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Laser desorption fourier transform mass spectrometric study of porphyrins attached to hydrocarbon spacers
Author(s) -
Antolovich Michael,
Nguyen T. Hiep,
PaddonRow Michael N.,
Willett Gary D.
Publication year - 1992
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210271013
Subject(s) - fourier transform ion cyclotron resonance , porphyrin , chemistry , mass spectrum , ion , analytical chemistry (journal) , mass spectrometry , ionization , photochemistry , desorption , laser , organic chemistry , optics , physics , chromatography , adsorption
The 248 nm laser desorption Fourier transform ion cyclotron resonance positive‐ and negative‐ion mass spectra are presented for two novel porphyrin‐spacer‐quinone bichromophoric systems in which the spacer consists of a polynorbornyl‐type hydrocarbon and also for a model tetraphenylporphyrin compound. The compounds are 1,2,3,4‐tetrahydro‐1.4‐methano‐7,10,13,16‐tetraphenylbenzo [ g ] quinoxalino [2,3‐ b ] porphyrin, 5,20‐dihydro‐5,20‐methano‐l,4‐dimethoxy‐8,11,14,17‐tetrapherylnaphtho [2,3‐ g ]quinoxalino[2,3‐b] porphyrin and 5,10,15,20‐tetraphenyl‐porphyrin. The two‐step laser desorption multiphoton ionization mass spectra recorded at laser powers < 2 MW cm −2 produce only the parent ions M + ˙ and M − ˙. At increased laser powers of up to 5 MW cm −2 the [M + H] + and [M H] − ions are observed to increase significantly in relative abundance. At laser powers >8 MW cm −2 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 60 ] + ˙.