One‐Component Thioxanthone Acetic Acid Derivative Photoinitiator for Free Radical Polymerization

Abstract

Acetic acid-based thioxanthone (TXCH2 COOH) was synthesized and characterized and used as a photoinitiator for free radical photopolymerization of methyl methacrylate (MMA) in the absence and presence of a tertiary amine (MDEA) in different solvents. Different absorption properties were observed depending on the solvent. Fluorescence and phosphorescence experiments were also carried out successfully. The fluorescence quantum yield was found to be 0.09 and the phosphorescence lifetime was calculated as 138 ms at 77 K. The photoinitiator undergoes efficient intersystem crossing into the triplet state and the lowest triplet state possesses π-π* configuration. Laser flash photolysis experiments show that transient absorption of TXCH2 COOH is similar to the parent thioxanthone and the triplet lifetime was calculated as 2.3 μs at 630 nm.

Efficient Benzodioxole‐based unimolecular photoinitiators: From synthesis to photopolymerization under UV‐A and visible LED light irradiation

“…For comparison, 2‐thioxanthone‐thioacetic acid (TXS) and 2‐thioxanthone‐acetic acid (TXCH 2 COOH), two highly efficient unimolecular Type II photoinitiators in literature based on photodecarboxylation mechanism, were also synthesized according to Yagci et al . without modification …”

“…The very low φ f of ITX ensure high quantum yields of inter system crossing (ISC). The efficient ISC combined with long triplet lifetime makes thioxanthone attractive as Type II photoinitiator . Thioxanthone derivative with an electron drawing spacer as in TXC exhibited nearly identical φ f to ITX, with the value of 2.95 × 10 −2 .…”

Studies of the binding mode of TXNHCH 2 COOH with calf thymus DNA by spectroscopic methods

“…TXNHCH 2 COOH (2-(9-oxo-9H-thioxanthen-2ylamino) acetic acid) was synthesized as reported in the literature [49,50].…”

“…Several thioxanthone derivatives e.g. mercapto [15], acetic acid [16][17][18][19], anthracene [20][21][22] and polymeric [23][24][25][26], visible [27][28][29][30] and water soluble [23,31,32] ones were synthesized and used as photoinitiator for various formulations. Some of these inititators are widely used for printing inks, food packaging and coatings and the electronics industry.…”

Thioxanthone acetic acid ammonium salts: highly efficient photobase generators based on photodecarboxylation

“…23 In order to detect the generated CO 2 of the PBGs, a methanol solution of TX-TBD (2.4×10 -2 M) was placed in a sealed bottle which was connected to anther bottle containing an aqueous solution of Na 2 CO 3 (1.8×10 -4 M) and phenolphthalein (2.1×10 -4 M) (Fig. 6a).…”