Exploring the Synthesis and Electronic Properties of Axially Substituted Boron Subphthalocyanines with Carbon‐Based Functional Groups. Issue 36 (13th July 2020)

• Record Type: Journal Article
• Authors: Bukuroshi, Esmeralda; Petersen, Anne Ugleholdt; Broløs, Line; Bender, Timothy P.; Nielsen, Mogens Brøndsted
• Is Part Of: European journal of inorganic chemistry. Issue 36(2020)
• Page Start: 3481
• Page End: 3495
• Publication Date: 2020-07-13
• Subjects: Alkynes -- Boron -- Cross‐coupling -- Cyclic voltammetry -- Macrocycles; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.202000525
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : With peripheral fluorination and chlorination known to significantly influence the solubility, fluorescence quantum yield and redox properties of boron subphthalocyanines (BsubPcs), it is the intent of this study to further expand a matrix of BsubPcs to correlate structural changes to properties. Here, we have adapted previous synthetic methodologies for accessing axially substituted BsubPcs with a variety of alkyne substituents along with incorporating various peripheral halogens. While axial substitution of BsubPcs results in minimal shifts of longest‐wavelength absorptions, relative fluorescence quantum yields decrease with the increasing number of axial carbon–carbon triple bonds. Cyclic voltammetry studies reveal that BsubPcs can form a radical anion more easily with each additional carbon–carbon triple bond, the most significant change happening when going from one to two triple bonds. Also, the reduction profile is influenced by peripheral halogenation as well as by the radical‐stabilizing ability of an axial arylethynyl group. In all, axial alkyne‐based substituents have influential impact on the characteristics of BsubPcs. Abstract : A selection of halogenated boron subphthalocyanines (BsubPcs) with axial oliogyne groups was prepared by acetylenic coupling reactions. The length of the oligoyne and nature of its end‐group plays a significant role on the redox properties, in particular in regard to the first reduction generating the radical anion species. The ability of the axial group to stabilize a radical on the boron atom seems to determine how easily the BsubPc is reduced.