Magnetic properties trimers

The structures of the trinuclear species Cr3(OH)45 + and the two tetranuclear species a- and /7-Cr4(OH)6< + have not been established. Linear as well as cyclic trimeric structures (structures 4a, 4b, and 5 in Fig. 1) have been considered (27, 37), as has another cyclic structure such as that shown in Fig. 10. However, the kinetic, thermodynamic, spectroscopic, and magnetic properties appear to provide no evidence to favor the one rather than the other (27). The number of possible... 

The electronic and magnetic properties of vanadium tetramethoxide are consistent with a trimeric structure involving six-coordinate vanadium atoms, while the electronic spectrum of deep blue V(OBu )4 is consistent with a slightly distorted monomeric, tetrahedral structure.181... 

The question of the applicability of the semiclassic adiabatic approach to the vibronic problems in the JT systems is rather complicated in general and the thorough answer can be done with regard to a particular problem. In our brief discussion of this question we will refer to two areas - thermodynamic properties and resonance (optical) problems. In Ref. [9] the magnetic properties of mixed-valence dimeric and trimeric clusters are considered in the framework of... 

The transition-metal component of [Pt(bipy)2][TCNQ]3 is also diamagnetic. The structure86 consists of stacks of trimers, [T CNQ], surrounded by non-interacting Pt(bipy)2+ cations. Adjacent trimers are closely spaced with an interplanar separation of only 3.33 A as compared with 3.23 A within the trimer. The magnetic properties of this system have been studied much less extensively than those of [TMPD]2[Ni(mnt)2]. Single crystal EPR spectra do show, however, that spins are interacting along the TCNQ stacks. Structurally, this compound is very different from the 1 2 compound [Pt(bipy)2][TCNQ]258> (Sect. 2) which forms Da stacks with the two TCNQ moieties <7-bonded to each other.. ... 

The range of experimental methods employed has not so far been very wide further work on the spectroscopic, thermochemical, and magnetic properties and on the kinetics of the formation and substitution reactions can be expected to be illuminating. Most work has been done on the trimeric chloride, the lowest stable member of the series, and the most abundant. As in the boron hydride series, significant advances are likely to result from investigations of the higher polymers. 

Botar, B., Kogerler, P. and Hill, C. (2007). Tetrairon and Hexairon Hydroxo/Acetato Clusters Stabilized by Multiple Polyoxometalate Scaffolds. Structures, Magnetic Properties, and Chemistry of a Dimer and a Trimer, Inorg. Chem., 46, pp. 5398-5403. 

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