Macrocyclic and Acyclic Molecules Synthesized from Dipyrrolylmethanes: Receptors for Anions (original) (raw)
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Inorganic Chemistry, 2007
Reagents were purchased from Aldrich and used without further purification. All reactions were carried out in oven dried round bottom flasks. With the exception of DMF, solvents were used as purchased. DMF was dried by stirring overnight with BaO and then was distilled over CaH 2 under reduced pressure. Nuclear magnetic resonance (NMR) spectra were recorded on a Bruker AM 500 spectrometer at 500 MHz. Chemical shifts of the receptors were expressed in ppm and calibrated against TMS as an external reference. Elemental analyses were performed at Desert Analytics, Tucson, AZ. Mass spectral data were obtained from the Mass Spectrometry Laboratory at the University of Kansas on a ZAB HS Mass spectrometer. H 2 L 2+ •Cr 2 O 7 2-(1): L (21 mg, 0.042 mmol) was added to [n-Bu 4 N][ClCrO 3 ] (81 mg, 0.214 mmol) in CHCl 3 (10 mL), and the mixture was stirred at rt for 14 h. A dirty-orange precipitate formed, was filtered, and the residue was washed repeatedly with CHCl 3 (~ 50 mL). The crude product was crystallized from slow evaporation of a H 2 O/CH 3 CN solution to yield orange crystals. Yield: 61%. 1 H NMR (400 MHz, D 2 O): 7.75 (br, 6H, Ar), 3.75 (br, 8H, NCH 2 CH 2), 3.50 (br, 8H, NCH 2), 3.05 (br, 6H, CH 3). FAB MS: m/z
Journal of the American Chemical Society, 2003
With an eye toward the eventual selective modification of noncovalent structures, we used ESI-MS, X-ray crystallography, and NMR spectroscopy to study the anion's influence on the structure and dynamics of self-assembled ion pair receptors formed from guanosine G 1. We compared five complexes of formula (G 1)16‚2Ba 2+ ‚4Acontaining different organic anions: 2,4,6-trinitrophenolate (2), 2,6dinitrophenolate (3), 4-methyl-2,6-dinitrophenolate (4), 4-methoxy-2,6-dinitrophenolate (5), and 2,5dinitrophenolate (6). Crystallography reveals that anion-nucleobase hydrogen bond geometry is sensitive to both phenolate basicity and structure. For the 2,6-substituted anions 2-5, progressive shortening of anion-nucleobase hydrogen bonds is correlated with increased phenolate basicity. Lipophilic Gquadruplexes with different anions also have much different kinetic stabilities in CD 2Cl2 solution. Proton NMR shows that free 6 exchanges faster with G-quadruplex-bound anion than do the 2,6-dinitrophenolates 2-5. The increased lability of 6 is probably because, unlike the 2,6-dinitrophenolates, this anion cannot effectively chelate separate G8‚M 2+ octamers via anion-nucleobase hydrogen bonds. In addition to these structural effects, the anion's basicity modulates the anion exchange rate between its free and bound states. 2D EXSY NMR shows that 3 and 5 exchange about 7 times slower than the less basic picrate (2). The use of 3, a relatively basic dinitrophenolate that hydrogen bonds with the amino groups of the two "inner" G 4quartets, resulted in extraordinary kinetic stabilization of the G-quadruplex in CD2Cl2. Thus, no isomerization product (G 1)8‚Ba 2+ ‚(G 1)8‚Sr 2+ ‚4(3) was observed even 2 months after the separate G-quadruplexes (G 1)16‚2Ba 2+ ‚4(3) and (G 1)16‚2Sr 2+ ‚4(3) were combined in CD2Cl2. In sharp contrast, G-quadruplexes containing the isomeric 6 anion have isomerization half-lives of approximately t1/2 ) 30 min under identical conditions. All the evidence indicates that the structure and electronics of the organic anions, bound to the assembly's periphery, are crucial for controlling the kinetic stability of these cation-filled G-quadruplexes. (1) (a) Whitesides, G. M.; Simanek, E. E.; Mathias, J. P.; Seto, C. T.; Chin, D. N.; Mammen, M.; Gordon, D. M. Marlow, A. L.; Fettinger, J. C.; Fabris, D.; Haverlock, T. J.; Moyer, B. A.; Davis, J. T. Angew. Chem., Int. Ed. 2000, 39, 1283-1285. (d) Fenniri, H.; Mathivanan, P.; Vidale, K. L.; Sherman, D. M.; Hallenga, K.; Wood, K. V.; Stowell, J. G. J. Am. Chem. Soc. 2001, 123, 3854-3855. (e) Carrasco, H.; Foces-Foces, C.; Perez, C.; Rodriguez, M. L.; Martin, J. D.
Recent advances (during the 2007-2014 period) in the coordination and organometallic chemistry of compounds containing natural and artificially prepared radionuclides (actinides and technetium), are reviewed. Radioactive isotopes of naturally stable elements are not included for discussion in this work. Actinide and technetium complexes with O-, N-, N,O, N,S-, P-containing ligands, as well π-organometallics are discussed from the view point of their synthesis, properties, and main applications. On the basis of their properties, several mono-, bi-, tri-, tetra-or polydentate ligands have been designed for specific recognition of some particular radionuclides, and can be used in the processes of nuclear waste remediation, i.e., recycling of nuclear fuel and the separation of actinides and fission products from waste solutions or for analytical determination of actinides in solutions; actinide metal complexes are also usefulas catalysts forcoupling gaseous carbon monoxide,as well as antimicrobial and anti-fungi agents due to their biological activity. Radioactive labeling based on the short-lived metastable nuclide technetium-99m ( 99m Tc) for biomedical use as heart, lung, kidney, bone, brain, liver or cancer imaging agents is also discussed. Finally, the promising applications of technetium labeling of nanomaterials, with potential applications as drug transport and delivery vehicles, radiotherapeutic agents or radiotracers for monitoring metabolic pathways, are also described.
Organometallic 1998, 17, 4259-4262.pdf
The crystal structure of di-n-butyltin pyridine-2-phosphonate-6-carboxylate, [C 14 H 24 NO 6 -PSn] 2 , features centrosymmetric dimers disposed about a central Sn 2 O 2 core. The phosphonate carboxylate dianion is µ 2 -tetradentate, coordinating one tin atom via one of the phosphonate oxygen atoms, the pyridine nitrogen atom, and one of the carboxylate oxygen atoms; the latter atom also coordinates the second tin atom of the dimer. The remaining positions in the seven-coordinate, distorted pentagonal bipyramidal geometry are occupied by a water molecule and two n-butyl groups that occupy axial positions. The lattice is stabilized by hydrogen-bonding contacts leading to an arrangement of parallel, orthogonally related chains of dimeric units. In methanol solution, the dimer is involved in a dissociation equilibrium that is fast on the NMR time scale. (1) (a) Gielen, M.; Joosen, E.; Mancilla, T.; Jurkschat, K.; Willem, R.; Roobol, C.; Bernheim, J.; Atassi, G.; Huber, F.; Hoffmann, E.; Preut, H.; Mahieu, B. Main Group Met. Chem. 1987, 10, 147. (b) Gielen, M.; Acheddad, M.; Bouâ lam, M.; Biesemans, M.; Willem, R. Bull. Soc. Chim. Belg. 1991, 100, 743. (c) Gielen, M.; Acheddad, M.; Mahieu, M.; Willem, R. Main Group Met. Chem. 1991, 14, 73. (d) Willem, R.; Biesemans, M.; Bouâ lam, M.; Delmotte, A.; El Khloufi, A.; Gielen, M. Appl. Organomet. Chem. 1993, 7, 311. (2) (a) Huber, F.; Preut, H.; Hoffmann, E.; Gielen, M. Acta Crystallogr. 1989, C45, 51. (b) Gielen, M.; Acheddad, M.; Tiekink, E. R. T.
Supplementary Information Chem. Commun. 2012 D'Errico et al
All the reagents were obtained from commercial sources (Sigma-Aldrich) and were used without further purification. 1 H and 13 C-NMR spectra were acquired on a Varian Mercury Plus 400 MHz and on a Varian Unit Inova 700 MHz in CD 3 OD or CDCl 3 . Chemical shifts are reported in parts per million (δ) relative to the residual solvent signals: CD 2 HOD 3.31 and CHCl 3 7.27 for 1 H-NMR; CD 2 HOD 49.0 and CHCl 3 77.0 for 13 C-NMR. 1 H-NMR chemical shifts were assigned by 2D NMR experiments. The abbreviations s, bs, d, dd and m stand for singlet, broad singlet, doublet, doublet of doublets and multiplet, respectively. HPLC analyses and purifications were carried out on a Jasco UP-2075 Plus pump equipped with a Jasco UV-2075 Plus UV detector using a 4.60 x 150 mm LUNA (Phenomenex) silica column (particle size 5 µm) eluted with a linear gradient of MeOH in AcOEt (from 0 to 5% in 15 min, flow 1.0 mL min -1 , system A), with a linear gradient of AcOEt in n-hexane (from 0 to 100% in 30 min, flow 1.0 mL min -1 , system B) or using a 4.8 x 150 mm C-18 reverse-phase column (particle size 5 µm) eluted with a linear gradient of MeOH in H 2 O (from 0 to 100% in 30 min, flow 1.3 mL min -1 , system C). UV spectra were recorded on a Jasco V-530 UV spectrophotometer. High Resolution MS spectra were recorded on a Bruker APEX II FT-ICR mass spectrometer using electrospray ionization (ESI) technique in positive mode. Elemental analyses were performed on a Thermo Finnigan Flash EA 1112 CHN analyser. IR spectra were recorded on a Jasco FT-IR 430 spectrophotometer. Optical rotations were determined on a Jasco polarimeter using a 1 dm cell at 25 °C; concentrations are in g/100 mL. Preparative PLC chromatography was performed using F254 silica gel plates (0.5 mm thick, Merck). Analytical TLC analyses were performed using F254 silica gel plates (0.2 mm thick, Merck). TLC spots were detected under UV light (254 nm). For MTS assays the UV absorbance at 490 nm was read using a Beckman Anthos 96 well Microplate Reader.
Synthesis, spectroscopic characterization, electrochemical behavior and computational analysis of mixed diamine ligand gold(III) complexes: antiproliferative and in vitro cytotoxic evaluations against human cancer cell lines Abstract The gold(III) complexes of the type [(DACH)Au(en)]Cl 3 , 1,2-Diaminocyclohexane ethy-lenediamine gold(III) chloride [where 1,2-DACH = cis-, trans-1,2-and S,S-1,2diaminocyclohexane and en = ethylenediamine] have been synthesized and characterized using various analytical and spectro-scopic techniques including elemental analysis, UV– Vis and FTIR spectra; and solution as well as solid-state NMR measurements. The solid-state 13 C NMR shows that 1,2-diaminocyclohexane (1,2-DACH) and ethylenediamine (en) are strongly bound to the gold(III) center via N donor atoms. The stability of the mixed diamine ligand gold(III) was determined by 1 H and 13 C NMR spectra. Their electrochemical behavior was studied by cyclic voltammetry. The structural details and relative stabilities of the four possible isomers of the complexes were also reported at the B3LYP/LANL2DZ level of theory. The coordination sphere of these complexes around gold(III) center adopts distorted square planar geometry. The computational study also demonstrates that trans-conformations is slightly more stable than the cis-conformations. The antiproliferative effects and cyto-toxic properties of the mixed diamine ligand gold(III) complexes were evaluated in vitro on human gastric SGC7901 and prostate PC3 cancer cells using MTT assay. The antiproliferative study of the gold(III) complexes on PC3 and SGC7901 cells indicate that complex 1 is the most effective antiproliferative agent among mixed ligand based gold(III) complexes 1–3. The IC 50 data reveal that the in vitro cytotoxicity of complexes 1 and 3 against SGC7901 cancer cells are fairly better than that of cisplatin.