Bidentate Donor Ligands Research Articles

New palladium (II) complexes from halogen substituted Schiff base ligands: Synthesis, spectroscopic, biological activity, density functional theory, and molecular docking investigations

Two novel palladium (II) complexes Pd(L1)2 and Pd(L2)2 derived from ON donor bidentate ligands: 2-(((2-bromo-4-chlorophenyl)imino)methyl)phenol (HL1) and 2-(((-bromo-4-methylphenyl)imino)methyl)phenol (HL2) are reported. The structures of the complexes are unequivocally established using 1H NMR, 13C{H}NMR, Fourier transform-infrared, UV–Vis, TGA, elemental analysis (CHN), mass spectrometry (HRMS), and single crystal X-ray diffraction (SCXRD). The SCXRD revealed that the complexes crystallized as a monoclinic system in P2(1)/c space group, in which two ligands coordinated to one Pd(II) center via oxygen and nitrogen atoms of phenolate and imine in a bidentate fashion, resulting in a square planar geometry. The ligands and their complexes were tested for anticancer activity against breast cancer (MCF-7) and colon cancer (HT-29) cell lines, as well as their toxicity profile on HepG-2, a liver cell line, using MTT assays, and compared to 5-fluorouracil (the control). Pd(L1)2 was found to be more active and selective than Pd(L2)2, and it reduced the cancerous cells' viability by more than 70%. Pd(L2)2 reduced the viability of MCF-7 and HT-29 cell lines by more than 50%. However, the ligands were unable to reduce cancerous cell viability by more than 40%. Both complexes had no effect on the HepG-2 liver cell line at lower concentrations. The two complexes had higher antioxidant activity against DPPH radicals, with IC50 values of 33.16 and 38.40 μgmL−1, respectively, than the ligands, which had IC50 values of 50.76 and 60.90 μgmL−1. Hirshfeld surface (HS) analysis was used to investigate the non-covalent interaction (NCI) of the complexes and their ligands. The tendency of a pair of chemical species to form crystal packing interactions is computed, which provides the complexes with good contacts in the crystal packing. The DFT studies were performed for the ligands and their complexes at the M06-2X/6-311G (d,p) and LANL2DZ/6–31 + G (d, p) levels of theory, respectively. The structural characteristics, charges (Mulliken and NPA), global reactivity descriptors, MEP, and dipole moments were investigated using this method. Furthermore, a molecular docking study predicted the interactions in the protein–ligand complex.

Polypyridyl Coordinated Re(I) complexes for human tenascin-C (TNC) as an Antibreast Cancer Agent: An Intuition from Molecular Modeling and Simulations

Breast cancer continues to be the biggest cause of mortality for women worldwide, taking the lives of millions each year. As a result, scientists are now exploring the possibility of metal-based complexes as anticancer therapies. Notwithstanding, polypyridyl coordinated Re(I) complexes have demonstrated tremendous promise as cancer-fighting medications. Therefore, the intent of this research is to investigate theoretically the spectral properties, compute density functional theory (DFT), and simulate molecular docking of polypyridyl coordinated Re(I) complexes containing functionalized 2,2′-bipyridine N,N′-donor bidentate ligands: 5,5′-DiMBpy coordinated in (1a), 4,4′-DiMBpy coordinated in (2a), and 4,4′-DiMoxBp coordinated in (3a) for cancer therapy application. Intriguingly, the complex Re(2a) achieved the greatest MolDock score and H-bond energy following interactions with the target receptors utilized, followed by Re(1a) and Re(3), respectively. Thus elucidating the studied compounds to be efficient in the mitigation of breast cancer.

ON donor tethered copper (II) and vanadium (V) complexes as efficacious anti-TB and anti-fungal agents with spectroscopic approached HSA interactions

Antimicrobial drug resistance poses a significant threat worldwide, hence triggering an urgent situation for developing feasible drugs. 3D-transition metal coordination complexes being multifaceted, offer tremendous potency as drug candidates. However, there are fewer reports on non-toxic and safe transition metal complexes; therefore, we hereby attempted to develop novel copper and vanadium-based therapeutic agents. We have synthesised six metal complexes viz., [VVO2(Quibal-INH)] (1), [CuII(Quibal-INH)2] (2), [VVO(Quibal-INH) (cat)] (3), [CuII(Quibal-INH) (cat)] (4), [VVO(Quibal-INH) (bha)] (5) and [CuII(Quibal-INH) (bha)] (6). Quibal-INH (L) is an ON bidentate donor ligand synthesized from Schiff base reaction between 4-(2-(7-chloroquinolin-3-yl)vinyl)benzaldehyde (Quibal) and Isoniazid (INH). The synthesized compounds were characterized using analytical techniques involving ATR-IR, UV–Vis, EPR, 1H NMR, 13C NMR, and 51V NMR. Ligand (L) and compound 3 exhibited moderate growth inhibitory activity towards Candida albicans and Cryptococcus neoformans fungal species. Compound 6 has been identified as active against the above fungal species with no toxicity and hemolysis activity on the healthy cells. Compound 5 exhibited significant activity against the Mycobacterium tuberculosis H37Rv strain. Further, compounds 4, 5 and 6 exhibited excellent free radical scavenging activity. All the developed compounds were found to exhibit stability over a wide range of pH conditions. The complexes were additionally studied for their interaction with human serum albumin (HSA) with the UV–vis spectroscopic technique.

Synthesis of titanium(iv) 3,6-di-tert-butylcatecholate complexes

Two synthetic approaches were used for the synthesis of 3,6-di-tert-butylcatecholate derivatives of titanium(iv). These approaches are based on the exchange reaction between sodium catecholate and titanium(iv) chloride and the reaction of 3,6-di-tert-butylpyrocatechol with titanium tetrabutoxide. Depending on the reaction conditions, the former method allows the synthesis of the titanium monocatecholate complex 3,6-CatTiCl2(THF)2 (3,6-Cat is doubly deprotonated 3,6-di-tert-butylpyrocatechol) or bimetallic sodium titanium catecholate derivatives. Using the latter method, it is possible to synthesize six-coordinate titanium(iv) bis-cate-cholate complexes in high yields after the introduction of neutral bidentate donor ligands (TMEDA, DME, 2,2′-bipyridyl) to the reaction mixture.

Aerobic Aliphatic Hydroxylation Reactions by Copper Complexes: A Simple Clip-and-Cleave Concept.

A simple imine clip-and-cleave concept has been developed for the selective hydroxylation of non-activated CH bonds in aliphatic aldehydes with dioxygen through a copper complex. The synthetic protocol involves reaction of a substrate aldehyde with N,N-diethyl-ethylendiamine to give the corresponding imine, which is used as a bidentate donor ligand forming a copper(I) complex with [Cu(CH3 CN)4 ][CF3 SO3 ]. After exposure of the reaction mixture to dioxygen acidic cleavage and aqueous workup liberates the corresponding β-hydroxylated aldehyde. The concept for the hydroxylation of trimethylacetaldehyde as well as adamantane and diamantane 1-carbaldehydes was investigated and the corresponding β-hydroxy aldehydes were obtained with high selectivities. The results of low temperature stopped-flow measurements indicate the formation of a bis(μ-oxido)dicopper complex as reactive intermediate. According to density functional theory (DFT, RI-BLYP-D3/def2-TZVP(SDD)/ COSMO(CH2 Cl2 )//RI-PBE-D3/def2-TZVP(SDD)) computations CH bonds suitably predisposed to the [Cu2 O2 ]2+ core undergo hydroxylation in a concerted step with particularly low activation barriers, which explains the experimentally observed regioselectivities.

In situ quenching of monoaryl bismuth (III) dihalides with nitrogen donor ligands: Isolation of adducts and their spectral characterization

The molecular addition of amphoteric molecules of organobismuth (III) compounds namely, o-tolylbismuth and p-tolylbismuth dihalides with nitrogen donor bidentate ligands 1, 10 phenanthroline and 2, 2′-bipyridine have been isolated and characterized by UV–visible, IR, NMR and Photoluminescence (PL) spectroscopy. The compounds have been isolated from non-aqueous media; they have empirical formulae of the type ArBiX2- L (X = Cl, Br, I; L = Phen, Bipy). IR study indicate that there are strong extended interactions existing crystalline phases of the phenyl derivatives, while UV absorption for o-and p-tolylbismuth dihalides shows bathochromic effect due to + I nature of methyl substituent and corresponding hypsochromic shift in complexes due to coordination at bismuth center. 1HNMR spectra of complex exhibit the peaks for free ligands thereby suggesting the dissociation of complex in solution phase. Room temperature PL spectra suggest the presence of monomeric-dimeric species with Bi3+ luminescence in the complex in comparison with organobismuth (III) dihalides.

Structural and solution equilibrium studies on half-sandwich organorhodium complexes of (N,N) donor bidentate ligands

Characterization, solution stability, chloride affinity and crystal structures of [Rh(η5-C5Me5)(N^N)(H2O)]2+complexes and their correlation analysis.

Comparative equilibrium and structural studies of new pentamethylcyclopentadienyl rhodium complexes bearing (O,N) donor bidentate ligands

Complex formation processes of the (O,N) donor ligands 6-methylpicolinic acid (6-Mepic), quinoline-2-carboxylic acid (2-QA) and 3-isoquinolinecarboxylic acid (3-iQA) with the organometallic moiety (η5-pentamethylcyclopentadienyl)rhodium(III) (RhCp*) were studied in aqueous solution by the combined use of pH-potentiometry, 1H NMR spectroscopy and UV-Vis spectrophotometry. The solid phase structures of the [RhCp*(L)Cl] complexes bearing 6-Mepic and 2-QA were characterized by single-crystal X-ray diffraction analysis. Studies revealed the exclusive formation of mono complexes of the form [RhCp*(L)(H2O)]+ (L = deprotonated form of the ligands) and [RhCp*(L)(OH)]. The positively charged aqua species predominate at physiological pH even in the micromolar concentration range. The H2O/Cl− co-ligand exchange constants showed that all complexes preferably retain the chlorido ligand at the third coordination site at chloride ion concentrations present in the serum. In addition in vitro cytotoxicity of these [RhCp*(L)Cl] complexes was evaluated in three human cancer cell lines (A549, SW480 and CH1/PA-1) where they showed minor cytotoxic potency.

Bimetallic C-C Bond-Forming Reductive Elimination from Nickel.

Ni-catalyzed cross-coupling reactions have found important applications in organic synthesis. The fundamental characterization of the key steps in cross-coupling reactions, including C-C bond-forming reductive elimination, represents a significant challenge. Bimolecular pathways were invoked in early proposals, but the experimental evidence was limited. We present the preparation of well-defined (pyridine-pyrrolyl)Ni monomethyl and monophenyl complexes that allow the direct observation of bimolecular reductive elimination to generate ethane and biphenyl, respectively. The sp(3)-sp(3) and sp(2)-sp(2) couplings proceed via two distinct pathways. Oxidants promote the fast formation of Ni(III) from (pyridine-pyrrolyl)Ni-methyl, which dimerizes to afford a bimetallic Ni(III) intermediate. Our data are most consistent with the subsequent methyl coupling from the bimetallic Ni(III) to generate ethane as the rate-determining step. In contrast, the formation of biphenyl is facilitated by the coordination of a bidentate donor ligand.

Synthesis and Characterization of fac-[M(CO)3(P)(OO)] and cis-trans-[M(CO)2(P)2(OO)] Complexes (M = Re, 99mTc) with Acetylacetone and Curcumin as OO Donor Bidentate Ligands

The synthesis and characterization of neutral mixed ligand complexes fac-[M(CO)3(P)(OO)] and cis-trans-[M(CO)2(P)2(OO)] (M = Re, (99m)Tc), with deprotonated acetylacetone or curcumin as the OO donor bidentate ligands and a phosphine (triphenylphosphine or methyldiphenylphosphine) as the monodentate P ligand, is described. The complexes were synthesized through the corresponding fac-[M(CO)3(H2O)(OO)] (M = Re, (99m)Tc) intermediate aqua complex. In the presence of phosphine, replacement of the H2O molecule of the intermediate complex at room temperature generates the neutral tricarbonyl monophosphine fac-[Re(CO)3(P)(OO)] complex, while under reflux conditions further replacement of the trans to the phosphine carbonyl generates the new stable dicarbonyl bisphosphine complex cis-trans-[Re(CO)2(P)2(OO)]. The Re complexes were fully characterized by elemental analysis, spectroscopic methods, and X-ray crystallography showing a distorted octahedral geometry around Re. Both the monophosphine and the bisphosphine complexes of curcumin show selective binding to β-amyloid plaques of Alzheimer's disease. At the (99m)Tc tracer level, the same type of complexes, fac-[(99m)Tc(CO)3(P)(OO)] and cis-trans-[(99m)Tc(CO)2(P)2(OO)], are formed introducing new donor combinations for (99m)Tc(I). Overall, β-diketonate and phosphine constitute a versatile ligand combination for Re(I) and (99m)Tc(I), and the successful employment of the multipotent curcumin as β-diketone provides a solid example of the pharmacological potential of this system.

Catalyzed Tandem C–N/C–C Bond Formation for the Synthesis of Tricyclic Indoles using Ir(III) Pyrazolyl-1,2,3-Triazolyl Complexes

A series of new pyrazolyl-1,2,3-triazolyl N–N′ bidentate donor ligands (2a–c, 3a–d) were prepared via Cu(I)-catalyzed Huisgen cycloaddition reactions between 1-propargylpyrazoles and 4-substituted phenyl azides. The electron-withdrawing ability of the substituents follows the trend PhCH2 < p-CH3Ph < Ph < p-CF3Ph < p-NO2Ph, as illustrated in the gradual downfield shift of the 1,2,3-triazolyl-C4′ 13C NMR resonances. A series of Rh and Ir complexes containing these pyrazolyl-1,2,3-triazolyl or bis(pyrazol-1-yl)methane donor ligands of general formulae [Ir(N–N′)Cp*Cl]X (X = BArF4, BPh4; 5–8), [Rh(N–N′)Cp*Cl]X (X = BArF4, BPh4; 9–11), and [Rh(N–N′)(CO)2]BArF4 (13–16) (BArF4 = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) were synthesized and fully characterized. The solid-state structures of 5, 6a′, 6b, 7b, 8, 9, 10a, 10a′, 11, and 15c were determined by X-ray diffraction studies. As the electron-withdrawing strength of the phenylene substituent on the triazolyl ring is increased, the M–N3′(triazole) bond le...

Studies on DNA binding, electrochemical activation, DNA photocleavage, and biopotency of N and O donor bidentate ligands with Cu(II), Co(II), and Zn(II)

Three Schiff-base ligands, namely 2-(3,4-dimethoxybenzylideneamino)phenol (HL1 ), 2-(3-hydroxy-4-nitrobenzylidene-amino)phenol (HL2 ), and 2-(3-methoxy-4-hydroxy-benzylideneamino)phenol (HL3 ) and their Cu(II), Co(II), and Zn(II) complexes were synthesized and characterized by spectroanalytical techniques. The UV-Vis and magnetic moment data revealed square-planar Cu(II) and tetrahedral Co(II) and Zn(II). Conductivity data showed the non-electrolytic nature of the complexes. Absorption and viscometric titration as well as cyclic voltammetry studies revealed the complexes as avid binders of calf thymus (CT) DNA through intercalation. A profound effect of substituents on the Schiff base was observed on binding of complexes to CT-DNA and in cleavage of supercoiled pBR322 DNA. All the complexes showed DNA cleavage in the presence of mercaptopropionic acid (MPA) except HL1 complexes. The cleavage activity increased with longer exposure time of irradiation at 365 nm and higher complex concentration. The cleavage reactions in the presence of MPA involve hydroxyl radical. The synthesized Schiff bases and their metal complexes were also tested for antibacterial and antifungal activities. The metal complexes exhibited higher antibacterial and antifungal activities than the parent ligands and their biopotency is discussed.

Synthesis and Coordination Chemistry of Two N2-Donor Chelating Di(indazolyl)methane Ligands: Structural Characterization and Comparison of Their Metal Chelation Aptitudes

The N(2)-donor bidentate ligands di(1H-indazol-1-yl)methane (L(1)) and di(2H-indazol-2-yl)methane (L(2)) (L in general) have been synthesized, and their coordination behavior toward Zn(II), Cd(II), and Hg(II) salts has been studied. Reaction of L(1) and L(2) with ZnX(2) (X = Cl, Br, or I) yields [ZnX(2)L] species (1-6), that, in the solid state, show a tetrahedral structure with dihapto ligand coordination via the pyrazolyl arms. The reaction of L(1) and L(2) with Zn(NO(3))(2)·6H(2)O is strongly dependent on the reaction conditions and on the ligand employed. Reaction of L(1) with equimolar quantities of Zn(NO(3))(2)·6H(2)O yields the neutral six-coordinate species [Zn(NO(3))(2)(L(1))], 7. On the other hand the use of L(1) excess gives the 2:1 adduct [Zn(NO(3))(2)(L(1))(2)], 8 where both nitrates act as a unidentate coordinating ligand. Analogous stoichiometry is found in the compound obtained from the reaction of L(2) with Zn(NO(3))(2)·6H(2)O which gives the ionic [Zn(NO(3))(L(2))(2)](NO(3)), 10. Complete displacement of both nitrates from the zinc coordination sphere is observed when the reaction between L(1) excess and the zinc salt was carried out in hydrothermal conditions. The metal ion type is also determining structure and stoichiometry: the reaction of L(2) with CdCl(2) gave the 2:1 adduct [CdCl(2)(L(2))(2)] 11 where both chlorides complete the coordination sphere of the six-coordinate cadmium center; on the other hand from the reaction of L(1) with CdBr(2) the polynuclear [CdBr(2)(L(1))](n) 12 is obtained, the Br(-) anion acting as bridging ligands in a six-coordinate cadmium coordination environment. The reaction of L(1) and L(2) with HgX(2) (X = Cl, I, SCN) is also dependent on the reaction conditions and the nature of X, two different types of adducts being formed [HgX(L)] (14: L = L(1), 16, 17: L = L(1) or L(2), X = I, 19: L = L(2), X = SCN) and [HgX(L)(2)] (15: L = L(2), X = Cl, 18: L = L(1), X = SCN). The X-ray diffraction analyses of compounds 1, 2, 4, 5, 7, 8, 10-12, 14, 15, and 19 are also reported. The variations of the coordination geometry parameters in the complexes are compared and discussed.

Molybdenum Carbonyl Complexes Bearing PN Ligands Based on 2‐Aminopyridine

AbstractMolybdenum complexes of the general formula Mo(PN)(CO)4containing both achiral and chiral phosphorus‐nitrogen donor bidentate ligands based on 2‐aminopyridine were prepared and characterized by their NMR and IR spectra. The oxidative addition of allyl bromide to Mo(PN)(CO)4was studied with PN =N‐(diisopropylphosphanyl)‐2‐aminopyridine (PN‐iPr). X‐ray structures of representative compounds were determined. The mechanism of the oxidative addition of allyl bromide to Mo(PN‐iPr)(CO)4was analyzed by DFT/B3LYP calculations. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2009)

Lewis acidity of group 14 tetrahalides in gas phase

Donor–acceptor complexes of silicon, germanium and tin tetrahalides with nitrogen-containing donors MX 4· nL (M=Si,Ge,Sn; X=F,Cl,Br; L=NH 3, Py, 2,2′bipy, 1,10-phen) have been theoretically studied at the B3LYP/DZP level of theory. It was found that some of the complexes possess negative Gibbs free energies, i.e. their decomposition into components is thermodynamically favorable. At the same time the formation of normal covalent (by means of the bond length) donor–acceptor bond was evidenced. Scanning of the potential energy surface (PES) revealed that such complexes are metastable species with barriers to dissociation 4–60 kJ mol −1. Energies of the element-nitrogen donor–acceptor bond are strongly dependent on the coordination polyhedron type; however, for the given type of the coordination polyhedron they are independent on the nature of the donor molecule (NH 3, Py, bipy, phen). It is shown that the reorganization energy of the acceptor molecule (36–280 kJ mol −1) governs the stability of the complexes. The reorganization energies of the donor molecules (1–32 kJ mol −1) are much smaller. Dissociation enthalpies of the complexes decrease in order Sn>Ge>Si, in line with increasing reorganization energy of the acceptor. At the same time, the donor–acceptor bond energy changes nonmonotonically: Ge<Si<Sn. The values of the gas phase dissociation enthalpy should not be used to estimate the metal-nitrogen bond energy. On the basis of theoretical studies, the most promising candidates for stable gaseous complexes of group 14 halides are complexes of tin tetrahalides with bidentate donor ligands, such as SnF 4phen.

New Approach to the Chemistry of Technetium(V) and Rhenium(V) Phenylimido Complexes: Novel [M(NPh)PNP]3+ Metal Fragments (M = Tc, Re; PNP = Aminodiphosphine) Suitable for the Synthesis of Stable Mixed-Ligand Compounds

Ligand-exchange reactions of the aminodiphosphine ligand bis[(2-diphenylphosphino)ethyl]amine hydrochloride (PNHP x HCl) with labile M(NPh)Cl3(PPh3)2 precursors (M = Re, Tc) in the presence of triethylamine yield monocationic phenylimido mer,cis-[M(NPh)Cl2(PNHP)]Cl (M = Re, 1; Tc, 2) intermediate complexes. X-ray analyses show that in both compounds the aminodiphosphine acts as a tridentate ligand dictating a mer,cis arrangement. Two chloride ligands, respectively in an equatorial and in the axial position trans to the linear M-NPh moiety, fill the remaining positions in a distorted-octahedral geometry. The chloride trans to the metal-imido core is labile, and is replaced by an alcoholate group, without affecting the original geometry, as established in mer,cis-[Re(NPh)(OEt)Cl(PNHP)]Cl 4. Otherwise, ligand-exchange reactions involving the aminodiphosphine bis[(2-diphenylphosphino)ethyl]methylamine (PNMeP), in which the central secondary amine has been replaced by a tertiary amine function, or its hydrochloride salt (PNMeP x HCl) give rise to three different species, depending on the experimental conditions: fac,cis-[Re(NPh)Cl2(PNMeP)]Cl 3a, cis,fac-Re(NPh)Cl3(PNMeP) x HCl 3b, and mer,trans-[Re(NPh)Cl2(PNMeP)]Cl 3c, which are characterized in solution by multinuclear NMR studies. The monodentate groups incorporated in these intermediate compounds, either halides and/or ethoxide, undergo substitution reactions with bidentate donor ligands such as catechol, ethylene glycol, and 1,2-aminophenol to afford stable mixed ligand complexes of the type [M(NPh)(O,O-cat)(PNP)]Cl [PNP = PNHP M = Re 5, Tc 6; PNP = PNMeP M = Re 7], [Re(NPh)(O,O-gly)(PNP)]Cl [PNP = PNHP 8, PNMeP 9] and [Re(NPh)(O,N-ap)(PNMeP)]Cl 10. X-ray diffraction analyses of the representative compounds 5 and 8 reveal that the aminodiphosphine switches from the meridional to the facial coordination mode placing the heteroatom of the diphosphine trans to the phenylimido unit and the bidentate ligand in the equatorial plane. Solution-state NMR studies suggest an analogous geometry for 6, 7, 9, and 10. Comparison with similar mixed ligand complexes including the terminal nitrido group is discussed.

N,N′-Bis(3-nitrobenzylidene)-trans-1,2-cyclohexanediamine

The title compound, C20H20N4O4, is a potentially N,N′-bidentate donor ligand with two chiral C atoms. In the crystal structure, the mol­ecules form centrosymmetric dimers via C—H⋯N hydrogen bonds.

Heterobimetallic complexes as oxygen donor bidentate ligands: synthesis of early–late trinuclear complexes

The early–late heterometallic complexes [TiCp ∗((OCH 2) 2Py)(μ-O)M(COD)] (M = Rh, Ir) behave as four-electron donor ligands yielding the polynuclear cationic complexes [TiCp ∗(OCH 2) 2 Py(μ-O) {M(COD)} 2]OTf (M = Rh ( 1), Ir ( 2)). The molecular structure of complex 1 has been established through an X-ray diffraction study.

Synthesis and Characterisation of Mixed Ligand Complexes of Cu(II) Containing Optically Active R-(+)- &amp; S-(–)-1,1′-bi-2-Naphthol (BINOL)

The novel mixed ligand complexes of Cu(II) with optically active R-(+)- / S-(–)-1,1′-bi-2-naphthol and N, N′ – donor bidentate ligands have been synthesised and characterised by elemental analysis and various spectral studies.

Hydrogen Bonding as a Construction Element for Bidentate Donor Ligands in Homogeneous Catalysis: Regioselective Hydroformylation of Terminal Alkenes.

AbstractFor Abstract see ChemInform Abstract in Full Text.