Joseph A.O. Woods

SYNTHESIS AND CHARACTERISATION OF SOME NICKEL(II) β-KETOAMINES AND THEIR ADDUCTS WITH 2,2′-BIPYRIDINE AND 1,10-PHENANTHROLINE

ABSTRACT A series of nickel(II) β-ketoimine complexes, {Ni[CH3-C(O)CHC(CH3)NR]2, R=CH3, C4H9}, and ketoiminates, {Ni[CH3C(O)CH(CH3)C(-N(CH2)nN-)C(CH3)CHC(O)CH3], n=2, 6, 8, 9}, and their adducts with 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) have been synthesized and characterized using elemental analyses, magnetic susceptibility, conductivity, infrared and electronic spectral measurements. The ketoimine ligands coordinate to the nickel atom in a bidentate fashion using the N2O2 chromophore. A range of stereochemistries was observed for the nickel(II) ketoiminates from four-coordinate tetrahedral and square-planar geometry to six-coordinate octahedral geometry. Conductivity measurements indicate that the compounds are non-electrolytes. The influence of bridging chain lengthening on the adopted geometry is discussed and possible structures for the compounds are suggested.

SYNTHESIS, ELECTRONIC, AND MAGNETIC PROPERTIES OF SOME 3-SUBSTITUTED 2,4-PENTANEDIONATOOXOVANADIUM(IV) COMPLEXES AND THEIR 4-METHYLPYRIDINE ADDUCTS

Oxovanadium(IV) complexes of various 3-substituted 2,4-pentanediones [VO(H3CCOCHRCOCH3]2 where R = CH3, C2H5, i-C3H7, n-C4H9, i-C4H9, C6H5, CH3CO, C6H5CH2, have been synthesized and their adducts with 4-methylpyridine prepared. The compounds were characterized by elemental analyses, magnetic susceptibility, infrared and electronic spectral measurements. The infrared vanadyl stretching frequency ν(V = O) were observed in the range 940–998 cm−1 indicating the non-existence of polymeric structures. The infrared and electronic spectral studies indicate that the oxovanadium(IV) β-diketone complexes assume a square-pyramidal geometry while the adducts adopt a six-coordinate octahedral geometry. The effective magnetic moments (μeff) for the complexes at room temperature are between 1.71 and 1.76 B.M. indicating the compounds are magnetically dilute. Possible structures for the compounds are suggested.

Synthesis and Characterization of Nickel(II) Complexes of Benzoic Acid and Methyl Substituted Benzoic Acid Hydrazides and X‐Ray Structure of Ni[C6H5CONHNH2]3Cl2·3CH3OH

Nickel(II) complexes of benzoic acid hydrazides (BAH) and o, m, and p‐substituted methylbenzoic acid hydrazides (MBAH) have been prepared and characterized by elemental analysis, room temperature magnetic susceptibility measurements, infrared and electronic reflectance spectral studies. The biological activities of the compounds and x‐ray structure of Ni[C6H5CONHNH2]3Cl2·3CH3OH are also reported. The microanalyses showed that the hydrazides reacted with the nickel(II) salts in 1:3 (metal:ligand) molar ratio. The hydrazide ligand behaves as a neutral bidentate chelating ligand with coordination involving the carbonyl oxygen and the amino nitrogen of the hydrazide moiety. The effective magnetic moments (μeff), infrared and electronic spectra of the compounds are consistent with a six‐coordinate pseudo‐octahedral arrangement of the ligands around the nickel ion. The x‐ray diffraction analysis of Ni[C6H5CONHNH2]3Cl2·3CH3OH showed that it crystallizes as a triclinic system with a P‐1 space group, a=10.2289(5), b=12.0707(6), c=14.0477(7) Å, α=67.5540(10)°, β=69.2360(10)°, γ=73.7860(10)°. The nickel ion is coordinated by three units of benzoic acid hydrazide with the chloride ions and the methanol solvates uncoordinated in the crystal lattice. The compounds show some measurable activity against selected bacteria and fungi.

SYNTHESIS AND STRUCTURAL FEATURES OF COPPER(II) COMPLEXES OF BENZOIC ACID AND METHYL SUBSTITUTED BENZOIC ACID HYDRAZIDES AND X-RAY STRUCTURE OF Cu[C6H5CONHNH2]2(NO3)2

ABSTRACT The synthesis, spectroscopic, magnetic and biological activities of copper(II) complexes of benzoic acid hydrazides (BAH) and o, m, and p-substituted methylbenzoic acid hydrazides (MBAH) and the single crystal X-ray structure for bis(benzoic acid hydrazide)copper(II) nitrate {Cu[BAH]2-(NO3)2} (BAH=Benzoic acid hydrazide) are reported. The composition of the ligands was established by elemental analyses, 1H NMR, and GC-MS. Magnetic susceptibility, electronic and infrared spectral data are consistent with a mononuclear square-planar geometry with bidentate coordination of the hydrazide ligands to give essentially a CuN2 2 chromophore. Cu[BAH]2(NO3)2 crystallizes from methanol solution under ambient temperature in a monoclinic system with a P21/c space system. The copper atom has a nearly regular, four-coordinated, square-planar arrangement with the nitrate anions being uncoordinated in the crystal lattice. The compounds did not show significant activity against selected bacteria and fungi.

Synthesis and Physico‐Chemical Properties of Some Copper(II) β‐Ketoamines and Their Adducts with 2,2′‐Bipyridine and 1,10‐Phenanthroline

The copper(II) β‐ketoamine complexes, {Cu[CH3C(O)C(Cl)C(CH3)NR]2, R=CH3, C4H9} and ketoiminates, {Cu[CH3C(O)C(Cl)(CH3)C(‐N(CH2)nN‐)C(CH3)(Cl)CC(O)CH3], n=2, 6, 8, 9} and their 2,2‐bipyridine (bipy) and 1,10‐phenanthroline (phen) adducts have been synthesized and characterized by elemental analyses, conductance, magnetic susceptibility, infrared and electronic spectral measurements. The available conductance data in nitromethane indicate that the compounds are non‐electrolytes while the room temperature magnetic moments (1.88–2.20 B.M.) suggests the absence of magnetic interaction between the Cu(II) ions. The ketoimine ligands coordinate to the copper atom in a bidentate fashion using the N2O2 chromophore to give a four‐coordinate square‐planar geometry. Infrared and electronic spectra results are consistent with the adoption of a six‐coordinate octahedral arrangement for the adducts of the copper(II) complexes with 2,2′‐bipyridine and 1,10‐phenanthroline. Probable structures for the compounds are suggested.

Nickel(II) Complexes of Some 3-Substituted-2, 4-Pentanediones and Their Adducts with 2,2′-Bipyridine and 1,10-Phenanthroline

Abstract Nickel(II) complexes of 3-substituted-2, 4-pentanediones (R-acacH,R = Cl, Ph, NO2) and their adducts with 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) have been synthesised and characterised by microanalyses, conductance, magnetic and spectral measurements. Four different nickel(II) complexes of 3-phenyl-2, 4-pentanedione have been isolated. The conductance data show that they are non-electrolytes except for the [Ni(phen)3I (Ph-acac)2, [Ni(phen)3] (Cl-acac)2 and [Ni(phen)3] (NO2-acac)2 adducts which are 1:2 electrolytes in nitromethane. The ligand field spectral bands of [Ni(NO2-acac)2]·2H2O suggest that this compound is a mixture of octahedral and tetrahedral species in solution. The infrared spectral shifts in the adducts suggest the formation of Ni-N bonds while the presence of carbonyls in different environments was observed in [Ni (NO2-acac)2 · phen2], [Ni (phen)3] (Cl-acac)2, [Ni(phen)3I (Ph-acac)2 and [Ni(phen)3] (NO2-acac)2. Octahedral coordination about the nickel (II) ion and t...

Synthesis and Characterization of Some Nickel(II) and Copper(II) Complexes of 2-substituted-4,4,4-trifluoro1-(2-thienyl)butane-1,3-dione (TTAH), their 2,2′ -Bipyridine and 1,10-Phenanthroline Adducts and X-Ray Structure of (2,2′ -Bipyridine)Bis(4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionato)Nickel(II)

The nickel(II) and copper(II) complexes of 2-substituted-4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dione (R-TTAH) and their 2,2′ -bipyridine and 1,10-phenanthroline adducts have been prepared and characterized by microanalysis, conductance, magnetic and spectral measurements. The conductance data in nitromethane indicate that the compounds are non-electrolytes except for [Cu(Phen)2TTA](TTA) and [Ni(Phen)3](TTA)2, which are 1:1 and 1:2 electrolytes respectively. The room temperature magnetic moments suggest that they are magnetically dilute compounds while the electronic spectral (solid and solution) bands of the ligands shifted upon chelation. The infrared spectra showed the different shifts of the carbonyl frequencies and a six-coordinate octahedral geometry formed by coordination of the nickel(II) ion through four oxygen atoms of the 4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dione (TTAH) and two nitrogen atoms of the bipyridine was established for (2,2′ -bipyridine)bis{4,4,4-trifluoro-1-(2-thienyl)butane-1,3-dionato}nickel(II) using X-ray crystallography.

Synthesis and Structural Studies of Some Ternary Copper(II) Complexes Containing β‐Diketones with 1,10‐Phenanthroline and 2,2′‐Bipyridyl and X‐Ray Structure of [Cu(C6H5COCHCOCH3)(bipy)Cl]

Some mixed‐ligand copper(II) complexes of benzoylacetone (Ph‐acacH) and acetylacetone (acac‐H) with 2,2′‐bipyridyl (bipy) and 1,10‐phenanthroline (phen), [Cu(Ph‐acac)(N‐N)(X)]; X = Cl, NO3, N‐N = bipy or phen and [Cu(acac)(N‐N)NO3], have been synthesised and characterised using elemental analyses, magnetic susceptibility measurements, infrared and electronic spectra studies. The electronic spectra and magnetic susceptibility studies are consistent with the adoption of a square‐pyramidal geometry for the complexes. [Cu(Ph‐acac)(bipy)Cl] crystallizes from methanol solution under ambient temperature in the monoclinic system with the space group P21/c, a = 19.7700(12), b = 13.0381(12), c = 17.0357(7) Å, V = 4015.1(5) Å3, α = 90 °, β = 113.8870(10)°, γ = 90° in a highly distorted square‐pyramidal geometry. The square pyramid consists of one unit each of benzoylacetone and 2,2′‐bipyridyl in a bidentate form as the basal unit with a chloride ion occupying the apical position.

Synthesis and Physicochemical Studies of Nickel(II) Complexes of 2-substituted-1,3-diphenyl-1,3-propanedione, their 2,2′-Bipyridine and 1,10-Phenanthroline Adducts and X-Ray Structure of (2,2′-Bipyridine)Bis(1,3-diphenyl-1, 3-propanedionato) Nickel(II)

The nickel(II) complexes of 2-substituted-1,3-diphenyl-1,3-propanedione and their 2,2′-bipyridine and 1,10-phenanthroline adducts have been prepared and characterized by microanalysis, conductance, magnetic and spectral measurements. The conductance data in nitromethane indicate that the compounds are non-electrolytes. The room temperature magnetic moments suggest that they are magnetically dilute compounds. The electronic spectra revealed the π3-π4 bathochromic shifts, which were observed upon chelation while the infrared spectra showed the different shifts of the carbonyl frequencies. The X-ray crystallography showed that nickel ion is coordinated by two units of 1,3-diphenyl-1,3-propanedione and a unit of bipyridine giving it a six coordinate octahedral geometry.

Synthesis and Physicochemical Studies of Some Mn(II), Co(II) and Ni(II) Substituted Benzoates

Abstract Complexes of Mn(II), Co(II), and Ni(II) with 3,5-dinitrobenzoic (3,5-DNB), 3,5-dimethylbenzoic (3,5-DMB) and 2,4,6-trimethylbenzoic (2,4,6-TMB) acids have been synthesized and characterised by microanalysis, conductance, room temperature magnetic susceptibility, infrared, and electronic reflectance spectral measurements. The infrared spectra data indicate a bidentate coordination of the carboxylate ions to the metal while the electronic spectra show that the Co(II) and Ni(II) complexes are octahedral while the Mn(II) complexes are either tetrahedral or octahedral. The magnetic measurements suggest the presence of some metal-metal interactions. The complexes are non-electrolytes.