Development of [CpRu(eta(6)-benzylcarbamate)]X salts as two-stage photobase generators

作者：George Stephen P; Moore Curtis E; Carpenter Alex E; Rheingold Arnold L; Blackwell James M^*; Figueroa Joshua S

来源：Inorganica Chimica Acta, 2014, 422: 146-151.

DOI：10.1016/j.ica.2014.06.033

• Lithography
• Photobase generators
• Arene-complexation
• Photolysis
• Ruthenium

In order to develop a new class of transition-metal-based, two-stage photobase generators (PBGs), the synthesis, structural characterization, spectroscopic properties and base-generation ability of a series of [CpRu(eta(6)-benzylcarbamate)]X salts (X = [PF6], [O3SCF3]) are reported. Treatment of [CpRu(NCMe)(3)] PF6 with the N,N-dialkylcarbamate PBGs 2-nitrophenylmethyl N,N-dicyclohexylcarbamate (2NC), 4-nitrophnylmethyl N, N-dicyclohexylcarbamate (4NC) and 3,5-dimethoxyphenylmethyl N, N-dicycloh exylcarbamate (DMC) results in eta(6)-complexation of the arene fragment and formation of the corresponding [CpRu(eta(6)-benzylcarbamate)]PF6 salt. The [PF6] salt, [CpRu(eta(6)-DMC)]PF6, is converted to the triflate salt (triflate = [O3SCF3] = [OTf]) by treatment with Me3SiOTf. The molecular structures of the [CpRu (eta(6)-benzylcarbamate)] X salts were determined by X-ray diffraction and varied by the orientation of the carbmamate unit relative to the eta(5)-Cp ligand. Experimental UV-Vis data and Time-Dependent DFT calculations suggest that the [CpRu(eta(6)-benzylcarbamate)](+) cations possess high-energy excitations that potentially render these salts as useful two-stage PBGs. The photobase generation ability of the [CpRu(eta(6)-benzylcarbamate)]X salts at 254 nm irradiation is assessed in both acetonitrile solution and polymethacrylate thin films. The irradiation studies demonstrate that eta(6)-coordination of a benzylcarbamate PBG does not deactivate photolytic base generation.

• 出版日期2014-10-1