Metal bis-dithiolene complexes,

Following the idea of McConnell [44] who proposed in 1967 that a stacking arrangement such as.., D+ A D+ A D+ A-... of donor and acceptor could lead to molecule-based magnets, the combination between metal bis-dithiolene complexes and metalloceniums was performed originally only to promote cooperative ferromagnetic interactions [45]. 

The first metal bis-dithiolene complex with an SCO moiety as counter-ion was reported in 2005 [99], namely [Fe(sal2-trien)][Ni(dmit)2] (Fig. 8). Usually, [Fe(sal2-trien)]+ is a Fera complex which exhibits very modest magnetic properties a gradual and incomplete spin transition is observed when it is combined with (PF6) and (BPI14), and the complex remains in the LS state with Cl-, I-and (NO3)-. 

The photoinduced ET reactions of metal bis(mnt) complexes have also been studied by Persaud and Langford (56) using photoelectrochemistry. Their research addressed a fundamental aspect of the CT photochemistry of the metal bis(dithiolene) complexes whether or not photooxidation can occur from the lower energy MLCT excited states. Acetonitrile solutions of M(mnt)2 2 (M = Ni, Pd, Pt, and Cu) were investigated using optically transparent Sn02 electrodes. For the Ni and Pt complexes, weak (nA) cathodic currents were... 

Although only rarely luminescent in ambient fluid solutions, square-planar transition metal bis(dithiolene) complexes do display significant and varied photochemical reactivity. Much of the photoreactivity described above for dianionic bis(dithiolene) complexes involves excited-state oxidation and often leads to radical formation. In addition, the excited states of these complexes are receiving attention for their potential as materials for optical (15), nonlinear optical (10-13), and electrooptical (16) devices. The relevance of this work to those applications is addressed in other parts of chapter 8 in this volume (87b). 

Chapter 1 deals with synthesis, where we learn that there are many ways to make dithiolene complexes, either from preformed ligands or through the chemical reactivity of bound sulfur species. Synthesis is at the core of most of the coordination chemistry that has been done on dithiolene complexes. Chapter 2 deals with structures and structural trends of the most common simple dithiolene complexes. Indeed, it was the square-planar nature of most late transition metal bis(dithiolene) complexes and the unprecedented trigonal-prismatic six-coordination of some of the tris(dithiolene) complexes that was one of three major drivers for early work in the held. 

This chapter first gives background on compounds that can be qualified as benchmarks in the field of molecular organic and inorganic conductors and superconductors. Focus is then further given to systems based on metal bis-dithiolene complexes. The last section considers the processing methods that can be applied to grow films of molecular conductors and superconductors. 

Synthesis of Conductors and Superconductors Based on Metal Bis-Dithiolene Complexes... 

Metal bis-dithiolene complexes exhibiting conducting or superconducting properties can be neutral or in a fractional oxidation state. In FOSCs, the associated cation is of the closed-shell type, while in DA compounds, the metal bis-dithiolene is an acceptor and the donor is an open-shell cation. As already mentioned in Section 4.2.2.3, the most encountered... 

Neutral metal bis-dithiolene complexes were isolated from a very few ligands considering the number of existing bis-dithiolene ligands. A selection is shown in Figure 4.26. Most neutral metal bis-dithiolene complexes are not conductive. Only the TTF-dithiolene ones exhibit a metallic behaviour. Examples of conducting neutral complexes, that is [Ni(dmit)2], [Ni(tmdt)2], and [Ni(dtdt)2], are described in this section. 

T. Waters, X.-B. Wang and L.-S. Wang, Coord. Chem. Rev., 2007, 251, 474. Review describing the use of electrospray to transfer negatively charged transition metal complexes to the gas phase for photoelectron spectroscopy. Examples discussed include square planar and octahedral halide complexes, metal-metal bonded species, transition metal bis(dithiolene) complexes, and mononuclear and polynuclear iron-sulfur clusters. 

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