Selective synthesis and spectroscopic properties of alkyl-substituted lanthanide(III) mono-, di-, and triphthalocyanines

Abstract

Methods for the selective synthesis of mono ( R PcLnOAc), di ( R Pc 2 Ln), and triphthalo cyanines ( R Pc 3 Ln 2 ) of rare earth metals (Ln = Lu, Er, Eu) from symmetrically substituted 2, 3,9,10,16,17,23,24 octaalkylphthalocyanines R PcH 2 (R = Et, Bu) were developed. The syn thesized complexes were characterized by NMR spectroscopy, mass spectrometry, and elec tronic absorption spectra. The conditions for 1 H NMR spectra recording were optimized. Regularities in changing the spectral properties of the synthesized compounds, depending on the lanthanide nature and the planarity of metal phthalocyanine complexes, were found.Rare earth metals (REM) have high coordination numbers and, hence, can form complexes of different compositions with phthalocyanines. 1-3 The unique physi cochemical properties of these complexes provide wide potentialities for their use in different fields of science and technology. 4-8 Accessibility of the phthalocyanine com plexes is a determining factor for practical use. However, their synthesis often produces a mixture of compounds, which impedes isolation and decreases the yields of target products. Therefore, the development of selective meth ods for the synthesis of lanthanide mono , di , and triphthalocyanines and studies of their structure and prop erties are of great significance.In this work, we studied conditions for the directed synthesis of several symmetric alkyl substituted mono , di , and triphthalocyanine complexes of REM and deter mined their spectral characteristics. The use of free ph thalocyanines as the starting compounds was shown to be more efficient than the use of the corresponding phthalo dinitriles, 9 because the reaction time is shortened sub stantially, isolation and purification become simpler, and, in most cases, the yield of target products increases. Results and DiscussionEthyl and butyl substituted phthalocyanines 1 and 2 were used as phthalocyanine ligands. Earlier, these com pounds were obtained in 21 and 38% yields, respec tively, by the reflux of diethyldiiminoisoindoline in N,N dimethylaminoethanol 10 or dibutylphthalodinitrile in n pentanol in the presence of metallic sodium. 11 It turned out that the reflux of solutions of 4,5 diethyl or 4,5 dibutylphthalodinitriles in isoamyl alcohol in the pres ence of lithium methoxide affords phthalocyanines 1 and 2 in 62-64% yields (Scheme 1). Scheme 1 R = Et (1), Bu (2) Reagents and conditions: i. C 5 H 11 i OH, MeOLi, 130 °С, 5-6 h.Monophthalocyanine complexes 3 and 4 were synthe sized under the conditions similar to the preparation of the tetracrown substituted lanthanide complexes. 12 The * Dedicated to Academician A. L. Buchachenko on the occa sion of his 70th birthday.

A3B‐Type Phthalocyanine‐Based Homoleptic Lanthanide(III) Double‐Decker π‐Radical Complexes Bearing Functional Hydroxy Groups: Synthetic Approach, Spectral Properties and Electrochemical Study

“…The reaction of BnO,Bu PcH 2 with Ln(acac) 3 ·nH 2 O (Ln = Eu, Lu) in n-hexadecanol, a method that is similar to a procedure developed earlier in our group [11] for the synthesis of lanthanide(III) complexes based on symmetrical 2,3,9,10,16,17,23,24-octabutylphthalocyanine ( Bu PcH 2 ), led to the selective formation of double-decker complexes 1a and 1b. An important feature of the synthesis technique reported herein concerns the synthesis of europium complex 1a, which was prepared by heating the starting reagents at 180°C in the presence of lithium methoxide (Scheme 1, pathway A) instead of DBU that was required for the synthetic procedure reported in ref.…”

“…An important feature of the synthesis technique reported herein concerns the synthesis of europium complex 1a, which was prepared by heating the starting reagents at 180°C in the presence of lithium methoxide (Scheme 1, pathway A) instead of DBU that was required for the synthetic procedure reported in ref. [11] This allowed the reaction time to be decreased from 2-3 h to 20 min, while also generating a higher yield of the target compound. These advantages that result from the use of lithium methoxide in the synthetic procedure instead of DBU may derive from the noncoordinating nature of the lithium methoxide: the tendency of DBU to form coordinating bonds with the lanthanide ion of the intermediate half-sandwich mono-(phthalocyanine) compound [12] should create steric hindrance at the metal centre that prevents further complexation.…”

Synthesis and Study of Physicochemical Properties of New Substituted Tetrathieno[2,3-b]porphyrazines

“…Perhaps, this is due to the low stability of π-radical thienoporphyrazine structures. Even the standard synthetic route (Lu acetylacetonate; lithium methoxide; 190ºC; n-octanol) [13] did not yield double-decker complex. Novel porphyrazines 2-6 were characterized by high resolution MALDI-TOF mass spectrometry, UV-Vis and 1 H NMR spectroscopy.…”

“…Similar features have been previously reported for triple-decker phthalocyanine complexes [16,17] and are due to the interaction of the inner and external deck. [13] The spectra of porphyrazines 2-5 in a non-coordinating solvent (C 6 H 6 ) exhibit aggregation behaviour that is (Table 1). Due to the steric effect of external decks the aggregation was minimal in the case of the triple-decker compound 6.…”

Sandwich-Type Lanthanide(III) Dinaphthalocyanine Complexes Possessing an Intensive Absorption in the Near IR Region: Synthesis and Investigation of Properties

“…This method considerably differs from the synthesis in solution [11][12][13] since the starting nitrile serves simultaneously as the reagent and the reaction medium. According to this method, the synthesis of dinaphthalocyanines 2-4 was performed by melting of a mixture of dinitrile 1 with the corresponding lanthanide acetates by the gradual increase of temperature from 220 to 310 °C and by keeping at this temperature until the reaction mixture was solidified (~2 h).…”