Search results for "complex"

Studies on coordination compounds—VIII. Syntheses, structural, magnetic, spectral and thermal properties of some cobalt(II), nickel(II) and copper(II…

1995

Abstract The complexes bis[triaqua(2-aminopyrimidine)-μ-sulphato-O,O′-cobalt(II)] dihydrate (1), catena-[diaqua(2(2-aminopyrimidine))-μ-sulphato-O,O′nickel(II)]2-amino-pyrimidine (2), [pentaaqua(2-aminopyrimidine)nickel(II)]sulphate 2-aminopyrimidine (3) and catena-[aqua(2(2-aminopyrimidine))-μ-sulphato-O,O′-copper(II)] dihydrate (4) were prepared, structure determined by X-ray methods and physical properties studied by magnetic, IR, NMR, EPR and reflectance methods. The thermal behaviour was studied by TG and mass spectrometric methods. The results are discussed on a structural basis.

Coordination Chemistry of Cu2+ Complexes of Small N-Alkylated Tetra-azacyclophanes with SOD Activity

2018

A new tetraaza-pyridinophane macrocycle (L1) N-alkylated with two isopropyl and one methyl groups symmetrically disposed has been prepared and its behavior compared with those of the unsubstituted pyridinophane (L3) and the related compound with three methyl groups (L2). The protonation studies show that, first, a proton binds to the central methylated amine group of L1, while, second protonation leads to a reorganization of the protons that are at this stage attached to the lateral isopropylated amines. The X-ray structure of [HL1]+ agrees with the UV–vis and NMR studies as well as with the results of DFT calculations. The stability of the Cu2+ complexes decreases on increasing the bulkine…

Organic chelate-free and azido-rich metal clusters and coordination polymers from the use of Me3SiN3: a new synthetic route to complexes with beautif…

2019

In this Feature Article, we highlight the feasibility of a new, recently developed approach towards the synthesis of high-spin molecules and single-molecule magnets (SMMs). The key to the preparation of such molecular compounds is the organic azide precursor Me3SiN3, which fosters the formation of 3d-metal azido clusters and coordination polymers without requiring the assistance of any organic chelating/bridging group. All the isolated compounds contain metallic cores which are surrounded by end-on bridging N3− groups. Consequently, the reported molecular materials exhibit ferromagnetic exchange interactions between the spin carriers, resulting in the stabilization of the maximum possible s…

P-Chirogenic Triazole-Based Phosphine: Synthesis, Coordination Chemistry, and Asymmetric Catalysis

2020

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

Bringing a Molecular Plus One: Synergistic Binding Creates Guest-Mediated Three-Component Complexes

2020

Cethyl-2-methylresorcinarene (A), pyridine (B), and a set of 10 carboxylic acids (Cn) associate to form A·B·Cn ternary assemblies with 1:1:1 stoichiometry, representing a useful class of ternary systems where the guest mediates complex formation between the host and a third component. Although individually weak in solution, the combined strength of the multiple noncovalent interactions organizes the complexes even in a highly hydrogen-bond competing methanol solution, as explored by both experimental and computational methods. The interactions between A·B and Cn are dependent on the pKa values of carboxylic acids. The weak interactions between A and C further reinforce the interactions betw…

Generation and Oligomerization of N-Ferrocenyl Ketenimines via Open-Shell Intermediates

2016

In the presence of oxidant (Ag[SbF6]) and base, N-ferrocenyl thioamide Fc-NHC(S)CH3 (H-1; Fc = Fe(η5-C5H5)(η5-C5H4)) converts in an unexpected multistep reaction sequence to a novel N,S-heterocyclic ring, which initiates an oligomerization reaction. Key intermediates toward the resulting complicated material are Ag6(1)6 silver clusters of the anionic N,S-chelating ligand 1− and EPR-active piano stool complexes resulting from ring-slipped cyclopentadienyl ligands, as well as electrophilic N-ferrocenyl ketenimine Fc-N═C═CH2 (2) and its ferrocenium cation 2•+ formed by hydrosulfide elimination. Mechanistic insight is achieved using X-ray diffraction and mass spectrometry, as well as EPR and NM…

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.