C. zyxwvutsrqpon A. Muedas, D. Sulzle, H. Schwarz 1517 Kurzmitteilung zyxwvu / Short Communication Mass-Spectrometric Characterization of Isomeric NNCCN and NCNCN Ions and Neutrals Cksar A. Muedas, Detlev Sulzle'*', and Helmut Schwarz* Institut fur Organische Chemie der Technischen Universitat Berlin, StraBe des 17. Juni 135, W-1000 Berlin 12, F.R.G. Received March 30, 1992 Key Words: Interstellar chemistry / Heterocumulenes / Charge-reversal mass spectrometry / Neutralization-reionization mass spectrometry / Collisional activation Neutralization-reionization mass spectrometry as well as ions of CzN3 Loss of Nz to generate C,N+ is the critical dis- charge reversal and collisional activation experiments serve criminant, and the assignment is further substantiated by sub- to distinguish and assign the connectivities NNCCN and jecting these fragment ions to collisional activation experi- NCNCN to isomeric pairs of anions, neutral radicals and cat- ments by using tandem-mass spectrometry facilities. Recent work in our laboratory has dealt with the study of cu- mulenes of cosmochemical and theoretical relevance"]. Particularly challenging is the prospect of distinguishing isomeric structures in heteroatom-containing species. The use of tandem-mass spectro- metry is once again utilized in this report for the characterization of two isomers of C2N3, namely NNCCN and NCNCN as such neutrals and their corresponding cations and anions in the gas phase. Results and Discussion Scheme 1 depicts our approach to the generation of two isomers of C2N3in our tandem mass spectrometer. The formation of di- Scheme 1 CH,CN zyxwvuts 0- -HO. 1 CH2CN N20 1 -H20 H2N\ FNH 'CN HN [*I Present address: Schering AG, Postfach 6503 11, W-1000 Berlin 65. F.R.G. NC' C" CC" NN" zyx d z T - mlz NCNCN' / 2+ - mlz Figure 1. CR mass spectra oE a) C2Nc from deprotonation and diazotization of CH3CN, b) C2N3 from deprotonation and deam- ination of cyanoguanidine zyx Chem. Ber. 1992, zyxwvutsrq 125, 1517 - 1520 zyxwvuts 0 VCH Verlagsgesellschaft mbH, D-6940 Weinheim, 1992 0009 - 2940/92/0606- 1517 ! $ 3.50 + .25/0