The article describes syntheses, crystal structures and magnetic properties of six defective dicubane type NiII4 clusters of compositions NiII4(HL1)2(µ3‐X)2(µ1,1‐N3)2(µ1,3‐carboxylato)2·nH2O (1, X = ...OMe–, carboxylato = o‐benzoylbenzoato, n = 0; 2, X = {(OMe–)0.83(N3–)0.17}, carboxylato = phenyl acetato, n = 2; 3, X = {(OMe–)0.80(N3–)0.20}, carboxylato = salicylato, n = 0; 4, X = OH–, carboxylato = o‐benzoylbenzoato, n = 2; 5, X = {(N3–)0.58(OMe–)0.42}, carboxylato = o‐benzoylbenzoato, n = 2) and NiII4(HL1)2(µ1,1,1‐N3)2(µ1,1‐N3)2(N3)2(H2O)2·4DMF (6), where H2L1 is 2‐Formyl‐6‐{(2‐hydroxy‐1,1‐dimethyl‐ethylimino)‐methyl}‐4‐ethyl‐phenol, and this is the partially hydrolyzed product of initially employed ligand H3L, 2,6‐bis‐{(2‐hydroxy‐1,1‐dimethyl‐ethylimino)‐methyl}‐4‐ethyl‐phenol. Each of the two compartments of each HL1– in 1–6 is occupied by a NiII ion, to form a NiII2 fragment. The common bridges between the two metal ions in a dinuclear fragment are µ‐phenoxo of HL1– and one µ3‐core ligand (methoxo/hydroxo/mixture of methoxo and µ1,1,1‐azido) while the additional bridge in 1–5 is a µ1,3‐carboxylato. Two dinuclear fragments are interlinked by two µ1,1‐azido and two µ3‐core ligands. Interestingly, the µ3‐methoxo compound 1 and the µ3‐hydroxo compound 4 are interconvertible in both ways as the function of the solvents. Variable‐temperature and variable‐field magnetic studies reveal overall ferromagnetic interactions in each of 1–6.
This manuscript describes six defect‐dicubane NiII4 compounds containing two µ3‐methoxo or µ3‐hydroxo or µ3‐azido or mixture of µ3‐methoxo/µ3‐azido core ligands. Solvent‐dependent and both‐way interconversion between µ3‐methoxo and µ3‐hydroxo systems takes place. All exhibit overall ferromagnetic interactions.
The ability to append targeting biomolecules to chelators that efficiently coordinate to the diagnostic imaging radionuclide, 99mTc, and the therapeutic radionuclide, 188Re, can potentially enable ...receptor-targeted “theranostic” treatment of disease. Here we show that Pt(0)-catalyzed hydrophosphination reactions are well-suited to the derivatization of diphosphines with biomolecular moieties enabling the efficient synthesis of ligands of the type Ph2PCH2CH2P(CH2CH2–Glc)2 (L, where Glc = a glucose moiety) using the readily accessible Ph2PCH2CH2PH2 and acryl derivatives. It is shown that hydrophosphination of an acrylate derivative of a deprotected glucose can be carried out in aqueous media. Furthermore, the resulting glucose–chelator conjugates can be radiolabeled with either 99mTc(V) or 188Re(V) in high radiochemical yields (>95%), to furnish separable mixtures of cis- and trans-M(O)2 L 2+ (M = Tc, Re). Single photon emission computed tomography (SPECT) imaging and ex vivo biodistribution in healthy mice show that each isomer possesses favorable pharmacokinetic properties, with rapid clearance from blood circulation via a renal pathway. Both cis-99mTc(O)2 L 2+ and trans-99mTc(O)2 L 2+ exhibit high stability in serum. This new class of functionalized diphosphine chelators has the potential to provide access to receptor-targeted dual diagnostic/therapeutic pairs of radiopharmaceutical agents, for molecular 99mTc SPECT imaging and 188Re systemic radiotherapy.
A small number of sociologists of sport have opted to produce what have been defined as autoethnographies or narratives of self. These are highly personalized accounts that draw upon the experiences ...of the author/researcher for the purposes of extending sociological understanding. Such work is located at the boundaries of disciplinary practices and raises questions as to what constitutes proper research. In this paper, I explore this issue by focusing upon the criteria used by various audiences to pass judgment on an autoethnography/narrative of self that I submitted to, and eventually had published, in a leading journal. The problems of having inappropriate criteria applied to this work are considered, and the charge of self-indulgence as a regulatory mechanism is discussed. Reactions to a more trusting tale are then used to signal various criteria that might be more relevant to passing judgment upon this kind of tale in the future.
Synthesis, single crystal X-ray structure, catechol oxidase activity and ESI-MS (positive) of one mixed-valence diphenoxo-bridged dinuclear CoIIICoII complex derived from a Robson type ...tetraiminodiphenolate macrocyclic ligand are described. This work presents rare example of cobalt system showing catechol oxidase activity and unique examples of hydrogen-bonded metal complex⋯solvent aggregates in gas phase (predominant species in ESI-MS). Display omitted
•One mixed-valence CoIIICoII complex derived from a Robson type macrocyclic ligand.•Rare example of an active cobalt catalyst for catechol oxidase activity.•Single crystal X-ray structure and ESI-MS spectra.•Unique examples of hydrogen bonded metal complex⋯solvent aggregates in gas phase (ESI-MS).•Drastic change of properties as a result of slight change in ligand periphery.
This paper presents the synthesis, crystal structure, catechol oxidase activity and electrospray ionization mass spectra (ESI-MS positive) of a mixed-valence CoIIICoII compound CoIIICoIIL(N3)3· 0.5CH3CN·0.27H2O (1) derived from the Robson type tetraiminodiphenolate macrocyclic ligand H2L, which is the 2+2 condensation product of 2,6-diformyl-4-methylphenol and 2,2-dimethyl-1,3-diaminopropane. Compound 1 crystallizes in the monoclinic P21/n space group. The structure consists of two independent units of diphenoxo-bridged CoIIICoII moieties where the CoIII center is hexacoordinated (distorted octahedral) having O(phenoxo)2N(imine)2N(azide)2 environment, while CoII center is pentacoordinated (distorted square pyramidal) having O(phenoxo)2N(imine)2N(azide) environment. Catechol oxidase activity of 1 has been investigated using 3,5-di-tert-butylcatechol (3,5-DTBCH2) as the substrate, revealing that it is an active catalyst with Kcat value 114.24h–1. Electrospray ionization mass spectra (ESI-MS positive) of 1 and 1+3,5-DTBCH2 in acetonitrile have been recorded. No complex⋯substrate aggregate in the spectrum of 1+3,5-DTBCH2 has been identified. However, interestingly, two hydrogen bonded metal complex⋯solvent aggregates {CoII(LH2)(N3)}⋯(CH3CN)+ and {CoIII(LH2)(N3)2}⋯(CH3CN)+ have been identified in the spectrum of 1. Catecholase activity has also been studied with pyrocatechol and tetrachlorocatechol (TCCH2) as substrates. While no activity has been found with TCCH2, weak activity has been observed with pyrocatechol.
A series of intermolecular transition metal frustrated Lewis pairs (FLPs) based on zirconocene alkoxide complexes (Cp2Zr(OMes)+ 1 or (Cp*2Zr(OMes)+ 2) with nitrogen Lewis bases (NEt3, NEtiPr2, ...pyridine, 2-methylpyridine, 2,6-lutidine) are reported. The interaction between Zr and N depends on the specific derivatives used, in general more sterically encumbered pairs leading to a more frustrated interaction; however, DOSY NMR spectroscopy reveals these interactions to be dynamic in nature. The pairs undergo typical FLP-type reactivity with D2, CO2, THF, and PhCCD. The catalytic dehydrocoupling of Me2NH·BH3 is also reported. Comparisons can be made with previous work employing phosphines as Lewis bases suggesting that hard–hard or hard–soft acid–base considerations are of little importance compared to the more prominent roles of steric bulk and basicity.
Reactions of the copper(II) metallo-ligand derived from N,N′-bis(3-ethoxysalicylidene)-1,4-butanediamine with perchlorate salts of NaI, KI, CaII, SrII and BaII produce nearly linear trinuclear ...CuIIMI/IICuII compounds.
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•An unexplored compartmental ligand, N,N′-bis(3-ethoxysalicylidene)-1,4-butanediamine.•Five heterotrinuclear CuIIMI/IICuII compounds (MI/II = NaI, KI, CaII, SrII, BaII).•Structural resemblance among NaI, KI, CaII, SrII and BaII.•SHAPE analysis versus Addison’s geometric parameter – First report of mismatching.•Surprising observation in bond lengths: KO < NaO.
The work in this investigation deals with syntheses, crystal structures and ESI-MS positive of five compounds of composition (CuIIL)2NaI(ClO4) (1), (CuIIL)2KI(ClO4) (2), {CuIIL(H2O)}CaII(CuIIL)(ClO4)2 (3), (CuIIL)(µ-ClO4)SrII{CuIIL(MeOH)0.6}(ClO4)·1.2MeOH (4) and (CuIIL)(µ-ClO4)BaII{CuIIL(MeOH)}(ClO4)·MeOH (5), where H2L = N,N′-bis(3-ethoxysalicylidene)-1,4-butanediamine. The s-block metal ion in all of these five compounds occupies an O8 (four phenoxo and four ethoxy) site provided by two L2− ligands. While NaI, KI and CaII are eight-coordinated, SrII and BaII are nine-coordinated due to additional coordination by an oxygen atom of a bridging perchlorate ligand. In all of 1–5, the two CuII and MI/II are positioned in almost linear way (CuII–MI/II–CuII angle range = 168.24–175.39°). The geometries of the coordination environments have been understood from SHAPE analyses. A disagreement has been observed for the first time between the results of SHAPE analyses and Addison geometric parameter for the pentacoordinated environment. Some interesting structural features regarding composition, metal-ligand bond lengths and twisting of the aromatic rings have been observed. UV-Vis spectra indicates two d-d absorption of copper(II) centers in each of the five compounds. ESI-MS positive reveals the appearance of some tri/di/mononuclear ions.
Lamotrigine ethanol monosolvate Hall, Charlie L; Potticary, Jason; Sparkes, Hazel A ...
Acta crystallographica. Section E, Crystallographic communications,
05/2018, Letnik:
74, Številka:
Pt 5
Journal Article
Recenzirano
Odprti dostop
Lamotrigine is an active pharmaceutical ingredient used as a treatment for epilepsy and psychiatric disorders. Single crystals of an ethano-late solvate, C
H
Cl
N
·C
H
OH, were produced by slow ...evaporation of a saturated solution from anhydrous ethanol. Within the crystal structure, the lamotrigine mol-ecules form dimers through N-H⋯N hydrogen bonds involving the amine N atoms in the
position of the triazine group. These dimers are linked into a tape motif through hydrogen bonds involving the amine N atoms in the
position. The ethanol and lamotrigine are present in a 1:1 ratio in the lattice with the ethyl group of the ethanol mol-ecule exhibiting disorder with an occupancy ratio of 0.516 (14):0.484 (14).
γ,δ-Unsaturated alcohols are prepared efficiently in two steps from o-hydroxycinnamaldehyde. The TMSOTf-mediated reaction of the γ,δ-unsaturated alcohols with aldehydes creates two oxygen ...heterocycles and three new stereocenters in a single pot. The approach is versatile, and by varying the boronic acid, Grignard reagent, and aldehyde, different substituents may be introduced, while use of a chiral base in the conjugate addition gives enantioenriched products.
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