Dmit ligand

An enormous amount of research has gone into the synthesis and characterization of dmit ligand complexes and related selenium and oxygen isologues. Interest centers on the isolation of... 

As seen, in confirmation of the charge delocalization of the electron transfers, most distances inside the dmit ligand remain essentially unaltered. Nevertheless, the progressive shortening of the Ni-S bond suggests a non negligible contribution of the metal d orbitals to the frontier orbitals. 

Despite the diversity of ligand types, more than one-half of all structurally characterized homoleptic bis(dithiolene) complexes contain the mnt or dmit ligands (Table II A and B, Entries 1 and 30 Fig. 1). Extended packing arrangements of some mnt complexes are addressed by Lewis and Dance (18). Investigations of the dmit ligand and associated derivatives with a wide range of different cations account for the numerous examples. 

Perhaps the most extensively studied metallo-bis(dithiolenes) that possess more elaborated dithiolene donors are those that utilize the dmit ligand, and DFT calculations have recently been used to investigate the nature of the ground-state one-electron levels of [Ni(dmit)2)], [Pt(dmit)2)], and [Pt(dmit)2)J (380). Despite the increased complexity of the dithiolene ligands in these complexes (Fig. 36), their electronic structure is remarkably similar to that of the simple or parent metallo-bis(dithiolenes) that have been discussed previously. This finding is most evident in the electron density contour plots of the HOMOs and LUMOs for [Ni(S2C2Me2)2], [Ni(dmit)2], and [Ni(H2 timdt)2)], and these are presented in Fig. 37. An atomic orbital population analysis reveals that the HOMO possesses b u symmetry, and is almost entirely comprised of out-of-plane ligand pn orbitals with only a few percent metal... 

The Nine Superconductors Derived from the dmit Ligand... 

As in the dmid-based systems discussed above, the [Cp2W(dmit)]+ cations in the related [Cp2W(dmit)](TCNQF4) compound are also arranged as head-to-tail dimers. However, these dimers are not face-to-face (dmit over dmit) but laterally displaced, with short S - S contacts [3.433(4) and 3.749(5) A (Fig. 14)]. These interactions within the dimers form the mngs of the ladder. The leg of the ladder is built on the interaction between the Cp rings and the dmit ligand (Fig. 15). The spin gap value is 40 K. 

Another very important group of organic acceptors employed as components for organic metals during the last decade is presented by dithiolene metal complexes [e.g., l,3-dithiole-2-thione-4,5-dithiolate (dmit) ligand and... 

Other examples of monocyclic dithiolato stannates are two series of diorganohalo- and diorganopsendohalo-tin complexes, containing DMIO and DMIT ligands, which were recently obtained from organotin hahdes and the dithiolato Zn derivatives (Scheme 4)191.309.318 these reagents were used in a 2 1 ratio, the DMIO or... 

Figure 4.18 Synthesis of the [dmit] ligand, its storable derivatives and [M(dmit)2] compounds. (FOSC = fractional oxidation state compound DA = donor-acceptor compound)...

NIOS salts or CT-complexes, which contain donors of various types, such as Per or TTF (Chapter 12.1). More than one-half are again Ni-, Pd-, or Au- complexes based on the dmit ligand, but recent literature also reports many examples of Z)Zj (l,2-dithiolene) complexes deriving from mnt (with metals such as Au, Co, Cu, Fe, Ni, Pd, Pt), tfd , dddt , dmise , dcit , and dmbit (Ni and pd).n>i8,19,199,200,231 examples of CT salts containing... 

Third-order NLO effects, of interest for potential applications, for example in optical limiting ° impose no symmetry constraints. Thus, studies on this type of nonlinearity have addressed both homoleptic and heteroleptic 1,2-dithiolene complexes. Among the members of the former class, study on TBA salts of monoanionic nickel Al5(l,2-dithiolene) complexes with ligands such as phdt , dddt , pddt , cddt, and -substituted 1,2-diphenyl-1,2-ethyl-enedithioate ° have been published. Underhill and co-workers have reported on the nonlinear properties of unsymmetrically substituted w(l,2-dithiolene) complexes, such as iw[l-butyl-2-phenylethene-l,2-dithiolato(2 )-S,S ]nickel(II), embedded in PMMA-based composites (PMMA=polymethylmethacrylate), or in sol-gel materials.As regards the latter class, some works have dealt with complexes containing mnt and dmit ligands. ... 

The well-known synthesis of the dmit ligand (40) was first reported in 1975 from carbon disulphide and sodium in dimethylformamide (DMF) [63]. The dmit ligand can be separated of the sodium trithiocarbonate (39) obtained in the reaction by precipitating the zinc complex (41), formed in aqueous ammonia, with methanol (Scheme 1.11). This procedure was later improved [64] and the dmit ligand better protected by converting the tetraalkylammonium zinc complex (41) into the benzoyl derivative (42) by reaction with benzoyl chloride. The dmit dianion (40) can be regenerated from the benzoyl derivative by treating with sodium methoxide. Fmfher treatment with the metal salt (M = Ni, Pd, Pt, Fe, Au, Cu, Rh) affords the dmit complex [61]. 

Formation of sulphur containing donor molecules from the dmit ligand has been recently reviewed by Svenstrup and Becher [65]. 

The dmit ligand was first synthesised by Steimecke et al. in 1975 [192]. The extensive studies on conductive materials using metal(dmit)2 complexes were started when the tetraethylammonium salt was... 

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