Search results for "Ordination"
showing 10 items of 1367 documents
Organotin(IV) Complexes Containing Sn–O–Se Moieties: A Structural Inventory
2018
This review focuses on organotin compounds exhibiting Sn–O–Se moieties, the molecular structures of which have been previously resolved by single-crystal X-ray diffraction analysis. Three distinct classes of compounds have been identified. Thus, the various modes of coordination of selenite, selenate and organoseleninate anions with tin atoms of organotin(IV) fragments are illustrated and detailed.1 Introduction2 Organotin(IV) Selenite Complexes3 Organotin(IV) Selenate Complexes4 Organotin(IV) Organoseleninate Complexes5 Summary
Rh(I) Coordination Chemistry of Chiral α-Aminophosphine(η6-arene)chromium Tricarbonyl Ligands
2003
The diastereoselective addition of Ph(2)PH to the chiral ortho-substituted eta(6)-benzaldimine complexes (eta(6)-o-X-C(6)H(4)CH=NAr)Cr(CO)(3) (1, X = MeO, Ar = p-C(6)H(4)OMe; 2, X = Cl, Ar = Ph) leads to the formation of the corresponding chiral aminophosphines (alpha-P,N) Ph(2)P-CH(Ar(1))-NHAr(2) (3, Ar(1) = o-C(6)H(4)(OCH(3))[Cr(CO)(3)], Ar(2) = p-C(6)H(4)OCH(3); 4, Ar(1) = o-C(6)H(4)Cl[Cr(CO)(3)], Ar(2) = Ph) in equilibrium with the starting materials. The uncomplexed benzaldimine (o-ClC(6)H(4)CH=NPh), 2', analogously produces an equilibrium amount of the corresponding aminophosphine Ph(2)P-CH(Ar(1))-NHAr(2) (4', Ar(1) = o-C(6)H(4)Cl, Ar(2) = Ph). Depending on the equilibrium constant, t…
Tri- and tetranuclear heteropivalate complexes with core {Fe2Ni O} (x = 1, 2): Synthesis, structure, magnetic and thermal properties
2019
Abstract The reactions of complex [Fe2Ni(O)(Piv)6(Et2O)(H2O)2] (1) with 1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy) gave the following new coordination compounds: the trinuclear complex [Fe2Ni(O)(Piv)6(phen)H2O]·(C2H5)2O (2), the tetranuclear ones [Fe2Ni2(OH)2(Piv)8(phen)2] (3) and [Fe2Ni2(OH)2(Piv)8(bpy)2] (4), depending on the crystallization conditions. According to single crystal X-ray diffraction data, all the compounds have molecular structures. The Mossbauer spectra of 1–3 correspond to high-spin Fe3+ ions in an octahedral environment consisting of oxygen atoms. The DC magnetic susceptibility studies and quantum-chemical analysis of intra- and intermolecular J pathways using…
Cobalt Corroles with Bis‐Ammonia or Mono‐DMSO Axial Ligands. Electrochemical, Spectroscopic Characterizations and Ligand Binding Properties
2018
International audience; Four bis-ammonia ligated cobalt corroles and four mono-DMSO ligated cobalt corroles with different mesoaryl substituents on the macrocycle (A 2 Band A 3-corroles) were synthesized and investigated as to their electrochemical and spec-troscopic properties under different solution conditions. The complexation energies of the investigated cobalt corroles were theoretically calculated to illustrate the propensity of the cobalt center for pentacoordination or hexa-coordination with various axial ligands (DMSO, CO, py and NH 3). The structure of one hexacoordinate bis-NH 3 cobalt corrole complex was also determined by X-ray diffraction.
Synthesis and characterization of new coordination compounds by the use of 2-pyridinemethanol and di- or tricarboxylic acids
2021
The development of synthetic approaches towards new coordination polymers has attracted significant interest due to their fascinating physical properties, as well as their use in a wide range of technological, environmental and biomedical applications. Herein, the initial combination of 2-pyridinemethanol (Hhmp) with 1,4-benzenedicarboxylic acid (H2bdc) or 1,3,5-benzenetricarboxylic acid (H3btc) has been proven a fruitful source of such new species providing access to five new coordination compounds, namely [M2(Hbtc)2(Hhmp)4]·DMF (M = CoII, 1·DMF;NiII, 2·DMF), [Ni(bdc)(Hhmp)2]n·4H2O (3·4H2O), [Zn2(bdc)(hmp)2]n·DMF (4·DMF) and [Fe3(bdc)3(Hhmp)2]n (5). 4·DMF and 5 are the first metal–organic …
Synthesis, crystal structure and magnetic properties of bis[μ-bis(3-(pyridin-2-yl)-1,2,4-triazole-N′,N1,N2)] bis[triaqua nickel(II)] tetranitrate
1998
Abstract A new dinuclear nickel(II) coordination compound of formula Ni2(Hpt)2(H2O)6(NO3)4 (Hpt=3-(pyridin-2-yl)-1,2,4-triazole) was synthesized. The structure was solved at 298 K by single-crystal X-ray analysis. Bisμ-bis(3-(pyridin-2-yl)-1,2,4-triazole-N′,N1,N2) bistriaqua nickel(II) tetranitrate (C14H24N12O18Ni2) crystallizes in the triclinic space group P-1, a=7.2266(1), b=9.9144(1), c=11.2647(1) A, α=66.854(1)°, β=74.000(1)°, γ=86.400(2)°, V=712.42(1) A3, Z=1 (dinuclear units), 2823 reflections (1 > 2σ(I)), R1=0.0442, wR2=0.1197. The Ni(II) ions are bridged by two neutral Hpt ligands coordinating via N1 and N2 in the equatorial plane, Ni(1)-Ni(1)′=4.098(1) A. The Hpt bridging mode is a…
Thermodynamic studies of iron(III) complex of some new dihydroxamic acids model of rhodotorulic acid
2018
Abstract The objective of this research is to elucidate the coordination chemistry and the structure of complexes formed with siderochelates organic ligands and the physico-chemical studies of iron(III) complexation. Three dihydroxamic acids synthesized ((LCyEt)2−, (LCyPr)2− and (LO)2−) mimicking a fungal siderophore, rhodotorulic acid. They were evaluated with iron(III) chelation by potentiometric and spectrophotometric titrations in 0.1 M KNO3. These measurements revealed the formation of dileptic and trileptic complexes in excess ligand conditions. The chemical model includes five species of [Fem(L)lHh](3m−2l+h)+ with general formula: [Fe(L)]+, [Fe(L)(OH)], [Fe(L)(OH)2]−, [Fe(L)2H] and […
Pseudopeptidic ligands: exploring the self-assembly of isophthaloylbisglycine (H2IBG) and divalent metal ions.
2012
We present a systematic study of the complexation of the new pseudopeptidic ligand isophthaloylbisglycine (H(2)IBG) with divalent metal ions of varying ionic radius. This work represents the initial employment of H(2)IBG in the coordination chemistry of alkaline earth, 3d transition, Zn(II) and Cd(II) metal elements. Infrared, NMR, thermal, magnetic, adsorption and theoretical studies of these compounds are also discussed.
Heterocycle-appended porphyrins: synthesis and challenges
2020
Abstract Porphyrin and their versatile metal complexes represent a special class of coordination compounds possessing unique physical-chemical properties. The achievements in the development of the synthetic approaches for the modification of the porphyrin macrocycle allowed the preparation of a variety of functional derivatives for diverse applications. Among a broad diversity of synthetically available metalloporphyrins meso-substituted tetrapyrroles are comprehensively investigated. However, β-substituted porphyrins could be considered as the most suitable models for mimicking the key roles of naturally occurring dyes in vital processes. The introduction of various substituents to the β-…
N-Glycosylamines of 4,6-O-ethylidene-alpha-D-glucopyranose: synthesis, characterisation and structure of CO2H, Cl and F ortho-substituted phenyl deri…
2000
A saccharide based ligand suitable for metal binding (HLCOOH) has been synthesized using 4,6-O-ethylidene-alpha-D-glucopyranose (4,6-O-EGP) and anthranilic acid. A few analogous glycosylamines with chloro and fluoro ortho substitutions have also been synthesized and characterised. Complexes of HLCOOH with Na+, K+, Mg2+, Ca2+, Ba2+, Cd2+ and Hg2+ have been isolated and characterised fully. The crystal structures of 4,6-O-EGP, the chloro analogue of HLCOOH and the K+ complex of L-COOH are established. The anomeric nature, orientation of the binding core and the co-ordination aspects of K+ have been derived from these structures.