The nephelauxetic effect calculation and accuracy of the interelectronic repulsion parameters I. Cubic high-spin d 2, d 3, d 7, and d 8 systems

König, E.

doi:10.1007/bfb0118887

Cited by 176 publications

(21 citation statements)

References 46 publications

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“…The splitting parameter value of 10,430 cm -1 is close to an average value for a [Co(II)NO 5 ] chromophore, while the nephelauxetic parameter of 0.90 is an indicative of a lower degree of covalency. The crystal field parameters (10Dq, B and b) have been calculated with König's formulas [46]. The Co(II) complex exhibits a magnetic moment of 5.10 B.M.…”

Section: Electronic Epr Spectra and Magnetic Momentsmentioning

confidence: 99%

Thermal behaviour of some biologically active species based on complexes with a triazolopyrimidine pharmacophore

Olar

Calu

Badea

et al. 2016

J Therm Anal Calorim

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A series of complexes of type M(pmtp)(CH 3 COO) 2 ÁnH 2 O ((1) M: Co, n = 4.5; (2) M: Ni, n = 3.5; (3) M: Cu, n = 0.5; (4) M: Zn, n = 0; pmtp: 5-phenyl-7-methyl-1,2,4-triazolo[1,5-a]pyrimidine) were synthesised by one-pot condensation. The complexes were characterized by elemental analysis, ESI-MS, IR, UV-Vis-NIR, EPR spectra, magnetic susceptibility at room temperature as well as thermogravimetric analysis. The modifications in the IR spectra of complexes are in accordance with the condensation process and indicate the triazolopyrimidine coordination as unidentate. The electronic and EPR spectra together with magnetic moments indicate an octahedral stereochemistry for paramagnetic ions, except for Cu(II) with a square pyramidal geometry. Processes such as water elimination, acetate into carbonate transformation, as well as oxidative degradation of the triazolopyrimidine derivative were evidenced during thermal decomposition. The complexes exhibited an improved antimicrobial activity in comparison with the ligand, on both planktonic and biofilm-embedded microbial cells. The best antimicrobial activity in both susceptible and resistant strains was obtained for complex (3) followed by complex (1), which can be related to both oxidation state and stereochemical versatility. At high concentrations, the Cu(II) complex exhibits both cytotoxicity on HT 29 tumour cell line and anti-inflammatory activity.

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Section: Electronic Epr Spectra and Magnetic Momentsmentioning

confidence: 99%

Thermal behaviour of some biologically active species based on complexes with a triazolopyrimidine pharmacophore

Olar

Calu

Badea

et al. 2016

J Therm Anal Calorim

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“…The ligand field transition 4 A 2 (F) → 4 T 2 (P) ( 1 ) is obscured by the fundamental stretching vibration of dissolved water. Thus the crystal field parameter 10 Dq and the Racah parameter B were calculated from the Tanabe-Sugano matrices describing the 4 T 1 (F) and 4 T 1 (P) levels (König 1971):…”

Section: Co 2؉ In Hydrous Albite Glassmentioning

confidence: 99%

“…However, below 5.1 wt% water content only minor changes occur in the electronic absorption spectrum of Ni 2ϩ . Ligand field parameters of the dry glass (10 Dq ϭ 5160 cm Ϫ1 , B ϭ 897 cm Ϫ1 ) were calculated using equa-tions for octahedral d 8 configuration given by König (1971):…”

Section: Ni 2؉ In Hydrous Albite Glassmentioning

confidence: 99%

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The influence of water on the environment of transition metals in silicate glasses

Nowak

Keppler

1998

American Mineralogist

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The effect of water (ϭ H 2 O ϩ OH) on the environment of Co 2ϩ and Ni 2ϩ in albite glass was investigated by electronic absorption spectroscopy. The visible spectra of Co 2ϩ-doped glasses change only slightly over the range of water concentrations studied. Co 2ϩ is in a distorted tetrahedral environment, producing a dark blue color in the glasses. Up to about 5 wt% water, Ni 2ϩ-doped glasses are brown and only minor variations in the spectra are seen. At 5.6 wt% water, however, the color of these glasses changes abruptly from brown to light green and a new type of absorption spectrum is observed. Three bands are observed in the visible spectra of the brown glasses. Two bands near 20 500 cm Ϫ1 can be assigned to Ni 2ϩ in a distorted octahedral environment. A third band at 15 500 cm Ϫ1 could either be due to the distorted octahedral site or to a small amount of tetrahedrally coordinated Ni 2ϩ. The spectra of the green glasses with 5.6 and 5.7 wt% H 2 O resemble closely spectra of aqueous NiCl 2-solution containing the [Ni(H 2 O) 6 ] 2ϩ complex. The formation of such a hydration shell around transition metals in hydrous silicate melts should strongly effect partitioning of these elements between silicate melts, minerals, and a metal phase. Consideration of ligand field stabilization energies, suggests that hydrated Ni 2ϩ is stabilized in the melt such that mineral-melt and metal-silicate melt partition coefficients decrease by one to two orders of magnitude relative to a dry melt at 1100 ЊC.

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“…4 T 2g (F) n 1 1000 nm, 4 T 1g (F) ! [31] According to the weak field approximation, the energies of the transitions may be obtained from Eqs. 4 T 1g (P) n 3 460 nm.…”

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confidence: 99%

Synthesis and Characterization of Coordination Polymers of 1,2‐bis‐(4‐Thio‐1,3,5‐hexahydro‐1‐triazinyl)ethane

Gurnule¹,

Paliwal

Kharat

2003

Synthesis and Reactivity in Inorganic and Metal-Organic Chemist

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Coordination polymers of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) with the 1,2-bis-(4-thio-1,3,5-hexahydro-1-triazinyl)ethane (H 2 BTHTE) ligand have been prepared in DMF solution. The coordination polymers have been characterized by their elemental analyses, magnetic susceptibility and by electronic and infrared spectral measurements. The thermal stability of each polymer was determined by thermogravimetric analysis. The thermal stability of the coordination polymers obtained from the thermograms is in the following order: Fe > Zn > Mn = Co > Ni > Cu. The Cu(II), Co(II), Ni(II) and Fe(II) coordination polymers are of sixcoordinated octahedral geometry while the Mn(II) and Zn(II) coordination polymers are of four-coordinated tetrahedral structure. The ligand field and nephelauxetic parameters have been determined from the spectra using the ligand field theory of spin-allowed transitions and which were found to be consistent with six-coordinated structures for the Cu(II), Co(II), Ni(II) and Fe(II) coordination polymers. Elemental analyses indicate a ligand metal ratio of 1:1 in all of the coordination polymers and the coordination of water molecules with the central metal atom in the case of the Cu(II), Fe(II), Co(II) and Ni(II) coordination polymers.

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The nephelauxetic effect calculation and accuracy of the interelectronic repulsion parameters I. Cubic high-spin d 2, d 3, d 7, and d 8 systems

Cited by 176 publications

References 46 publications

Thermal behaviour of some biologically active species based on complexes with a triazolopyrimidine pharmacophore

Thermal behaviour of some biologically active species based on complexes with a triazolopyrimidine pharmacophore

The influence of water on the environment of transition metals in silicate glasses

Synthesis and Characterization of Coordination Polymers of 1,2‐bis‐(4‐Thio‐1,3,5‐hexahydro‐1‐triazinyl)ethane

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