Laser desorption fourier transform mass spectrometric study of porphyrins attached to hydrocarbon spacers

✍ Scribed by Michael Antolovich; T. Hiep Nguyen; Michael N. Paddon-Row; Gary D. Willett

• Book ID: 102964779
• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 650 KB
• Volume: 27
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210271013

✦ Synopsis

The 248 nm laser desorption Fourier transform ion cyclotron resonance positive-and negative-ion mass spectra are presented for two novel porphyri-pacer-quinone bichromophoric systems in which the spacer consists of a polynorbornyl-type hydrocarbon and also for a model tetraphenylporphyrin compound. The compounds are 1,2,3,4tetrahydro-1,4-methano-7,lO,l3,lfj-tetraphenylbenzo 1g j quinoxalinoI 2,341 porphyrin, 5,20-dihydro-5,20-methano-1,4-dimethoxy-8,11,14,17-tetraphenylnaphtho ( 2,3-g] quinoxalino ( 2,3-b 1 porphyrin and 5,10,15,20-tetraphenylporphyrin. The two-step laser desorption mukiRhoton ionization mass spectra recorded at laser powers < 2 MW cm-' produce only the parent ions M+' and M-*. At increased laser powers of up to 5 MW em-' the ( M + HI+ and IM -HIions are observed to increase significantly in relative abundance. At laser powers > 8 MW cm-' the porphyrins show extensive photodissociation and rearrangement and, in one case, the production of an extensive distribution of carbon cluster fragment ions including the fullerene [C,, 1 +*.