Synthesis and structural studies of new Mannich base ligands and their metal complexes

Al-Jeboori, Mohamad J.; Abdulghani, Ahlam Jameel; Al-Karawi, Ahmed Jasim M.

doi:10.1007/s11243-008-9134-3

Cited by 24 publications

(24 citation statements)

References 20 publications

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“…The magnetic moment value of the green Cu(II) complex, as well as the other analytical data, is in agreement with a distorted octahedral structure [28][29][30]. The spectra of the Zn(II) and Cd(II) complexes exhibited bands assigned to the ligand field [24]. These complexes are diamagnetic as expected for the d 10 system.…”

Section: Electronic Spectra Magnetic Moments and Conductivity Measursupporting

confidence: 81%

“…The observed magnetic moment of this complex is typical for a high-spin octahedral structure of polymeric Mn(II) complex. The electronic spectra of the Fe(II) and Co(II) complexes are consistent with the octahedral assignment [24,27]. The magnetic moment of these complexes is typical for a high-spin octahedral structure.…”

Section: Electronic Spectra Magnetic Moments and Conductivity Measursupporting

confidence: 75%

“…These data together with the magnetic moment indicate an octahedral geometry around the Cr(III) atom [26]. The Mn(II) complex showed the π → π * (CT) transitions and an additional peak at 643 nm assigned to the d-d transition in a distorted octahedral geometry [24][25][26]. The observed magnetic moment of this complex is typical for a high-spin octahedral structure of polymeric Mn(II) complex.…”

Section: Electronic Spectra Magnetic Moments and Conductivity Measurmentioning

confidence: 72%

“…The magnetic moment values were consistent with the octahedral structures. The spectra of Zn(II) and Cd(II) complexes of L 2 showed similar behavior to those of L 1 suggesting octahedral geometries [24]. The molar conductivities indicate that the Cr(III) complex is a 1:2 electrolyte, while the other complexes are non-electrolyte (Table 1) [31,32].…”

Section: Electronic Spectra Magnetic Moments and Conductivity Measurmentioning

confidence: 84%

“…Bands related to the (CT) transition were observed in the spectra of the complexes (Table 3). The electronic spectrum of the Cr(III) complex displayed two additional bands, which could be attributed to the spin allowed d- [24,25]. The band 4 A 2 g (F) → 4 T 1 g (p) (ν 3 ), transition may be at higher frequency and hidden by the (CT) or ligand band.…”

Section: Electronic Spectra Magnetic Moments and Conductivity Measurmentioning

confidence: 95%

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Formation of polymeric assemblies of six-coordinate metal complexes with mixed bridges of dicarboxylato-azido moieties

et al. 2014

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New biscarboxylato zwitterionic ligands, namely bis(N-carboxylatoethyl)-4,4-dipyridinum) L 1 and bis(Ncarboxylatopropyl)-)-4,4-dipyridinum) L 2 , were synthesized from the reaction of 4,4-dipyridine with 3-bromopropanoic acid and 4-bromobutanoic acid, respectively. The reaction of these ligands and the azido coligand with some metal ions resulted in the formation of polymeric complexes of general formulae [Cr 2 (L n)(N 3) 4 ]Cl 2 •H 2 O and [M 2 (L n)(N 3) 4 ] xH 2 O, where (M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); n = 1, 2; x = 1, 1, 1, 1, 0, 1, and 1, respectively.) The oxygens of the carboxylato group are coordinated to the metal ion in a bidentate fashion. The mode of bonding and overall geometry of the complexes were determined through IR, UV-VIS, NMR and mass spectral studies, magnetic moment measurements, elemental analysis, metal content, chloride content and conductance. These studies revealed the formation of polymeric assemblies of six-coordinate complexes with distorted octahedral geometries about metal centers.

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Section: Electronic Spectra Magnetic Moments and Conductivity Measursupporting

confidence: 81%

Section: Electronic Spectra Magnetic Moments and Conductivity Measursupporting

confidence: 75%

Section: Electronic Spectra Magnetic Moments and Conductivity Measurmentioning

confidence: 72%

Section: Electronic Spectra Magnetic Moments and Conductivity Measurmentioning

confidence: 84%

Section: Electronic Spectra Magnetic Moments and Conductivity Measurmentioning

confidence: 95%

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Formation of polymeric assemblies of six-coordinate metal complexes with mixed bridges of dicarboxylato-azido moieties

et al. 2014

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Lanthanide Complexes Formed with the Tri‐ and Tetraacetate Derivatives of Bis(aminomethyl)phosphinic Acid: Equilibrium, Kinetic and NMR Spectroscopic Studies

et al. 2012

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The lanthanide(III) complexes formed with the tri‐ and tetraacetate derivatives of bis(aminomethyl)phosphinic acid, L1 and L2, respectively, have been studied by pH potentiometry, spectrophotometry and 1H and 17O NMR spectroscopy. L1 forms [Ln(L1)]–, [Ln(L1)2]4–, protonated [Ln(HL1)] and Ln(H2L1)]+, and [Ln(L1)(OH)]2– hydroxido complexes. Heptadentate L2 forms [Ln(L2)]2– and protonated [Ln(HL2)]– and [Ln(H2L2)] complexes in solution and it shows a strong propensity to form [Ln2(L2)]+ dinuclear complexes, which has not been observed previously. The stability constants (log KLnL) of the complexes increase in the order [Ln(L1)]– < [Ln(L2)]2– following the order of increasing number of acetate pendants attached to the bis(aminomethyl)phosphinic acid (BAP) backbone. Within the LnIII series, the log KLnL values increase from La3+ to Gd3+ and remain practically constant for the heavier lanthanides. Despite the lower basicity, the ligands that contain a phosphinate group generally form similar (L1) or more stable (L2) Ln3+ complexes than the structurally similar N‐benzylethylenediamine‐N,N′,N′‐triacetic acid (L3) and propylenediamine‐N,N,N′,N′‐tetraacetic acid (L4), respectively. This indicates that the hard phosphinate group may be coordinated to the Ln3+ ions in the complexes, whereas the larger negative charge of the BAP derivatives may also have an extra stabilizing effect. The kinetic inertness of [Ln(L1)] and [Ln(L2)] is lower than that of similar [Ln(EDTA)]– (EDTA = ethylenediamine‐N,N,N′,N′‐tetraacetic acid), but the rate constants that characterize the dissociation of [Ln(L2)]2– are at least two orders of magnitude lower than those obtained for [Ln(L4)]–. Variable‐temperature 17O transverse and longitudinal relaxation rates and NMR spectroscopic chemical shifts have been measured to assess the water exchange and rotational dynamics of [Gd(L2)]. The chemical shifts evidenced monohydration of the complex. The water exchange rate, kex298 = (2.7 ± 0.4) × 107 s–1 is about ten times higher than that of [Ln(DTPA)]2– (DTPA = diethylenetriamine‐N,N,N′,N″,N″‐pentaacetic acid). The rotational correlation time, τRO298 = 270 ± 30 ps, is long considering the small size of the chelate, which points to aggregation in aqueous solution, in accordance with the high value of the proton relaxivity measured.

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Biomimetics of mononuclear and dinuclear Cu(II) and Fe(III) complexes of a newly synthesized piperazyl Mannich base with or without thiocyanate towards catechol

Ayeni

Watkins

2018

Monatsh Chem

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Synthesis and structural studies of new Mannich base ligands and their metal complexes

Cited by 24 publications

References 20 publications

Formation of polymeric assemblies of six-coordinate metal complexes with mixed bridges of dicarboxylato-azido moieties

Formation of polymeric assemblies of six-coordinate metal complexes with mixed bridges of dicarboxylato-azido moieties

Lanthanide Complexes Formed with the Tri‐ and Tetraacetate Derivatives of Bis(aminomethyl)phosphinic Acid: Equilibrium, Kinetic and NMR Spectroscopic Studies

Biomimetics of mononuclear and dinuclear Cu(II) and Fe(III) complexes of a newly synthesized piperazyl Mannich base with or without thiocyanate towards catechol

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