An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The novel ligand DIG(3)tren has three N',N ''-diisopropylguanidinyl (DIG) moieties. We report on the structures of two cobalt complexes that show how an isopropylamino group from each DIG acts as a flap that can either close over the metal or rotate away from the metal to open up a site for auxiliary ligand binding. Two of the -NH(iPr) flaps are open in pink [Co(DIG(3)tren)(OAc)]OAc (1), and each of these flaps provides a hydrogen bond to stabilize acetate binding to trigonal bipyrimidal cobalt. The flaps are closed in blue [Co(DIG(3)tren)][BPh4](2) (2), yielding a rare example of a trigonal (mono)pyramidal [ML](2+) ion.

Dioxygen-sensitive dinuclear manganese complexes of the phenoxo-hinged dinucleating ligand 2,6-bis([N,N'-bis(2-picolyl)amino]methyl)-4-tert-butylphenolato (bpbp(-)) containing exogenous labile THF, water and perchlorato ligands are described. The manganese(II) complexes [Mn-2(bpbp)(ClO4)(2)(THF)](+) (1) and [Mn-2(bpbp)(ClO4)(H2O)(2)](2+) (2) have been isolated as the salts 1 center dot ClO4 center dot THF center dot 3H(2)O, 1-B(C6H5)(4)center dot 4THF and 2 center dot(ClO4)(2)center dot H2O. Complexes 1 and 2 are spontaneously oxidised in air in solution and the solid state. The reaction products of the air oxidation in THF, water and methanol solutions are labile dinuclear Mn-II-Mn-III, Mn-2(III) and Mn-III-Mn-IV complexes containing water- and methanol-derived exogenous ligands. In addition, a Mn-4 complex has been isolated. Magnetic susceptibility data confirm the Mn-II-Mn-III oxidation state assignment with an S = 2/S = 5/2 model with weak antiferromagnetic coupling (J = -3.7 cm(-1)) in [Mn-2(bpbp)(CH3O)(2)(H2O)(2)](ClO4)(2) [3 center dot(ClO4)(2)]. A tetranuclear complex, [Mn-4(O)(4-n)(OH)(n)(bpbp)(2)](ClO4)(4) [n = 1 or 2; 7 center dot(ClO4)(4)], recovered from THF shows a Mn4O6 adamantane-type core with the O bridges furnished by the two phenolato groups and four hydroxide/oxide bridges. We have arrived at two feasible formulations for the core metal oxidation states and oxobridge protonation states, namely [Mn-4(III)(O)(2)(OH)(2)(bpbp)(2)](4+) and [(Mn3MnIV)-Mn-III(O)(3)(OH)(bpbp)(2)](4+), for 7, on the basis of a bond valence sum analysis of the crystal structure, elemental analysis and XANES. Thus, complex 7 is at least two oxidation state levels lower than known complexes with the Mn4O6 adamantane core structure. The magnetism of 7 was fitted well to an Mn-4(III) three-J model. Complex cations related to 3 by homology, and to 7 by hydration/solvation, have been identified by ESI mass spectrometry. The [Mn-2(bpbp)(OH)(2)(H2O)(2)](2+) ion (4) present in aqueous solutions on dissolution of 1 center dot ClO4 center dot THF center dot 3H(2)O in air or by simple dissolution of 3 in water-containing solvent is isoelectronic to 3. In the presence of significant amounts of water the Mn-II-Mn-III complexes 3 and 4 are susceptible to further metal oxidation and concomitant aquo ligand deprotonation to give ions assignable to [Mn-III/(IV)(2)(bpbp)O(OCH3)(2)(H2O)](2+) (5) and [Mn-2(III)(bpbp)(OH)(3)(H2O)](2+) (6). ESI mass spectra of water or methanol solutions of 1, 2, 3 and 7 show predominantly an ion assignable to the oxide [Mn-2(bpbp)(O)](2+) (8). Cation 8 is most likely not present in solution. Using mild source conditions and MS-MS techniques, the gas-phase fragmentation pathways to generate 8 have been mapped.

Template copolymerization methods have been utilized to prepare porous materials with immobilized cobalt complexes that catalyze the hydrolytic kinetic resolution of epoxides.

The first structurally characterized Fe(II)-Fe(III) complex containing a M2(mu-OH)2 diamond core is a Robin and Day class II mixed-valence complex.

Superoxide reductases (SORs) are nonheme iron-containing enzymes that reduce HO 2 to H 2 O 2 . Exogenous substrates such as N \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}_{3}^{-}\end{equation*}\end{document} and CN − have been shown to bind to the catalytic iron site of SOR, and cyanide acts as an inhibitor. To understand how these exogenous ligands alter the physical and reactivity properties of the SOR iron site, acetate-, azide-, and cyanide-ligated synthetic models of SOR have been prepared. The x-ray crystal structures of azide-ligated [Fe III (S Me2 N 4 (tren))(N 3 )] + (3), dimeric cyanide-bridged ([Fe III (S Me2 N 4 (tren))] 2 -μ-CN) 3+ (5), and acetate-ligated [Fe III (S Me2 N 4 (tren))(OAc)] + (6) are described, in addition to x-ray absorption spectrum-derived and preliminary crystallographic structures of cyanide-ligated [Fe III (S Me2 N 4 (tren))(CN)] + (4). Cyanide coordination to our model (4) causes the redox potential to shift anodically by 470 mV relative to acetate-ligated 6 and 395 mV relative to azide-ligated 3. If cyanide coordination were to cause a similar shift in redox potential with SOR, then the reduction potential of the catalytically active Fe 3+ center would fall well below that of its biological reductants. These results suggest therefore that cyanide inhibits SOR activity by making the Fe 2+ state inaccessible and thus preventing the enzyme from turning over. Cyanide inhibits activity in the metalloenzyme superoxide dismutase via a similar mechanism. The reduced five-coordinate precursor to 3, 4, and 6 [Fe II (S Me2 N 4 (tren))] + (1) was previously shown by us to react with superoxide to afford H 2 O 2 via an [Fe III (S Me2 N 4 (tren))(OOH)] + intermediate. Cyanide and azide do not bind to 1 and do not prevent 1 from reducing superoxide.

The X-protein of the hepatitis B virus (HBV) is essential for virus infection and contributes to the development of HBV-induced hepatocellular carcinoma (HCC), a disease which causes more than one million deaths each year. Here we describe the design of a novel PROTAC (proteolysis targeting chimeric molecule) capable of simultaneously inducing the degradation of the X-protein, and antagonizing its function. The PROTAC was constructed by fusing the N-terminal oligomerization and C-terminal instability domains of the X-protein to each other, and rendering them cell-permeable by the inclusion of a polyarginine cell-penetrating peptide (CPP). It was predicted that the oligomerization domain would bind the X-protein, and that the instability domain would cause the X-protein to be targeted for proteasomal degradation. Addition of the PROTAC to HepG2 liver cancer cells, engineered to express full-length and C-terminally truncated forms of the X-protein, resulted in the degradation of both forms of the X-protein. A cell-permeable stand-alone form of the oligomerization domain was taken up by HepG2 cells, and acted as a dominant-negative inhibitor, causing inhibition of X-protein-induced apoptosis. In summary, the PROTAC described here induces the degradation of the X-protein, and antagonizes its function, and warrants investigation in a preclinical study for its ability to prevent or treat HBV infection and/or the development of HCC.