Oligomeric cyclization of dinitriles in the synthesis of phthalocyanines and related compounds: the role of the alkoxide anion

Oliver, Stuart W.; Smith, Thomas D.

doi:10.1039/p29870001579

Cited by 51 publications

(27 citation statements)

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“…These results of different distribution of the structural isomers show that in comparison to the metal phthalocyanines 5 and 6 a different kind of mechanism is operative in the formation of metal-free phthalocyanine 7. Smith and Oliver [2] and Borodkin [3] demonstrated that the initial reaction of phthalonitrile with sodium alkoxide leads to the sodium salt of 1-imido-3-alkoxyindoline I (Figure 2). If the substituted phthalonitrile 2 is treated with lithium in 2-ethylhexanol, two types of substituted precursors I a and I b could be formed (Figure 2).…”

Section: Resultsmentioning

confidence: 97%

“…They carry different positive charges on their carbon atoms ( Figure 3) and therefore the nucleophilic attack of an 2-ethylhexanolate anion at the CN groups in the 2-position in 2 would lead preferentially to the formation of isoindoline I a ( Figure 2). The next step in the reaction sequence is the nucleophilic attack of Ia to another phthalonitrile, [2] again at the 2-cyano group. A dimer is formed which can now either react with another phthalonitrile 2 in the same way to form a trimer, etc., or undergoes self-condensation.…”

Section: Resultsmentioning

confidence: 99%

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Influence of Substituents, Reaction Conditions and Central Metals on the Isomer Distributions of 1(4)-Tetrasubstituted Phthalocyanines

1999

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The 1(4)-and 2(3)-tetraalkoxy-substituted nickel (5), copper (6), and metal-free phthalocyanines 7 and 8 were synthesized from the corresponding substituted phthalonitriles 2 and 4, respectively, and the four structural isomers formed for each phthalocyanine were separated by HPLC. In the case of 1(4)-tetraalkoxy-substituted phthalocyanines, the ratio of the four isomers was found to be different from the expected statistical distribution of D 2h :C s :C 2v :C 4h 12.5:50:25:12.5. For the 1(4)-substituted metal-free phthalocyanine 7 a very high proportion of the C 4h isomer (87 %) is formed. In the case of the 1(4)-substituted metal phthalocyanines 5 and 6 the strikingly low proportion of the D 2h isomer (found: 2 ± 4 % compared to statistical distribution: 12.5 %) is interpreted by a template mechanism (given in Scheme 2) in which strong steric hindrance of the respective neighboring groups prevent the formation of the D 2h isomer. To investigate further the mechanism of formation of phthalocyanines the synthesis of 1(4)-and 2(3)-tetraalkoxy-substituted metal phthalocyanines containing chiral alkoxy groups (13 ± 17) was studied under different reaction conditions starting from the corresponding alkoxy-substituted phthalonitriles 10 and 11. In all investigated cases the chiral alkoxy groups in the starting phthalonitrile again affect the distribution of the structural isomers of the formed phthalocyanines, leading to a higher proportion of the C 4h isomer in comparison with the 1(4)-tetraalkoxysubstituted phthalocyanines with racemic alkoxy groups.

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Section: Resultsmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Influence of Substituents, Reaction Conditions and Central Metals on the Isomer Distributions of 1(4)-Tetrasubstituted Phthalocyanines

1999

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“…72,73 Direct cyclotetramerization reactions of this nitrile using a magnesium template lead to formation of a small cavity "concave" tetraazaporphyrin (Scheme 13). 69,[71][72][73] The reaction pathway for preparation of the "concave" analog of 2,3-naphthalocyanine complexes is presented in Scheme 14. It starts from dimethyltriptycene, which can be further brominated by a radical mechanism using N-bromosuccinimide to result in formation of 1,2-bis(dibromomethyl)triptycene in high yield.…”

Section: Scheme 12mentioning

confidence: 99%

“…For instance, 2,3-dicyanodibenzobarrelene can be prepared by the reaction between anthracene and dimethyl acetylenedicarboxylate followed by formation of the amide and the nitrile under standard reaction conditions. [69][70][71] The Diels-Alder reaction of anthracene with chloromaleo(fumaro)nitrile can be also used for preparation of 2,3-dicyanodibenzobarrelene. 72,73 Direct cyclotetramerization reactions of this nitrile using a magnesium template lead to formation of a small cavity "concave" tetraazaporphyrin (Scheme 13).…”

Section: Scheme 12mentioning

confidence: 99%

Synthesis of substituted phthalocyanines

Nemykin¹,

Luk’yanets²

2010

Arkivoc

155

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This review summarizes the synthetic strategies for substituted phthalonitriles and phthalocyanines. Preparation of alkyl-, aryl-, halo-, nitro-, alkoxy-, aryloxy-, alkylthio-, arylthio-, and amino-substituted phthalocyanines along with the derivatives of phthalocyanine carboxylicand sulfoacids is overviewed. Influence of the substituents on the position of Q-band in UV-vis spectra of substituted phthalocyanines is also briefly discussed.

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“…Formation of such intermediates was pioneered by Oliver and Smith at the end of the 1980s. 180 Although these authors initially suggested that AA intermediates can only be formed from phthalonitriles with electron-withdrawing groups, several years later Leznoff and co-workers proved that the reaction between 4,5-bis-(3,3-dimethyl-1-butynyl)phthalonitrile with lithium methoxide in boiling methanol could also result in the formation of the desired AA compounds 29a-d (Scheme 13A). 181 Moreover, Kobayashi and co-workers have shown that even the sterically demanding 3,6-diphenylphthalonitrile can form "half-Pc" intermediates under mild reaction conditions (Scheme 13B).…”

Section: Targeted Synthesis Of Aabb-type Asymmetric Phthalocyanines Fmentioning

confidence: 99%

Synthetic approaches to asymmetric phthalocyanines and their analogues

Nemykin¹,

Dudkin²,

Dumoulin³

et al. 2014

Arkivoc

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This review summarizes synthetic strategies for the preparation of asymmetric phthalocyanines and their analogues. Cross-condensation between two phthalonitrile components, crosscondensation between one phthalonitrile and one non-nitrile component, targeted synthesis of AABB-type compounds, the subphthalocyanine ring-expansion method, as well as postmodification approaches on pre-formed symmetric and asymmetric systems, are discussed. Methodologies for targeted preparation of specific types of asymmetric phthalocyanines and their analogues are also briefly overviewed.

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Oligomeric cyclization of dinitriles in the synthesis of phthalocyanines and related compounds: the role of the alkoxide anion

Cited by 51 publications

References 0 publications

Influence of Substituents, Reaction Conditions and Central Metals on the Isomer Distributions of 1(4)-Tetrasubstituted Phthalocyanines

Influence of Substituents, Reaction Conditions and Central Metals on the Isomer Distributions of 1(4)-Tetrasubstituted Phthalocyanines

Synthesis of substituted phthalocyanines

Synthetic approaches to asymmetric phthalocyanines and their analogues

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