Search results for "Chela"
showing 10 items of 415 documents
Synthesis, structural characterization and electrochemical activity of oxidovanadium(IV/V) complexes of a diprotic ONS chelating ligand
2010
Abstract The present work reports the chemistry of a few oxidovanadium(IV) and (V) complexes of the ONS chelating ligand S-benzyl-β-N-(2-hydroxyphenylethylidine) dithiocarbazate (H2L). Major objective of this work is to arrive at some general conclusions about the influence of binding environment generated by the replacement of an O-donor center by a S-donor point in a ligand (of a similar arrangement of the other O- and N-donor points) on the redox behavior and on the structural features of comparable [VO(OEt)(ONS)] and [VO(OEt)(ONO)] complexes. Synthesis, characterization by various physicochemical techniques (UV–Vis, IR, EPR and elemental analysis), exploration of electrochemical activit…
[68Ga]Ga-DO2A-(OBu-l-tyr)2: Synthesis, 68Ga-radiolabeling and in vitro studies of a novel 68Ga-DO2A-tyrosine conjugate as potential tumor tracer for …
2009
The synthesis, (68)Ga-labeling and in vitro study of the novel tyrosine chelate derivative [(68)Ga]Ga-1,4,7,10-tetraazacyclododecane-1,7-diacetic acid-4,10-di-(O-butyl)-l-tyrosine ([(68)Ga]Ga-DO(2)A-(OBu-l-tyr)(2)) as a potential tracer for imaging tumor metabolism by positron emission tomography (PET) is presented. This approach combines the biological amino acid transporter targeting properties of l-tyrosine with the outstanding availability of (68)Ga(III) via the (68)Ge/(68)Ga generator. In vitro studies utilizing the F98-glioblastoma cell line revealed specific uptake of [(68)Ga]Ga-DO2A-(OBu-l-tyr)(2) that was comparable to that of the reference O-(2-[(18)F]fluoroethyl)-l-tyrosine (FET)…
Complexes of organometallic compounds
1974
Abstract Several new complexes formed by PhTlCl 2 with tridentate ligands (with ONO and SNO donor atoms) and a tetradentate ligand (with ONNO donor atoms), have been prepared. The complexes show 1/1 organothallium(lll)/Ligand ( = L 2− ) stoichiometry. Their nature and configuration are investigated in the solid state by vibrational spectroscopy, and in solution by electronic spectroscopy. The existence of chelation by the dianionic ligands on Tl III is inferred, and suggestions are made concerning the Tl III coordination number and the stereochemistry of the complexes.
Mixed micelles composed of Peptides and Gadolinium complexes as tumor-specific contrast agents in MRI: a SANS study
2004
A detailed structural investigation on mixed micelle aggregates as target-specific contrast agents for magnetic resonance imaging technique has been carried out by way of small angle neutron scattering measurements. These mixed micelles are formed by two new amphiphilic molecules formed by a bioactive peptide and a claw moiety. The first molecule, C18H37CONH(AdOO)(x)-G-CCK8 (C18LxCCK8, x = 2, 5), contains an 18-carbon-atom alkylic chain bound to the C-terminal of the cholecystokinin octapeptide amide (CCK 26-33 or CCK8) and is able to bind to the overexpressed CCK receptor of some tumor cells. The second molecule, C(18)H(37)CONHLys(DTPAGlu)CONH25- (C18DTPAGlu) or its gadolinium complex [C(1…
Coordination properties of imino(2-pyridyl)methylpalladium(II) compounds. Preparation and thermal rearrangement of binuclear adducts with palladium(I…
1988
Abstract The imino(2-pyridyl)methylpalladium(II) compound py-2-C(R′)NR (R = C 6 H 4 OMe-p, R′ = trans-PdCl(PPh 3 ) 2 ) reacts with [PdCl 2 (CH 2 CHPh)] 2 , [PdCl 2 - (NCMe) 2 ], and K[PtCl 3 (CH 2 CH 2 )] to give binuclear complexes [MCl 2 {py-2- C(R′)NR}] (M = Pd, Pt), in which the α-diimino group acts as a chelating bidentate ligand. In hot 1,2-dichloroethane, these complexes undergo a PPh 3 and chloride ligand exchange at rates which depend markedly on the metal M (Pd ⪢ Pt), to yield the new derivatives [MCl(PPh 3 ){py-2-C(cis-PdCl 2 (PPh 3 ))NR}]. The ligand exchange is followed by a much slower decomposition to [MCl 2 (PPh 3 ) 2 ]. Labile intermediates of the same type, [MCl(PPh …
Coordination properties of imino(2-pyridyl)methylpalladium(II) compounds. Reactions with the chloride-bridged allyl dimers [MCl(η3-2-MeC3H4)]2 (MPd,…
1990
Abstract The imino(2-pyridyl)methylpalladium(II) compounds py-2-CR 1 NR [R 1 = trans -PdCl(PPh 3 ) 2 , R = C 6 H 4 OMe- p ( Ia ), Me ( Ib ), CMe 3 ( Ic ); R 1 = Pd(dmtc)(PPh 3 ), R = C 6 H 4 OMe- p ( Id )] react with [MCl(η 3 - 2-MeC 3 H 4 )] 2 (M = Pd, Pt) in a molar ratio 1/0.5 and in the presence of NaClO 4 to yield the binuclear cationic complexes II , [M(η 3 -2-MeC 3 H 4 )(py-2-CR 1 NR)]ClO 4 , where the α-diimino group acts as σ,σ N , N ′ chelating ligand. In the absence of NaClO 4 and with a molar ratio 1/1, the reaction leads initially to formation of a ionic intermediate A , [M(η 3 - 2-MeC 3 H 4 )(py-2-CR 1 NR)] [MCl 2 (η 3 -2-MeC 3 H 4 )], which subsequently undergoes exchange …
Five-coordinate complexes of palladium(ii) and platinum(ii) with α-diimine and 1,5-cyclooctadiene ligands
2001
The five-coordinate complexes [PtMe(cod)(N–N′)]BF4 [cod = η2,η2-cyclooctadiene, N–N′ = (6-R2)C5H3N-2-CHNR1 (R1 = C6H4OMe-4, R2 = H (1), Me (2); R1 = CMe3, R2 = H (3), Me (4); R1 = (R)-bornyl, R2 = Me (5))] are readily obtained from the reaction of [PtClMe(cod)] with N–N′ in the presence of NaBF4. The preparation of [PtMe(cod)(6)]BF4 (6 = 4-MeOC6H4NCHCHNC6H4OMe-4), [PdMe(cod)(N–N′)]BF4 and [PtCl(cod)(N–N′)]BF4 (N–N′ = 2, 4) requires chloride abstraction by AgBF4 from [PtClMe(cod)], [PdClMe(cod)] and [PtCl2(cod)], respectively, followed by coordination of N–N′. The NMR spectral data suggest a trigonal-bipyramidal structure with chelating cod and N–N′ ligands, where the α-diimine and one CC bo…
Organometallic Complexes with Biological Molecules: VIII. Synthesis, Solid State andin vivo Investigation of Triorganotin(IV) Derivatives ofL-Homocys…
1997
Several new triorganotin(IV) derivatives of L-homocysteic acid (L-HCAH) with formula R3Sn(L-HCA) (R=Me, nBu, Ph) have been synthesized. Their solid-state configurations were determined by IR and Mossbauer spectroscopy. The tin(IV) atom is five-coordinated in all the complexes, with the L-homocysteic acid behaving as a monoanionic bidentate ligand coordinating the tin(IV) atom through a chelating or bridging carboxylate group. The sulfonate (SO3−) and NH3+ groups of L-homocysteic acid maintain their free acid configuration and hence do not participate to the coordination of the tin(IV) atom. Coordination hypotheses have been checked through the correlation between the Mossbauer parameter iso…
Diorganotin(IV)-2-mercaptopyrimidine complexes
1998
The complexes formed between the diorganotin(IV) moieties, R 2 Sn(IV), and the ligand 2-mercaptopyrimidine, (H)SPym, were investigated. Complexes R 2 SnHal(SPym) and R 2 Sn(SPym) 2 [R = Me, i Pr, n Bu, i Bu, t Bu, cyclohexyl(Cy), Ph] were synthesized, and characterized by elemental analysis. In the solid state, chelation of SPym through S and N donors was established by IR spectroscopy, and the nature of the environment of tin centers was investigated by 119 Sn Mossbauer spectroscopy. From the dynamics of 119 Sn nuclei determined by variable-temperature measurements on representative compounds [Me 2 SnCl(SPym) and Cy 2- SnBr(SPym)], as well as by point-charge model treatment of nuclear quad…
Two complexes of Pt(IV) and Au(III) with 2,2'-dipyridylamine and 2,2'-dipyridylaminide ligands
2014
Two noble metal complexes involving ancillary chloride ligands and chelating 2,2′-bipyridylamine (Hdpa) or its deprotonated derivative (dpa), namely [bis(pyridin-2-yl-κN)amine]tetrachloridoplatinum(IV), [PtCl4(C10H9N3)], and [bis(pyridin-2-yl-κN)aminido]dichloridogold(III), [AuCl2(C10H8N3)], are presented and structurally characterized. The metal atom in the former has a slightly distorted octahedral coordination environment, formed by four chloride ligands and two pyridyl N atoms of Hdpa, while the metal atom in the latter has a slightly distorted square-planar coordination environment, formed by two chloride ligands and two pyridyl N atoms of dpa. The difference in conjugation between the…