Manipulation of electronic structure via supporting ligands: a charge disproportionate model within the linear metal framework of asymmetric nickel string [Ni(7)(phdptrany)(4)Cl](PF(6)).

This paper describes the synthesis and physical properties of an uniquely asymmetric heptanickel string complex exhibiting a charge disproportionate model along the linear nickel framework.

Further investigations of linear trirhodium complexes: experimental and theoretical studies of [Rh3(dpa)4Cl2] and [Rh3(dpa)4Cl2](BF4) [dpa = bis(2-pyridyl)amido anion].

The linear trirhodium compound, Rh3(dpa)4Cl2 (1), and its one-electron oxidation product, [Rh3(dpa)4Cl2]BF4 (2), have been synthesized and studied extensively. The magnetic measurement for compound 1 shows that it possesses one unpaired electron that is assigned to occupy the sigma(nb) orbital (2A2) by DFT calculations. Upon oxidation, a beta-spin electron of 1 is removed, that causes compound 2 to exhibit a triplet ground state. DFT calculations indicate that the two unpaired electrons of 2 occupy sigma(nb) and delta* orbitals (3B1), which is supported by 1H NMR spectrum. Unlike their isoelectronic analogues [Co3(dpa)4Cl2] (3) and [Co3(dpa)4(Cl)2]BF4 (4), both compound 1 and 2 do not display the spin-crossover phenomenon. The reason may be attributed to the relative large energy gap between 3B1 and open-shell singlet 1B1 states.

Supramolecular assembly of gold(I) complexes of diphosphines and N,N'-bis-4-methylpyridyl oxalamide.

We report herein the supramolecular assembly and spectroscopic and luminescent properties of gold(I) complexes of diphosphines (dppm [bis(diphenylphosphino)methane], dppp [1,3-bis(diphenylphosphino)propane], and dpppn [1,5-bis(diphenylphosphino)pentane]) and N,N'-bis-4-methylpyridyl oxalamide (L). The dppm and dppp cases form the rectangular structures, [dppm(Au(2))L](2)(ClO(4))(4) and [dppp(Au(2))L](2)(ClO(4))(4), with four gold(I) ions at the corners, as well as two L and two dppm or dppp ligands as edges, featuring 38- and 42-membered rings for the former and the latter, respectively. Remarkably, the packing of the dppp complexes shows interesting one-dimensional rectangular channels in the solid state, most likely due to intermolecular pi...pi interactions. The dpppn complex has been structurally characterized as a one-dimensional coordination polymer, {[(dpppn)(3.5)(Au(7))L(3.5)](PF(6))(7)}. The absorptions and emissions of the compounds are in general due to intraligand transitions, but aurophilic or pi...pi interactions could also make partial contributions. The dipyridyl amide system with the amides incorporated into the bridging ligands as well as the one-dimensional rectangular channels in the solid state for the dppp-based rectangle make this a promising family of metal-containing cyclic peptides in crystal engineering and molecular-recognition studies.