Magnetic properties of tetranuclear cobalt(II) cluster with pyridine alcoholate ligand

Abstract

Effective magnetic moment of bis(2-methylbenzimidazole)dinitratocopper(II) monoethanolate measured using Gouy method is given in this chapter.

Substance

Tetranuclear cobalt(II) cluster with dipyridyl ketone; {Co₄[OC(OH)(2-pyridyl)₂[OAc]₄}.7H₂O

Gross Formula

C₅₂H₆₄Co₄N₈O₂₄

Properties

Molar magnetic susceptibility, product of molar magnetic susceptibility with temperature, Weiss constant and exchange energy

Structure

{Co4[OC(OH)(2-pyridyl)2[OAc]4}.7H2O;

2-pyridyl = 2-pyridylketone

Data

T [K]	χ M [cm3 mol–1]	χ M T [cm3 K mol–1]	pm or μeff [μB]	Θ P [K]	Method	Remarks
293 25	0.0232 0.0751	6.53 3.02	3.63/Co	–69.29	–	cubane core

1. T: Temperature
2. χ_g: Specific susceptibility
3. χ_M: Molar susceptibility
4. p_m, μ_eff: Effective magnetic moment per molecule
5. Θ_P: Paramagnetic Curie constant (Weiss constant)

Additional Remarks

• (i) Plot of χ_M^–1 versus T is shown in Fig. 1 whereas plts of χ_M versus T and χ_MT versus T are shown in Fig. 2

• (ii) Magnetic behavior (<100 K) indicated antiferromagnetic interactions

• (iii) Curie-Weiss behavior observed, with:

  • C = 8.14 cm³ K mol^–1

  • θ = –69.26 K

• (iv) Various coupling constants obtained were:

  • J₁ = –21.86 cm^–1

  • J2 = ^–14.81 cm^–1

  • J₃ = –10.55 cm^–1

  • g = 2.03

Fig. 1

{Co₄[OC(OH)(2-pyridyl)₂[OAc]₄}.7H₂O. Temperature dependence of χ_M^–1. The solid line represents the best-fit curve

Fig. 2

{Co₄[OC(OH)(2-pyridyl)₂[OAc]₄}.7H₂O. Temperature dependence of χ_M and χ_MT. The solid line represents the best-fit curve

Symbols and Abbreviations

Short form	Full form
T	temperature
χg	magnetic susceptibility per gram (specific susceptibility)
χM	magnetic susceptibility per mole (molar susceptibility)
p m	effective magnetic moment per molecule
μ eff	effective magnetic moment
Θ P	paramagnetic Curie constant (Weiss constant)
χ M −1	inverse molar susceptibility
g	Lande factor
θ	Curie constant
C	Curie temperature