Structures and Other Properties of Polyynes and their Isomers: Theoretical and Experimental Results - Polyynes: Synthesis, Properties, and Applications - page 379

TABLE 17.16
Fundamental Vibrational Frequencies of the Remaining C 4 H 2 Isomers
(All This Work)

Isomer F1 F2 F3 F4 F5 F6 F7 F8 F9 F10 F11 F12

4O2(s) 3213 3135 2163 1745 1386 963 925 769 513 419 204 155

- [5.3]R [27]R [770]R [2.2]R [18]R [6.4]R [0.1]R [81]R [0]R [0.9]R [0.2]R [3.5]R

4O3(s) 3465 2930 2230 1768 1007 883 663 631 584 364 315 99.7

- [68]R [38]R [2.8]R [46]R [0.9]R [3.6]R [44]R [5.5]R [53]R [11]R [9.3]R [18]R

4O4(s) 3087 3083 1758 1669 1119 949 942 722 618 224 181 167

- [45] [0]R [0]R [90] [0]R [12] [0]R [0]R [56] [0]R [22] [51]

4C1(s) 3239 3150 1780 1489 1382 980 960 794 509 429 387 251

- [2.4]R [13]R [86]R [2.8]R [7.3]R [1.3]R [14]R [70]R [22]R [2.3]R [1.1]R [6.0]R

4C2(s) 3183 3106 1530 1505 1229 1119 1065 1018 965 952 494 435

- [0.6]R [6.9]R [31]R [9.6]R [3.6]R [10]R [2.5]R [0]R [4.6]R [9.2]R [72]R [0]R

4C4(s) 3205 3198 1353 1335 1175 1057 1018 996 943 696 615 609

- [0.3]R [0.3] [43] [1.2]R [1.0] [0]R [35]R [21] [2.3] [0.6] [11] [0]R

4C5(s) 3228 3212 1412 1288 1248 1044 1033 920 791 613 559 536

- [0]R [0.1]R [0.2]R [2.5]R [17]R [2.8]R [7.9]R [53]R [41]R [2.5]R [0.1]R [29]R

4C6(s) 3193 3100 1831 1460 1166 1036 965 890 812 676 220 10.7

- [0.1]R [0.6]R [322]R [5.9]R [19]R [15]R [0.7]R [28]R [8.0]R [80]R [11]R [20]R

17.4.4 E LECTRONIC S PECTRA

Selections of bands from reported UV spectra are listed in Table 17.17 .

The UV spectrum of 4O1(s) was measured as early as 1935 in which the
following progressions (in cm 1 ) in the vibronic spectrum of 4O1(s): 2132,
2114, 2105, 2102, 2092, 2084, 2080, 2073, 2067, 2065, 2061, 2057, and 2035
were reported [100]. Woo and Chu [101] determined a total of 460 bands of
4O1(s) from 263.32 to 297.00 nm. Because of this large number, the reader is
referred to the original publication. Eastmond et al. [102] have determined
l max values for the triethylsylidyne-endcapped derivative in methanol and
hexane. Their results are very useful for HPLC work because they have
also determined molar absorption coefficients. Kloster-Jensen et al. [103]
reported 130 bands between 121.9 and 275.7 nm. Okabe [104] reported 28
bands between 121.1 and 172.7 nm. Chang and Graham [94] studied the
vibrational structures of the band systems at 246.6 and 247.0 nm in an Ar
matrix at 9K. From the results they deduced fundamental vibrational
frequencies of 2187, 874, 627, and 482 cm 1 . Fahr and Nayak [105] deter-
mined the UV absorption spectrum of 4O1(s) from 160 to 260 nm in interv-
als of 0.2 nm at seven different temperatures, but have tabulated selected
absorption cross sections at 5 nm intervals only. The cross sections listed in
the table are not at wavelengths of absorption maxima. The strongest