Synthesis, structure and functions of discrete titanium-based multinuclear architectures

Going Up the Ladder: Stacking Four 4,4′-Bipyridine Moieties within a Ti(IV)-Based Tetranuclear Architecture

“…The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.inorgchem.2c02566. 1 H, 13 C, and 1 H− 15 N HSQC NMR spectra, MS spectra, crystallographic data and tables, and molecular models of Ti 2 (4) 2 and Ti 2 (4) 2 (HO i Pr) 2 (PDF)…”

“…Depending on the ligand/metal combinations, these species are widely diverse in terms of nuclearity, topology, and geometry . In this context, Ti­(IV) has been intensively employed to elaborate self-assembled architectures, and in particular, Ti­(IV) ions associated with dicatechol − or bis-biphenol − ligands are largely used to construct sophisticated helicates or cages . Triple-stranded titanium helices have TiO 6 nodes, whereas in double-stranded helices, the metal cations adopt TiO 4 or TiO 4 L 2 coordination spheres, where the auxiliary ligands L are typically oxygen, nitrogen, or halogen ligands that act as stabilizing spectators.…”

“…4 In this context, Ti(IV) has been intensively employed to elaborate self-assembled architectures, and in particular, Ti(IV) ions associated with dicatechol 5−9 or bis-biphenol 10−12 ligands are largely used to construct sophisticated helicates or cages. 13 Triple-stranded titanium helices have TiO 6 nodes, whereas in double-stranded helices, the metal cations adopt TiO 4 or TiO 4 L 2 coordination spheres, where the auxiliary ligands L are typically oxygen, nitrogen, or halogen ligands that act as stabilizing spectators. The spacer separating the two bidentate ligands in each strand generally does not participate in forming the helical framework but can influence the assembly process by providing or limiting the flexibility 8,14−16 or providing functionality.…”

“…1 H NMR (300 MHz, CDCl 3 ): δ 8.84 (dd, J = 5.1, 0.8 Hz, 2H), 8.28 (t, J = 1.5 Hz, 2H), 8.08 (dt, J = 7.7, 1.5 Hz, 2H), 8.05 (dd, J = 1.7, 0.8 Hz, 2H), 7.72 (dt, J = 7.7, 1.5 Hz, 2H), 7.58 (t, J = 7.7 Hz, 2H), 7.54 (dd, J = 5.1, 1.7 Hz, 2H), 7.44− 7.30 (m, 8H), 6.94 (d, J = 8.5 Hz, 2H), 3.80 (s, 6H), 3.25 (s, 6H), 1.38 (s, 18H), 1.34 (s, 18H). 13 A solution of 9 (0.47 g, 0.49 mmol) in 48% (w/ w) aqueous HBr (10 mL) was refluxed for 5 days under argon. After cooling to 0 °C, the mixture was added to an excess of a vigorously stirred saturated solution of NaHCO 3 (aqueous).…”

“…1 H NMR (300 MHz, CD 3 OD): δ 8.73 (d, J = 5.2 Hz, 2H), 8.25 (s, 2H), 8.22 (t, J = 1.5 Hz, 2H), 7.97 (d, J = 8.0 Hz, 2H), 7.77 (dd, J = 5.2, 1.5 Hz, 2H), 7.68 (d, J = 7.8 Hz, 2H), 7.54 (t, J = 7.8 Hz, 2H), 7.41 (d, J = 2.5 Hz, 2H), 7.33−7.24 (m, 6H), 6.96−6.83 (m, 2H), 1.38 (s, 18H), 1.33 (s, 18H). 13 Compound Ti3(DMF) 2 . In a sealable vial, titanium(IV) isopropoxide (2.5 μL, 8.5 μmol) was added to a degassed solution of 3H 4 (7.0 mg, 7.8 μmol) in anhydrous toluene (2.5 mL).…”