Supplementary Information

Transcript

1 Supplementary Information Thermochromism in an organic crystal based on the co-existence of σ- and π-dimers YASUSHI MORITA 1,2 *, SHUICHI SUZUKI 1, KOZO FUKUI 2, SHIGEAKI NAKAZAWA 3, HIROSHI KITAGAWA 4, HIDEO KISHIDA 5, HIROSHI OKAMOTO 5, AKIRA NAITO 6, AKIKO SEKINE 7, YUJI OHASHI 7, MOTOO SHIRO 8, KATSUNARI SASAKI 8, DAISUKE SHIOMI 3, KAZUNOBU SATO 3, TAKEJI TAKUI 3 *, KAZUHIRO NAKASUJI 1 1 Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka , Japan. 2 PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama , Japan. 3 Departments of Chemistry and Materials Science, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka , Japan. 4 Department of Chemistry, Graduate School of Science, Kyushu University, Fukuoka, Fukuoka , Japan. 5 Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba , Japan. 6 Faculty of Engineering, Yokohama National University, Hodogaya-ku, Yokohama , Japan. 7 Department of Chemistry and Materials Science, Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo , Japan. 8 Rigaku Corporation, Akishima, Tokyo , Japan. morita@chem.sci.osaka-u.ac.jp; takui@sci.osaka-cu.ac.jp S1

2 Figure S1 The colour change of the crystal in Figure 2 depending on the temperature. S2

3 p / mm q / mm r / mm The crystal in Figure The crystal using measurements of the polarized electronic spectra Figure S2 A schematic structure of the crystal habit: The table shows approximate lengths of the crystal used in Figure 2 and in the measurements of the polarized electronic spectra at various temperatures. S3

4 Figure S3 The disordered arrangement and numbers of atoms for definition method for setting two atoms. The distances of C1 C2, C1 C12, C26 C27, and C26 C37 were defined to be 1.51 Å S1. The distances of C101 C2, C101 C12, C126 C27, and C126 C37 were defined to be 1.40 Å S1. The occupancy of C1 was refined by the least-square method. The occupancy of C26 was defined to be equal to that of C1. The sum of the occupancies of C1 and C101, and C26 and C126 was fixed to be 1. S4

5 Table S1 Crystal data of 2 at 93 K. empirical formula C 46 H 62 N 4 formula weight crystal colour, habit colourless, block crystal dimensions, mm crystal system monoclinic space group P2 1 /n (#14) a, Å (3) b, Å (5) c, Å (3) α, deg 90 β, deg (1) γ, deg 90 V, Å (1) Z 4 D calc, g cm F(000) µ, cm 1 (Cu Kα) 4.96 diffractometer Rigaku RAXIS-RAPID Imaging Plate radiation (λ, Å) (graphite monochromated) 2θ max, deg temperature, K 93 structure solution direct methods (SIR2003) refinement full matrix least-squares using all reflections number of unique reflections 6962 number of observed reflections with I > 2σ(I) 3069 number of variables 453 R1 (calculated on F) (I > 2σ(I)) wr2 (calculated on F 2 ) (all reflections) S, goodness of fit final max/min Δρ, eå / 0.41 S5

6 Table S2 Atomic coordinates and equivalent isotopic displacement parameters (Å 2 ) for the crystal structural analysis of 2 at 93 K. atom x y z Beq occ N(9) (3) (2) (3) 4.17(9) N(11) (3) (2) (3) 3.86(8) N(30) (3) (2) (3) 3.78(8) N(32) (4) (2) (3) 4.9(1) C(1) (3) (1) (4) 3.0(1) 0.811(10) C(2) (3) (2) (3) 3.39(9) C(3) (3) (2) (3) 2.25(7) C(4) (3) (2) (3) 2.38(7) C(5) (3) (2) (3) 2.32(7) C(6) (4) (2) (3) 3.31(9) C(7) (4) (2) (3) 3.66(9) C(8) (4) (2) (3) 3.30(9) C(10) (3) (2) (3) 2.67(8) C(12) (3) (2) (3) 2.82(8) C(13) (3) (2) (3) 2.23(7) C(14) (4) (2) (3) 3.36(9) C(15) (4) (2) (3) 3.04(8) C(16) (3) (2) (3) 2.76(8) C(17) (4) (2) (4) 4.3(1) C(18) (4) (2) (4) 4.4(1) C(19) (4) (2) (3) 3.09(8) C(20) (4) (2) (4) 4.0(1) C(21) (5) (3) (4) 5.3(1) C(22) (4) (3) (4) 4.7(1) C(23) (4) (2) (4) 3.8(1) C(24) (4) (2) (3) 3.8(1) C(25) (4) (2) (3) 3.6(1) C(26) (3) (2) (3) 3.2(1) 0.811(10) C(27) (3) (2) (3) 3.6(1) C(28) (4) (2) (3) 3.20(9) C(29) (4) (2) (3) 2.96(8) C(31) (4) (2) (3) 3.11(9) C(33) (4) (2) (3) 3.33(9) C(34) (3) (2) (3) 2.85(8) C(35) (4) (2) (3) 3.00(8) C(36) (3) (2) (3) 2.65(8) C(37) (4) (2) (3) 3.54(9) C38) (4) (2) (3) 2.63(8) C(39) (4) (2) (3) 3.14(9) S6

7 C(40) (4) (2) (3) 2.73(8) C(41) (4) (2) (3) 3.04(8) C(42) (5) (2) (4) 4.7(1) C(43) (4) (2) (3) 3.54(9) C(44) (4) (2) (3) 3.69(9) C(45) (4) (2) (3) 3.7(1) C(46) (4) (2) (3) 3.28(9) C(47) (4) (2) (3) 3.9(1) C(48) (5) (2) (4) 5.3(1) C(49) (4) (2) (3) 3.9(1) C(50) (4) (3) (4) 5.5(1) C(101) 1.016(1) (4) 0.675(1) 1.2(3) C(126) (4) (3) 0.905(1) 1.4(3) H(1) H(2) H(3) H(4) H(5) H(6) H(7) H(8) H(9) H(10) H(11) H(12) H(13) H(14) H(15) H(16) H(17) H(18) H(19) H(20) H(21) H(22) H(23) H(24) H(25) H(26) H(27) H(28) H(29) H(30) S7

8 H(31) H(32) H(33) H(34) H(35) H(36) H(37) H(38) H(39) H(40) H(41) H(42) H(43) H(44) H(45) H(46) H(47) H(48) H(49) H(50) H(51) H(52) H(53) H(54) H(55) H(56) H(57) H(58) H(59) H(60) *B eq = 8/3π 2 (U 11 (aa*) 2 + U 22 (bb*) 2 + U 33 (cc*) 2 + 2U 12 (aa*bb*)cosγ + 2U 13 (aa*cc*)cosβ + 2U 23 (bb*cc*)cosα S8

9 Table S3 Crystal data of 2 at 153 K. empirical formula C 46 H 62 N 4 formula weight crystal colour, habit light green, block crystal dimensions, mm crystal system monoclinic space group P21/n (#14) a, Å (3) b, Å (5) c, Å (3) α, deg 90 β, deg (1) γ, deg 90 V, Å (1) Z 4 D calc, g cm F(000) µ, cm 1 (Cu Kα) 4.90 diffractometer Rigaku RAXIS-RAPID Imaging Plate radiation (λ, Å) (graphite monochromated) 2θ max, deg temperature, K 153 structure solution direct methods (SIR2003) refinement full matrix least-squares using all reflections number of unique reflections 7056 number of observed reflections with I > 2σ(I) 3430 number of variables 453 R1(calculated on F) (I > 2σ(I)) wr2 (calculated on F 2 ) (all reflections) S, goodness of fit final max/min Δρ, eå / 0.31 S9

10 Table S4 Atomic coordinates and equivalent isotopic displacement parameters (Å 2 ) for the crystal structural analysis of 2 at 153 K. atom x y z Beq occ N(9) (3) (2) (3) 4.80(9) N(11) (3) (2) (3) 4.53(8) N(30) (3) (2) (3) 4.44(8) N(32) (4) (2) (3) 5.32(9) C(1) (3) (1) (4) 3.2(1) 0.762(10) C(2) (3) (2) (3) 4.01(9) C(3) (3) (2) (3) 2.95(7) C(4) (3) (2) (3) 3.02(7) C(5) (3) (2) (3) 3.02(7) C(6) (4) (2) (3) 3.99(9) C(7) (4) (2) (3) 4.23(9) C(8) (4) (2) (3) 3.91(9) C(10) (3) (2) (3) 3.35(8) C(12) (3) (1) (3) 3.36(8) C(13) (3) (2) (3) 2.81(7) C(14) (4) (2) (3) 4.03(9) C(15) (3) (2) (3) 3.79(8) C(16) (3) (2) (3) 3.56(8) C(17) (5) (2) (4) 5.6(1) C(18) (4) (2) (4) 5.5(1) C(19) (4) (2) (3) 4.07(9) C(20) (4) (3) (4) 5.9(1) C(21) (6) (3) (5) 7.5(2) C(22) (4) (3) (4) 7.2(2) C(23) (4) (2) (4) 5.4(1) C(24) (4) (2) (4) 5.4(1) C(25) (4) (2) (4) 5.1(1) C(26) (3) (2) (3) 3.3(1) 0.762(10) C(27) (3) (2) (3) 4.2(1) C(28) (4) (2) (3) 3.97(9) C(29) (4) (2) (3) 3.58(8) C(31) (4) (2) (3) 3.84(9) C(33) (4) (2) (3) 3.93(9) C(34) (3) (2) (3) 3.55(8) C(35) (4) (2) (3) 3.65(8) C(36) (3) (2) (3) 3.48(8) C(37) (4) (2) (3) 4.15(9) C(38) (4) (2) (3) 3.25(8) C(39) (4) (2) (3) 3.91(9) S10

11 C(40) (3) (2) (3) 3.55(8) C(41) (4) (2) (3) 4.09(9) C(42) (5) (3) (4) 6.2(1) C(43) (4) (2) (3) 4.6(1) C(44) (4) (2) (4) 4.9(1) C(45) (4) (2) (3) 4.9(1) C(46) (4) (2) (3) 4.20(9) C(47) (4) (2) (4) 5.1(1) C(48) (5) (3) (4) 7.5(2) C(49) (4) (2) (4) 5.2(1) C(50) (5) (3) (5) 7.5(2) C(101) 1.017(1) (3) 0.676(1) 3.1(3) C(126) (4) (3) 0.901(1) 3.2(3) H(1) H(2) H(3) H(4) H(5) H(6) H(7) H(8) H(9) H(10) H(11) H(12) H(13) H(14) H(15) H(16) H(17) H(18) H(19) H(20) H(21) H(22) H(23) H(24) H(25) H(26) H(27) H(28) H(29) H(30) S11

12 H(31) H(32) H(33) H(34) H(35) H(36) H(37) H(38) H(39) H(40) H(41) H(42) H(43) H(44) H(45) H(46) H(47) H(48) H(49) H(50) H(51) H(52) H(53) H(54) H(55) H(56) H(57) H(58) H(59) H(60) *B eq = 8/3π 2 (U 11 (aa*) 2 + U 22 (bb*) 2 + U 33 (cc*) 2 + 2U 12 (aa*bb*)cosγ + 2U 13 (aa*cc*)cosβ + 2U 23 (bb*cc*)cosα S12

13 Table S5 Crystal data of 2 at 213 K. empirical formula C 46 H 62 N 4 formula weight crystal colour, habit green, block crystal dimensions, mm crystal system monoclinic space group P2 1 /n (#14) a, Å (3) b, Å (6) c, Å (4) α, deg 90 β, deg (2) γ, deg 90 V, Å (1) Z 4 D calc, g cm F(000) µ, cm 1 (Cu Kα) 4.83 diffractometer Rigaku RAXIS-RAPID Imaging Plate radiation (λ, Å) (graphite monochromated) 2θ max, deg temperature, K 213 structure solution direct methods (SIR2003) refinement full matrix least-squares using all reflections number of unique reflections 7145 number of observed reflections with I > 2σ(I) 3351 number of variables 453 R1 (calculated on F) (I > 2σ(I)) wr2 (calculated on F 2 ) (all reflections) S, goodness of fit final max/min Δρ, eå / 0.42 S13

14 Table S6 Atomic coordinates and equivalent isotopic displacement parameters (Å 2 ) for the crystal structural analysis of 2 at 213 K. atom x y z Beq occ N(9) (3) (2) (3) 5.37(9) N(11) (3) (2) (3) 5.01(8) N(30) (3) (2) (3) 5.12(8) N(32) (4) (2) (3) 6.1(1) C(1) (3) (1) (4) 3.9(1) 0.766(10) C(2) (3) (2) (3) 4.57(9) C(3) (3) (2) (3) 3.64(8) C(4) (3) (2) (3) 3.52(7) C(5) (3) (2) (3) 3.59(8) C(6) (4) (2) (3) 4.61(9) C(7) (4) (2) (3) 4.73(9) C(8) (3) (2) (3) 4.38(9) C(10) (3) (2) (3) 3.96(8) C(12) (3) (1) (3) 3.94(8) C(13) (3) (2) (3) 3.36(7) C(14) (4) (2) (4) 4.8(1) C(15) (3) (2) (3) 4.41(9) C(16) (3) (2) (3) 4.32(9) C(17) (5) (3) (4) 7.0(2) C(18) (5) (2) (4) 6.9(1) C(19) (4) (2) (4) 5.1(1) C(20) (5) (3) (6) 9.3(2) C(21) (7) (4) (6) 10.5(2) C(22) (5) (5) (5) 12.8(3) C(23) (5) (3) (6) 8.4(2) C(24) (5) (3) (5) 8.5(2) C(25) (5) (3) (5) 7.7(2) C(26) (3) (2) (3) 3.9(1) 0.766(10) C(27) (3) (2) (3) 4.8(1) C(28) (4) (2) (3) 4.59(9) C(29) (4) (2) (3) 4.15(8) C(31) (3) (2) (3) 4.30(9) C(33) (4) (2) (3) 4.25(9) C(34) (3) (2) (3) 4.14(9) C(35) (4) (2) (3) 4.25(9) C(36) (3) (2) (3) 4.19(9) C(37) (4) (2) (3) 4.8(1) C(38) (3) (2) (3) 3.69(8) C(39) (4) (2) (3) 4.55(9) S14

15 C(40) (4) (2) (3) 4.23(8) C(41) (4) (2) (4) 5.0(1) C(42) (5) (3) (5) 8.0(2) C(43) (4) (3) (4) 6.0(1) C(44) (4) (3) (4) 6.4(1) C(45) (4) (2) (4) 6.2(1) C(46) (4) (2) (4) 5.3(1) C(47) (5) (3) (4) 6.5(1) C(48) (6) (3) (5) 10.2(2) C(49) (5) (2) (4) 6.7(1) C(50) (5) (3) (6) 10.1(2) C(101) (9) (3) (9) 2.7(3) C(126) (4) (3) 0.899(1) 3.4(3) H(1) H(2) H(3) H(4) H(5) H(6) H(7) H(8) H(9) H(10) H(11) H(12) H(13) H(14) H(15) H(16) H(17) H(18) H(19) H(20) H(21) H(22) H(23) H(24) H(25) H(26) H(27) H(28) H(29) H(30) S15

16 H(31) H(32) H(33) H(34) H(35) H(36) H(37) H(38) H(39) H(40) H(41) H(42) H(43) H(44) H(45) H(46) H(47) H(48) H(49) H(50) H(51) H(52) H(53) H(54) H(55) H(56) H(57) H(58) H(59) H(60) *B eq = 8/3π 2 (U 11 (aa*) 2 + U 22 (bb*) 2 + U 33 (cc*) 2 + 2U 12 (aa*bb*)cosγ + 2U 13 (aa*cc*)cosβ + 2U 23 (bb*cc*)cosα S16

17 Table S7 Crystal data of 2 at 273 K. empirical formula C 46 H 62 N 4 formula weight crystal colour, habit deep green, block crystal dimensions, mm crystal system monoclinic space group P2 1 /n (#14) a, Å (4) b, Å (7) c, Å (4) α, deg 90 β, deg (2) γ, deg 90 V, Å (2) Z 4 D calc, g cm F(000) µ, cm 1 (Cu Kα) 4.76 diffractometer Rigaku RAXIS-RAPID Imaging Plate radiation (λ, Å) (graphite monochromated) 2θ max, deg temperature, K 273 structure solution direct methods (SIR2003) refinement full matrix least-squares using all reflections number of unique reflections 7251 number of observed reflections with I > 2σ(I) 2441 number of variables 453 R1 (calculated on F) (I > 2σ(I)) wr2 (calculated on F 2 ) (all reflections) S, goodness of fit final max/min Δρ, eå / 0.27 S17

18 Table S8 Atomic coordinates and equivalent isotopic displacement parameters (Å 2 ) for the crystal structural analysis of 2 at 273 K. atom x y z Beq occ N(9) (3) (2) (3) 6.6(1) N(11) (3) (2) (3) 6.19(9) N(30) (4) (2) (3) 6.6(1) N(32) (4) (2) (4) 7.7(1) C(1) (3) (1) (4) 4.1(2) 0.629(10) C(2) (3) (2) (3) 5.7(1) C(3) (4) (2) (3) 5.01(9) C(4) (3) (2) (3) 4.52(8) C(5) (3) (2) (3) 4.81(9) C(6) (4) (2) (4) 6.0(1) C(7) (4) (2) (4) 6.6(1) C(8) (3) (2) (3) 5.3(1) C(10) (3) (2) (3) 4.96(9) C(12) (3) (1) (3) 4.80(9) C(13) (3) (2) (3) 4.13(8) C(14) (4) (2) (4) 6.1(1) C(15) (4) (2) (4) 5.7(1) C(16) (4) (2) (4) 5.6(1) C(17) (5) (3) (5) 9.2(2) C(18) (5) (3) (5) 9.4(2) C(19) (4) (2) (4) 7.3(1) C(20) (5) (4) (7) 14.2(3) C(21) (8) (5) (7) 15.9(4) C(22) (5) (7) (7) 22.6(7) C(23) (6) (3) (8) 16.0(4) C(24) (7) (5) (6) 16.3(4) C(25) (6) (3) (7) 12.9(3) C(26) (3) (3) (3) 4.2(2) 0.629(10) C(27) (3) (2) (3) 6.1(1) C(28) (4) (2) (4) 5.7(1) C(29) (4) (2) (3) 5.17(9) C(31) (4) (2) (3) 5.5(1) C(33) (4) (2) (3) 5.18(9) C(34) (3) (2) (3) 5.3(1) C(35) (4) (2) (3) 5.21(9) C(36) (4) (2) (3) 5.5(1) C(37) (4) (2) (4) 5.9(1) C(38) (4) (2) (3) 4.46(8) C(39) (4) (2) (4) 5.7(1) S18

19 C(40) (4) (2) (3) 5.6(1) C(41) (4) (2) (4) 6.1(1) C(42) (6) (4) (6) 11.6(2) C(43) (4) (3) (4) 8.9(2) C(44) (5) (3) (5) 9.4(2) C(45) (5) (3) (5) 9.2(2) C(46) (5) (2) (4) 7.6(1) C(47) (5) (3) (5) 9.5(2) C(48) (7) (4) (6) 14.8(3) C(49) (6) (3) (5) 9.9(2) C(50) (6) (3) (6) 12.9(3) C(101) (7) (3) (8) 5.0(2) C(126) (4) (3) (9) 5.5(3) H(1) H(2) H(3) H(4) H(5) H(6) H(7) H(8) H(9) H(10) H(11) H(12) H(13) H(14) H(15) H(16) H(17) H(18) H(19) H(20) H(21) H(22) H(23) H(24) H(25) H(26) H(27) H(28) H(29) H(30) S19

20 H(31) H(32) H(33) H(34) H(35) H(36) H(37) H(38) H(39) H(40) H(41) H(42) H(43) H(44) H(45) H(46) H(47) H(48) H(49) H(50) H(51) H(52) H(53) H(54) H(55) H(56) H(57) H(58) H(59) H(60) *B eq = 8/3π 2 (U 11 (aa*) 2 + U 22 (bb*) 2 + U 33 (cc*) 2 + 2U 12 (aa*bb*)cosγ + 2U 13 (aa*cc*)cosβ + 2U 23 (bb*cc*)cosα S20

21 Table S9 Crystal data of 2 at 333 K. empirical formula C 46 H 62 N 4 formula weight crystal colour, habit dark green, block crystal dimensions, mm crystal system monoclinic space group P2 1 /n (#14) a, Å (1) b, Å (2) c, Å (1) α, deg 90 β, deg (5) γ, deg 90 V, Å (6) Z 4 D calc, g cm F(000) µ, cm 1 (Cu Kα) 4.68 diffractometer Rigaku RAXIS-RAPID Imaging Plate radiation (λ, Å) (graphite monochromated) 2θ max, deg temperature, K 333 structure solution direct methods (SIR2003) refinement full matrix least-squares using all reflections number of unique reflections 7538 number of observed reflections with I > 2σ(I) 3499 number of variables 453 R1 (calculated on F) (I > 2σ(I)) wr2 (calculated on F 2 ) (all reflections) S, goodness of fit final max/min Δρ, eå 3 0.0/0.0 S21

22 Table S10 Atomic coordinates and equivalent isotopic displacement parameters (Å 2 ) for the crystal structural analysis of 2 at 333 K. atom x y z Beq occ N(9) (3) (2) (3) 7.8(1) N(11) (3) (2) (3) 7.43(9) N(30) (4) (2) (3) 7.9(1) N(32) (4) (2) (4) 9.4(1) C(1) (4) (1) (4) 4.9(2) 0.548(11) C(2) (3) (2) (3) 7.0(1) C(3) (4) (2) (3) 6.7(1) C(4) (3) (2) (3) 5.80(8) C(5) (3) (2) (3) 6.13(9) C(6) (4) (2) (4) 7.4(1) C(7) (4) (2) (4) 8.0(1) C(8) (3) (2) (3) 6.4(1) C(10) (3) (2) (3) 5.96(9) C(12) (3) (1) (3) 6.13(9) C(13) (3) (2) (3) 5.06(7) C(14) (4) (2) (4) 7.5(1) C(15) (4) (2) (4) 7.0(1) C(16) (4) (2) (4) 6.9(1) C(17) (7) (3) (6) 12.6(2) C(18) (6) (3) (6) 13.1(3) C(19) (5) (3) (5) 10.1(2) C(20) (5) (5) (8) 18.1(5) C(21) 0.554(1) (6) 0.667(1) 26.3(9) C(22) (6) (8) (7) 27.8(9) C(23) (7) (4) 0.695(1) 20.2(6) C(24) 1.188(1) (6) (7) 22.5(6) C(25) (7) (3) (9) 17.4(4) C(26) (3) (3) (3) 5.1(2) 0.548(11) C(27) (3) (2) (4) 7.7(1) C(28) (4) (2) (4) 7.2(1) C(29) (4) (2) (3) 6.30(9) C(31) (4) (2) (3) 6.9(1) C(33) (4) (2) (3) 6.36(9) C(34) (3) (2) (3) 6.6(1) C(35) (4) (2) (3) 6.41(9) C(36) (4) (2) (3) 7.0(1) C(37) (3) (2) (3) 7.1(1) C(38) (3) (2) (3) 5.49(8) C(39) (4) (2) (3) 7.1(1) S22

23 C(40) (4) (2) (4) 7.1(1) C(41) (4) (2) (4) 7.7(1) C(42) (7) (4) (7) 15.9(3) C(43) (5) (4) (5) 11.9(2) C(44) (5) (4) (6) 12.3(2) C(45) (6) (3) (6) 13.3(3) C(46) (6) (3) (5) 11.1(2) C(47) (7) (4) (6) 13.6(3) C(48) (9) (5) (8) 20.5(5) C(49) (6) (3) (6) 13.4(3) C(50) (7) (4) (8) 17.2(4) C(101) (6) (2) (6) 5.8(2) C(126) (3) (2) (7) 6.7(2) H(1) H(2) H(3) H(4) H(5) H(6) H(7) H(8) H(9) H(10) H(11) H(12) H(13) H(14) H(15) H(16) H(17) H(18) H(19) H(20) H(21) H(22) H(23) H(24) H(25) H(26) H(27) H(28) H(29) H(30) S23

24 H(31) H(32) H(33) H(34) H(35) H(36) H(37) H(38) H(39) H(40) H(41) H(42) H(43) H(44) H(45) H(46) H(47) H(48) H(49) H(50) H(51) H(52) H(53) H(54) H(55) H(56) H(57) H(58) H(59) H(60) *B eq = 8/3π 2 (U 11 (aa*) 2 + U 22 (bb*) 2 + U 33 (cc*) 2 + 2U 12 (aa*bb*)cosγ + 2U 13 (aa*cc*)cosβ + 2U 23 (bb*cc*)cosα S24

25 Table S11 Intermolecular distances in units of Å between the diazaphenalenyl skeletons without disordered carbon atoms. a 93 K 153 K 213 K 273 K 333 K N9 N30 b 3.590(6) 3.605(6) 3.613(6) 3.599(7) 3.593(6) N11 C28 b 3.160(6) 3.164(6) 3.162(6) 3.187(7) 3.257(7) N32 C7 b 3.795(6) 3.812(6) 3.810(6) 3.750(7) 3.752(7) C3 C36 b 3.262(6) 3.261(6) 3.275(6) 3.297(7) 3.291(7) C5 C34 b 3.618(6) 3.622(6) 3.621(6) 3.586(7) 3.554(6) C13 C38 b 3.116(5) 3.116(5) 3.124(5) 3.132(6) 3.134(5) a Uncertainties of the distances between the disordered carbon atoms remain due to the restriction based on the suppositions in the legend of Figure S3. b The numbering of atoms is given in the following picture. S25

26 Figure S4 Two types of the disordered dimer structures for 2 at 153 K in the crystal (right), and their occupancies at five different temperatures determined by X-ray structure analyses. The orange and the green crosses denote the occupancies of the σ-dimer and π-dimer with error bars (2.5 standard uncertainty), respectively. Each dimer structure is not influenced by temperature variation. The crystal structure analyses suggest that an occupancy of the π-dimer increases on raising the temperature. We have noted that small changes in the occupancies of σ- and π-dimers from 93 K to 213 K occur and the experimental occupancy around 0.2 of the π-dimer at 93 K is seemingly too large on the assumption that the ratio of the π-dimer to all the dimers obeys Boltzmann distribution. These observations were due to the restrictions based on the suppositions in the legend of Figure S3. S26

27 Figure S5 a, Temperature-dependent electronic absorption spectra of 2 in the crystal using KBr pellet: 100, 150, 200, 250, and 300 K (from bottom to top). b, Polarized absorption spectra of 2 with polarized light parallel to the c axis (solid line) and perpendicular to the c axis (dashed line) on the crystal plane (010) at 300 K. S27

28 Figure S6 Pictures of the crystal of 2 at 300 K under polarized light: The directions of the polarized light are (a) parallel and (b) perpendicular to the c axis. S28

29 Figure S7 Optimized σ-dimer and π-dimer structures of 2 and the difference of the total energy between two dimers. The dimer structures were optimized at B3LYP/6-31G* level with Gaussian 03 by using the crystal structures of the σ- and π-dimers as the initial structures S2. The calculated ΔE σ-π value (3.0 kcal mol 1 ) is surprisingly good agreement with the experimental one (2.6 kcal mol 1 ). S29

30 Relative ESR intensity Magnetic Field/mT Temperature/K Figure S8 Temperature dependence of the ESR intensity of 2 in hexane ( M). Open squares denote the experimental values normalized at 320 K. Solid line shows the calculated values with the following thermodynamic parameters: ΔH = 12.2(9) kcal mol 1 and ΔS = 31(3) eu. Inset shows an observed spectrum at 320 K. S30

31 Figure S9 Temperature-dependent electronic spectra of 2 in hexane ( M). In the spectra, a broad absorption band around 550 nm decreased with lowering the temperature, and finally disappeared at 200 K, which indicates that the radical 2 forms the σ-dimer structure at low temperature S3,4. S31

32 Figure S10 Pictures of the calculated highest occupied molecular orbital (HOMO) and the calculated lowest unoccupied molecular orbital (LUMO) of 1 and 2. The dimer structures were optimized by using Gaussian 03 at the B3LYP/6-31G* level of theory S2. The vanishing E value derived from the fine-structure triplet-state ESR spectrum is also in good agreement with the predicted symmetrical electronic structures of the HOMO and the LUMO for the π-dimer of 2. S32

33 Figure S11 a. Temperature dependence of χ para T (product of magnetic susceptibility and temperature) of 2 in the solid state S5. Open squares denote the experimental values. Solid line shows the estimated paramagnetic contributions from S =1/2 monoradical impurities (0.1%). The result shows that the molecular assemblages of 2 in the crystal are in the spin-singlet state. On raising the temperature to 350 K, a small but a significant increase in χ para T was observed, suggesting the existence of a thermally accessible triplet state. b. Temperature dependence of triplet signal intensity. Open squares denote the experimental values. Solid line shows the calculated values by the modified singlet-triplet model with ΔE S T = 4.19(2) 10 3 K. Inset shows the observed triplet-state ESR spectrum of the powdered crystalline sample of 2 at 350 K. The intensity of the triplet signal is proportional to the number of the triplet π-dimer. S33

34 Figure S12 Temperature dependence of triplet signal intensity of 1. Open circles denote the experimental values. Solid line shows the calculated values by the singlet triplet model with ΔE S T = 3.34(3) 10 3 K. Inset shows the observed triplet ESR spectrum of the powdered crystalline sample of 1 at 300 K (g = 2.003, D /hc = cm 1, and E /hc < 10 3 cm 1 ). S34

35 References [S1] Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. J. Chem. Soc., Perkin Trans. 2, S1 S19 (1987). [S2] Gaussian 03, Revision B.05, Frisch, M. J., Trucks, G. W., Schlegel, H. B., Scuseria, G. E., Robb, M. A., Cheeseman, J. R., Montgomery, Jr., J. A., Vreven, T., Kudin, K. N., Burant, J. C., Millam, J. M., Iyengar, S. S., Tomasi, J., Barone, V., Mennucci, B., Cossi, M., Scalmani, G., Rega, N., Petersson, G. A., Nakatsuji, H., Hada, M., Ehara, M., Toyota, K., Fukuda, R., Hasegawa, J., Ishida, M., Nakajima, T., Honda, Y., Kitao, O., Nakai, H., Klene, M., Li, X., Knox, J. E., Hratchian, H. P., Cross, J. B., Bakken, V., Adamo, C., Jaramillo, J., Gomperts, R., Stratmann, R. E., Yazyev, O., Austin, A. J., Cammi, R., Pomelli, C., Ochterski, J. W., Ayala, P. Y., Morokuma, K., Voth, G. A., Salvador, P., Dannenberg, J. J., Zakrzewski, V. G., Dapprich, S., Daniels, A. D., Strain, M. C., Farkas, O., Malick, D. K., Rabuck, A. D., Raghavachari, K., Foresman, J. B., Ortiz, J. V., Cui, Q., Baboul, A. G., Clifford, S., Cioslowski, J., Stefanov, B. B., Liu, G., Liashenko, A., Piskorz, P., Komaromi, I., Martin, R. L., Fox, D. J., Keith, T., Al-Laham, M. A., Peng, C. Y., Nanayakkara, A., Challacombe, M., Gill, P. M. W., Johnson, B., Chen, W., Wong, M. W., Gonzalez, C. & Pople, J. A.; Gaussian, Inc., Wallingford CT, [S3] Small, D., Rosokha, S. V., Kochi, J. K. & Head-Gordon, M. J. Phys. Chem. A. 109, (2005). [S4] Zaitsev, V., Rosokha, S. V., Head-Gordon, M. & Kochi, J. K. J. Org. Chem. 71, (2006). [S5] Morita, Y., Aoki, T., Fukui, K., Nakazawa, S., Tamaki, K., Suzuki, S., Fuyuhiro, A., Yamamoto, K., Sato, K., Shiomi, D., Naito, A., Takui, T. & Nakasuji, K. Angew. Chem. Int. Edn. 41, (2002). S35