First Nanoparticles of a Conductor Based on the Organic Donor Molecule BETS: κ-(BETS)2FeCl4.

Nanoparticles of the molecular superconductor (BETS)2FeCl4 were obtained by the electrochemical oxidation of BETS in the presence of [(C2H5)4N]FeCl4 and an amphiphilic imine (OATM), acting as a growth controlling agent. When the reaction was carried out with a molar ratio OATM/BETS of 10, roughly spherical nanoparticles exhibiting sizes in the 10-40 nm range were observed. X-ray diffraction patterns evidenced the growth of (BETS)2FeCl4 nanoparticles with the κ-type structure. The current-voltage characteristic recorded on an individual nanoparticle aggregate was fitted with a Shockley diode model. A saturation current of 1216 pA and a threshold voltage of 0.62 V were extracted from this model. This latter value was consistent with roughly half of the energy gap of the semiconducting nano-crystalline aggregate.

Characterization of Charge States in Conducting Organic Nanoparticles by X-ray Photoemission Spectroscopy.

The metallic and semiconducting character of a large family of organic materials based on the electron donor molecule tetrathiafulvalene (TTF) is rooted in the partial oxidation (charge transfer or mixed valency) of TTF derivatives leading to partially filled molecular orbital-based electronic bands. The intrinsic structure of such complexes, with segregated donor and acceptor molecular chains or planes, leads to anisotropic electronic properties (quasi one-dimensional or two-dimensional) and morphology (needle-like or platelet-like crystals). Recently, such materials have been synthesized as nanoparticles by intentionally frustrating the intrinsic anisotropic growth. X-ray photoemission spectroscopy (XPS) has emerged as a valuable technique to characterize the transfer of charge due to its ability to discriminate the different chemical environments or electronic configurations manifested by chemical shifts of core level lines in high-resolution spectra. Since the photoemission process is inherently fast (well below the femtosecond time scale), dynamic processes can be efficiently explored. We determine here the fingerprint of partial oxidation on the photoemission lines of nanoparticles of selected TTF-based conductors.

Possible observation of the signature of the bad metal phase and its crossover to a Fermi liquid in Κ-(BEDT-TTF)2Cu(NCS)2bulk and nanoparticles by Raman scattering.

Κ-(BEDT-TTF)2Cu(NCS)2has been investigated by Raman scattering in both bulk and nanoparticle compounds. Phonon modes from 20 to 1600 cm-1have been assigned. Focusing on the unexplored low frequency phonons, a plateau in frequencies is observed in the bulk phonons between 50 and 100 K and assigned to the signature of the bad metal phase. Nanoparticles of Κ-(BEDT-TTF)2Cu(NCS)2exhibit anomalies at 50 K associated to the crossover from a bad metal to a Fermi liquid whose origins are discussed.

A new compound in the BEDT-TTF family [BEDT-TTF = bis-(ethyl-enedi-thio)-tetra-thia-fulvalene] with a tetra-thio-cyanato-cuprate(II) anion, (BEDT-TTF)4[Cu(NCS)4].

A new phase combining BEDT-TTF and [Cu(NCS)4]2- as the counter-anion, namely bis-[bis(ethyl-enedi-thio)-tetra-thia-fulvalenium] tetra-thio-cyanato-cuprate(II) bis-[bis(ethyl-ene-di-thio)-tetra-thia-fulvalene], (C10H8S8)2[Cu(NCS)4]·2C10H8S8 or (BEDT-TTF)4[Cu(NCS)4] was obtained during a galvanostatic electrocrystallization process. As previously observed with BEDT-TTF-based compounds with oxalatometallate anions, the BEDT-TTF mol-ecules in (BEDT-TTF)4[Cu(NCS)4] exhibit the so-called pseudo-κ arrangement, with two BEDT-TTF mol-ecules being positively charged and two electronically neutral. The bond lengths and angles in the two unique BEDT-TTF mol-ecules differ slightly. The crystal structure consists of layers of BEDT-TTF mol-ecules extending parallel to (001). The width of this layer corresponds to the length of the a axis [16.9036 (17) Å]. The BEDT-TTF layers are separated by layers of centrosymmetric square-planar [Cu(NCS)4]2- dianions.

Colloidal solutions of organic conductive nanoparticles.

Although molecular metals have been known for decades, their insolubility, low vapor pressure, and synthesis routes have prevented them from being integrated into electronic devices. We have prepared stable colloidal solutions of the organic metal TTF-TCNQ that overcome such difficulties. The solutions contain well-dispersed nanoparticles stabilized by long alkyl chain amines. They afford soluble powders by evaporation and homogeneous thin films by drop-casting. Powders and films show room temperature conductivities in the 0.01-0.1 S cm(-1) range.

A facile route for the preparation of nanoparticles of the spin-crossover complex [Fe(Htrz)2(trz)](BF4) in xerogel transparent composite films.

Films and monoliths containing the spin crossover complex [Fe(Htrz)(2)(trz)](BF(4)) (trz = 1,2,4-triazole) as nanoparticles have been obtained. The dispersion and consecutive inclusion of the Fe complex in a silica matrix prepared from tetramethoxysilane or tetraethoxysilane afford monoliths or films with a violet colour at room temperature, which turns white above 380 K. This change of colour is reversible. This thermochromic behaviour has been characterized by measuring the magnetic properties together with thermogravimetric studies and Raman spectroscopy, the result of which all demonstrate that both films and monoliths undergo a spin crossover. Microscopy studies confirm the occurrence of the Fe complex as nanoparticles, in both the monoliths and the films. The facile synthesis of these materials as nanoparticles in transparent films should open the possibility of the synthesis of high quality films.

Tuning of the charge in octahedral ferric complexes based on pyridoxal-N-substituted thiosemicarbazone ligands.

Four novel mononuclear coordination compounds namely: [Fe(Hthpy)(2)](SO(4))(1/2).3.5H(2)O , [Fe(Hthpy)(2)]NO(3).3H(2)O , [Fe(H(2)mthpy)(2)](CH(3)C(6)H(4)SO(3))(3).CH(3)CH(2)OH and [Fe(Hethpy)(ethpy)].8H(2)O , (H(2)thpy = pyridoxalthiosemicarbazone, H(2)mthpy = pyridoxal-4-methylthiosemicarbazone, H(2)ethpy = pyridoxal-4-ethylthiosemicarbazone), were synthesized in the absence or presence of organic base, Et(3)N and NH(3). Compounds and are monocationic, and were prepared using the singly deprotonated form of pyridoxalthiosemicarbazone. Both compounds crystallise in the monoclinic system, C2/c and P2(1)/c space group for and , respectively. Complex is tricationic, it is formed with neutral bis(ligand) complex and possesses an interesting 3D channel architecture, the unit cell is triclinic, P1[combining macron] space group. For complex , the pH value plays an important role during its synthesis; is neutral and crystallises with two inequivalent forms of the ligand: the singly and the doubly deprotonated chelate of H(2)ethpy, the unit cell is monoclinic, C2/c space group. Notably, in and , there is an attractive infinite three dimensional hydrogen bonding network in the crystal lattice. Magnetic measurements of and revealed that a rather steep spin transition from the low spin to high spin Fe(iii) states occurs above 300 K in the first heating step. This transition is accompanied by the elimination of solvate molecules and thus, stabilizes the high spin form due to the breaking of hydrogen bonding networks; compared to and , which keep their low spin state up to 400 K.

Electrical conductivity and spin crossover: a new achievement with a metal bis dithiolene complex.

Three new compounds based on the cationic complex [Fe(III)(3-R-salEen)(2)]+ (salEen stands for N-(2-ethylamino)ethyl)-salicylaldimine, R = H, CH(3)O) with the electroactive Ni(dmit)(2) species as a counterion (dmit stands for 1,3-dithia-2-thione-4,5-dithiolato) have been synthesized and structurally and magnetically characterized. Compound 1 ([Ni(dmit)(2)][Fe(3-OMe-salEen)(2)]. CH(3)OH) shows an apparent hysteresis loop, due to an irreversible desolvatation process. Compound 2 ([Ni(dmit)(2)](NO(3))[Fe(salEen)(2)](2)) exhibits a gradual and incomplete spin transition. Compound 3 ([Ni(dmit)(2)](5)[Fe(salEen)(2)](2), 6CH(3)CN) is a fractional oxidation state complex, which behaves like a semiconductor and exhibits a gradual but complete spin transition between 300 and 4 K.

New BEDT-TTF/[Fe(C5O5)3]3- hybrid system: synthesis, crystal structure, and physical properties of a chirality-induced alpha phase and a novel magnetic molecular metal.

The paramagnetic and chiral anion [Fe(C5O5)3]3- (C5O52-=croconate) has been combined with the organic donor BEDT-TTF (=ET=bis(ethylenedithio)tetrathiafulvalene) to synthesize a novel paramagnetic semiconductor with the first chirality-induced alpha phase, alpha-(BEDT-TTF)5[Fe(C5O5)3].5H2O (1), and one of the few known paramagnetic molecular metals, beta-(BEDT-TTF)5[Fe(C5O5)3].C6H5CN (2). Both compounds present layers of BEDT-TTF molecules, with the alpha or beta packing modes, alternating with layers containing the high-spin S=5/2 Fe(III) anions and solvent molecules. In the alpha phase, the alternation of the chiral [Fe(C5O5)3]3- anions along the direction perpendicular to the BEDT-TTF chains induces an alternation of the tilt angle of the BEDT-TTF molecules, giving rise to the observed alpha phase. The alpha phase presents a semiconductor behavior with a high room-temperature conductivity (6 S.cm-1) and an activation energy of 116 meV. The beta phase presents a metallic behavior down to ca. 120 K, where a charge localization takes place with a reentrance to the metallic state below ca. 20 K followed by a metal-semiconductor transition at ca. 10 K. The magnetic properties are dominated by the paramagnetic S=5/2 [Fe(C5O5)3]3- anion with an extra Pauli-type paramagnetism in the metallic beta phase. The ESR spectra confirm the presence of the high-spin Fe(III)-containing anion and show a progressive localization in the organic sublattice along with an antiferromagnetic coupling below ca. 120 K that, in the metallic beta phase, could be at the origin of the transition from the metallic to the activated conductivity regime. The correlation between crystal structure and conductivity behavior has been studied by means of tight-binding band structure calculations which provide a rationalization of the charge distribution and conductivity results.

Ligand influence on connectivity and processing: magnetic crystals based on metalloceniums and films of TCNE-based magnets (TCNE=tetracyanoethylene).

Molecular materials built from coordination complexes exhibit properties that can be explained through intermolecular electronic interactions driven by the ligand moieties. The nature of the ligand in the precursor molecules governs the connectivity of the magnetic phases and the possibility of producing them by using a gas-phase process. Metallocenium, metal bisdithiolate materials, and solvated and solvent-free [M(tcne)2] (tcne=tetracyanoethylene) magnets illustrate such features.

A chirality-induced alpha phase and a novel molecular magnetic metal in the BEDT-TTF/tris(croconate)ferrate(III) hybrid molecular system.

The novel paramagnetic and chiral anion [Fe(C5O5)3]3- has been combined with the organic donor BEDT-TTF (= ET = bis(ethylenedithio)tetrathiafulvalene) to yield the first chirality-induced alpha phase and a paramagnetic metal.

Synthesis, crystal structure and properties of the semiconducting salts (TTF)2[Ni(dtcr)2] and (ET)2[Ni(dtcr)2] based on [Ni(dtcr)2] dianions (dtcr = dithiocroconate).

The first examples of CT salts based on [Ni(dtcr)2] dianions (1) (dtcr = dithiocroconate = 4,5-disulfanylcyclopent-4-ene-1,2,3-trionate), (TTF)2[Ni(dtcr)2] (TTF = tetrathiafulvalene) (2) and (ET)2[Ni(dtcr)2] [ET = bis(ethylenedithio)tetrathiafulvalene] (3) are reported. The redox-active dianion 1, containing oxo-groups in the periphery of the molecule, has been selected to investigate the role of the oxo-groups in promoting intermolecular interactions and hopefully their conducting properties. The salts 2 and 3 have been prepared by electrocrystallisation methods and 3 shows a semi-metallic behaviour: sigma = 1 x 10(-3) omega(-1) cm(-1) at room temperature, with a low activation energy 60 meV, while crystals of 2 were unsuitable for conductivity measurements. The X-ray structural characterisation shows an alternate dianion-(cation)2 stacking and the capability of the oxo-groups to promote interstack contacts. In 2, the TTF donors are present as face-to-face dimers of monocations (D2)2+. The stacking arrangement is different in 3, where ET monocations stack along two directions ([110] and [110]) in the same manner, with the repeating sequence (ET)-(ET)-[Ni(dtcr)2]-(ET)-(ET) and are almost parallel to each other, with interplanar distances of 3.575 angstroms. Both structures are built on a dianion and two donor molecules, each one with a charge of +1. Diffuse reflectance combined with vibrational spectra complement structural results well. Crystal data: both 2 and 3 crystallise in the monoclinic space group P2(1)/c with a = 8.6340(8) angstroms, b = 21.586(2) angstroms, c = 7.5960(8) angstroms, beta = 95.625(11) degrees and V = 1408.9(2) angstroms3 for 2 and with a = 9.3700(7), b = 7.4410(6), c = 28.278(2) angstroms, beta = 99.039(6) degrees, V = 1947.1(3) angstroms3 for 3.

Metallic polycrystalline thin films of the single-component neutral molecular solid Ni(tmdt)2.

Metallic thin films of the single-component, neutral, molecular solid Ni(tmdt)2 have been prepared by electrocrystallization on passivated silicon substrates. Metallicity is achieved down to 6 K despite the polycrystalline morphology.

[Fe(sal2-trien)][Ni(dmit)2]: towards switchable spin crossover molecular conductors.

A cooperative spin transition behaviour with a wide hysteresis loop (30 K) around 240 K has been observed, for the first time, in a salt based on the redox active [Ni(dmit)(2)](-), anion and the [Fe(sal(2)-trien)](+) spin crossover cation.

Electronic factors affecting second-order NLO properties: case study of four different push-pull bis-dithiolene nickel complexes.

The paper presents a detailed experimental and theoretical study of the four mixed nickel-bisdithiolene complexes [Ni(Pr(i)(2)pipdt)(dmit)] (1b, Pr(i)(2)pipdt = 1,4-diisopropyl-piperazine-3,2-dithione; dmit = 1,3-dithiolo-2-tione-4,5-dithiolato), [Ni(R(2)pipdt)(mnt)] (2b", R = 2-ethylhexyl; mnt = maleonitriledithiolato), [Ni(Pr(i)(2)timdt)(dmit)] (3b, Pr(i)(2)timdt = 1,3-diisopropyl-imidazoline-2,4,5-trithione), and [Ni(Pr(i)(2)timdt)(mnt)] (4b), and their models. All the complexes, with common (C(2)S(2))Ni(C(2)S(2)) core and two different terminal groups, are uncharged and square-planar coordinated. Previous measurements of the first molecular hyperpolarizability indicated that some of the species are potential NLO chromophores due to the pi-delocalized character of two frontier levels (HOMO and LUMO) which is asymmetrically perturbed by the combination of one push (R(2)pipdt, R(2)timdt) with one pull ligand (dmit and mnt). The X-ray structure of complex 1b is presented and its geometry is compared with those available in the literature for the four types of complexes under study. The results of electrochemical and spectroscopic measurements (oxidation and reduction potentials, IR, dipole moment, molecular absorptivities, etc.) indicate rather different responses between the pairs of complexes 1-2 and 3-4. Hence, DFT calculations on the model compounds 1a-4a, where hydrogen atoms replace the alkyl groups of R(2)pipdt and R(2)timdt, have been carried out to correlate geometries and electronic structures. Moreover, the first molecular hyperpolarizabilities have been calculated and their components have been analyzed with the simplest two-level approximation. The derived picture highlights the different roles of the two push and pull ligands, but also the peculiar perturbation of the pi-electron density induced by the terminal CS(3) grouping of the ligand dmit.

A substituted EDOT precursor: diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate.

The title compound, C(10)H(12)O(6)S, has been obtained as dark-yellow chunk-shaped crystals, together with the expected thin white needles. The structures of the two phases are identical. Two independent molecules compose the asymmetric unit: one molecule is totally planar, whereas a methyl group of the second molecule points out of the plane. Each molecule participates in several intra- and intermolecular hydrogen bonds and short contacts. The overall structure can be regarded as parallel sheets of molecules. Within a sheet, molecules are connected to one another in an infinite network via numerous short intermolecular contacts. Sheets are connected via hydrogen bonds and short contacts, in particular involving the methyl groups.

(BETS)2[Fe(tdas)2]2: a new metal in the molecular conductor family.

The structure of bis[4,5-ethylenedithio-2-(4,5-ethylenedithio-1,3-diselenacyclopent-4-en-2-ylidene)-1,3-diselenacyclopent-4-enium] bis(mu-1,2,5-thiadiazole-3,4-dithiolato-kappa3S4,S5:S4)bis[(1,2,5-thiadiazole-3,4-dithiolato-kappa2S4,S5)iron(III)], (BETS)(2)[Fe(tdas)(2)](2) [BETS is alternatively called bis(ethylenedithio)tetraselenafulvalenium] or (C(10)H(8)S(4)Se(4))(2)[(Fe(C(2)N(2)S(3))(2))(2)], consists of segregated columns of dimers of BETS and columns of dimers of [Fe(tdas)(2)]. Each dimer displays inversion symmetry. Numerous chalcogen-chalcogen contacts are observed within and between the columns, producing a network of interactions responsible for the metal-like behaviour of the compound.

Structural and Magnetic Properties of M(mnt)(2) Salts (M = Ni, Pt, Cu) with a Ferrocene-Based Cation, [FcCH(2)N(CH(3))(3)](+). Interplay between M.M and M.S Intermolecular Interactions.

A series of metal bis-mnt complexes (mnt = 1,2-dithiolatomaleonitrile) with the trimethylammonium methylferrocene cation have been synthesized and characterized using X-ray diffraction, magnetic susceptibility, and differential scanning calorimetry measurements. The complexes have the formulas (FcCH(2)NMe(3))[Ni(mnt)(2)] (2), (FcCH(2)NMe(3))[Pt(mnt)(2)] (3), and (FcCH(2)NMe(3))(2)[Cu(mnt)(2)] (4) (where Fc = ferrocene). At 300 K, the crystal structures of 1:1 complexes 2 and 3 are very similar. They consist of pairs of [M(mnt)(2)](-) in a slipped configuration packed in stacks. Each [M(mnt)(2)](-) stack is separated from adjacent stacks by two columns of cations. Within the pairs, the [M(mnt)(2)](-) anions interact via short M.S contacts, while there are no short contacts between the pairs. Complex 4, which has a 2:1 stoichiometry, exhibits a markedly different packing arrangement of the anionic units. Due to the special position of the Cu atom in the asymmetric unit cell, [Cu(mnt)(2)](2)(-) dianions are completely isolated from each other. The magnetic susceptibility behavior of the nickel complex is consistent with the presence of magnetically isolated, antiferromagnetically (AF) coupled [Ni(mnt)(2)](-) pairs with the AF exchange parameter, J = -840 cm(-)(1). The platinum complex undergoes an endothermic structural phase transition (T(p)) at 247 K. Below T(p) its structure is characterized by the formation of magnetically isolated [Pt(mnt)(2)](2)(2)(-) dimers in an eclipsed configuration with short Pt.Pt and S.S contacts between monomers. In the magnetic properties, the structural changes reveal themselves as an abrupt susceptibility drop implying a substantial increase of the AF exchange parameter. A mechanism of the phase transition in the platinum compound is proposed. For compound 4, paramagnetic behavior is observed.

Metal Complexes of Dithiolate Ligands: 5,6-Dihydro-1,4-dithiin-2,3-dithiolato (dddt(2-)), 5,7-Dihydro-1,4,6-trithiin-2,3-dithiolato (dtdt(2-)), and 2-Thioxo-1,3-dithiole-4,5-dithiolato (dmit(2-)). Synthesis, Electrochemical Studies, Crystal and Electronic Structures, and Conducting Properties.

New precursors to potentially conductive noninteger oxidation state (NIOS) compounds based on metal complexes [ML(2)](n)()(-) [M = Ni, Pd, Pt; L = 5,6-dihydro-1,4-dithiin-2,3-dithiolato (dddt(2)(-)), 5,7-dihydro-1,4,6-trithiin-2,3-dithiolato (dtdt(2)(-)), and 2-thioxo-1,3-dithiole-4,5-dithiolato (dmit(2)(-)); n = 2, 1, 0] have been investigated. Complexes of the series (NR(4))[ML(2)] (R = Me, Et, Bu; L = dddt(2)(-), dtdt(2)(-)) have been isolated and characterized, and the crystal structure of (NBu(4))[Pt(dtdt)(2)] (1) has been determined {1 = C(24)H(44)NPtS(10), a = 12.064(2) Å, b = 17.201(3) Å, c = 16.878(2) Å, beta = 102.22(2) degrees, V = 3423(1) Å(3), monoclinic, P2(1)/n, Z = 4}. Oxidation of these complexes affords the corresponding neutral species [ML(2)](0). Another series of general formula (cation)(n)()[M(dmit)(2)] [cation = PPN(+), BTP(+), and (SMe(y)()Et(3)(-)(y)())(+) with y = 0, 1, 2, and 3, n = 2, 1, M = Ni, Pd] has also been studied. All of these (cation)(n)()[M(dmit)(2)] complexes have been isolated and characterized [with the exception of (cation)[Pd(dmit)(2)] for cation = (SMe(y)()Et(3)(-)(y)())(+)]. The crystal structures of (PPN)[Ni(dmit)(2)].(CH(3))(2)CO (2) and (SMeEt(2))[Ni(dmit)(2)] (3) have been determined {2 = C(45)H(36)NNiS(10)P(2)O, a = 12.310(2) Å, b = 13.328(3) Å, c = 15.850(3) Å, alpha = 108.19(3) degrees, beta = 96.64(2) degrees, gamma = 99.67(2) degrees, V = 2373(1) Å(3), triclinic, P&onemacr;, Z = 2; 3 = C(11)H(13)NiS(11), a = 7.171(9) Å, b = 17.802(3) Å, c = 16.251(3) Å, beta = 94.39(4) degrees, V = 2068(2) Å(3), monoclinic, P2(1)/n, Z = 4} NIOS salts derived from the preceding precursors were obtained by electrochemical oxidation. Electrochemical studies of the [M(dddt)(2)] complexes show that they may be used for the preparation of NIOS radical cation salts and [M(dddt)(2)][M'(dmit)(2)](x)() compounds, but not for the preparation of (cation)[M(dddt)(2)](z)() NIOS radical anion salts. The electrochemical oxidation of the [M(dtdt)(2)](-) complexes always yields the neutral [M(dtdt)(2)](0) species. The crystal structure of [Pt(dddt)(2)][Ni(dmit)(2)](2) (4) has been determined and is consistent with the low compaction powder conductivity (5 x 10(-)(5) S cm(-)(1) at room temperature) {4 = C(20)H(8)Ni(2)PtS(28), a = 20.336(4) Å, b = 7.189(2) Å, c = 14.181(2) Å, beta = 97.16(2) degrees, V = 2057(1) Å(3), monoclinic, C2/m, Z = 2}. The crystal structures of the semiconducting NIOS compounds (BTP)[Ni(dmit)(2)](3) (5) and (SMe(3))[Ni(dmit)(2)](2) (6) have been determined {5 = C(43)H(22)PNi(3)S(30), a = 11.927(2) Å, b = 24.919(2) Å, c = 11.829(3) Å, alpha = 93.11(1) degrees, beta = 110.22(1) degrees, gamma = 83.94(1) degrees, V = 3284(1) Å(3), triclinic, P&onemacr;, Z = 2; 6 = C(15)H(9)Ni(2)S(21), a = 7.882(1) Å, b = 11.603(2) Å, c = 17.731(2) Å, alpha = 77.44(1) degrees, beta = 94.39(1) degrees, gamma = 81.27(1) degrees, V = 1563(1) Å(3), triclinic, P&onemacr;, Z = 2}. The parent compound (SEt(3))[Ni(dmit)(2)](z) (unknown stoichiometry) is also a semiconductor with a single-crystal conductivity at room temperature of 10 S cm(-)(1). By contrast, the single-crystal conductivity at room temperature of (SMeEt(2))[Pd(dmit)(2)](2) (7) is rather high (100 S cm(-)(1)). 7 behaves as a pseudometal down to 150 K and undergoes an irreversible metal-insulator transition below this temperature. The crystal structure of 7 has been determined {7 = C(17)H(13)NPd(2)S(21), a = 7.804(4) Å, b = 36.171(18) Å, c = 6.284(2) Å, alpha = 91.68(4) degrees, beta = 112.08(4) degrees, gamma = 88.79(5) degrees, V = 1643(1) Å(3), triclinic, P&onemacr;, Z = 2}. The electronic structure of (SMeEt(2))[Pd(dmit)(2)](2) (7) and the possible origin of the metal-insulator transition at 150 K are discussed on the basis of tight-binding band structure calculations.