Chemistry 5.13 Problem Set 1 solutions Prof. Timothy F. Jamison 1) For C, H, O only, max IHD is observed when the number of H is zero (0). The number of O atoms will not affect the IHD, as usual. Thus, max IHD = n + 1, where n = # of C atoms. Examples include carbon dioxide (CO2), diamond (Csp3)n, graphite (Csp2)n, and buckminsterfullerene (C60), and all other fullerenes (e.g., C70, etc.) Chemical Formula: C6H6 Elemental Analysis: C, 92.26; H, 7.74 MS: 78 IR: only C-H and C=C stretches 2a) Chemical Formula: C7H8 Elemental Analysis: C, 91.25; H, 8.75 MS: 92 IR: only C-H and C=C stretches Me b) c) Me d) Chemical Formula: C2H6O Elemental Analysis: C, 52.14; H, 13.13. MS: 46 IR: ~3500 cm-1 (broad) OH Chemical Formula: C4H8O Elemental Analysis: C, 66.63; H, 11.18. MS: 72 IR: only C-H stretches O e) Me O f) CH2Cl2 g) CHCl3 h) CCl4 i) H3C C N j) Me C60 (buckminsterfullerene) Me Chemical Formula: C4H10O Elemental Analysis: C, 64.82; H, 13.60. MS: 74 IR: only C-H stretches Chemical Formula: CH2Cl2 Elemental Analysis: C, 14.14; H, 2.37; Cl, 83.49 MS: 84, 86 (approx 3:1 ratio - remember that Cl is about 3:1 35Cl : 37Cl) IR: only C-H stretches Chemical Formula: CHCl3 Elemental Analysis: C, 10.06; H, 0.84; Cl, 89.09 MS: 118, 120, 122 (approx 3 : 3 : 1 ratio) IR: only C-H Chemical Formula: CCl4 Elemental Analysis: C, 7.81; Cl, 92.19 MS: 154, 156 (base peak), 158, 160 IR: "none" (except fingerprint region) Chemical Formula: C2H3N Elemental Analysis: C, 58.51; H, 7.37; N, 34.12 MS: 41 IR: 2267 cm-1 Me Chemical Formula: C6H14 Elemental Analysis: C, 83.63; H, 16.37 MS: 86 IR: only C-H IR data in all cases exclude the Fingerprint Region (< 1500 cm-1), and values for C-H stretches need not be included. Chemistry 5.13 Problem Set 1 solutions 3) Prof. Timothy F. Jamison Fall 2006 O NH NH NH2 O 4) luminol Chemical Formula: C8H7N3O2 IHD = 8 – (7/2) + (3/2) + 1 = 7 (2 rings, 5 π-bonds) MS: 177 Elemental Analysis: C, 54.24; H, 3.98; N, 23.72. IR: 2950 to 2850 (N-H of NH2 and NH groups), 1660 (C=O) Given: • no oxygen (C+H+N = 100%) • MF: C4H9N • IHD: 4 – 9/2 + 1/2 + 1 = 1 (1 ring or 1 π-bond) NH N H Elemental Analysis: C, 67.55; H, 12.75; N, 19.69. MS: 71 IR: 2932 - probably N–H stretches Me pyrrolidine Me (S)-2-methylazetidine Me Me N H Examples include: 5) Me N H meso-2,3-dimethylaziridine (S,S)-2,3-dimethylaziridine Given: HC CH Elemental Analysis: C, 92.26; H, 7.74. • no oxygen (C+H = 100%) • Empirical formula: CH • MF: (CH)n • IHD = n – n/2 + 1 = n/2 + 1 acetylene cyclobutadiene benzene C2H2 IHD = 2 C4H4 IHD = 3 C6H6 IHD = 4 H2C C C CH2 cubane 1,2,3-butatriene (a cumulene) cyclooctatetraene dihydronaphthalene C8H8 IHD = 5 C4H4 IHD = 3 C8H8 IHD = 5 C10H10 IHD = 6