Rajamani Raghunathan

Fluorite and Mixed-Metal Kagome-Related Topologies in Metal–Organic Framework Compounds: Synthesis, Structure, and Properties

Two new three-dimensional metal-organic frameworks (MOFs) [Mn(2)(mu(3)-OH)(H(2)O)(2)(BTC)] x 2 H(2)O, I, and [NaMn(BTC)], II (BTC = 1,2,4-benzenetricarboxylate = trimellitate) were synthesized and their structures determined by single-crystal X-ray diffraction (XRD). In I, the Mn(4) cluster, [Mn(4)(mu(3)-OH)(2)(H(2)O)(4)O(12)], is connected with eight trimellitate anions and each trimellitate anion connects to four different Mn(4) clusters, resulting in a fluorite-like structure. In II, the Mn(2)O(8) dimer is connected with two Na(+) ions through carboxylate oxygen to form mixed-metal distorted Kagome-related two-dimensional -M-O-M- layers, which are pillared by the trimellitate anions forming the three-dimensional structure. The extra-framework water molecules in I are reversibly adsorbed and are also corroborated by powder XRD studies. The formation of octameric water clusters involving free and coordinated water molecules appears to be new. Interesting magnetic behavior has been observed for both compounds. Electron spin resonance (ESR) studies indicate a broadening of the signal below the ordering temperature and appear to support the findings of the magnetic studies.

Microscopic model for photoinduced magnetism in the molecular complex [Mo(IV)(CN)2(CN -CuL)6]8+ perchlorate

A theoretical model for understanding photomagnetism in the heptanuclear complex

Microscopic model for high-spin versus low-spin ground state in [Ni 2 M(CN) 8 ](M=Mo V ,W V ,Nb IV ) magnetic clusters

[Mo(IV )(CN)_2(CN-CuL)_6]^8^+

Theoretical approach for computing magnetic anisotropy in single molecule magnets

perchlorate is developed. It is a many-body model involving the active orbitals on the transition metal ions. The model is exactly solved using a valence bond approach. The ground state solution of the model is highly degenerate and is spanned by five S=0 states, nine S=1 states, five S=2 states and one S=3 state. The orbital occupancies in all these states correspond to six Cu(II) ions and one diamagnetic Mo(IV ) ion. The optically excited charge-transfer (CT) state in each spin sector occur at nearly the same excitation energy of 2.993 eV for the physically reasonable parameter values. The degeneracy of the CT states is largest in the S=3 sector and so is the transition dipole moment from the ground state to these excited states. Thus laser irradiation with light of this energy results in most intense absorption in the S=3 sector. The life-time of the S=3 excited states is also expected to be the largest as the number of states below that energy is very sparse in this spin sector when compared to other spin sectors. These twin features of our model explain the observed photomagnetism in the

Impact of Average, Local, and Electronic Structure on Visible Light Photocatalysis in Novel BiREWO6 (RE = Eu and Tb) Nanomaterials

[Mo(IV )(CN)_2(CN-CuL)_6]^8^+

Modelling magnetic anisotropy of single-chain magnets in |d/J| ≥ 1 regime

complex.

Magnetostructural Studies on Ferromagnetically Coupled Copper(II) Cubanes of Schiff‐Base Ligands

Conventional superexchange rules predict ferromagnetic exchange interaction between Ni(II) and M (M=Mo(V), W(V), Nb(IV)). Recent experiments show that in some systems this superexchange is antiferromagnetic. To understand this feature, in this paper we develop a microscopic model for Ni(II)-M systems and solve it exactly using a valence bond approach. We identify the direct exchange coupling, the splitting of the magnetic orbitals and the inter-orbital electron repulsions, on the M site as the parameters which control the ground state spin of various clusters of the Ni(II)-M system. We present quantum phase diagrams which delineate the high-spin and low-spin ground states in the parameter space. We fit the spin gap to a spin Hamiltonian and extract the effective exchange constant within the experimentally observed range, for reasonable parameter values. We also find a region in the parameter space where an intermediate spin state is the ground state. These results indicate that the spin spectrum of the microscopic model cannot be reproduced by a simple Heisenberg exchange Hamiltonian.

A kinetic model for photoswitching of magnetism in the high spin molecule [Mo(IV)(CN)2(CN–Cu(II)(tren))6](ClO4)8

We present a theoretical approach to calculate the molecular magnetic anisotropy parameters,

Magneto-structural study on a tetracopper(II) Schiff base complex stabilizing a decanuclear water aggregate

D_{M}

Modeling Molecular Magnets with Large Exchange and On-Site Anisotropies

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