86
3 Luminescent Mechanochromism of a Chiral Complex: Distinct …
Synthesis of (S)-1.
THF, 0 °C, 1 h
ZnBr 2
0 °C, 4 h
MgBr / THF
(S)-2
N
N
C
C
Au
Au
Cl
Cl
N
N
C
C
Au
Au
(S)-1
(S)-1 was prepared from (S)-2
10 (0.145, 0.20 mmol) according to the procedure similar to that described for the preparation of (rac)-1. Yield: 74% (0.127 g,
0.149 mmol, orange solid).
1 H NMR (400 MHz, CDCl3, δ): 7.01–7.06 (m, 2H),
7.16–7.20 (m, 6H), 7.30 (dd, J = 1.6, 8.0 Hz, 4H), 7.52 (t, J = 7.8 Hz, 2H), 7.71–
7.75 (m, 4H) 8.09 (d, J = 8.0 Hz, 2H), 8.19 (d, J = 8.8 Hz, 2H).
13 C NMR (100 MHz,
CDCl3, δ): 122.7 (C), 123.3 (CH), 126.0 (CH), 126.1 (CH), 127.5 (CH), 129.2 (CH),
129.3 (CH), 131.0 (C), 131.6 (C), 132.0 (CH), 133.8 (C), 140.6 (CH), 162.5 (C),
164.4 (C). MS-ESI (m/z): [M + Na] + calculated for C 34 H 22 Au 2 N 2 Na+, 875.10;
found, 875.10. Anal. Calcd. For C 34 H 22 Au 2 N 2 : C, 47.90; H, 2.60; N, 3.29. Found:
C, 48.23; H, 2.75; N, 3.09.
3.2.2 Preparation of the Single Crystals of (rac)-1G
and (S)-1G
The resulting solid was dissolved in CH 2 Cl 2 in a vial and hexane was carefully
layered for crystallization and allowed to stand at room temperature to give CH 2 Cl 2
included crystals (rac)-1G and (S)-1G.
3.3 Single Crystal X-ray Diffraction (XRD) Analyses
To investigate the crystal structures, single-crystal X-ray diffraction (XRD) analyses of (rac)-1G and (S)-1G crystals were performed. Single-crystal XRD analysis
revealed that (rac)-1G crystallized in the Pbcn space group. In the (rac)-1G crystal,
two molecules of the same enantiomer formed a dimer unit, denoted as an S-S or
R-R dimer, where each molecule was connected through aurophilic interactions with
Au–Au distances of 3.06, 3.34, and 3.06 Å and CH-π interactions (Fig. 3.2a). Both
the S-S and R-R dimers contained an inversion center (red dots in Fig. 3.2b). The S-S
3 Luminescent Mechanochromism of a Chiral Complex: Distinct …
Synthesis of (S)-1.
THF, 0 °C, 1 h
ZnBr 2
0 °C, 4 h
MgBr / THF
(S)-2
N
N
C
C
Au
Au
Cl
Cl
N
N
C
C
Au
Au
(S)-1
(S)-1 was prepared from (S)-2
10 (0.145, 0.20 mmol) according to the procedure similar to that described for the preparation of (rac)-1. Yield: 74% (0.127 g,
0.149 mmol, orange solid).
1 H NMR (400 MHz, CDCl3, δ): 7.01–7.06 (m, 2H),
7.16–7.20 (m, 6H), 7.30 (dd, J = 1.6, 8.0 Hz, 4H), 7.52 (t, J = 7.8 Hz, 2H), 7.71–
7.75 (m, 4H) 8.09 (d, J = 8.0 Hz, 2H), 8.19 (d, J = 8.8 Hz, 2H).
13 C NMR (100 MHz,
CDCl3, δ): 122.7 (C), 123.3 (CH), 126.0 (CH), 126.1 (CH), 127.5 (CH), 129.2 (CH),
129.3 (CH), 131.0 (C), 131.6 (C), 132.0 (CH), 133.8 (C), 140.6 (CH), 162.5 (C),
164.4 (C). MS-ESI (m/z): [M + Na] + calculated for C 34 H 22 Au 2 N 2 Na+, 875.10;
found, 875.10. Anal. Calcd. For C 34 H 22 Au 2 N 2 : C, 47.90; H, 2.60; N, 3.29. Found:
C, 48.23; H, 2.75; N, 3.09.
3.2.2 Preparation of the Single Crystals of (rac)-1G
and (S)-1G
The resulting solid was dissolved in CH 2 Cl 2 in a vial and hexane was carefully
layered for crystallization and allowed to stand at room temperature to give CH 2 Cl 2
included crystals (rac)-1G and (S)-1G.
3.3 Single Crystal X-ray Diffraction (XRD) Analyses
To investigate the crystal structures, single-crystal X-ray diffraction (XRD) analyses of (rac)-1G and (S)-1G crystals were performed. Single-crystal XRD analysis
revealed that (rac)-1G crystallized in the Pbcn space group. In the (rac)-1G crystal,
two molecules of the same enantiomer formed a dimer unit, denoted as an S-S or
R-R dimer, where each molecule was connected through aurophilic interactions with
Au–Au distances of 3.06, 3.34, and 3.06 Å and CH-π interactions (Fig. 3.2a). Both
the S-S and R-R dimers contained an inversion center (red dots in Fig. 3.2b). The S-S