Copper(II), nickel(II) and cobalt(III) complexes of the macrocyclic ligand C-meso-7,14-diphenyl-5,6-butano-12,13-butano-1,4,8,11-tetraazacyclotetradeca-4,11-diene

Summary Metal complexes of the macrocyclic tetraaza ligand C-meso-7,14-diphenyl-5,6-butano-12,13-butano-1,4,8,11-tetraazacyclotetradeca-4,11-diene (L) are described. The copper(II) and nickel(II) complexes, isolated as their perchlorate salts, are 4-coordinate species. Several cobalt(III) complexes,trans-[CoLX₂]⁺(X = Cl^–, Br^–, NO ₂ ^– or N ₃ ^– have also been characterised. The most probable stereochemistry of the ligand in the metal complexes is the C-meso-N-meso arrangements of the chiral centres. The N-meso stereochemistry leads to the bulky phenyl groups lying in equatorial positions. I.r. and d-d spectra are reported for the various complexes described.     

Secondary interactions in the crystal structure of heterovalent 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenatogold(III) dibromoaurite(I)

The complex [Au(C₁₄H₂₂N₄)][AuBr₂] with two types of gold atoms (Au(III) and Au(I)) was obtained. In the cation 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenatogold(III), the Au atom is coordinated by four N atoms of the tetraazamacrocyclic amide ligand to make up a distorted square. The dibromoaurite(I) anion is linear. The conformation and packing of the structure is determined and stabilized by weak intermolecular hydrogen bonds C-H…Br and C-H…Au, an aurophilic interaction Au(I)…Au(III), and coordination bonds Au…N.     

(5,7,7,12,14,14-六甲基-1,4,8,11-四氮杂环十四-4,11-二烯)合镍双(O,O'-二烃基二硫代磷酸酯)的合成与研究

合成了4个含四氮杂大环配体和O,O'-二烃基二硫代磷酸根的镍配合物[Ni(hmtade){SSP(OR)₂}₂](hmtade=5,7,7,12,14,14-六甲基-1,4,8,11-四氮杂环十四-4,11-二烯;R=C₆H₅,2-naphthyl,C₆H₅CH₂CH₂,cyclohexyl),用元素分析、摩尔电导、红外光谱和¹H NMR、³¹PNMR、电子光谱及差热分析对其结构进行了表征.研究结果表明:配合物均为非电解质,O,O'-二烃基二硫代磷酸根作为单齿配体对镍中心配位.对四氮杂大环的构型进行了讨沦.     

Macrocyclic ligands with potential axial interactions. The preparation of copper(II), nickel(II) and cobalt(III) complexes of 7,14-o-hydroxyphenyl-5,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene

Summary The new macrocyclic ligand 7,14-o-hydroxyphenyl-5,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene (1=L) has been prepared and complexes with copper(II), nickel(II) and cobalt(III) characterised. The nickel(II) complex is a yellow square-planar species, while the purple-red copper(II) complex is probably tetragonal in both the solid state and solution. The complexes appear to have an N-meso arrangement of the chiral nitrogen centres with the HOC₆H₄ groups occupying equatorial sites so that axial interactions with the metal do not occur. A variety oftrans-[CoLX₂]ClO₄ complexes (X=Cl, Br, NO₂, or N₃) have been characterised.     

Crystal structure and spectroscopic properties of a new five-coordinate mixed-ligand nickel(II) complex with a macrocyclic ligand: [Ni(trans[14]diene)SCN]ClO4 (trans[14]diene = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene)

A new five-coordinate nickel(II) complex of a trans[14]diene macrocyclic ligand has been prepared and characterized by X-ray crystallography, u.v. and i.r. spectroscopy. The coordination environment of the nickel(II) ion is a distorted square pyramid with the nickel(II) ion deviating from the level plane 0.25 Å and the SCN ligand at the apical side.     

Kinetics of the Base-Catalysed Isomerization of trans-meso-CH3Co(H2O)L2+ (L = 5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene)

The isomerization of the complex trans-meso-CH₃Co(H₂O)L²⁺ (L = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) to trans-primary, rac-CH₃Co(H₂O)L²⁺ has been investigated from pH range 7.11 to 8.09 in aqueous solution. The reaction rate law has been determined as: -d[meso-CH₃Co(H₂O)L²⁺]/dt = k_OH [OH^?][meso-CH₃Co(H₂O)L²⁺], where k_OH = 600 ± 10 M^?1s^?1 at 25 °C and μ = 0.5 M. The activation parameters of the reaction were also studied with ΔH^± = 19.1 ± 0.9 Kcal mol^?1 and ΔS^± = 18.0 ± 0.8 cal K^?1mol^?1. A mechanism that involves a secondary NH inversion is proposed.     

Manganese(II) and palladium(II) complexes containing a new macrocyclic Schiff base ligand: antibacterial properties

Complexes of tetradentate macrocyclic Schiff base ligand, L, with Mn^II and Pd^II ions have been synthesized by the template condensation of 1,10-phenanthroline-2, 9-dicarboxaldehyde, 2,3-diamino-1,4-naphthoquinone and 1,2-dibromoethane in EtOH. The complexes were characterized by physicochemical and spectroscopic methods and an octahedral geometry is suggested for their structure. They have been screened for antibacterial activity against several bacteria, and the results are compared with the activity of penicillin.     

Synthesis of Cu(II) complexes containing 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene (L) and diisobutyldithiophosphinate or isobutylxanthate. Crystal Structure of [CuL](iso-Bu2PS2)2

The reaction of Cu(II) complex with 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotet-radeca-4,11-diene (L) and iso-Bu₂PS₂⁻ or iso-BuOCS₂⁻ anions gave stable paramagnetic compounds [CuL](iso-Bu₂PS₂)₂ (I) (μ_eff = 1.77 μB) and [CuL](iso-BuOCS₂)₂ (II) (μ_eff = 1.76 μB). According to X-ray diffraction, the crystal structure of I is composed of discrete centrosymmetric complex cations [CuL]²⁺ and iso-Bu₂Ps₂⁻ anions. The CuN₄ coordination unit is a square. The Cu...S distance (iso-Bu₂PS₂⁻) equal to 3.047 ? attests to possible S-coordination. Compounds I and II were studied by EPR.     

Nickel(II) complexes with different chromospheres containing macrocyclic ligands: spectroscopic and electrochemical studies

The mixed donor tetradentate (L(1)=N(2)O(2)) and pentadentate (L(2)=N(2)O(2)S) ligands have been prepared by the interaction of 1,3-diaminopropane and thiodiglycolic acid with diamine. These ligands possess two dissimilar coordination sites. Different types of complexes were obtained which have different stoichiometry depending upon the type of ligands. Their structural investigation have been based on elemental analysis, magnetic moment and spectral (ultraviolet, infrared, (1)H NMR, (13)C NMR and mass spectroscopy methods). The Ni(II) complexes show magnetic moments corresponding to two unpaired electrons except [Ni(L(1))](NO(3))(2) which is diamagnetic. Ligand field parameters of these complexes were compared. N(2)O(2)S donor ligand complexes show higher values of ligand field parameters, which are used to detect their geometries. The redox properties and stability of the complexes toward oxidation waves explored by cyclic voltammetry are related to the electron-withdrawing or releasing ability of the substituents of macrocyclic ligands moiety. The Ni(II) complexes displayed Ni(II)/Ni(I) couples irreversible waves associated with Ni(III)/Ni(II) process.     

Trinuclear thiocyanate-bridged compounds of the type [ML]2[Mn(NCS)4](ClO4)2 (where M = Cu(II), Ni(II); L = N-dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene)

The complexes of general formula [ML]2[Mn(NCS)4](ClO4)2 (where M = Cu(II), Ni(II); L = N-dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) were obtained and the crystal structures of both heteronuclear compounds were determined at 173 K. Complex [CuL]2[Mn(NCS)4](ClO4)2 (1) crystallizes in a monoclinic space group, C2/c, with a = 41.297(9) A, b = 7.571(2) A, c = 16.417(4) A, beta = 96.97(15) degrees, Z = 8, whereas complex [NiL]2[Mn(NCS)4](ClO4)2.H2O (2) crystallizes in a monoclinic space group, P2/c, with a = 21.018(5) A, b = 7.627(2) A, c = 16.295(4) A, beta = 104.47(1) degrees, Z = 4. The magnetic behaviour of (1) and (2) has been investigated over the temperature range 1.8-300 K. Complex (1) displays ferromagnetic coupling inside the trinuclear core of CuMnCu and compound (2) behaves like a mononuclear Mn(II) system. The magnetic properties of the second compound (2) with a similar trinuclear structure shows that Ni(II) ions have a diamagnetic character and a rather weak zero-field splitting at the central Mn(II) ion occurs. Finally, the magnitudes of the Cu(II)-M(II) interactions with M = Ni and Mn have been compared and qualitatively justified.     

Platinum(II) complexes containing the 3,3-dimethylglutarimidate ligand

Reaction of cis-[PtCl₂(PPh₃)₂] with excess 3,3-dimethylglutarimide (dmgH) and sodium chloride in refluxing methanol gives the mono-imidate complex cis-[PtCl(dmg)(PPh₃)₂], which was structurally characterized. The plane of the imidate ligand is approximately perpendicular to the platinum coordination plane which, coupled with restricted rotation about the Pt–N bond, results in inequivalent methyl groups and CH₂ protons of the dmg ligand in the room temperature ¹H NMR spectrum. These observations were corroborated by a theoretical study using density functional theory methods. The analogous bromide complex cis-[PtBr(dmg)(PPh₃)₂] can be prepared by replacing NaCl with NaBr in the reaction mixture.     

Nickel(II) and zinc(II) complexes of a pyridine ligand bearing a tetrathiafulvalene substituent

The synthesis, crystal structures, and electrochemical properties of the coordination complexes, NiBr₂(ept)₂ and ZnBr₂(ept)₂ (ept?=?4,5-ethylenedioxy-3??-(3??-pyridyl)-tetrathiafulvalene) are reported. Both complexes are mononuclear, with monodentate coordination of the ept ligand through the pyridine nitrogen. Cyclic voltammetry measurements for both complexes show a sizable interaction involving the electroactive ept ligand, with stabilization of the oxidized forms of the complexes.     

Distorted pentacoordinate copper(II) complexes containing a tridentate ligand

Summary Copper(II) complexes with a tridentate chelating ligand within the general 2N, X (X = O or S) donor class, containing abis(benzimidazolyl) donor set, were prepared and characterized. X-band e.p.r. spectra of the complexes indicateg >g and the largeg and lowA have been interpreted in terms of a distorted basal plane. Superimposed on theg component are five SHF lines withA _N = 16±2G, supporting the interaction of two nitrogen atoms with the copper nucleus. Thus, the basal plane of the complex comprises 2N atoms, with the ligand hetero atom being axially coordinated.