A study of binding interactions between terpyridine derivatives and cucurbit[10]uril

The binding interactions of a series of 2,2′:6′,2″-terpyridine (TPY) derivatives and their metal complexes with cucurbit[10]uril (CB[10]) were investigated by ¹H NMR, UV/Vis, emission spectroscopy, and ESI mass spectrometry. ¹H NMR titrations revealed CB[10] could encapsulate methylated TPY (MTPY), and the binding ratio between guest MTPY and host was 1:1 and 2:1 via ESI-MS characterization. For the transition metal complexes composed of Fe(II) or Ru(II) or Rh(III) and TPY derivatives, the octahedral TPY?metal?TPY core can be included in the cavity of CB[10]. Three binding modes (1:1, 1:2 and 1:3) have been detected for the binding of the metal?MPTY complexes with CB[10] by ESI-MS.     

固固反应合成三碘化锑、三碘化铋与硫脲配合物

通过三碘化锑和三碘化铋与硫脲间的室温固固反应合成了三碘化锑、三碘化铋的硫脲配合物 ,其组成为 :M[CS( NH2 ) 2 ]3 I3 ( M=Sb,Bi)。两种配合物的晶体结构均属于单斜晶系 ,锑配合物 Sb[CS( NH2 ) 2 ]3 I3 的晶胞参数为 :a=1 .4 772 nm,b=1 .6 5 82 nm,c=2 .0 6 74 nm,β=90 .81°,铋配合物 Bi[CS( NH2 ) 2 ]3 I3 的晶胞参数为 :a=1 .4 0 1 0 nm,b=2 .0 1 6 8nm,c=2 .0 397nm,β=90 .84°。远红外光谱表明硫脲中的 N原子而非硫原子参与了配位     

Mechanistic study of enantiomeric recognition with native gamma-cyclodextrin by capillary electrophoresis,reversed-phase liquid chromatography,nuclear magnetic resonance spectroscopy,electrospray mass spectrometry and circular dichroism techniques

The possible mechanisms for the chiral recognition of 2(S)-(3,5-bis-trifluoromethyl-phenyl)-2-[3(S)-(4-fluorophenyl)-4-(1H-[1,2,4]triazol-3-ylmethyl)-morpholin-2(R)-yloxy]-ethanol (compound A) and its enantiomer with native gamma-cyclodextrin (gamma-CD) were investigated using capillary electrophoresis (CE), reversed-phase liquid chromatography (RPLC), proton (1H), fluorine (19F) and carbon (13C) nuclear magnetic resonance spectroscopy (NMR), electrospray mass spectrometry (ESI-MS) and circular dichroism (CD). All experiments provided clear evidence of the formation of diastereomeric complexes between the enantiomers and gamma-CD. Proton, fluorine and carbon NMR spectra suggested that both aromatic rings, with mono-fluoro and bis-tri-fluoro functional groups, on the guest molecule were partially included into the cavity of the gamma-CD. ESI-MS spectra indicated that the diastereomeric complexes have a 1:1 stoichiometric ratio. The binding constants of the diastereomeric complexes obtained by CE, RPLC and CD were compared. The effects of the gamma-CD concentration, organic modifiers and temperature on the CE-chiral separation were also investigated.     

Heterobridged dinuclear, tetranuclear, dinuclear-based 1-d, and heptanuclear-based 1-D complexes of copper(II) derived from a dinucleating ligand: syntheses, structures, magnetochemistry, spectroscopy, and catecholase activity

The work in this paper presents syntheses, characterization, crystal structures, variable-temperature/field magnetic properties, catecholase activity, and electrospray ionization mass spectroscopic (ESI-MS positive) study of five copper(II) complexes of composition [Cu(II)(2)L(μ(1,1)-NO(3))(H(2)O)(NO(3))](NO(3)) (1), [{Cu(II)(2)L(μ-OH)(H(2)O)}(μ-ClO(4))](n)(ClO(4))(n) (2), [{Cu(II)(2)L(NCS)(2)}(μ(1,3)-NCS)](n) (3), [{Cu(II)(2)L(μ(1,1)-N(3))(ClO(4))}(2)(μ(1,3)-N(3))(2)] (4), and [{Cu(II)(2)L(μ-OH)}{Cu(II)(2)L(μ(1,1)-N(3))}{Cu(II)(μ(1,1)-N(3))(4)(dmf)}{Cu(II)(2)(μ(1,1)-N(3))(2)(N(3))(4)}](n)·ndmf (5), derived from a new compartmental ligand 2,6-bis[N-(2-pyridylethyl)formidoyl]-4-ethylphenol, which is the 1:2 condensation product of 4-ethyl-2,6-diformylphenol and 2-(2-aminoethyl)pyridine. The title compounds are either of the following nuclearities/topologies: dinuclear (1), dinuclear-based one-dimensional (2 and 3), tetranuclear (4), and heptanuclear-based one-dimensional (5). The bridging moieties in 1-5 are as follows: μ-phenoxo-μ(1,1)-nitrate (1), μ-phenoxo-μ-hydroxo and μ-perchlorate (2), μ-phenoxo and μ(1,3)-thiocyanate (3), μ-phenoxo-μ(1,1)-azide and μ(1,3)-azide (4), μ-phenoxo-μ-hydroxo, μ-phenoxo-μ(1,1)-azide, and μ(1,1)-azide (5). All the five compounds exhibit overall antiferromagnetic interaction. The J values in 1-4 have been determined (-135 cm(-1) for 1, -298 cm(-1) for 2, -105 cm(-1) for 3, -119.5 cm(-1) for 4). The pairwise interactions in 5 have been evaluated qualitatively to result in S(T) = 3/2 spin ground state, which has been verified by magnetization experiment. Utilizing 3,5-di-tert-butyl catechol (3,5-DTBCH(2)) as the substrate, catecholase activity of all the five complexes have been checked. While 1 and 3 are inactive, complexes 2, 4, and 5 show catecholase activity with turn over numbers 39 h(-1) (for 2), 40 h(-1) (for 4), and 48 h(-1) (for 5) in dmf and 167 h(-1) (for 2) and 215 h(-1) (for 4) in acetonitrile. Conductance of the dmf solution of the complexes has been measured, revealing that bridging moieties and nuclearity have been almost retained in solution. Electrospray ionization mass (ESI-MS positive) spectra of complexes 1, 2, and 4 have been recorded in acetonitrile solutions and the positive ions have been well characterized. ESI-MS positive spectrum of complex 2 in presence of 3,5-DTBCH(2) have also been recorded and, interestingly, a positive ion [Cu(II)(2)L(μ-3,5-DTBC(2-))(3,5-DTBCH(-))Na(I)](+) has been identified.     

Solvation of the bismuth(III) ion by water, dimethyl sulfoxide, N,N'-dimethylpropyleneurea, and N,N-dimethylthioformamide. An EXAFS, large-angle X-ray scattering, and crystallographic structural study

The structure of the solvated bismuth(III) ion in aqueous, dimethyl sulfoxide, N,N'-dimethylpropyleneurea, and N,N-dimethylthioformamide solution has been studied by means of EXAFS and large-angle X-ray scattering (LAXS). The crystal structures of the solid compounds octakis(dimethyl sulfoxide)bismuth(III) perchlorate, [Bi(OS(CH3)2)8](ClO4)3, hexakis(N,N'-dimethylpropyleneurea)bismuth(III) perchlorate, [Bi(OCN2(CH2)3(CH3)2)6](ClO4)3, and nonaaquabismuth(III) trifluoromethanesulfonate, [Bi(H2O)9](CF3SO3)3 (redetermination), have been determined. The aqueous solutions must be strongly acidic, since the hydrated bismuth(III) ion starts to hydrolyze into Bi6O4(OH)4(6+) complexes already at an excess of strong acid at 1.0 mol.dm-3. For very acidic aqueous perchlorate solutions, the LAXS and EXAFS data gave a satisfactory fit for eight-coordination of the bismuth(III) ion, with a mean Bi-O bond distance of 2.41(1) A. The crystal structure of octakis(dimethyl sulfoxide)bismuth(III) perchlorate shows that the bismuth(III) ion coordinates eight dimethyl sulfoxide molecules via the oxygen atoms in a distorted square antiprismatic configuration. The mean Bi-O bond distance is 2.43 A and the mean Bi...S distance 3.56 A. For the dimethyl sulfoxide solution, the corresponding mean distances were found to be 2.411(6) and 3.535(12) A. The N,N'-dimethylpropyleneurea-solvated bismuth(III) ion is octahedrally coordinated in both solid state and solution with the Bi-O bond distances of 2.324(5) and 2.322(3) A, respectively. The bismuth(III) ion is six-coordinated in the sulfur donor solvent N,N-dimethylthioformamide with a mean Bi-S bond distance of 2.794(8) A. A comparison with the structure of the solvated lanthanum(III) ion shows that the bismuth(III) ion is smaller for all coordination numbers. New effective ionic radii for the bismuth(III) ion in different coordination numbers are proposed, based on results in this study and in the literature.     

Synthesis, structure and solution NMR properties of (Ph4P)[M(SeC[O]Tol)3], M = Zn, Cd and Hg

Metal selenocarboxylate salts (PPh4)[M(SeC[O]Tol)3] (M = Zn (1), Cd (2) and Hg (3); Tol = C6H4-p-CH3) have been synthesized by reacting Zn(NO3)2 .6H2O, Cd(NO3)2 .4H2O or HgCl2 with (Na+)TolC[O]Se- and PPh4Cl in the ratio of 1 : 4 : 1. The structures of these compounds were determined by single-crystal X-ray diffraction methods. The crystal structures contain discrete cations and anions. In the each anion, the metal center is bound to three TolC[O]Se ligands, primarily through Se, though some long M...O interactions also occur. NMR spectra (113Cd, 199Hg and 77Se, as appropriate) are reported for solutions of [M(SeC[O]Tol)3]-, and of [M(SeC[O]Tol)3](-) - [M(SC[O]Ph)3]- mixtures (M = Zn-Hg), in CH2Cl2 at reduced temperatures. In addition, ESI-MS data have been obtained for [M(SeC[O]Tol)(3)](-) - [M(SC[O]Ph)3]- mixtures (M = Zn-Hg) in acetone and in CH2Cl2. The NMR and ESI-MS studies show that the complexes [M(SeC[O]Tol)n(SC[O]Ph)(3-n)]- (n= 3-0) persist in solution.     

Copper(II) coordination chemistry of westiellamide and its imidazole, oxazole, and thiazole analogues

The copper(II) coordination chemistry of westiellamide (H(3)L(wa)), as well as of three synthetic analogues with an [18]azacrown-6 macrocyclic structure but with three imidazole (H(3)L(1)), oxazole (H(3)L(2)), and thiazole (H(3)L(3)) rings instead of oxazoline, is reported. As in the larger patellamide rings, the N(heterocycle)-N(peptide)-N(heterocycle) binding site is highly preorganized for copper(II) coordination. In contrast to earlier reports, the macrocyclic peptides have been found to form stable mono- and dinuclear copper(II) complexes. The coordination of copper(II) has been monitored by high-resolution electrospray mass spectrometry (ESI-MS), spectrophotometric and polarimetric titrations, and EPR and IR spectroscopies, and the structural assignments have been supported by time-dependent studies (UV/Vis/NIR, ESI-MS, and EPR) of the complexation reaction of copper(II) with H(3)L(1). Density functional theory (DFT) calculations have been used to model the structures of the copper(II) complexes on the basis of their spectroscopic data. The copper(II) ion has a distorted square-pyramidal geometry with one or two coordinated solvent molecules (CH(3)OH) in the mononuclear copper(II) cyclic peptide complexes, but the coordination sphere in [Cu(H(2)L(wa))(OHCH(3))](+) differs from those in the synthetic analogues, [Cu(H(2)L)(OHCH(3))(2)](+) (L = L(1), L(2), L(3)). Dinuclear copper(II) complexes ([Cu(II) (2)(HL)(mu-X)](+); X = OCH(3), OH; L = L(1), L(2), L(3), L(wa)) are observed in the mass spectra. While a dipole-dipole coupled EPR spectrum is observed for the dinuclear copper(II) complex of H(3)L(3), the corresponding complexes with H(3)L (L = L(1), L(2), L(wa)) are EPR-silent. This may be explained in terms of strong antiferromagnetic coupling (H(3)L(1)) and/or a low concentration of the dicopper(II) complexes (H(3)L(wa), H(3)L(2)), in agreement with the mass spectrometric observations.     

Structural, kinetic, and theoretical studies on models of the zinc-containing phosphodiesterase active center: medium-dependent reaction mechanisms

Dinuclear zinc(II) complexes [Zn(2)(bpmp)(mu-OH)](ClO(4))(2) (1) and [Zn(2)(bpmp)(H(2)O)(2)](ClO(4))(3) (2) (H-BPMP=2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol) have been synthesized, structurally characterized, and pH-driven changes in metal coordination observed. The transesterification reaction of 2-hydroxypropyl p-nitrophenyl phosphate (HPNP) in the presence of the two complexes was studied both in a water/DMSO (70:30) mixture and in DMSO. Complex 2 was not reactive whereas for 1 considerable rate enhancement of the spontaneous hydrolysis reaction was observed. A detailed mechanistic investigation by kinetic studies, spectroscopic measurements ((1)H, (31)P NMR spectroscopy), and ESI-MS analysis in conjunction with ab initio calculations was performed on 1. Based on these results, two medium-dependent mechanisms are presented and an unusual bridging phosphate intermediate is proposed for the process in DMSO.     

Identification of bismuth-thiolate-carboxylate clusters by electrospray ionization mass spectrometry

The known thermal and hydrolytic stability of bismuth-sulfur bonds indicates that biological targets for bismuth likely involve thiol or thiolate functionalities, such as in L-cysteine. Complexes of bismuth with cysteine or other thiol-carboxylic acid ligands have been isolated and characterized providing a preliminary view of the potential participation of these functional groups in the biochemical mechanisms involving bismuth. A broader assessment of bismuth-thiolate interactions has been possible using electrospray ionization mass spectrometry (ESI-MS). A wide range of complexes has been observed containing mercaptosuccinic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and/or 2-amino-3-mercaptopropionic acid (cysteine). The identification of various multibismuth multiligand cluster ions defines new chemistry for bismuth.     

Versatile ligand behavior of hydrotris(4-ethyl-3-methyl-5-thioxo-1,2,4-triazolyl)borate. Syntheses and crystal structures of Cu(I) and Bi(III) complexes

Preparations of copper(I) and bismuth(III) complexes of hydrotris(4-ethyl-3-methyl-5-thioxo-1,2,4-triazolyl)borate (Tr(Et,Me)) are described. These complexes have been characterized by means of spectroscopy and microanalysis. Molecular structures of [Cu(Tr(Et,Me))](2) x 2.5CH(3)CN x 0.5H(2)O (3a) and [Bi(Tr(Et,Me))(2)]NO(3) x 2CHCl(3) (4a) have been determined by single-crystal X-ray diffraction. In the centrosymmetric dimeric copper(I) complex, Tr(Et,Me) acts in the k(3)S,S',H:kS' ' coordination mode. The metal is found in a distorted trigonal geometry as the ligand exhibits an "S(3)-inverted" conformation at the boron center so that a weak [B-H.Cu] agostic interaction renders the overall coordination of the (3 + 1) type. On the other hand, in the bismuth complex, Tr(Et,Me) presents the k(3)S,S',S' ' coordination mode and the "S(3)-normal" conformation. The metal is found in a regular octahedral geometry bound by six thioxo groups of two ligands. Species distributions in solution have been studied using electrospray ionization mass spectrometry upon dissolution of 3a and 4a crystals in acetonitrile. Monomeric and polynuclear copper(I) complexes with different M:L ratios are present in solution, while for 4a only the monomeric species is present.     

Inclusion complexes of pantoprazole with β-cyclodextrin and cucurbit[7]uril: experimental and molecular modeling study

The inclusion complexes of the proton pump inhibitor (PPI) pantoprazole sodium (PNZ_Na) with β-cyclodextrin (βCD) and cucurbit[7]uril (CB[7]) have been investigated. Fluorescence spectroscopy and electrospray ionization mass spectrometry (ESI-MS) were used to characterize these complexes. The fluorescence intensity of PNZ_Na was remarkably enhanced by both hosts, indicating the formation of the complexes. Nevertheless, the two hosts are of comparable cavity size their effect on the fluorescence of PNZ_Na was quite different. The ESI-MS data on the other hand confirmed the formation of a 1:1 PNZ_Na: host inclusion complexes for the two hosts. We further utilized molecular dynamics to shed more light on the mechanism of complexation and on the stability of these complexes in aqueous media. The complexes were stabilized over the 20 ns of simulation time mainly via hydrogen bonding interactions in addition to hydrophobic effects and van der Waals interactions. Snapshots collected during the simulations for both complexes have clearly shown that the mode of insertion of PNZ into the two host’s cavities are different which explain the difference in fluorescence enhancement of PNZ obtained in presence of each of these hosts.     

Bismuth(III) Flavonolates: The Impact of Structural Diversity on Antibacterial Activity,Mammalian Cell Viability and Cellular Uptake

A series of homoleptic and heteroleptic bismuth(III) flavonolate complexes derived from six flavonols of varying substitution have been synthesised and structurally characterised. The complexes were evaluated for antibacterial activity towards several problematic Gram-positive (Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE)) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. The cell viability of COS-7 (monkey kidney) cells treated with the bismuth flavonolates was also studied to determine the effect of the complexes on mammalian cells. The heteroleptic complexes [BiPh(L)₂] (in which L=flavonolate) showed good antibacterial activity towards all of the bacteria but reduced COS-7 cell viability in a concentration-dependent manner. The homoleptic complexes [Bi(L)₃] exhibited activity towards the Gram-positive bacteria and showed low toxicity towards the mammalian cell line. Bismuth uptake studies in VRE and COS-7 cells treated with the bismuth flavonolate complexes indicated that Bi accumulation is influenced by both the substitution of the flavonolate ligands and the degree of substitution at the bismuth centre.     

Variable coordination modes of NO2(-) in a series of Ag(I) complexes containing triorganophosphines, -arsines,and -stibines. Syntheses,spectroscopic characterization (IR, 1H and 31P NMR,electrospray ionization mass), and structures of [AgNO2(R(3)E)(x)] adducts (E = P,As, Sb,x = 1-3)

Adducts of triorganophosphine, triphenylarsine, and triphenylstibine with silver(I) nitrite have been synthesized and characterized both in solution ((1)H, (31)P NMR) and in the solid state (IR, single-crystal X-ray structure analysis). In addition aggregates of AgNO(2) and ER(3) (E = P, As, Sb) have been identified in solution by electrospray ionization mass spectrometry (ESI-MS). The topology of the structures in the solid state was found to depend on the nature of ER(3) and on the stoichiometric ratio AgNO(2):ER(3). The adducts AgNO(2):EPh(3) (1:1) (E = P or Sb) are one-dimensional polymers, the role of NO(2)(-) being to bridge successive metal atoms by coordination of the two oxygens to one silver atom and the nitrogen lone pair to a successive Ag. The adduct AgNO(2):P(o-tolyl)(3) (1:1) is mononuclear, due to steric hindrance of the phosphine, the nitrite being O,O'-bidentate, a rare example of a quasi-linear P-Ag-X array. AgNO(2):P(p-F-C(6)H(4))(3) (1:1) is a dimer, the nitrite being coordinated through both oxygens, the first unidentate, the second bridging bidentate. P(o-tolyl)(3) and Pcy(3) form 1:2 adducts, also mononuclear, the nitrite still an O,O'-chelate. In contrast, the adduct AgNO(2):AsPh(3) (1:2) is a centrosymmetric dimer, essentially an aggregate of a pair of [Ag(O(2)N)(AsPh(3))(2)] arrays with one nitrite oxygen being the bridging atom. The adducts AgNO(2):EPh(3) (1:3) (E = As, Sb) are mononuclear, the nitrite behaving as a consistently strong O,O'-chelate. The E = As adduct is a triclinic solvated form, whereas the unsolvated E = Sb species is monoclinic. ESI-MS spectra of acetonitrile solutions of these complexes show the existence of [Ag(ER(3))](+), [Ag(CH(3)CN)](+), [Ag(CH(3)CN)(2)](+), [AgCl(2)](-), [Ag(NO(2))(2)](-), [Ag(ER(3))(CH(3)CN)](+), and [Ag(ER(3))(2)](+) as well as higher aggregates [Ag(2)(NO(2))(ER(3))(2)](+), [Ag(2)(NO(2))(3)](-) and [Ag(2)Cl(2)(NO(2))](-), which are less prevalent.     

Mixed ligand cobalt(II) picolinate complexes: synthesis, characterization, DNA binding and photocleavage

Complexes of the type [Co(pic)(2)(NN)], where pic = picolinate, NN = dipyrido[3,2-d:2',3'-f]quinoxaline (dpq) (4) and 4b,5,7,7a-tetrahydro-4b,7a-epiminomethanoimino-6H-imidazo[4,5-f][1,10]-phenanthroline-6,13-dione (bipyridyl-glycoluril) (bpg) (6) have been synthesized and characterized by elemental analysis, IR, UV-vis, NMR and ESI-MS spectroscopy and thermogravimetic analysis (TGA). Their physicochemical properties are compared with previously synthesized complexes, where NN = (H(2)O)(2) (1), 2,2'-bipyridine (bpy) (2), 1,10-phenanthroline (phen) (3) and dipyrido[3,2-a:2',3'-c]phenazine (dppz) (5). The crystal structures of the complexes 4-6 were solved by single-crystal X-ray diffraction. The complexes 4 and 5 crystallize from a mixture of chloroform and methanol in monoclinic and orthorhombic crystal systems, respectively, whereas complex 6 crystallizes from dimethyl sulfoxide (DMSO) in a tetragonal crystal system. The coordination sphere consists of two oxygen atoms and two nitrogen atoms from the two picolinates and two nitrogen atoms from the dpq, dppz or bpg ligand, respectively. Co(ii)/Co(iii) oxidation potentials have been determined by cyclic voltammetry. The DNA binding of complexes 1-5 has been investigated using thermal melting, fluorescence quenching and viscosity measurements, which indicate the partial intercalation of complex 5 with an apparent binding constant (k(app)) of 8.3 × 10(5) M(-1). DNA cleavage studies of complexes 1-5 have been investigated using gel electrophoresis in the presence of H(2)O(2) as an oxidizing agent and also by photoirradiation at 365 nm. The mechanistic investigations suggest that singlet oxygen ((1)O(2)) is the major species involved in the DNA cleavage by these complexes. The structures of complexes 2-6 were optimized with density functional theory (DFT) method (B3LYP/6-31G(d,p)). The low vertical ionization potential values indicate photoredox pathways for the DNA cleavage activity by complexes 4 and 5, which is corroborated by DNA cleavage experiments.     

Synthesis and molecular structure of the dihydrobis(thioxotriazolinyl)borato complexes of zinc(II), bismuth(III), and nickel(II). M...H-B interaction studied by Ab initio calculations

Reacting the heterocycle 5-thioxo-1,4-dihydro-4-ethyl-3-methyl-1,2,4-triazole (thioxotriazoline) with sodium tetrahydroborate in the molar ratio of approximately 2:1 at 130 degrees C provides the new ligand dihydrobis(thioxotriazolinyl)borato, [Bt(Et,Me)](-), as its sodium salt. The neutral complexes of this anionic ligand with zinc(II), bismuth(III), and nickel(II) have been synthesized and characterized by X-ray crystallography. In every complex, the ligand is coordinated to the metal in the S(2) mode, generating eight-membered chelate rings. The bismuth and nickel complexes exhibit two M.H-B interactions responsible for the dodecahedral and octahedral geometries, respectively. For the zinc complex, the trigonal-bipyramidal coordination is achieved with an apical Zn.H-B interaction. The crystal structures for the three complexes are described, and ab initio calculations on Bi(III), Ni(II), and Zn(II) compounds have been performed in order to assess the nature of the M.H-B interaction and its role for the definition of the molecular geometries.     

New bonding modes for boraamidinate ligands in heavy group 15 complexes: fluxional behavior of the 1:2 complexes, LiM[PhB(NtBu)2]2 (M = As, Sb, Bi)

The reactions of MCl3 with Li2[PhB(NtBu)2] in 1:1, 1:1.5, and 1:2 molar ratios in diethyl ether produced the monoboraamidinates ClM[PhB(NtBu)2] (1a, M = As; 1b, M = Sb; 1c, M = Bi), the novel 2:3 boraamidinate complexes [PhB(NtBu)2]M-micro-N(tBu)B(Ph)N(tBu)M[PhB(NtBu)2] (2b, M = Sb; 2c, M = Bi), and the bisboraamidinates LiM[PhB(NtBu)2]2 (3a, 3a.OEt2, M = As; 3b, M = Sb; 3c.OEt2, M = Bi), respectively. The 2:3 complexes 2b and 2c were also observed in the reactions carried out in a 1:2 molar ratio at room temperature. All complexes have been characterized by multinuclear NMR spectroscopy (1H, 7Li, 11B, and 13C) and by single-crystal X-ray structural determinations. The molecular units of the mono-boraamidinates 1a-c are isostructural, but their crystal packing is distinct as a result of stronger intermolecular close contacts going from 1a to 1c. In the novel 2:3 bam complexes 2b and 2c, each metal center is N,N'-chelated by a bam ligand and these two [M(bam)]+ units are bridged by the third [bam]2- ligand. The structures of the unsolvated bis-boraaminidate complexes 3a and 3b consist of [Li(bam)]- and [M(bam)]+ monomeric units linked by Li-N and M-N bonds to give a tricyclic structure. Solvation of the Li+ ion by diethyl ether results in a bicyclic structure composed of four-membered BN2As and six-membered BN3AsLi rings in 3a.OEt2. In contrast, the analogous bismuth complex 3c.OEt2 exhibits a tetracyclic structure. Variable-temperature NMR studies reveal that the nature of the fluxional behavior of 3a-c in solution is dependent on the group 15 center.     

Bismuth-ferrocene carboxylates: synthesis and structure

The reaction of ferrocenedicarboxylic acid with triphenylbismuth in a 1?:?1 ratio under solvothermal conditions afforded the 1D coordination polymer [Bi(2)(μ(2)-η(2)-OOCFcCOO-μ(2)-η(2))(η(2)-OOCFcCOO-η(2))(μ(2)-η(2)-OOCFcCOO-η(2))](n) (1). In this polymer two types of bismuth centers (hepta- and octacoordinate) are present and are interconnected by the bridging coordination of ferrocene dicarboxylate ligands. The reaction of ferrocenecarboxylic acid with triphenylbismuth in a 1?:?3 ratio, in toluene, under refluxing conditions, afforded the 1D coordination polymer [Bi(μ(2)-η(2)-FcCOO)(η(2)-FcCOO)(2)](n) (2). In the solid state, 2 exists as a helical polymer, where the inner bismuth chain is enclosed by an external sheath of ferrocene carboxylate ligands. In solution, however, 2 decomposes into the monomeric repeat unit [Bi(FcCOO)(3)] which is indicated by ESI-MS as well as cyclic voltammetric studies. Thus, a single, quasi-reversible redox event is seen for 2 in solution. The reaction of triphenylbismuth with ferrocenecarboxylic acid in a 1?:?1 stoichiometry afforded the molecular dimer [Bi(2)(μ(2)-η(2)-FcCOO)(2)(η(2)-FcCOO)(4)(H(2)O)(4)]·(2FcCOOH) (3). Compounds 1-3 reveal rich supramolecular architectures in the solid state as a result of the presence of C-HO, C-Hπ and ππ interactions.     

黄芩苷与铝离子配合物的电喷雾质谱研究

利用电喷雾多级串联质谱(ESI-MS^n)研究了黄芩苷与铝离子在不同浓度配比时形成的络合物,并通过质谱碎裂规律对其结构进行了初步确认。研究结果表明,黄芩苷与铝离子主要形成比较稳定的1：1和1：2配合物,分别为[AIR^1R^2L]^ 和[AlL2]^ ,其中L=[M-H]^-,R^1=CH3OH,R^2=CH3O。     

TCM active ingredient oxoglaucine metal complexes: crystal structure, cytotoxicity, and interaction with DNA

The alkaloid oxoglaucine (OG), which is a bioactive component from traditional Chinese medicine (TCM), was synthesized by a two-step reaction and used as the ligand to react with transition metal salts to give four complexes: [OGH][AuCl(4)]·DMSO (1), [Zn(OG)(2)(H(2)O)(2)](NO(3))(2) (2), [Co(OG)(2)(H(2)O)(2)](ClO(4))(2) (3), and [Mn(OG)(2)(H(2)O)(2)](ClO(4))(2) (4). The crystal structures of the metal complexes were confirmed by single crystal X-ray diffraction. Complex 1 is an ionic compound consisting of a charged ligand [OGH](+) and a gold complex [AuCl(4)](-). Complexes 2-4 all have similar structures (inner-spheres), that is, octahedral geometry with two OG coordinating to one metal center and two aqua ligands occupying the two apical positions of the octahedron, and two NO(3)(-) or ClO(4)(-) as counteranions in the outer-sphere. The complexation of OG to metal ion was confirmed by ESI-MS, capillary electrophoresis and fluorescence polarization. The in vitro cytotoxicity of these complexes toward a various tumor cell lines was assayed by the MTT method. The results showed that most of these metal-oxoglaucine complexes exhibited enhanced cytotoxicity compared with oxoglaucine and the corresponding metal salts, with IC(50) values ranging from 1.4 to 32.7 μM for sensitive cancer cells, which clearly implied a positive synergistic effect. Moreover, these complexes appeared to be selectively active against certain cell lines. The interactions of oxoglaucine and its metal complexes with DNA and topoisomerase I were investigated by UV-vis, fluorescence, CD spectroscopy, viscosity, and agarose gel electrophoresis, and the results indicated that these OG-metal complexes interact with DNA mainly via intercalation. Complexes 2-4 are metallointercalators, but complex 1 is not. These metal complexes could effectively inhibit topoisomerase I even at low concentration. Cell cycle analysis revealed that 1-3 caused S-phase cell arrest.     

固固相反应合成牛磺酸水杨醛钾与锑、铋的配合物

合成了牛磺酸水杨醛钾,并采用室温固固相反应法合成了牛磺酸水杨醛钾与三氯化锑和三氯化铋的配合物,其组成为:K2MC18H20O8N2S2 (M = Sb, Bi)。两种配合物的晶体结构均属于单斜晶系,锑配合物的晶胞参数为:a = 1.2869 nm, b = 1.7636 nm, c = 1.9917 nm, β= 93.79埃活榕浜衔锏木О问篴 = 1.4770 nm, b = 2.0334 nm, c = 2.0149 nm, β= 94.05。红外光谱表明N、Cl原子参与了配位,中心离子的配位数为5。