Enantiomerically Pure Copper(II) Cubanes [Cu₄L₂(OMe)₄] from Chiral Bis‐1,3‐diketones H₂L through Diastereoselective Self‐Assembly

Abstract

Loaded dice: Copper cubanes 1 and ent‐1 were generated in a one‐pot reaction by diastereoselective self‐assembly, starting from ligands derived from L‐ and D‐tartaric acid, respectively. Both structures were confirmed by X‐ray structure analysis.

Supramolecular coordination chemistry

“…for magnetodichroism), and complexes like cubanes represent potential candidates. 75 The first icosanuclear Co II cluster has been isolated and it is also a rare example of a 3d metal cluster with O and N ligation. 76 A {Ni 8 } single molecule magnet has been constructed including pyrazolinone ligands, and has also been extended to include fluoride and azide bridges.…”

Tautomerization‐Mediated Molecular Switching Between Six‐ and Seven‐Membered Rings Stabilized by Hydrogen Bonding

“…[6] In sporadic later studies, tetraketones were used as synthetic intermediates. [7,8] In contrast, they are well-established building blocks in supramolecular coordination chemistry, [9][10][11][12] for example, for the formation of metallacrownethers. [13] In contrastt ot he smaller 1,3-diketones, tetraketones almost exclusively form planar bis-enols in solution and in the solid state.…”

“…In sporadic later studies, tetraketones were used as synthetic intermediates 7. 8 In contrast, they are well‐established building blocks in supramolecular coordination chemistry,9–12 for example, for the formation of metallacrown ethers 13…”

“…D 6 ,3 00.51 MHz): seven-membered ring protochelate: d = 0.58 (s, 6H,C H 3 ), 0.68 (s, 6H,C H 3 ), 0.91 (s, 6H,C H 3 ), 1.19-1.49 (m, 6H,C H 2 ), 1.70-1.90 (m, 2H,C H 2 ), 3.21 (d, 3 J H,H = 3.8 Hz, 2H,C H), 15.54 ppm (s, 2H,O H);s ix-membered ring protochelate: d = 0.61 (s, 6H,C H 3 ), 0.68 (s, 6H,C H 3 ), 0.93 (s, 6H,C H 3 ), 1.19-1.49 (m, 6H, CH 2 ), 1.70-1.90 (m, 2H,C H 2 ),3.36 (d,3 J H,H = 3.9 Hz, 2H,C H),12.53 ppm (s, 2H,O H);13 C{ 1 H} NMR (C 6 D 6 ,7 5.56 MHz): seven-membered ring protochelate: d = 9.7 (2 C, CH 3 ), 18.5 (2 C, CH 3 ), 20.4 (2 C, CH 3 ), 26.3 (2 C, CH 2 ), 31.8 (2 C, CH 2 ), 47.9 (2 C, C q ), 49.5 (2 C, CH), 59.7 (2 C, C q ), 123.8 (2 C, C=CÀO), 158.1 (2 C, OÀC=C), 211.7 ppm (2 C, C=O);s ix-membered ring protochelate: d = 9.0 (2 C, CH 3 ), 18.5 (2 C, CH 3 ), 20.6 (2 C, CH 3 ), 27.4 (2 C, CH 2 ), 30.7 (2 C, CH 2 ), 48.9 (2 C, C q ), 48.9 (2 C, CH), 58.0 (2 C, C q ), 121.1 (2 C, C=CÀO), 155.9(2 C, OÀC=C), 214.6 ppm (2 C, C=O);M S( EI + ): m/z (%): 179 (100, [C 11 H 15 O 2 ] + ), 247 (72, [MÀC 6 H 14 CÀCO] + ), 275 (9, [MÀC 6 H 14 C] + ), 330 (34, [MÀCO] + C), 358 (17, [M] + C); HRMS (EI + ): m/z calcd for C 22 H 30 O 4 : 358.2144;f ound:3 58.2140;I R( FT-ATR): ñ = 2957, 2870, 1655, 1620, 1574, 1556, 1456, 1377, 1267, 1221, 1145, 1067, 1025 cm À1 ;elemental analysis (%) calcd for C 22 H 30 O 4 :C73.71, H8 .44;f ound:C73.22, H8 .42. meso-1,2-Bis(3-oxobicyclo[2.2.1]heptan-2-yl)ethane-1,2-dione (3): Purification by recrystallization from Et 2 Oa nd washing with acetone;b right yellow solid;3 6%;c omplex NMR spectra in CDCl 3 and C 6 D 6 ;M S( EI + ): m/z (%): 109 (15, [C 8 H 9 O 2 ÀC 2 H 4 ] + ), 137 (100, [C 8 H 9 O 2 ] + ), 246 (30, [MÀCO] + C), 274 (2, [M] + C); HRMS (EI + ): m/z calcd for C 16 H 18 O 4 :2 74.1205;f ound:2 74.1232;I R( FT-ATR): ñ = 3250, 2961, 2873, 1736, 1694, 1620, 1480, 1456, 1325, 1288, 1262, 1189, 1167, 1085, 1067, 1033 cm À1 ;e lemental analysis (%) calcd for C 16 H 18 O 4 :C70.06, H6 .61;f ound:C70.03, H6 .32. NMR characterization for semiacetal structure 3a: 1 HNMR ([D 6 ]DMSO, 500.13 MHz): d = 1.18-1.28 (m, 2H,C H 2 ), 1.30-1.43 (m, 3H,C H 2 ), 1.44-1.51 (m, 1H,C H 2 ), 1.51-1.60 (m, 2H,C H 2 ), 1.61-1.70 (m, 2H,C H 2 ), 1.78-1.92 (m, 2H,C H 2 ), 2.14 (br s, 1H,C H), 2.37 (d, 3 J H,H = 3.1 Hz, 1H,C H), 2.46 (d, 3 J H,H = 3.6 Hz, 1H,C H), 2.55 (d, 3 J H,H = 3.5 Hz, 1H,C H), 3.95 (br s, 1H,C H), 7.59 ppm (s, 1H,O H); 13 C{ 1 H} NMR ([D 6 ]DMSO, 125.76 MHz): d = 22.0 (CH 2 ), 23.5 (CH 2 ), 27.5 (CH 2 ), 28.2 (CH 2 ), 34.8 (CH 2 ), 37.1 (CH), 37.4 (CH 2 ), 42.1 (CH), 45.9 (CH), 49.3 (CH), 57.9 (CH), 115.3 (C(OH)ÀO), 116.5 (C=CÀO), 144.6 (C=CÀO), 205.2 (C=O), 205.4 ppm (C=O).…”

New discrete and polymeric supramolecular architectures derived from dinuclear Co(ii), Ni(ii) and Cu(ii) complexes of aryl-linked bis-β-diketonato ligands and nitrogen bases: synthetic, structural and high pressure studies

“…The interaction of b-diketone ligands with metals from across the Periodic Table has been investigated since the beginning of the twentieth century 1 while the metallo-supramolecular chemistry of b-diketone derivatives 2 (and related malonate analogues) 3,4 has been explored more recently. 4 In particular, there has been much interest in systems in which more than one b-diketone motif have been incorporated into supramolecular architectures. 5 We 6-13 and others 15,16 have demonstrated the versatility of such systems in the formation of a variety of neutral triangles, 6,8,13,16 triple helices, 7 tetrahedra 6 and capsules.…”