On the Effect of Coordination and Protonation Preferences in the Amphiphilic Behavior of Metallosurfactants with Asymmetric Headgroups

Abstract

(9) were synthesized to model the stoichiometric, coordination, and protonation chemistry in the waxy metallosurfactants 1-4. Detailed data analysis and comparison between 1-4 and 5-9 involved mass spectrometric and spectroscopic methods along with crystallographic determination of 5 (P2 1 /c), 6 (P1), 7 (P2 1 /c), 8Ј (the analogue of 8 with tetraphenylborate counterions, P2 1 /c), and 9 (P1). DFT calculations were used to identify the frontier orbitals, polarizability, and dipole moments. Species 1-4 had their

Metals in anticancer therapy: Copper(II) complexes as inhibitors of the 20S proteasome

“…This coordination mode for copper has been observed in our laboratories with the analogous ligand HL tBu , where tertiary butyl groups occupy the 2- and 4- positions of the phenol ring. [20,22] Species 3 shows EPR parameters g ⊥ , A ∥ , and A ⊥ similar to those of 1 and 2 but with g ∥ = 2.30, thus, evidencing bonding along the z-axis typical of five-coordinate copper(II) ions. [19d]…”

“…One copper(II) ion is coordinated to a deprotonated ligand with distances of 1.93 Ǻ to the oxygen of the phenolate group, 1.99 Ǻ to the amine nitrogen, and 2.02 Ǻ for the pyridine nitrogen, resembling similar systems. [19,22] The coordination sphere is completed with the anionic chloro ligand occupying the fourth position 2.24 Ǻ away from the metal. The copper center adopts a distorted square-planar environment.…”

Comparative Activities of Nickel(II) and Zinc(II) Complexes of Asymmetric [NN′O] Ligands as 26S Proteasome Inhibitors

“…Moreover, a secondary amine in this ligand allows for the design of species with appended moieties to enhance water solubility 31,32 (currently at 4.5×10 -5 mol/L for the equivalent gallium complex27) or lipophilicity. 33,34,35,36 Such changes can address concerns with future oral administration as therapeutics.…”

“…Crystals of 2 appeared as colorless needles and crystallize in an orthorhombic P2 1 2 1 2 1 space group, also showing a similar facial coordination of the (L IA ) - ligands in a pseudo-octahedral geometry. However, whereas 1 exhibits a symmetrical all-trans environment described as [Ni<N am1 N am2 ><N py1 N py2 ><O (phO-)1 O (phO-)2 >]39 in a bent arrangement36, 2 is described as having an all-cis [Zn<N am1 O (phO-)2 ><N py1 N am2 ><O (phO-)1 N py2 >]. As observed by the 1 H-NMR spectrum with distinctive signals for methylene groups the two ligands present dissimilar conformations.…”

Synthesis, characterization, antibacterial and antitumoral activities of mononuclear zinc complexes containing tridentate amine based ligands with N3 or N2O donor groups

“…) 81.66(10) 77.95(6) N2-Zn1-N3 76.44(8) ----------torsion angle for this fragment (N1-C5-C6-N2) of -24.2(3)°. The zinc atom shows a deviation of 0.594 Å out of the N1/N2/N3/Cl2 plane.Although it has been shown that the ligand H2L2 usually provides a N2O1 donor set, when reacted with to ZnCl 2 .2H 2 O[34,16,35], it acts as a bidentate ligand through the aminic (N2) and the pyridinic nitrogen (N1) atoms (Figure 3). The distorted tetrahedral geometry presented by the zinc center is completed by two chloro ligands.…”