A Chiral Octadentate Ligand Derived from (R)-1,1Ј-Binaphthyl-2,2Ј-diamine
FULL PAPER
amount of concentrated NH3 (0 to 7%). A light yellow oil was ation, washed several times with MeOH, and dried under vacuum.
obtained in Ͼ 70% yield. [α]2D0 ϭ Ϫ95.11 (c ϭ 1.00·10Ϫ2, CHCl3). Elemental analysis for C64H66Cl4N12Ni2O16·2H2O (1552.77): calcd.
1H NMR (300 MHz, CDCl3, 25 °C, TMS) δ ϭ 0.85Ϫ0.95 (m, 2 (%) C 49.50, H 4.54, N 10.83; found C 49.22, H 4.63, N 10.78.
H, CH2-CH2-CH2), 1.16Ϫ1.27 (m,
2
H, CH2-CH2-CH2), UV/Vis (CH3CN): λmax (ε) ϭ 222 sh (97800), 260 (67500), 272
1.82Ϫ1.94 (m, 4 H, CH2), 2.52Ϫ2.64 (m, 4 H, CH2), 2.64 (s, 6 H, (56800), 282 (42600), 304 (15300), 356 (5400), 566 (8), 980 nm (2
CH3), 7.09Ϫ7.22 (m, 4 H, CH), 7.26Ϫ7.36 (m, 2 H, CH), 7.53 (d, molϪ1·dm3·cmϪ1). CD (CH3CN): λmax (∆ε) ϭ 214 (ϩ61.0), 225
J
H,H ϭ 8.3 Hz, 2 H, CH), 7.83Ϫ7.93 (m, 4 H, CH) ppm. 13C NMR (Ϫ63.2), 245 (ϩ4.72), 265 (Ϫ45.8), 278 sh (Ϫ13.0), 298 (ϩ11.7),
(75.5 MHz, [CDCl3, 25 °C, TMS): δ ϭ 32.0, 40.4, 40.8, 56.0, 121.9, 331 sh (ϩ1.9), 373 (Ϫ2.6), 583 nm (Ϫ0.1 molϪ1·dm3·cmϪ1).
124.6, 126.6, 126.9, 128.5, 129.1, 131.0, 135.1, 151.2 ppm. MS
Caution! Perchlorate complexes with organic ligands are potentially
explosive and should be handled with great care. Only small amounts
(FAB): m/z (%) ϭ 428 (100) [M ϩ1]ϩ.
(R)-(؊)-N,NЈ-Dimethyl-N,NЈ-bis{3-[bis(1-methyl-2-benzimidazolyl- of material should be prepared. We had no problems working with
methyl)]aminopropyl}-1,1Ј-binaphthyl-2,2Ј-diamine (L): (R)-(Ϫ)- the small amounts of perchlorate complex described here.
N,NЈ-Dimethyl-N,NЈ-bis[(3-aminopropyl)]-1,1Ј-binaphthyl-2,2Ј-
Molecular Modelling: The structures of the ligand and the corre-
sponding dinuclear zinc() complex were derived as follows. Start-
ing structures were submitted to SA calculations carried out in va-
diamine (5, 332.5 mg, 0.78 mmol) was dissolved in anhydrous
acetonitrile (40 mL). 2-(Chloromethyl)-1-methylbenzimidazole
(6)[11] (365.7 mg, 3.45 mmol) and dry sodium carbonate were then
cuo over 200 ps, starting from 10 K, heating the system to 500 K
added and the stirred mixture was boiled under reflux for 6 h under
in 80 ps, and then cooling it to 10 K in 110 ps. The time step was
N2. The reaction was followed by TLC (silica gel) using CH2Cl2/
set to 1 fs. The final structures were optimized by MM calculations,
MeOH (9:1, v:v), as eluent. The mixture was then cooled to room
using the conjugate gradient algorithm and requiring that the re-
temperature and the so-obtained precipitate filtered off; it consisted
of product and inorganic salts and thus was treated with CHCl3
and filtered again. The combined filtrates were finally dried under
sidual gradient of energy did not exceed 0.01 kcal·molϪ1·AϪ1. SA
˚
and MM calculations were carried out using the Universal Force
Field.[20] This cycle was repeated 50 times both for the ligand and
the dinuclear zinc() complex. The families of structures generated
were clustered according to RMSD and ranked by relative energies.
The conformers within 10 kJ·molϪ1 above the computed global
minimum conformation were further optimized by semiempirical
calculations using the PM3 method.[21] All calculations were per-
formed on a Silicon Graphics Indigo workstation using the
software packages InsightII and Cerius2 [Biosym/MSI 9685, Scran-
ton Road, San Diego, CA, USA].
vacuum to afford
a
yellow powder in 65% yield.
C64H66N12·1.5CHCl3 (1182.34): calcd. (%) C 66.53, H 5.80, N
14.22; found C 66.41, H 5.90, N 14.21. [α]2D0ϭ Ϫ87.40 (c ϭ
5.00·10Ϫ3, CHCl3). 1H NMR (300 MHz, CDCl3, 25 °C, TMS): δ ϭ
0.70Ϫ0.90 (m, 2 H, CH2-CH2-CH2-N), 1.00Ϫ1.30 (m, 2 H, CH2-
CH2-CH2-N), 1.45Ϫ1.65 (m, 4 H, CH2-CH2-CH2), 2.10Ϫ2.37 (m,
4 H, CH2-N-binaphthyl), 2.37 (s, 6 H, CH3-N-binaphthyl), 3.45 (s,
12 H, CH3-N-benzimidazole), 3.51Ϫ3.64 (d, 8 H, CH2-benzimid-
azole), 6.98Ϫ7.13 (m, 4 H, CH), 7.20Ϫ7.26 (m, 16 H, CH),
7.65Ϫ7.72 (m, 8 H, CH) ppm. 13C NMR (75.5 MHz, CDCl3, 25
°C, TMS): δ ϭ 24.1, 30.1, 40.1, 51.2, 52.2, 55.5, 109.4, 113.7, 120.0,
121.4, 122.4, 123.1, 124.3, 126.4, 126.5, 128.0, 128.6, 129.1, 129.6,
130.5, 134.6, 136.4, 142.4, 150.7, 151.7 ppm. MS (FAB): m/z (%) ϭ
1003 (100) [M ϩ1]ϩ. UV/Vis (CH3CN): λmax (ε) ϭ 208 (239000),
258 (71000), 271 sh (54400), 278 sh (43500), 286 (32400), 305 sh
(11900), 352 nm (6300 molϪ1·dm3·cmϪ1). CD (CH3CN): λmax
(∆ε) ϭ 214 (ϩ169.8), 225 (Ϫ124.5), 240 sh (Ϫ3.8), 248 (ϩ2.7), 260
sh (Ϫ36.1), 266 (Ϫ44.7), 301 (ϩ23.2), 368 nm (Ϫ5.9
molϪ1·dm3·cmϪ1).
Acknowledgments
The authors thank the University of Milano for support through
the FIRST, the University of Pavia for support through the FAR,
and the C. I. R. C. S. M. B.
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Caution! 1,1Ј-Binaphthyl-2,2Ј-diamine derivatives are not stable in
solution; after a few hours a deeper color orange is observed. These
compounds should be kept dry and protected from light.
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Synthesis of the Metal Complexes. [Zn2L](ClO4)4: A methanolic
solution of Zn(ClO4)2·7H2O (0.038 mmol) (4 mL) was added drop-
wise to a solution of the ligand L (0.019 mmol) in CHCl3/MeOH
(1:5, v:v) (20 mL). The mixture was stirred for 3 h at room tempera-
ture, and then the solvent was removed by rotary evaporation. The
residue was washed with a little water, filtered, and dried under
vacuum. Elemental analysis for C64H66Cl4N12O16Zn2 (1530.14):
calcd. (%) C 50.20, H 4.31, N 10.98; found C 50.33, H 4.41, N
10.95. UV/Vis (CH3CN): λmax (ε) ϭ 220 sh (99000), 254 (46300),
264 (44400), 272 (43000), 280 (37200), 300 sh (10500), 350 nm
(3000 molϪ1·dm3·cmϪ1). CD (CH3CN): λmax (∆ε) ϭ 213 (ϩ122.5),
225 (Ϫ95.1), 240 sh (Ϫ8.2), 263 (Ϫ31.9), 298 (ϩ9.3), 365 nm
(Ϫ2.8 molϪ1·dm3·cmϪ1).
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[Ni2L](ClO4)4·2H2O: This compound was prepared in a similar way
as for the zinc complex, but using Ni(ClO4)2·6H2O as metal salt.
A pale green precipitate was obtained after addition of the metal
salt to the ligand solution. The complex was separated by centrifug-
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2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 3943