First evidence of formation of stable DBU Zn-phthalocyanine complexes: synthesis and characterization

Abstract

Novel Zn (II) phthalocyanine and naphthalocyanine DBU complexes have been prepared in a one-pot synthesis reacting phthalonitrile precursors with an excess of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). For the first time, it has been well evidenced that DBU played the role of coordinating axial ligand together with the well known role of strong base. Also, DBU complexes showed better solubility in organic solvents due to the coordination of the bulky axial DBU ligand, compared to the Zn (II) phthalocyanines and naphthalocyanines without coordinated DBU. The coordinating properties of DBU toward ZnPcs (DBU free) complexes have also been investigated along with the ZnPc (pyridine) complex. Thermal analysis results reflecting the stability of the synthesized complexes under air are also presented.

Sustainable Approaches to the Synthesis of Metallophthalocyanines in Solution

“…From the perspective of green chemistry, the atom economy, namely, the amount of atoms of the reagents that are retained in the final products, of the “phthalonitrile route” is consistently higher than that of the “phthalic anhydride route”. Nevertheless, it still often requires an organic base, commonly 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), to catalyze the reagent tetramerization and reaction media such as alkyl alcohols (pentanol, hexanol), dimethylaminoethanol (DMAE) nitrobenzene, chlorobenzene, quinoline and α-chloronaphthalene [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], most of which are non-environmentally friendly. Given their extreme technological importance, many unconventional synthetic approaches have been studied and developed in parallel with their applications to increase their yields and sustainability while reducing their production cost, such as (i) microwave-assisted [ 22 ] and UV-assisted [ 23 , 24 ] processes, which are usually much faster and cleaner than their “standard” counterparts but requiring specific instrumentation and lacking scalability, and (ii) room-temperature reactions promoted by strong organic bases such as lithium diisopropylamide (LDA) [ 25 ] and pre-formed lithium alcoholate solutions [ 26 ].…”

Facile Access to CO2‐Sourced Polythiocarbonate Dynamic Networks And Their Potential As Solid‐State Electrolytes For Lithium Metal Batteries

“…However, adding this salt to the previously described solvent‐free formulation inhibited the crosslinking reaction. This was certainly due to strong binding of a high amount of lithium metal to DBU, known to be a good ligand for metal complex catalyzed reactions [42,43] . To solve this issue, we took advantage of the reprocessing ability of PN to prepare the SPE membranes through a facile protocol.…”

“…This was certainly due to strong binding of a high amount of lithium metal to DBU, known to be a good ligand for metal complex catalyzed reactions. [42,43] To solve this issue, we took advantage of the reprocessing ability of PN to prepare the SPE membranes through a facile protocol. The polymer was first reprocessed by hot pressing at 70 °C for 10 min to the desired shape and precise thickness.…”

1,8-Diazabicyclo[5.4.0]undec-7-en-8-ium bromido(phthalocyaninato)zincate

“…Crystals of 1 were obtained by heating of complex ZnPc-DBU, well characterized in literature (Del Sole et al 2005, Janczak et al, 2011, with n-pentanothiol slightly acidified with HBr under solvothermal conditions (evacuated glass elongated ampoule, 130 °C, 5 days). Elemental analysis of the ionic (ZnPcBr -)(DBUH + ) crystals was performed with energy dispersive spectroscopy (EDS) as well as with a Perkin-Elmer 2400 elemental analyser.…”