Intrachain contacts

The compounds [Fe(C5Me4SCMe3)2][M(mnt)2] (M = Ni, Pt) are the only cases of salts based on metallocenium derivatives and on [M(mnt)2 complexes where the crystal structure is based in parallel arrangements of the type I chain motif [49]. In the chains the [Pt(mnt)2]- units are considerably tilted in relation to the chain direction, and short interatomic D+A- intrachain contacts were observed, involving one C from the Cp and a S atom from the anion, with a C-S distance of the order of dtf/. Relatively short interchain interionic distances were observed, where the closest corresponds to a S... C, involving one S atom from the anion and a C atom from a Me group of the cation, exceeding dw by 10%. 

Fig. II (a) View of the crystal structure of [Cr(Cp )2][Ni(a-tpdt)2] along [1 —1 0], where it is possible to see three layers of chains aligned either along [1 —1 0] or [1 1 0], cl correspond to the closest D+A intrachain contacts and c2 to the closest A A interchain interlayer contacts, (b) View of two chain layers along the [1 0 2] direction. The chains of the layer on the right are aligned along [1 — 1 0] and on the left along [1 1 0]. c3 corresponds to the closer interchain contacts within the layers...

Fig. 15 (a) View of the crystal structure of [Fe(Cp )2][Ni(dmit)2] along the stacking direction, (b) View of one layer of the type II chains, cl corresponds to the intradimer (AA) closest contact, c2 to the closer D+A- intrachain contacts, c3 include various S-S short A-A- interchain contacts, and c4 concerns a short S-S interlayer (A A ) contact... 

At high temperatures (7>25 K), y l is nearly temperature independent, but a clear increase upon cooling is observed at low temperatures, indicating that FM interactions are dominant in [Fe(Cp )2][Ni(bds)2] [15]. These interactions are attributed to the D+A intrachain contacts. 

Fe(Cp )2]2[Cu(mnt)2]. In this compound both cations from the D+D+ pair in the repeat unit are perpendicular to the chain direction as shown in Fig. 26b. Short intrachain contacts were observed and involve the Cu from the anion and a C from one of the Me groups in the cation, with a Cu-C distance of 3.562 A. The side-by-side cations are relatively separated and the closer C-C separations exceeds [Pg.136]

In addition to the intrachain contact,, and dipolar, T j, terms both for q 0 and q = 2kF, considered so far, we should include the contact and dipolar interchain terms TXc and Txd, especially in the case of two chain compounds. We should then write the spin-lattice relaxation rate as a sum of all these terms [24] ... 

The intrachain contact term, T[ J, is usually the most important and is related to the one-dimensional regime (i.e., conduction along a stack). The electrons traveling along the chain experience two kinds of scattering, q 0 and q = 2kF. 

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