Tunji Owalude - Academia.edu (original) (raw)

Papers by Tunji Owalude

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Egyptian Journal of Basic and Applied Sciences, 2016

Two Co(II) complexes containing malonic and isonicotinic acids have been prepared by manual grind... more Two Co(II) complexes containing malonic and isonicotinic acids have been prepared by manual grinding of stoichiometric amounts of the starting materials. Elemental analysis (CHN), IR, UV-vis spectroscopic techniques, TGA-DTG investigation and X-ray powder diffraction analysis were used to characterize the two compounds. Isonicotinic acid coordinated to the metal via the pyridine ring nitrogen and one oxygen atom of the carboxylic group while malonic acid coordinated via both oxygen atoms of the carboxylate groups indicating bidentate coordination mode in the two compounds. The compounds were exposed to some volatile organic compounds (VOCs) containing nitrogen or oxygen donor atoms in the solid state and their vapochromic behaviours studied using colour changes, FT-IR and solid state UVvis spectroscopies. Heating the samples exposed to the VOCs for a few minutes at 100°C regenerates the original material without degradation, even after several heating cycles.

Research Square (Research Square), Feb 19, 2021

The coordination polymer [Cu 2 (TDPH) 4 (QNX)].DMF, (QNX = Quinoxaline; TDPH = 3,3thiodipropionic... more The coordination polymer [Cu 2 (TDPH) 4 (QNX)].DMF, (QNX = Quinoxaline; TDPH = 3,3thiodipropionic acid), has been prepared by reaction of copper acetate, TDPH, and quinoxaline. The compound was characterized by elemental analysis, FTIR spectroscopy, and single-crystal Xray diffraction. The crystal is monoclinic with a P21/n space group and dimensions of a = 12.889(3) Å, b = 14.983(4) Å, c = 14.091(3) Å, α = 90 °, β = 90.200(11) °, γ = 90 °, V = 2721.18 (2) Å 3 , Z = 4. The ligands are hexagonally coordinated to the Cu(II) centre in the form of Cu2O4N with one nitrogen atom from the quinoxaline ligand, and four oxygen atoms from four TDPH molecules in a monodentate fashion. The Cu-Cu bond length was 2.642(1) and 2.629(1) Å for the Cu1-Cu1 and Cu2-Cu2 bonds. The QNX ligand bridged the two copper atoms. The catalytic reduction of 4-nitrophenol to 4-aminophenol using NaBH4 in the presence of [Cu 2 (TDPH) 4 (QNX)].DMF, as catalyst was completed within 11 minutes. The 4-aminophenol product was confirmed using 1 H NMR spectroscopy.

Journal Of Chemical Society Of Nigeria, Jan 20, 2019

A new heterobimetallic ruthenium(II) complex with general formula [Ru(NCCH3)2(P(OMe)2Ph)2- (dppf)... more A new heterobimetallic ruthenium(II) complex with general formula [Ru(NCCH3)2(P(OMe)2Ph)2- (dppf)][BF4]2. {NCCH3 = acetonitrile P(OMe)2Ph = dimethylphenylphosphonite, dppf = 1,1’-bis-{diphenylphosphino}ferrocene} was synthesized from a one pot reaction of [Ru(COD)-(NCCH3)4][BF4]2, dimethylphenylphosphonite and 1,1’-bis{diphenylphosphino}ferroc-ene in dichloromethane under continuous stirring. The complex was characterized by NMR (31P{1H}, 1H and 13C), vibrational spectroscopy (FTIR) and elemental analysis. Catalytic performance of the complex in the transfer hydrogenation of cyclohexanone was investigated. An 80% conversion was achieved at a substrate to catalyst ratio of 1250 with 98% selectivity. Keywords: Heterobimetallic ruthenium, transfer hydrogenation, cyclohexanone, 1,1’-bis{diphenylphosphino}ferrocene, dimethylphenylphosphonite.

Dutse Journal of Pure and Applied Sciences, May 6, 2022

This research demonstrates the preparation of a new coordination polymer, {[Cu4(H2pydc)2(H1apy)(H... more This research demonstrates the preparation of a new coordination polymer, {[Cu4(H2pydc)2(H1apy)(H2O)2DMF].DMF}n, (H2pydc = pyridine-2,6-dicarboxylic acid, H1apy = 4amidinopyridine) under solvothermal condition by the self-assembly of pyridine-2,6-dicarboxylic acid, 4-amidinopyridene and copper(II) acetate. The compound was characterized by elemental analysis and infrared spectroscopic technique. The analysis indicated that the 4-amidinopyridine coordinated to the copper ions through the terminal nitrogen in a monodentate fashion while the pyridine-2,6-dicarboxylic acids coordinated through the carboxylate oxygens in monodentate mode. Both the elemental analysis and the infrared spectroscopic data agreed with the proposed stoichiometry. This result represent the first report of a tetranuclear Cu(II) coordination polymer having coordinated 4-amidinopyridine as the nitrogen donor moiety in its structure.

Inorganic and Nano-Metal Chemistry, May 26, 2022

Journal of Molecular Structure, Dec 1, 2016

Abstract A novel complex was synthesized from Cu(II), nicotinamide and itaconic acid and is formu... more Abstract A novel complex was synthesized from Cu(II), nicotinamide and itaconic acid and is formulated as [Cu(C5H4O4)2(C6H6N2O)2(H2O)2·2(H2O)] (1). The compound was characterized by elemental analysis, FTIR spectroscopy, UV-Vis and single crystal X-ray diffraction. The complex crystallizes in the triclinic P-1 space group, with a = 7.5111(2) A, b = 9.8529(3) A, c = 10.5118(4) A, α = 116.244(3)°, β = 90.291(3)°, γ = 103.335(3)°, V = 673.81(4) A3, Z = 1.The octahedral geometry around the copper(II) ion is of the form CuN2O4 consisting of two molecules of nicotinamide acting as monodentate ligand through the nitrogen atoms, two molecules itaconate ligand and two coordinated water molecules each coordinating through the oxygen atoms. The structure of 1 showed infinite chains build up linking the molecules together via strong O H⋯O and N H⋯O intermolecular hydrogen bonds generating a two dimensional network sheet along c axis. The antimicrobial study of the synthesized complex 1 was investigated and showed higher antibacterial activity against all the organisms comparing with Copper(II) nicotinamide 2 and Copper(II) itaconate 3.

Nigerian Journal of Chemical Research, 2017

A new ruthenium(II) complex containing both acetonitrile and propionitrile moieties as coordinati... more A new ruthenium(II) complex containing both acetonitrile and propionitrile moieties as coordinating ligands has been prepared. The treatment of the polymer [{RuCl 2 (COD)} x ], (COD = cycloocta-1,5-diene) (1) with a mixture of acetonitrile and propionitrile under reflux produced a new precursor [RuCl 2 (COD)(NCCH 3)(CH 3 CH 2 CN)] (2). Also the compound [RuCl 2 L 4 ] (3) (L = 2,6-dimethylphenylisocyanide) was prepared through a ligand exchange of a derivative of 1, [RuCl 2 (COD)(NCCH 3) 2 ] (4), with 2,6-dimethylphenylisocyanide. The two compounds were characterized by elemental analyses, IR and NMR (1 H and 13 C) measurements. The ruthenium in both compounds has distorted octahedral coordination geometry.

CrystEngComm

Removal of sulfur-containing compounds was necessitated by the negative environmental and human h... more Removal of sulfur-containing compounds was necessitated by the negative environmental and human health challenges posed by sulfur oxides that are released into the atmosphere upon combustion of sulfur-containing fuel oils.

Bayero Journal of Pure and Applied Sciences

This report demonstrates a simple procedure for the preparation of three Ru(II) hydrazine and hyd... more This report demonstrates a simple procedure for the preparation of three Ru(II) hydrazine and hydrazone complexes formulated as [Ru(NH2NH2)2L4][BPh4]2 (L = ethyldiphenylphosphine (3), and [Ru(NH2:CMe2)2L4][BPh4]2 (L = methyldiphenylarsine (4), L = ethyldiphenylphosphine (5). The complexes were characterized by IR, elemental analysis and 1H NMR spectroscopy. All the three complexes show N−N absorption in the range between 1031 – 1029 cm-1 indicating the presence of coordinated hydrazine. Evidence of ethyldiphenylphosphine coordination to the Ru(II) centre was further established by 31P NMR spectroscopic analysis of 3. The obtained complexes could have potential applications in other fields such as catalysis and synthesis of nanomaterials.

Acta Crystallographica Section E

Abstract: In the title RuII complex,[RuCl2 (C8H12)(C2H3N) 2] &# 183; CH3CN, the metal ion is coor... more Abstract: In the title RuII complex,[RuCl2 (C8H12)(C2H3N) 2] &# 183; CH3CN, the metal ion is coordinated to the centers of each of the double bonds of the cyclooctadiene ligand, to two chloride ions (in cis positions) and to two N-atom donors (from MeCN molecules) that complete the coordination sphere for the neutral complex. The coordination about the RuII atom can thus be considered to be octahedral with a slightly trigonal distortion. There is also one acetonitrile solvent molecule per molecule which is outside the coordination sphere of ...

Acta Crystallographica Section E Structure Reports Online, 2011

Abstract The literature is replete with symmetrical tetradentate bis-... more Abstract The literature is replete with symmetrical tetradentate bis-Schiff bases of 1,2-diamines with o-hydroxyaldehyde or ketones, but less attention has been focused on the analogous unsymmetrical tetradentate ones. Unsymmetrical Schiff bases of aromatic diamines are very difficult to obtain and are not easily isolated. This class of Schiff bases have very simple synthetic procedure and versatile coordination behavior. Metal complexes containing these Schiff bases in their structure usually possess exceptional antibacterial, antifungal and antitumor activities including anti-HIV activity. In this regard, two new unsymmetrical bis-Schiff bases, (Z)-N-(2-nitrophenyl)-N'-(2-((Z)-(2-oxoindolin-3-ylidene)amino) phenyl)acetimidamide (1) and (Z)-N-(2-nitrophenyl)-N'-((Z)- N-(2-oxoindolin-3-ylidene) carbamimidoyl) acetimidamide (2), were prepared from the condensation reactions of 2'-nitroacetanilide and 1H-indole-2,3-dione with o-phenylenediamine and guanidinium ions in ethanol. The corresponding symmetrical bis-Schiff bases (Z,Z)-1,3-bis(2-oxoindolin-3-ylidene)guanidine (3) and N-((2-(1-iminoethyl)-2-(2-nitrophenyl)hydrazinyl)methyl)-N-(2-nitrophenyl)acetimidamide (4) were also prepared. The data obtained from the elemental, IR and NMR spectroscopic analyses were used to propose structures for the four compounds.

X-ray Structure Analysis Online, 2012

Our interest in the ruthenium(II) complexes with chelating phosphine ligands stem from their demo... more Our interest in the ruthenium(II) complexes with chelating phosphine ligands stem from their demonstrated utility in the asymmetric hydrogenation of a wide range of substrates. 1 The title complex is therefore synthesized by modifying a literature procedure, 2 as a precursor to preparing a series of catalytically active phosphine and diphosphine ruthenium(II) compounds. The product was recrystallized from N2H4•H2O and ethanol as colourless needles. The structure of the related dimethylhydrazine complex was reported by Singleton et al. 3 In that report, the presence of a hydride ligand in the dimethylhydrazine derivative was only inferred from the observed peak of 0.65 eÅ-3 , since it could not be located from the final difference-Fourier map during analysis. However, in the present molecule, the hydrogen atoms of the Ru-H as well as those of the NH2 and NH2NH2 moieties were located from a difference Fourier map and refined isotropically. The remaining hydrogen atoms in both molecules were placed at idealized positions, and were refined using a riding model. The largest residual electron density for structure (2.881 e/Å 3) was located close to (less than 1.0 Å from) the ruthenium atom, and was most likely due to imperfect absorption corrections frequently X-ray Structure Analysis Online

International Journal of Biological and Chemical Sciences, 2009