2‐Acetylindan‐1,3‐dione and its Cu²⁺ and Zn²⁺ complexes as promising sunscreen agents

Abstract

In continuation of a previous spectroscopic and quantum chemical study on 2-acetylindan-1,3-dione (2AID), the spectral properties and photostability of 2AID and its Cu(2+) and Zn(2+) complexes in different solvents are reported. Comparison is made with the photostability of two commercially available sunscreens: benzophenone-3 and octylmethoxycinnamate. 2AID exhibits a higher photostability, high molar absorption coefficient (42 000 m(-1) cm(-1)) at lambda(max) and broad-spectrum UV-protection properties. The hypothesis that the strong intramolecular H-bonding is responsible for the higher photostability was confirmed by studying the photodegradation upon irradiation with UV light of 2AID in hydrogen bond-breaking solvent, DMSO. The data obtained show that 2AID undergoes rapid degradation in this solvent. It is found that Cu(2+) and Zn(2+)-2AID complexes show higher photostability in DMSO than 2AID itself.

A Mössbauer study on iron(II) complex of 2-acetyl-1,3-indandione ⎼ spin-crossover or structural changes

“…This phenomenon was supposed to explain also the high photostability of the compound -another interesting feature that has been observed [2]. High photostability was obtained for Cu(II) and Zn(II) metal complexes of 2AID even in hydrogen-bond breaking solvents in which the free ligand loses its photostability.…”

“…On the other hand, 2AID was suggested as an extracting and spectrophotometric agent for isolation and detection of Fe 3+ ions [3,4] and the formed complex has been characterized by optical methods. Challenged by the optical and complexation properties of 2AID we have studied a series of its metal complexes [2,5,6] by means of spectroscopic and theoretical methods as well as of its derivatives [7][8][9]. X-ray structures of metal complexes of 2AID were reported for the Co(II) [6] and the Fe(III) [5] complexes along with detailed magnetochemical, Mössbauer and EPR data.…”

Experimental and theoretical study on the structure and optical properties of 2-acyl-1,3-indandiones – Conformational effects

“…The suggested fast and reversible tautomerization of 2AID gave the first clue that it should be photostable upon irradiation with UV-light. Later this has been experimentally proven, showing that 2AID and its metal complexes with Zn(II) and Cu(II) are even more photostable than some commercially available sunscreens, and therefore were proposed as promising sunscreen agents [12]. Of these reasons we have recently undertaken a detailed study of the structural, optical and complexation properties of 2AID derivatives in which the methyl group is substituted by extended p-conjugated system, i.e., 2-cinnamoyl-1,3-indandione (compound 1 in Fig.…”

Synthesis, characterization and spectroscopic properties of some 2-substituted 1,3-indandiones and their metal complexes

“…On the other hand, 2-acyl derivatives of 1,3-indandione possess intramolecular hydrogen bonds, thus allowing tautomerization via an intramolecular proton transfer process. There are several experimental and theoretical studies on the tautomerization of 2-substituted 1,3-indandiones [33,34] and their photostabilty [35].…”