1-Hexyne infrared spectrum

Infrared spectrum, benzaldehyde, 730 butanoic acid, 771 cyclohexane., 436 cyclohexanol, 633 cyclohexanone, 730 cyclohexene. 436 cyclohexylamine, 952 diethyl ether, 671 ethanol, 421 hexane. 424 1-hexene, 424 1-hexyne, 424 phenol, 633... 

Diphenylacetylene with Mo(CO)a (298) in a sealed tube at 160°-170°C produces, in addition to two cyclobutadiene complexes, a yellow compound with the empirical formula [C9(CgH5)gO]Mo(CO)2, the infrared spectrum and chemical properties of which suit the tetraphenyl-cyclopentadienone complex of structure (11). On the other hand, the interaction of 3-hexyne with (CH3CN)gMo(CO)3 yields only the alkyne complex (570). 

The infrared spectrum of 1-hexyne shows a sharp absorption peak near 2100 cm due to stretching of its triple bond. However, 3-hexyne shows no absorption in that region. Explain. 

Infrared spectrum of the product of 1-iodo-2-methyl-4-nitrobenzene and 1-hexyne. The sharp peak at 2227 cm" is assigned to the triple bond in 1-hexynyl-2-methyl-4-nitrobenzene, and the two sharp peaks at 1518 and 1343 cm" are assigned to the nitro group. 

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