Heterometallic chains

In this sub-chapter, selected examples of lanthanide-based chains are described. We have chosen to comment on only systems with structural characterization and significant dynamic properties. Chains with a sole lanthanide ion as spin carrier are described first. 3d-4f and 3d-3d -4f heterometallic chains follow. Finally, chains comprising lanthanide and radical ligands conclude this chapter. 

Heteroleptic oxalate metalloligands were studied to produce frameworks. Rochon used [Cr(bpy)(ox)2] as building blocks to construct self-assembled frameworks with divalent Co " " and Mn " " transition metals (70). Their structures are composed of infinite diamond-shaped heterometallic chains that run parallel to the a unit cell axis. Each chain is homochiral, containing exclusively either A or A metal centers, with adjacent chains having opposite handedness (Fig. 6). 

In the past 5 years, a rational synthetic approach has been developed to obtain SMM and SCM systems [48]. This research project has led to a complete family of SCM compounds related to the original SCM compound described above [Mn2(saltmen)2Ni(pao)2(L)2](A)2 (A = CIO4 with L = 4-picoline, 4-t-butylpyridine, or N-methylimidazole and L = pyridine with A" = BF, PFg or ReO ]) [46]. The magnetic properties of these compounds have been studied in details highlighting a similar SCM behavior of these heterometallic chains independently of their inter-chain environments. 

Metal-Metal Bonds in Chains of Three or More Metal Atoms From Homometallic to Heterometallic Chains... 

Berry describes transition metal compounds in which there are chains of metal atoms. Such compounds are often considered as potential molecular wires for molecular electronic applications and the conductance of these compounds at the molecular level is discussed. In addition to compounds that feature homometallic chains, those with heterometallic chains are also described. 

Gu X, Xue D (2007) Self-assembly of 3-d 4d-4f coordinatitni liameworks based on 1-d inorganic heterometallic chains and linear organic linkers. CrystEngComm 9 471... 

The charge densities and compositions of many known solids with VxOy layers were screened for possible charge density matches with M(pyz)x (M = Fe, Co, Ni, Cu, Zn) layers [35, 52], as an aid in the synthesis of new heterometallic multilayered vanadates. Close matches were found with M(pyz)x (M = Fe, Co, Ni) coordination polymers, ranging from 0.022/A -0.053/A, and which might suitably form in the presence of the flexible types of V2O5 layers. For example, Co(pyz) layers of chains in Co(pyz)(V03)2 [53] have a charge density of... 

Towards Cd the cz s-[Cr(OH)2(en)2]+ unit acts as a chelating ligand and yields heterometallic Cd(/i-OH)2Cr moieties as components in structures. Examples are the straight cationic chain... 

A], with each of the heterometallic bonds supported by a bridging mesityl group of type A (Figure 4.51). In contrast with 451, which contains discrete tetranuclear cations, the trinuclear cations of 452 are further associated through Au-Au contacts of 3.132(2) A to form a unidimensional chain polymer (Figure 4.52a) [611]. 

Interesting examples of simple substituted heterometallic species are [(thf)M p-N(SiMe3)2 2M (th 2] (M/M = Li/Na, Li/K and Na/K) which were obtained from solutions of 1 1 mixtures of the metal salts.The unsolvated ( LiXtSiMe J , K- lSiXleO, ), has a polymeric, one-dimensional chain structure formed by alternating lithium and potassium centres bridged through the hexamethyldisilazides (Li—N= 1.935(1) A and K—N = 2.86(1) A) with linear coordination at K and almost linear coordination (N-Li= 176.4(3)°) atLi. ... 

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