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1.
A series of the first zinc(II) complexes of the general composition [Zn(Ln)2Cl2]·xSolv (1-5) involving kinetin [N6-furfuryladenine, L1, xSolv = CH3OH, complex 1] and its derivatives, i.e. N6-(5-methylfurfuryl)adenine (L2, xSolv = 2H2O, 2), 2-chloro-N6-furfuryladenine (L3, 3), 2-chloro-N6-(5-methylfurfuryl)adenine (L4, 4) and 2-chloro-N6-furfuryl-9-isopropyladenine (L5, 5), as N-donor ligands has been synthesized. The complexes have been fully characterized by elemental analyses (C, H, N), FTIR, Raman, 1H and 13C NMR spectroscopy, conductivity measurements, thermogravimetric (TG) and differential thermal (DTA) analyses. Single crystal X-ray analysis determined the molecular structures of 2-chloro-N6-furfuryl-9-isopropyladenine (L5) and the complex [Zn(L1)2Cl2]·CH3OH. The Zn(II) ion is tetrahedrally coordinated by two chlorido ligands and two molecules of the L1 organic compound. The two ligands L1 are coordinated to the central Zn(II) ion via the N7 atoms. This conclusion can also be drawn from multinuclear NMR spectroscopic experiments. 相似文献
2.
Using a phosphorus based Mannich condensation reaction the new pyridylphosphines {5-Ph2PCH2N(H)}C5H3(2-Cl)N (1-Cl) and {2-Ph2PCH2N(H)}C5H3(5-Br)N (1-Br) have been synthesised in good yields (60% and 88%, respectively) from Ph2PCH2OH and the appropriate aminopyridine. The ligands 1-Cl and 1-Br display variable coordination modes depending on the choice of late transition-metal complex used. Hence P-monodentate coordination has been observed for the mononuclear complexes AuCl(1-Cl) (2), AuCl(1-Br) (3), RuCl2(p-cymene)(1-Cl) (4), RuCl2(p-cymene)(1-Br) (5), RhCl2(Cp∗)(1-Cl) (6), RhCl2(Cp∗)(1-Br) (7), IrCl2(Cp∗)(1-Cl) (8), IrCl2(Cp∗)(1′-Cl) (8′), IrCl2(Cp∗)(1-Br) (9), cis-/trans-PdCl2(1-Cl)2 (10), cis-/trans-PdCl2(1-Br)2 (11), cis-PtCl2(1-Cl)2 (12) and cis-PtCl2(1-Br)2 (13). Reaction of Pd(Me)Cl(cod) (cod = cycloocta-1,5-diene) with either 1 equiv. of 1-Br or the known pyridylphosphines 1′-Cl, 1-OH or 1-H gave the P/N-chelate complexes Pd(Me)Cl(1-Br-1-H) (14)-(17). All new compounds have been fully characterised by spectroscopic and analytical methods. Furthermore the structures of 4, 5, 10 and 16 · (CH3)2SO have been elucidated by single crystal X-ray crystallography. A crystal structure of the dinuclear metallocycle trans,trans-[PdCl2{μ-P/N-{Ph2PCH2N(H)}C5H4N}]2 · CHCl3, 18 · CHCl3, has also been determined. Here 1-H bridges, using both P and pyridyl N donors, two dichloropalladium centres affording a 12-membered ring with the PdCl2 units adopting a head-to-tail arrangement. 相似文献
3.
Mihály Purgel Caroline M. Jonsson Ingegärd Andersson Imre Pápai Staffan Sjöberg 《Journal of inorganic biochemistry》2009,103(11):1426-1438
The stoichiometries and stability constants of a series of Al3+-N-phosponomethyl glycine (PMG/H3L) complexes have been determined in acidic aqueous solution using a combination of precise potentiometric titration data, quantitative 27Al and 31P NMR spectra, ATR-FTIR spectrum and ESI-MS measurements (0.6 M NaCl, 25 °C). Besides the mononuclear AlH2L2+, Al(H2L)(HL), and Al(HL)L2−, dimeric Al2(HL)L+ and trinuclear complexes have been postulated.1H and 31P NMR data show that different isomers co-exist in solution and the isomerization reactions are slow on the 31P NMR time scale. The geometries of monomeric and dimeric complexes likely double hydroxo bridged and double phosphonate bridged isomers have been optimized using DFT ab initio calculations starting from rational structural proposals. Energy calculations using the PCM solvation method also support the co-existence of isomers in solutions. 相似文献
4.
A mononuclear macrocyclic complex NiIIL3a (L3a = dianion of 2,3-dioxo-5,6:13,14-dibenzo-9,10-cyclohexyl-7,12-bis(methoxycarbonyl)-1,4,8,11-tetraazacyclotetradeca-7,11-diene), which shows high DNA cleavage activity in the presence of H2O2, was reported in our previous work. Considering that many systems for natural enzyme-mediated DNA cleavage contain two or more metal active sites, two new trinuclear complexes [Cu(NiL3a)2(dca)2]·2CH3OH (abbreviated as Cu(NiL3a)2) and [Ag(NiL3a)2(NO3)]·2CH3OH·0.5H2O (abbreviated as Ag(NiL3a)2) were synthesized in this work, where dca is the dicyanamide. The complexes were structurally characterized by single crystal X-ray analysis. The central Cu(II) or Ag(I) atom is linked to two [NiL3a] ligands by oxamido bridges forming a trinuclear structure. In Cu(NiL3a)2, the central Cu(II) ion is in an octahedral coordination geometry. Whereas in Ag(NiL3a)2, the central Ag(I) ion is in a rarely reported trigonal-prismatic coordination geometry. The DNA cleavage behavior of the complexes in the presence of H2O2 was studied in detail. Comparing with the NiL3a, the trinuclear complex Ag(NiL3a)2 nearly has no ability to cleave DNA, whereas Cu(NiL3a)2 is a much better DNA cleavage agent. Cu(NiL3a)2 can efficiently convert supercoiled DNA to nicked DNA with a rate constant of 0.074 ± 0.002 min−1 when 40 μM Cu(NiL3a)2 and 0.6 mM H2O2 are used. The cleavage mechanism between the complex Cu(NiL3a)2 and plasmid DNA is likely to involve singlet oxygen as reactive oxygen species. Circular dichroism (CD) and fluorescence spectroscopy indicate that both Cu(NiL3a)2 and NiL3a bind to DNA by a groove binding mode, and the binding between Cu(NiL3a)2 and DNA is much stronger than that between NiL3a and DNA. The present results may provide some information for the design of efficient multinuclear artificial nucleases. 相似文献
5.
Tatyana A. Rodina Andrey V. Gerasimenko Tatyana S. Philippova 《Inorganica chimica acta》2011,368(1):263-270
Crystalline bis(N,N-di-iso-butyldithiocarbamato-S,S′)(pyridine)cadmium(II) - adduct 1 was prepared and studied by means of multinuclear 13C, 15N, 113Cd CP/MAS NMR spectroscopy, single-crystal X-ray diffraction and simultaneous thermal analysis (STA). In molecular structure 1, the cadmium atom coordinates with four sulphur atoms and one nitrogen atom of pyridine, forming a coordination polyhedron [CdS4N], whose geometry is an almost ideal tetragonal pyramidal (C4v). The coordinated py molecule is in the apical position, while two structurally non-equivalent di-iso-butyldithiocarbamate ligands, playing the same terminal S,S′-chelating function, define the basal plane. To characterise additionally the structural state of the cadmium atom in this fivefold coordination, 113Cd chemical shift anisotropy (CSA) parameters, δaniso and η, were calculated from experimental MAS NMR spectra that revealed an almost axially symmetric 113Cd chemical shift tensor. From a combination of TG and DSC measurements taken under an argon atmosphere, we found that the mass of adduct 1 is lost in two steps involving initial desorption of coordinated py molecules with subsequent thermal destruction of liberated cadmium(II) di-iso-butyldithiocarbamate, with yellow-orange, fine-powdered solid CdS as the final product. 相似文献
6.
Reactions between sulfur diimides R(NSN)R′ (R=R′=tBu (1a), SiMe3 (1b), SnMe3 (1c); R=tBu, R′=SnMe3 (1d); R=SiMez3, R′=SnMe3 (1e)) and various organoboranes were studied, and the products were characterized by multinuclear magnetic resonance data (1H, 11B, 13C, 15N, 29Si and 119Sn NMR). Tetraalkyldiboranes(6) (Et2BH2BEt2 (2), dimeric 9-borobicyclo[3,3.1]nonane (3)) react with 1a and 1b by 1,3-hydroboration to give the N-sulfanyl-dialkylaminoboranes 4 and 5 which are instable with respect to eliminatio of short-lived [R---NS]. Trialkylboranes (Et3B (8)) react only sluggishly with 1a, but more readily with 1b mainly via S-ethylation, formally a 1,2-ethyloboration, to give the diethylborylamido-imino-ethanesulfinic acid 9b decomposes slowly at room temperature via ethene elimination to give 4b, followed by further decomposition via [R---NS] elimination. The compounds 9 can be prepared independently from the reaction between the N-lithio-imino-ethanesulfinic acid amide 10 and diorganoboron halides. The molecular structure of the lithium amide 10a (R=R′=tBu) was determined by X-ray analysis as a dimer in which the four nitrogen, two sulfur and two lithium atoms adopt a boat conformation, in contrast with other known derivatives of this type. If the sulfur diimides bear at least one trimethylstannyl group (1c-e), their reactions with Et3B (8), iPr3B (12) or 9-iso-butyl-9-borabicyclo[3,3,1]nonane (13) lead to the novel aminoboranes 14–16. These are products of a 1,1,-organoboration, since the Me3Sn group moves from one nitrogen atom to the other, and both the boryl and an alkyl group end up at the same nitrogen atom. 相似文献
7.
Effendy Fabio Marchetti Alessandro Marinelli Brian W. Skelton 《Inorganica chimica acta》2011,366(1):388-393
Syntheses, spectroscopic and thermal characterization are reported for the potentially tetradentate bis(O,O′-4-acyl-5-pyrazolone) pro-ligands HQ3QH and HQ4QH (in detail HQ3QH: 1,5-bis(5-hydroxy-1-phenyl-3-methyl-1H-pyrazol-4-yl)pentane-1,5-dione, HQ4QH: 1,6-bis(5-hydroxy-1-phenyl-3-methyl-1H-pyrazol-4-yl)hexane-1,6-dione) and their di-n-butyltin(IV) derivatives and . Single crystal X-ray structural characterizations of the proligand HQ4QH and of the binuclear tin(IV) complex are also reported; both the ligand and complex molecules are centrosymmetric, the latter having two independent molecules in the structure. Sn-C, O(acyl), O(pz) distances (〈 〉) are 2.121(3), 2.119(6) and 2.37(4) Å. 相似文献
8.
Eiko Matsuo Esther Leon Steve J. Matthews Polly Roy 《Biochemical and biophysical research communications》2014
Bluetongue virus core protein VP6 is an ATP hydrolysis dependent RNA helicase. However, despite much study, the precise role of VP6 within the viral capsid and its structure remain unclear. To investigate the requirement of VP6 in BTV replication, we initiated a structural and biological study. Multinuclear nuclear magnetic resonance spectra were assigned on his-tagged full-length VP6 (329 amino acid residues) as well as several truncated VP6 variants. The analysis revealed a large structured domain with two large loop regions that exhibit significant conformational exchange. One of the loops (amino acid position 34–130) could be removed without affecting the overall fold of the protein. Moreover, using a BTV reverse genetics system, it was possible to demonstrate that the VP6-truncated BTV was viable in BHK cells in the absence of any helper VP6 protein, suggesting that a large portion of this loop region is not absolutely required for BTV replication. 相似文献
9.
Pursuing the idea of using a biological nanovector to drive the non-specific cytotoxic activity of Pt(II) complexes toward biological targets, we have singled out thymidine (T) as a potential biological carrier for delivery of cisplatin-like drugs to DNA. Thymidine was functionalized by first reacting it with solid sodium hydride and 1,3-diiodopropane, producing high yields of N3-iodopropylthymidine. Further reaction with ethylenediamine gave the bio-ligand N3-(3-ethylenediamine)propylthymidine which reacts in turn with K2PtCl4, resulting in a cisplatin-like nucleoside.This derivative (or more soluble analogues) can be phosphorylated by the cellular enzyme pool and incorporated into the growing DNA chain, thus making them suitable candidates as potential antiproliferative agents, exploiting both alkylating and antimetabolite mechanisms. 相似文献
10.
Yi T Kim HJ Cho JY Woo KM Ryoo HM Kim GS Baek JH 《Biochemical and biophysical research communications》2006,347(1):178-184
Tetraspanin CD9 has been shown to regulate cell-cell fusion in sperm-egg fusion and myotube formation. However, the role of CD9 in osteoclast, another multinucleated cell type, is not still clear. Therefore, we investigated the role of CD9 in osteoclast differentiation. CD9 was expressed in osteoclast lineage cells and its expression level increased during the progression of RANKL-induced osteoclastogenesis. KMC8, a neutralizing antibody specific to CD9, significantly suppressed RANKL-induced multinucleated osteoclast formation and the mRNA expression of osteoclast differentiation marker genes. To define CD9-regulated osteoclastogenic signaling pathway, MAPK pathways were examined. KMC8 induced long-term phosphorylation of p44/42 MAPK, but not of p38 MAPK. Constitutive activation of p44/42 MAPK by overexpressing constitutive-active mutant of MEK1 almost completely blocked osteoclast differentiation. Taken together, these results suggest that CD9 expressed on osteoclast lineage cells might positively regulate osteoclastogenesis via the regulation of p44/42 MAPK activity. 相似文献