microM, whereas binding of Hg(2+) to 1b(H(2)) appears more complex. For 1c(Co), binding of Ag(+) and Hg(2+) also can be fit to a 1:1 isotherm, with K(D) approximately 109 and 83 microM, respectively. All four titrations show nonisosbesticity, including those apparently describable by the 1:1 isotherm, which indicates that there are intermediate stages as multiple ions bind. Neither 1b(H(2)) or 1c(Co) gives optical responses to Ni(2+), Zn(2+), Pb(2+), or Cu(2+) or to alkali (Li(+), Na(+), K(+), and Cs(+)) and alkaline earth (Mg(2+), Ca(2+), and Ba(2+)) metal ions. Nonetheless, "hard" ions are sensed electrochemically: Na(+) and Li(+) strongly shift the pz/pz(-) couple of 1b(H(2)()) and Co(III)/Co(II) couple of 1c(Co). For the addition of 4 equiv of Li(+) to 1c(Co), the Co(III)/Co(II) shifts +40 mV, and for the addition of 4 equiv of Na(+) to 1c(Co), the shift is +155 mV. The shifted redox waves of 1c(Co) all retain their reversibility. In contrast, for the addition of either 4 equiv of Li(+) or Na(+) to 1b(H(2)), the shifts of the pz/pz(-) couple are essentially the same, approximately 170 mV, and the shifted redox waves become broadened and less reversible, due to ion-induced aggregation. For 1c(Co) the shape of the titration curves [M]/[1b(H(2))] versus E(1/2) is concave to the x-axis, implying cooperative binding of multiple M(+) ions as part of the redox/binding system of equilibria.