Download PDF
Synlett 2004(7): 1167-1170  
DOI: 10.1055/s-2004-822912
LETTER
© Georg Thieme Verlag Stuttgart · New York

Dendritic EDA-Schiff Bases of the Salen-Type

Karsten Portnera, Martin Niegerb, Fritz Vögtle*a
a Kekulé Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
Fax: +49(228)735662; e-Mail: voegtle@uni-bonn.de;
b Institut für Anorganische Chemie, Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany
Fax: +49(228)735823; e-Mail: m.nieger@uni-bonn.de;
Further Information

Publication History

Received 8 December 2003
Publication Date:
28 April 2004 (online)

    Permissions and Reprints All articles of this category

Abstract

Dendronized salicylidene-ethylenediamine (salen) compounds are prepared for the first time through diaza-Cope re­arrangement in which the ethano carbons of the ethylenediamine (EDA) are substituted with two types of dendritic wedges: Fréchet-ether and ester-dendrons. The X-ray analysis of a dendritic salen with ester dendrons is presented.

Key words

dendrimers - Schiff bases - diaza-Cope rearrangement - salen ligands - valence isomerisation

18

General Procedure for diaza-Cope Rearrangements: The amount of 0.29 mmol meso-1,2-bis(2-hydroxyphenyl)-ethylenediamine(1) and 0.594 mmol of the specific formyl substituted dendron 2 or 3 are dissolved in ca. 20 mL MeCN and refluxed for approximately 4 h. In the cold, yellow crystals precipitate. Yield 225 mg (92%) for 6 and 245 mg (94%) for 7, respectively.
Compound 6: Yellow solid; mp 209-211 °C. 1H NMR (400 MHz, d 6-acetone): δ = 5.44 (s, 2 H, N-CH ethylene), 5.74 (s, 8 H, O-CH 2), 7.14 (d, 4 H, 4 J HH = 1.9 Hz, CH arom), 7.17 (t, 2 H, 4 J HH = 2.2 Hz, CH arom), 7.45-7.49 (m, 20 H, 3 J HH = 1.4 and 2.2 Hz, CH phenyl), 7.79-7.82 (m, 3 J HH = 2.0 Hz, CH arom), 7.91 (s, 2 H, N=CH). 13C NMR (100.6 MHz, d 6-acetone): δ = 75.3 (O-CH2), 79.2 (CHethylene), 102.8, 106.1, 117.4, 119.2 (CHarom), 121.6 (C quart,arom C-CN), 128.9, 129.2, 132.2, 133.9 (CHarom), 141.1 (CHarom-CH2), 142.1 (C quart,arom-Cethylene), 150.9 (Cquart,arom-OH), 153.5 (C quart,arom-OCH2), 164.8 (C=N). FAB-MS: m/z = 845.5 [M+], 741.5 [M+ - 104], 663.5 [741.5 - C6H6 +], 647.5 [741.5 - C6H6O+], 422.2 [M/2+]. Anal. Calcd for C56H48O6N2: C, 79.6; H, 5.73; N, 3.32. Found: C, 79.07; H, 5.46; N, 3.38;
Compound 7: Yellow crystals; mp 238-240 °C (acetone). 1H NMR (400 MHz, d 6-acetone): δ = 5.31 (s, 2 H, CH ethylene), 6.83 (m, 2 H, 3 J HH = 8.4 Hz, 4 J HH = 1.2 Hz, CH arom), 6.87 (m, 2 H, 4 J HH = 1.2 Hz, 3 J HH = 7.3 Hz, 3 J HH = 7.6 Hz, CH arom), 7.24 (t, 2 H, 3 J HH = 2.1 Hz, CH arom), 7.31 (m, 2 H, 4 J HH = 1.6 Hz, 3 J HH = 7.3 Hz, 3 J HH = 8.4 Hz, CH arom), 7.37 (m, 2 H, 3 J HH = 7.6 Hz, 4 J HH = 1.6 Hz, CH arom), 7.41 (d, 2 H, 3 J HH = 2.1 Hz, CH arom), 7.58-7.59 (m, 8 H, 4 J HH = 1.1 Hz, 3 J HH = 7.4 Hz, 3 J HH = 7.9 Hz, CH arom), 7.72 (m, 2 H, 4 J HH = 1.3 Hz, 3 J HH = 7.4 Hz, CH arom), 8.14 (m, 8 H, 4 J HH = 1.3 Hz, 3 J HH = 7.9 Hz, CH arom), 8.59 (s, 2 H, N=CH). 13C NMR (100.6 MHz, d 6-acetone): δ = 79.2 (CHethylene), 116.3, 117.4, 119.6, 120.2 (CHarom), 129.7 (Cquart, arom C-CN), 130.7, 130.8 (CHarom), 143.4 (Cquart, arom C-CN), 152.5 (Cquart, arom C-O), 161.9 (Cquart, arom C-O), 161.9 (Cquart, arom C-OH), 165.2 (C=N), 168.6 (CO2), 133.3 (Cquart, arom C-CO2), 133.6, 134.7 (CHarom). FAB-MS: m/z = 901.2 [M + H+], 450.1 [M/2+]. MALDI-TOF MS: m/z = 940.0 [M + K+], 924.0 [M + Na+], 901.0 [M+], 797.0 [M - C7H4O+]. Anal. Calcd for C56H40O10N2: C, 74.66; H, 4.47; N, 3.11. Found: C, 74.25; H, 4.47; N, 3.20.
X-Ray structure analysis of 7: C56H40N2O10·2C3H6O: yellow crystals, crystal dimension 0.03 × 0.15 × 0.50 mm3; M = 1017.06; triclinic, space group P-1 (No. 2), a = 9.3498 (8), b = 11.7346 (11), c = 12.4850 (13) Å, α = 101.320 (6)°, β = 95.220 (5)°, γ = 96.393 (5)°, V = 1325.8 (2) Å3, Z = 1, µ(MoK α) = 0.0.89 mm-1, T = 123 (2) K, F(000) = 534. 10418 Reflection up to 2θmax. = 50° were measured on a Nonius KappaCCD diffractometer with MoK α radiation, 4134 of which were independent and used for all calculations. The structure was solved by direct methods and refined to F2 anisotropically, the H atoms were refined with a riding model. The final quality coefficient wR2 (F2) for all data was 0.2429, with a conventional R(F) = 0.0793 for 321 parameters and 88 restraints.
Crystallographic data (excluding structure factors) for the structures reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication no. CCDC-221830 (9). Copies of the data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Centre, 12, Union Road, Cambrigde CB2 1EZ, UK; fax: +44 (1223)336033; e-mail: deposit@ccdc.cam.ac.uk].

19

General Procedure for the Complexation of 7 with Transition Metal Cations M ²+ : The amount of 0.056 mmol of 7 are solved in 3 mL CH2Cl2 and 3 mL of a solution of the corresponding M2+-triflate is added at once. The resulting solution is refluxed for approximately 2 h. In the cold, the M2+-complexes precipitate. The nickel(II)-triflate gives 36.3 mg (68%) of N,N′-disalicylidene-meso-1,2-bis(3,5-benzoyl-oxydiphenyl)ethylenediaminocobalt(II)(8) and cobalt(II)-triflate gives 29.2 mg (55%) of N,N′-disalicylidene-meso-1,2-bis(3,5-benzoyloxydiphenyl)ethylenediaminonickel
(II)(9).
Compound 8: Greyish green powder. MALDI-TOF MS: m/z = 980.0 [M + Na+], 956.9 [M+].
Compound 9: Grey powder. MALDI-TOF MS: m/z = 980.0 [M + Na+], 957.9 [M+], 854.0 [M - C7H4O+].