The influence of phenylated by-products on the MALDI analysis of chlorinated fullerenes

Seven‐Minute Synthesis of Pure Cs‐C60Cl6 from [60]Fullerene and Iodine Monochloride: First IR, Raman, and Mass Spectra of 99 mol % C60Cl6

“…[14] In 2003 we attempted to use S 8 -MALDI mass spectrometry to analyze chloro[60]fullerenes prepared by using entirely different procedures. [13] Although no positive ions containing chlorine atoms were observed by using sulfur as the MALDI matrix, samples of C 60 Cl 6 that had been prepared by using benzene as the solvent gave S 8 -MALDI mass spectra with C 60 + , C 60 Ph + , and C 60 Ph 2 + fragments while samples of C 60 Cl 6 prepared without the use of aromatic hydrocarbon solvents gave spectra with only the C 60 + fragment ion observed. There was no longer any doubt that C 60 Cl 6 was not as pure as had been assumed and that benzene was not a suitable solvent for its preparation.…”

“…The reported purity and yield of C 60 Cl 6 prepared by using the three reported syntheses that we have repeated were based on elemental analysis and IR and/or 13 C NMR spectroscopy. [5,12,20] However, elemental analysis only gives the average composition of a sample, IR spectroscopy is probably not sensitive enough to detect, for example, 10 % C 60 Cl 12 in a sample of C 60 Cl 6 , and 13 C NMR spectra of natural abundance, low-symmetry fullerene derivatives generally have such low signal-to-noise ratios that their value as an analytical tool is severely limited.…”

“…Nevertheless, after nearly 15 years the compositional purity of C 60 Cl 6 , which has always been assumed to be high, [5,11,12] has never been satisfactorily demonstrated (i.e., none of the three previous reports of its synthesis properly established its purity [5,11,12] ). In fact, recent work by us [13] and others [14] suggests that it may be only about 75 % pure. The facile transformation of fullerene CÀCl bonds into C À R or C À Ar bonds by Olah and co-workers in 1991 suggested that chlorofullerenes could be useful synthons.…”

“…[3,4] As far as chloro [60]fullerenes are concerned, the situation is paradoxical. Although chlorination was one of the first C 60 derivatizations reported in the literature, revealing the formation of C 60 Cl 6 [5] and putative C 60 Cl n compounds with up to 24 chlorine atoms s-bonded to the C 60 cage, [6,7] structurally-characterized compounds such as T h -C 60 Cl 24 , [8] C 1 -C 60 Cl 28 , [9] C 2 -C 60 Cl 30 , [9] and D 3d -C 60 Cl 30 [10] have only been reported in the past few months (the compound C 60 Cl 6 is believed to have the same structure as C s -C 60 Br 6 based on its 13 C NMR spectrum [5] ). Nevertheless, after nearly 15 years the compositional purity of C 60 Cl 6 , which has always been assumed to be high, [5,11,12] has never been satisfactorily demonstrated (i.e., none of the three previous reports of its synthesis properly established its purity [5,11,12] ).…”

Perchloropyracylene and its Fusion with C60 by Chlorine‐Assisted Radio‐Frequency Furnace Synthesis

“…Such a kind of fragmentation is a phenomenon well known for fulleA C H T U N G T R E N N U N G rene derivatives. [60][61][62][63][64] The perchlorinated pyracylene (C 14 Cl 8 ) is attached to the [6,6] bond of C 60 through a formal [2+2] addition resulting in a strained cyclobutane ring. The lengths of both the sp 3 -sp 3 [6,6] carbon bond (1.601 (9) ) and the four neighboring sp 2 -sp 3 [5,6] carbon bonds (1.518 (7) ) of the C 60 fragment are similar to the corresponding bond lengths of C 60 DielsAlder adducts (d 6:6 = 1.602(4), [65] 1.62(4) ; [66] d 5:6 = 1.529(4), [65] 1.52(4) [66] ) and the C 60 fullerene dimer (d 6:6 = www.chemeurj.org 1.581 (7); [67] d 5:6 = 1.530(8) [67] ).…”