TY - JOUR
T1 - Macrocyclic, Square Planar, Tetraalkynyl Tetraiodonium Salts
T2 - Structures, Stabilities, and Vibrational Frequencies via ab Initio Calculations
AU - Boldyrev, Alexander I.
AU - Zhdankin, Viktor V.
AU - Simons, Jack
AU - Stang, Peter J.
PY - 1992/12/1
Y1 - 1992/12/1
N2 - The geometries and stabilities of HCCH, ICCH, ICCI, IF3, IF2CCH, IF(CCH)2,I(CCH)3,I4(CC)44+, and four isomers of I4(CC)4F4 were calculated at the ab initio HF/LANL1DZ level. Final geometries were used for electron correlation calculations at the MP4/LANL1DZ level. The results of the calculations demonstrate considerable stability and suggest square planar structures for the macrocyclic tetraalkynyl tetraiodonium compounds. The tetracation I4C84+ is predicted to exist as a single isomer due to a pseudotetrahedral 8-1-2 configuration and to have a structure with only negligible deviations from a perfect square. In contrast, the neutral I4C8F4 species can exist as four different isomers as a consequence of the trigonal bipyramidal 10-I-3 configuration. These isomers have distinctly different geometries and energies due to the relative positions of the axial and equatorial C-I bonds. Macrocycles 16-19 have ring strain energy due to the existence of four unfavorable axial I-C bonds in each of the isomers. However, the calculated ring strain energy for the most stable isomer 16 is only 27 kcal/mol.
AB - The geometries and stabilities of HCCH, ICCH, ICCI, IF3, IF2CCH, IF(CCH)2,I(CCH)3,I4(CC)44+, and four isomers of I4(CC)4F4 were calculated at the ab initio HF/LANL1DZ level. Final geometries were used for electron correlation calculations at the MP4/LANL1DZ level. The results of the calculations demonstrate considerable stability and suggest square planar structures for the macrocyclic tetraalkynyl tetraiodonium compounds. The tetracation I4C84+ is predicted to exist as a single isomer due to a pseudotetrahedral 8-1-2 configuration and to have a structure with only negligible deviations from a perfect square. In contrast, the neutral I4C8F4 species can exist as four different isomers as a consequence of the trigonal bipyramidal 10-I-3 configuration. These isomers have distinctly different geometries and energies due to the relative positions of the axial and equatorial C-I bonds. Macrocycles 16-19 have ring strain energy due to the existence of four unfavorable axial I-C bonds in each of the isomers. However, the calculated ring strain energy for the most stable isomer 16 is only 27 kcal/mol.
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U2 - 10.1021/ja00052a062
DO - 10.1021/ja00052a062
M3 - Article
AN - SCOPUS:0001742398
SN - 0002-7863
VL - 114
SP - 10569
EP - 10572
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 26
ER -