2E14ᇶᗏ୍㔜㡯࢝ࣝ࣋ࣥࡢ㟁Ꮚⓗບ㉳≧ែ࡟㛵ࡍࡿ⌮ㄽⓗ◊✲㸦㜰ᕷ኱㝔⌮㸧‫ۑ‬ᮡᓮ◊ྖ࣭㇏⏣࿴⏨࣭బ⸨࿴ಙ࣭ሷぢ኱㍜࣭ᕤ఩Ṋ἞䛆ᗎㄽ䛇㻌 㟁Ẽⓗ࡟୰ᛶ࡛஧㓄఩ࡢⅣ⣲ཎᏊࢆᣢࡘ࢝ࣝ࣋ࣥ໬ྜ≀ࡣࠊ୍⯡࡟ࠊ(s2)㟁Ꮚ㓄⨨ࢆᣢࡘ୍㔜㡯≧ែ࡜ࠊ(s,p)㟁Ꮚ㓄⨨ࢆᣢࡘ୕㔜㡯≧ែࡀᑠࡉ࡞࢚ࢿࣝࢠ࣮ࢠࣕࢵࣉ࡛Ꮡᅾࡋࠊ࢜ࣞࣇ࢕ࣥ࡬ࡢ௜ຍ⎔໬཯ᛂࡸࠊWolff ㌿⛣཯ᛂࠊ1,2-㌿⛣཯ᛂ࡞࡝ࠊ㟁Ꮚ≧ែࢆ཯ᫎࡋ࡚ᵝࠎ࡞໬Ꮫ཯ᛂࢆ㉳ࡇࡍࡇ࡜ࡀ▱ࡽࢀ࡚࠸ࡿ[1]ࠋ࢝ࣝ࣋ࣥࡢ UV–vis ࢫ࣌ࢡࢺࣝែ࡟࠾ࡅࡿࢫࣆࣥከ㔜ᗘࡢỴᐃࡸࠊ྾཰ᙉᗘࡢ᫬㛫ኚ໬ᐃࡣࠊᇶᗏ≧ᐃ࡟ࡼࡿ཯ᛂ㏿ᗘᐃᩘࡢỴᐃ࡞࡝ࠊ࢝ࣝ࣋ࣥศᏊࡢ≀ᛶ⌮ゎ࡟㔜せ࡞ᙺ๭ࢆᢸࡗ࡚ࡁࡓࠋࡑࡋ࡚㏆ᖺࠊࢪ࢔ࢰ๓㥑య࡬ࡢග↷ᑕ࡟ࡼࡿ࢝ࣝ࣋ࣥศᏊ⏕ᡂ཯ᛂࡢ◊✲[2]ࡸࠊ࢝ࣝ࣋ࣥศᏊࡢບ㉳≧ែ࠿ࡽࡢ⦆࿴㐣⛬ࡢ◊✲[3]ࡀሗ࿌ࡉࢀࡿ࡞࡝ࠊ࢝ࣝ࣋ࣥࡢ㟁Ꮚⓗບ㉳≧ែࡑࡢࡶࡢࠊ≉࡟ࠊ➨୍㟁Ꮚບ㉳≧ែࡔࡅ࡛࡞ࡃࠊ➨஧ࠊ➨୕ບ㉳≧ែ࡞࡝ࠊ⣸እග㡿ᇦ࡟⌧ࢀࡿບ㉳≧ែ࡟ᑐࡍࡿ㛵ᚰࡶ㧗ࡲࡾࡘࡘ࠶ࡿࠋ ୍㔜㡯࢝ࣝ࣋ࣥࡢ➨୍㟁Ꮚບ㉳≧ែࡣࠊHOMO–LUMO ୍㟁Ꮚບ㉳ࡀ୺㓄⨨࡛࠶ࡾࠊᑠࡉ࡞ HOMO–LUMO ࢚ࢿࣝࢠ࣮ࢠࣕࢵࣉࢆ཯ᫎࡋ࡚ࠊ㛗Ἴ㛗㡿ᇦ࡟྾཰ᖏࡀ⌧ࢀࡿࠋ➨୍㟁Ꮚບ㉳≧ែࢆᢅࡗࡓ◊✲ࡣࠊᐇ㦂࣭⌮ㄽィ⟬࡜ࡶ࡟ከࡃሗ࿌ࡉࢀ࡚࠸ࡿࡀࠊ➨஧ࠊ➨୕㟁Ꮚບ㉳≧ែ࡞࡝ࠊ⣸እග㡿ᇦ࡟⌧ࢀࡿ㟁Ꮚ≧ែࢆ⌮ㄽⓗ࡟ྲྀࡾᢅࡗࡓ◊✲ࡣ࡯࡜ࢇ࡝࡞࠸ࠋࡇࢀࡽࡢບ㉳≧ែࡣ㠀᩿⇕࢝ࢵࣉࣜࣥࢢ◊✲ࡢࣔࢹࣝ⣔࡜ࡋ࡚ὀ┠ࡉࢀ࡚࠾ࡾࠊ㔞Ꮚ໬Ꮫィ⟬࡟ࡼࡿ⣔⤫ⓗ◊✲ࡣࠊᐇ㦂⤖ᯝࢆṇࡋࡃ⌮ゎࡍࡿࡓࡵ࡟ࡶ㠀ᖖ࡟㔜せ࡛࠶ࡿࠋᡃࠎࡣࠊ௦⾲ⓗ࡞୍㔜㡯࢔࡛ࣜࣝ࢝ࣝ࣋ࣥ࠶ࡿࣁࣟࢤࣥ⨨᥮ࣇ࢙ࢽࣝ࢝ࣝ࣋ࣥ (PhCY, where Y = F (1), Cl (2),and Br (3))࠾ࡼࡧ୍㔜㡯࢔࡛ࣝ࢟ࣝ࢝ࣝ࣋ࣥ࠶ࡿࣁࣟࢤࣥ⨨᥮ࢺࣜࣇ࣓ࣝ࢜ࣟࢳࣝ࢝ࣝ࣋ࣥ
(CF3CY, where Y = F (4), Cl (5), and Br (6)) ࡢ ບ ㉳≧ ែィ ⟬࠿ ࡽࠊ ୍㔜 㡯࢝ ࣝ࣋ ࣥ ࡀ
HOMO–LUMO ஧㟁Ꮚບ㉳≧ែࢆẚ㍑ⓗప࢚ࢿࣝࢠ࣮㡿ᇦ࡟ᣢࡘࡇ࡜ࢆぢฟࡋ࡚࠸ࡿ[4]ࠋ௒
ᅇᡃࠎࡣࠊᇶᗏ୍㔜㡯࢝ࣝ࣋ࣥ 1–6 ࡟ࡘ࠸࡚ࠊCASSCF/MRMP2 ィ⟬࡟ࡼࡿບ㉳≧ែィ⟬࠿
ࡽࠊUV–vis ࢫ࣌ࢡࢺࣝࡢᖐᒓࢆ⾜࠺࡜࡜ࡶ࡟ࠊHOMO–LUMO ஧㟁Ꮚບ㉳≧ែ࡟ᑐࡍࡿ⨨᥮ᇶຠᯝࡢ⪃ᐹࡸࠊ஧㟁Ꮚບ㉳≧ែ࡟࠾ࡅࡿᵓ㐀⦆࿴࡟ࡘ࠸࡚ࡶ᳨ウࢆ⾜ࡗࡓࠋ䛆ィ⟬᮲௳䛇㻌 ศᏊᵓ㐀ࡣ B3LYP/6-311G*ἲ࡟ࡼࡾ᭱㐺໬ࢆ⾜࠸ࠊCASSCF/cc-pVTZ Ἴື㛵ᩘࢆཧ↷㛵ᩘ࡜ࡋࡓ MRMP2 ィ⟬࡟ࡼࡾࠊᆶ┤ບ㉳࢚ࢿࣝࢠ࣮ࢆồࡵࡓࠋCASSCF ἲ࡟࠾ࡅࡿάᛶ✵㛫ࡣࠊPhCY ศᏊ⣔࡛ࡣ 12 㟁Ꮚ 10 ㌶㐨ࠊCF3CY ศᏊ⣔࡛ࡣ 18 㟁Ꮚ 12 ㌶㐨࡜ࡋࡓࠋ䛆⤖ᯝ䛸⪃ᐹ䛇 I. ᆶ┤ບ㉳䜶䝛䝹䜼䞊䛸 UV–vis 䝇䝨䜽䝖䝹 Figure 1 ࡟ࠊ2 ࡢ UV ࢫ࣌ࢡࢺࣝ࡜
MRMP2 ἲ࡟ࡼࡿ⌮ㄽࢫ࣌ࢡࢺࣝࢆ♧ࡍࠋ2 ࡣ௨๓࡟ࠊPliego ࡽ࡟ࡼࡾࠊCASPT2 ィ⟬ࡀሗ࿌
ࡉࢀࠊ307 nm ࡢ᭱ࡶᙉᗘࡢᙉ࠸྾཰ᖏࡣpp*ບ㉳≧ែ࡛࠶ࡿ 3 1A′≧ែ࡟ᖐᒓࡉࢀ࡚࠸ࡿ[5]ࡀࠊ
282 nm ࡟ほ ࡉࢀࡓ྾཰ᖏࡢᖐᒓࡣࡇࢀࡲ࡛ሗ࿌ࡀ࡞࠸ࠋMRMP2 ィ⟬࡟ࡼࡿ࡜ࠊ307 nm ࡢ྾཰ᖏࡣࠊ3 1A′≧ែ࡟ᖐᒓࡉࢀࠊPliego ࡽ࡟ࡼࡿᖐᒓࢆᨭᣢࡍࡿ⤖ᯝ࡜࡞ࡗࡓࠋ୍᪉ࠊ282 nm
࡟ほ ࡉࢀࡓ྾཰ᖏࡣࠊMRMP2 ἲ࡛ 4.57 eV (271 nm)࡟ồࡵࡽࢀࡓ 4 1A′࡟ᖐᒓࡋࡓࠋ4 1A′≧ែࡣࠊHOMO–LUMO ஧㟁Ꮚບ㉳ࡀ୺㓄⨨࡛࠶ࡾࠊ⡆౽࡞ບ㉳≧ែィ⟬ἲ࡛࠶ࡿ CIS ἲࡸࠊ᩿⇕㏆ఝࡢୗ࡛ࡢ TD-DFT ἲ࡞࡝࡛ࡣồࡵࡿࡇ࡜ࡀ࡛ࡁ࡞࠸ࠋࡇࡢࡼ࠺࡞ࠊHOMO–LUMO஧㟁Ꮚບ㉳≧ែࡣࠊ௒ᅇィ⟬ࡋࡓ඲࡚ࡢ୍㔜㡯࢝ࣝ࣋ࣥ࡟࠾࠸࡚ࠊ200–300 nm ࡢ㡿ᇦ࡟ồࡵࡽࢀ (1; 5.57 eV (223 nm), 3; 4.33 eV (286nm), 4; 6.14 eV (202 nm), 5; 4.68 eV (265 nm),6; 4.33 eV (286 nm))ࠊUV–vis ࢫ࣌ࢡࢺࣝ࡟ࡶᐤ୚ࡋ࡚࠸ࡿࡇ࡜ࡀ♧ࡉࢀࡓࠋࡇࡢ⤖ᯝࡣࠊ Figure 1. PhCCl (2)ࡢᐇ㦂 UV ࢫ࣌ࢡࢺࣝ࠾ࡼࡧ୍㔜㡯࢝ࣝ࣋ࣥࡢບ㉳≧ែ◊✲࡟࠾࠸࡚ࠊከ MRMP2 ⌮ㄽࢫ࣌ࢡࢺࣝ
㟁Ꮚບ㉳ࢆ⪃៖࡟ධࢀࡿࡇ࡜ࡀ㔜せ࡜࡞ࡿሙྜࡀ࠶ࡿࡇ࡜ࢆ♧ࡋ࡚࠸ࡿࠋ
II. HOMO–LUMO ୍㟁Ꮚ䛚䜘䜃஧㟁Ꮚບ㉳≧ែ䛻ᑐ䛩䜛⨨᥮ᇶຠᯝ Figure 2 ࡟♧ࡍࡼ࠺࡟ࠊ
HOMO–LUMO ୍㟁Ꮚ࠾ࡼࡧ஧㟁Ꮚບ㉳≧ែࡢᆶ┤ບ㉳࢚ࢿࣝࢠ࣮࡜ࠊࣁࣟࢤࣥཎᏊࡢ㟁Ẽ㝜ᛶᗘ࡜ࡢ㛫࡟୍ḟࡢ┦㛵ࡀ࠶ࡿࡇ࡜ࡀศ࠿ࡗࡓ㸦R2> 0.99㸧ࠋࡇࡢഴྥࡣࠊㄏ㉳ຠᯝ࡜ඹ㬆ຠᯝ࡟ࡼࡿ HOMO–LUMO ࢚ࢿࣝࢠ࣮ࢠࣕࢵࣉኚ໬࡟ࡼ
ࡗ࡚ࠊ୍㔜㡯–୕㔜㡯࢚ࢿࣝࢠ࣮ࢠࣕࢵࣉ࡜ྠࡌ

Figure 2. ࣁࣟࢤࣥཎᏊࡢ㟁Ẽ㝜ᛶᗘ࡜ᆶ┤ࡼ࠺࡟ㄝ࡛᫂ࡁࡿࠋHOMO–LUMO ஧㟁Ꮚບ㉳≧ບ㉳࢚ࢿࣝࢠ࣮ࡢ㛵ಀ ‫ ;ە‬PhCY (1e), ‫;ۑ‬ែࡢᅇᖐ┤⥺ࡢഴࡁࡣࠊ୍㟁Ꮚບ㉳≧ែࡢࡶࡢࡢ

PhCY (2e), ‫ ;ڦ‬CF3CY (1e), ‫ ;ڧ‬CF3CY (2e)⣙ 2 ಸ࡛࠶ࡾࠊບ㉳࡟㛵୚ࡍࡿ㟁Ꮚᩘࢆ཯ᫎࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋPhCY ศᏊ⣔࡜ CF3CY ศᏊ⣔ࡢᅇᖐ┤⥺ࡢഴࡁࡢ㐪࠸ࡣࠊࣇ࢙ࢽࣝᇶ࡜ࢺࣜࣇ࣓ࣝ࢜ࣟࢳࣝᇶࡢ㟁Ꮚ྾ᘬᛶࡢᙉࡉ࡟⏤᮶ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋ
III. HOMO–LUMO ஧㟁Ꮚບ㉳≧ែ䛻䛚䛡䜛ᵓ㐀⦆࿴ HOMO–LUMO ஧㟁Ꮚບ㉳≧ែࡣࠊ(p2)㟁Ꮚ㓄⨨࡛⾲ࢃࡉࢀࠊᇶᗏ≧ែ࡜ࡣ኱ࡁࡃ␗࡞ࡗࡓศᏊᵓ㐀ࢆ࡜ࡿ࡜⪃࠼ࡽࢀࡿࡢ࡛ࠊCASSCF/cc-pVTZ ἲ࡟ࡼࡿᵓ㐀᭱㐺໬ࢆヨࡳࡓࠋບ㉳≧ែィ⟬࡟⏝࠸ࡓࡶࡢ࡜ྠࡌάᛶ✵㛫࡛ࡣ state-specific CASSCF Ἴື㛵ᩘࡀ཰᮰ࡋ࡞࠿ࡗࡓࡓࡵࠊHOMO ࠾ࡼࡧ LUMO ࡢࡳࢆྵࡴCASSCF(2,2)࡟ࡼࡾᵓ㐀᭱㐺໬ࢆ⾜ࡗ࡚࠸ࡿࠋࡇࡢ⤖ᯝ࡟ࡘ࠸࡚ࡣࠊᙜ᪥Ⓨ⾲ࡍࡿணᐃ࡛࠶ࡿࠋ࠙ཧ⪃ᩥ⊩ࠚ[1] Reactive Intermediate Chemistry, Moss, R. A.; Platz, M. S.; Jones, M., Jr. Eds. Wiley-Interscience,Hoboken, 2004. [2] (a) Wang, J., et al. J. Am. Chem. Soc. 2006, 128, 16446–16447. (b) Lee, H.;
Miyamoto, Y.; Tateyama, Y. J. Org. Chem. 2009, 74, 562–567. [3] (a) Noller, B., et al. J. Am. Chem.
Soc. 2008, 130, 14908–14909. (b) Noller, B., et al. J. Phys. Chem. A 2009, 113, 3041–3050. [4] (a) ᮡᓮ࣭㇏⏣࣭బ⸨࣭ሷぢ࣭ᕤ఩ ศᏊᵓ㐀⥲ྜウㄽ఍ 2003, 4Ba03. (b) ᮡᓮ࣭㇏⏣࣭బ⸨࣭ሷぢ࣭ᕤ఩ ศᏊᵓ㐀⥲ྜウㄽ఍ 2004, 1P025. [5] Pliego, J. R., Jr. et al. J. Phys. Chem. A 1999, 103,7481–7486.