Dithiolate Ligands Research Articles

Metal (au, Pt, Pd, Ni) Bis(dithiolene) complexes as dual-action agents combating cancer and trypanosomatid infections

Cancer and infection diseases pose severe threats to public health worldwide stressing the need for more effective and efficient treatments. Thus, the search for broad-spectrum activity drugs seems justifiable and urgent. Herein, we investigate the anticancer and antitrypanosomatid (anti-Trypanosoma cruzi) activities of eight monoanionic metal bis(dithiolene) complexes, [Ph4P][M(R-thiazdt)2] with Mn+ = Au3+, Pt2+, Pd2+, Ni2+, containing N-alkyl-1,3-thiazoline-2-thione dithiolene ligands (R-thiazdt) with different alkyl groups (R = Et, tBu). Compared to auranofin (AF) and cisplatin (CP), two reference drugs in clinical use, all complexes showed high anticancer activities against A2780 ovarian cancer cells (IC50 values of 0.6–3.8 μM) some also being able to overcome CP resistance in A2780cisR cells. The selectivity index (SI), the IC50 values of normal cells (HDF) vs. A2780 cells, indicated good anticancer specificity (SI > 3) for most of the complexes but with clinical relevance for [Ph4P][Pd(tBu-thiazdt)2] (SI = 10). All complexes showed relevant antitrypanosomatid activities (IC50 values of 2.6–5.8 μM) some even exhibiting lower IC50 values than the reference drug nifurtimox (NFX). The mechanism of cell death seemed to be mediated mainly by the formation of reactive oxygen species (ROS), although to lesser extent for the gold complexes but superior to AF. Although ROS play a role in the main apoptotic pathways, cell death by apoptosis was not evident as shown by the caspase-3/7 assay and the morphological cell features studies by electron microscopy (SEM). Results obtained evidenced that [Ph4P][Pt(tBu-thiazdt)2] and [Ph4P][Pd(tBu-thiazdt)2] complexes might have potential as novel anticancer and antitrypanosomatid agents as alternatives to current therapeutics.

Preserving precise choreography of bonds in Z-stereoretentive olefin metathesis by using quinoxaline-2,3-dithiolate ligand

The Z-alkene geometry is prevalent in various chemical compounds, including numerous building blocks, fine chemicals, and natural products. Unfortunately, established Mo, W, and Ru Z-selective catalysts lose their selectivity at high temperatures required for industrial processes like reactive distillation, which limits their synthetic applications. To address this issue, we develop a catalyst capable of providing Z-alkenes with high selectivity under harsh conditions. Our research reveals a dithiolate ligand that, stabilised by resonance, delivers high selectivity at temperatures up to 150 °C in concentrated mixtures. This distinguishes the dithioquinoxaline complex from existing Z-selective catalysts. Notably, this trait does not compromise the new catalyst’s usability under classical conditions, matching the activity of known stereoretentive catalysts. Density Functional Theory calculations were employed to understand the reaction mechanism and selectivity, and to investigate the poisoning that the catalyst may undergo and how it competes with catalytic activity. Furthermore, the quinoxaline-based catalyst enables the valorisation of bio-sourced alkene feedstocks and the production of agricultural sex pheromones for pest control.

Atomically Precise Au24Pt(thiolate)12(dithiolate)3 Nanoclusters with Excellent Electrocatalytic Hydrogen Evolution Reactivity.

[Au24Pt(C6)18]0 (C6 = 1-hexanethiolate) is twice as active as commercial Pt nanoparticles in promoting the electrocatalytic hydrogen evolution reaction (HER), thereby attracting attention as new HER catalysts with well-controlled geometric structures. In this study, we succeeded in synthesizing two new Au-Pt alloy nanoclusters, namely, [Au24Pt(TBBT)12(TDT)3]0 (TBBT = 4-tert-butylbenzenethiolate; TDT = thiodithiolate) and [Au24Pt(TBBT)12(PDT)3]0 (PDT = 1,3-propanedithiolate), by exchanging all the ligands of [Au24Pt(PET)18]0 (PET = 2-phenylethanethiolate) with mono- or dithiolates. Although [Au24Pt(TBBT)12(TDT)3]0 was synthesized serendipitously, a similar cluster, [Au24Pt(TBBT)12(PDT)3]0, was subsequently obtained by selecting the appropriate reaction conditions and optimal combination of thiolate and dithiolate ligands. Single crystal X-ray diffraction analyses revealed that the lengths and orientations of -Au(I)-SR-Au(I)- staples in [Au24Pt(TBBT)12(TDT)3]0 and [Au24Pt(TBBT)12(PDT)3]0 were different from those in [Au24Pt(C6)18]0, [Au24Pt(PET)18]0, and [Au24Pt(TBBT)18]0, and these subtle differences were reflected in the geometric and electronic structures as well as the HER activities of [Au24Pt(TBBT)12(TDT)3]0 and [Au24Pt(TBBT)12(PDT)3]0. Accordingly, the HER activities of products [Au24Pt(TBBT)12(TDT)3]0 and [Au24Pt(TBBT)12(PDT)3]0 were, respectively, 3.5 and 4.9 times higher than those of [Au24Pt(C6)18]0 and [Au24Pt(TBBT)18]0.

Comparing fluoro- and trifluoromethyl-functionalized Ni(II) 1,1-dithiolates with 1,1′-bis-(diphenylphosphino)ferrocene co-ligand in DSSC applications

Four new heteroleptic Ni(II)-dithiolates with general formula [Ni(dppf)(dithiolate)] (dithiolate = 2-cyano-2-(4-fluorophenyl)ethene-1,1-bis(dithiolate) (Ni-1); 2-cyano-2(2-(trifluoromethyl)phenyl)ethene-1,1-bis(thiolate) (Ni-2); 2-cyano-2(3-(trifluoromethyl)phenyl)ethene-1,1-bis(thiolate) (Ni-3) and 2-cyano-2(4-(trifluoromethyl)phenyl)ethene-1,1-bis(thiolate) (Ni-4); dppf = 1,1′-bis(diphenylphosphino) ferrocene) have been synthesized and characterized spectroscopically as well as by single crystal X-ray diffraction technique. Single crystal X-ray analyses for Ni-1 and Ni-2 reveal distorted square planar geometry around Ni(II) that are satisfied by two sulfur and two phosphorus centers of the dithiolate and dppf ligands, respectively. These complexes have been used as photosensitizers in TiO2-based dye-sensitized solar cells (DSSCs) which suggest that the performance of fluoro-substituted sensitizer Ni-1 is superior to that of the other three trifluoromethyl-substituted sensitizers. Ni-1 showcases an efficiency (η) of 5.47 %, open circuit potential (Voc) of 0.699 V, short circuit current (Jsc) of 12.17 mA∙cm−2 and display 64 % incident photon-to-current conversion efficiency. The plausible reason for the variation in photovoltaic performances have been explained by integrated experimental methods and theoretical calculations. Results indicate that the small sized fluoro-group exhibits significant p-orbital overlap with the aromatic fragment of the dithiolate ligand, allowing facile photo-induced electron transfer from sensitizer to titania, thereby enhancing the electron donation from dppf→Ni(II)→dithiolate. Further, the cell fabricated with Ni-1 retains approximately 93 % of its initial conversion efficiency in 800 h time span.

Active Site Characterization of a Campylobacter jejuni Nitrate Reductase Variant Provides Insight into the Enzyme Mechanism.

Mo K-edge X-ray absorption spectroscopy (XAS) is used to probe the structure of wild-type Campylobacter jejuni nitrate reductase NapA and the C176A variant. The results of extended X-ray absorption fine structure (EXAFS) experiments on wt NapA support an oxidized Mo(VI) hexacoordinate active site coordinated by a single terminal oxo donor, four sulfur atoms from two separate pyranopterin dithiolene ligands, and an additional S atom from a conserved cysteine amino acid residue. We found no evidence of a terminal sulfido ligand in wt NapA. EXAFS analysis shows the C176A active site to be a 6-coordinate structure, and this is supported by EPR studies on C176A and small molecule analogs of Mo(V) enzyme forms. The SCys is replaced by a hydroxide or water ligand in C176A, and we find no evidence of a coordinated sulfhydryl (SH) ligand. Kinetic studies show that this variant has completely lost its catalytic activity toward nitrate. Taken together, the results support a critical role for the conserved C176 in catalysis and an oxygen atom transfer mechanism for the catalytic reduction of nitrate to nitrite that does not employ a terminal sulfido ligand in the catalytic cycle.

Synthesis of a novel triptycene-derived protected dithiolene ligand precursor for tri-nuclear mixed ligand metal dithiolene complexes

Abstract We synthesized a novel triptycene analogue, 3,3′,3″,3″′,3″″,3″″′-((triptycene-2,3,6,7,14,15-hexayl)hexakis(sulfanediyl))hexapropanenitrile (3), which served as a valuable precursor for the triptycene-derived tris-bidentate bridging dithiolene ligand, triptycene-2,3,6,7,14,15-hexakis(thiolate) (4), following the removal of the cyanoethyl moiety protection group. We determined the molecular and crystal structures of compound 3 and confirmed its capacity to yield compound 4. By reacting 3 with [NiCl2(BPY)] and [PtCl2(BPY)] (BPY: 2,2′-bipyridine) in methanol, we obtained crude samples of [Ni3(4)(BPY)3] and [Pt3(4)(BPY)3], respectively.

Aerosol-Assisted Chemical Vapor Deposition of 2H-WS2 From Single-Source Tungsten Dithiolene Precursors.

The tungsten carbonyl dimethyldithiolene (dmdt) complexes W(CO)4(dmdt), W(CO)2(dmdt)2, and W(dmdt)3 were evaluated as potential single-source precursors for the chemical vapor deposition of WS2. The results of TGA-MS, DIP-MS, and pyrolysis with NMR analysis were consistent with a thermal decomposition pathway in which loss of 2-butyne through a retro[3+2]cycloaddition of the dithiolene ligand generated terminal sulfido ligands. Aerosol-assisted chemical vapor deposition onto silicon substrates was performed using all three complexes, yielding 2H-WS2 thin films as characterized by Raman spectroscopy and GI-XRD. Film morphology and elemental composition of the films were determined using SEM, EDS, and XPS. Four-point probe measurements afforded a film resistivity of 8.37 Ωcm for a sample deposited from W(dmdt)3 in toluene at 600 °C.

Systematics of stable copper and silver clusters protected by small bite chelating bidentate sulfur and selenium ligands related to their polyhedral cavities: analogies to aliphatic compounds and three-dimensional spherical aromatic systems.

Silver and copper clusters capped by external chelating dithiolate ligands can be classified according to the cavities in their central coinage metal polyhedra. Silver clusters composed exclusively of fused tetrahedra are analogous to simple saturated organic compounds. The only interstitial atom that can be fit into an Ag4 tetrahedron is hydrogen. Silver polyhedra with larger trigonal prismatic or cubic cavities, including highly distorted cubic cavities, can accommodate halide and chalcogenide anions. The still larger 12-vertex icosahedral and cuboctahedral coinage metal cavities can accommodate oxoanions of the types SO32- and SO42- and their heavier congeners or alternatively interstitial coinage or platinum group metals leading to central M'@M12 units. Copper clusters with central cuboctahedra and silver clusters with central icosahedra possessing interstitial metal atoms approximate sphericality and provide examples of electron-rich metal superatoms with an average metal oxidation state of less than +1. Such copper cluster superatoms have two extra electrons corresponding to a filled 1S2 superatomic orbital. The silver cluster superatoms are electron richer with eight extra electrons corresponding to filled 1S2 + 1P6 superatomic orbitals. In these silver clusters seven or eight faces of the central Ag12 icosahedron are capped by additional silver atoms in order to provide these additional electrons.

Improved Bipolar Properties of Ester-Functionalized Discotic Diimine-Dithiolene Complexes.

A series of platinum diimine-dithiolene complexes with a 5,6-dihydro-1,4-dithiin-2,3-dithiolato (dddt2- ) dithiolene ligand and a bipyridine carrying tris-alkoxyphenyl fragments connected through an ester linker (bpyCn, n=8, 12, 16, 10(s), 20) (Scheme 1) has been developed. The mesomorphic properties of the ligands and of the platinum complexes have been investigated by a combination of DSC, POM and SAXS analyses. The platinum complexes were found to self-organize into columnar mesophases of hexagonal symmetry over large temperature range including room temperature. Their electronic properties were also characterized by a combination of electrochemistry, absorption and emission spectroscopy measurements and TD-DFT calculations. Besides being liquid crystalline, these compounds can undergo two oxidation processes and two reduction processes in a fully reversible manner, allowing the isolation of stable dicationic and dianionic species. Such a behavior is highly promising for the development of ambipolar semiconducting soft materials.

Advancing Our Understanding of Pyranopterin-Dithiolene Contributions to Moco Enzyme Catalysis.

The pyranopterin dithiolene ligand is remarkable in terms of its geometric and electronic structure and is uniquely found in mononuclear molybdenum and tungsten enzymes. The pyranopterin dithiolene is found coordinated to the metal ion, deeply buried within the protein, and non-covalently attached to the protein via an extensive hydrogen bonding network that is enzyme-specific. However, the function of pyranopterin dithiolene in enzymatic catalysis has been difficult to determine. This focused account aims to provide an overview of what has been learned from the study of pyranopterin dithiolene model complexes of molybdenum and how these results relate to the enzyme systems. This work begins with a summary of what is known about the pyranopterin dithiolene ligand in the enzymes. We then introduce the development of inorganic small molecule complexes that model aspects of a coordinated pyranopterin dithiolene and discuss the results of detailed physical studies of the models by electronic absorption, resonance Raman, X-ray absorption and NMR spectroscopies, cyclic voltammetry, X-ray crystallography, and chemical reactivity.

Investigations of the Photothermal Properties of a Series of Molecular Gold-bis(dithiolene) Complexes Absorbing in the NIR-III Region.

The photothermal properties of a series of neutral radical gold-bis(dithiolene) complexes absorbing in the near-infrared-III window (1550-1870 nm) have been investigated. This class of complexes was found to be good photothermal agents (PTAs) in toluene under 1600 nm laser irradiation with photothermal efficiencies around 40 and 60 % depending on the nature of the dithiolene ligand. To the best of our knowledge, these complexes are the first small molecular photothermal agents to absorb so far into the near infrared. To test their applicability in water, these hydrophobic complexes have been encapsulated into nanoparticles constituted by amphiphilic block-copolymers. Stable suspensions of polymeric nanoparticles (NPs) encapsulating the gold-bis(dithiolene) complexes have been prepared which show a diameter around 100 nm. The encapsulation rate was found to be strongly dependent on the nature of the dithiolene ligands. The photothermal properties of the aqueous suspensions containing gold-bis(dithiolene) complexes were then studied under 1600 nm laser irradiation. These studies demonstrate that water has strong photothermal activity in the NIR-III region that, cannot be overcome even with the addition of gold complexes displaying good photothermal properties.

Feinabstimmung der Redoxeigenschaften von heteroleptischen Molybdän‐Komplexen mittels Ligand‐Ligand‐Kooperativität

AbstractHeteroleptische Molybdänkomplexe mit 1,5‐Diaza‐3,7‐Diphosphacyclooctan (P2N2) und non‐innocent (nicht‐unschuldigen) Dithiolenliganden wurden synthetisiert und elektrochemisch charakterisiert. Dabei wurde festgestellt, dass die Reduktionspotentiale der Komplexe durch einen synergistischen Effekt moduliert werden, welcher durch DFT‐Berechnungen als Ligand‐Ligand‐Kooperativität über nicht‐kovalente Wechselwirkungen identifiziert werden konnte. Dieses Ergebnis konnte durch elektrochemische Studien in Kombination mit UV/Vis‐Spektroskopie und temperaturabhängiger NMR‐Spektroskopie bestätigt werden. Das beobachtete Verhalten erinnert an eine enzymatische Redoxmodulation durch Effekte basierend auf Interaktionen in der zweiten Ligandensphäre.

Fine-Tuning Redox Properties of Heteroleptic Molybdenum Complexes through Ligand-Ligand-Cooperativity.

Heteroleptic molybdenum complexes bearing 1,5-diaza-3,7-diphosphacyclooctane (P2 N2 ) and non-innocent dithiolene ligands were synthesized and electrochemically characterized. The reduction potentials of the complexes were found to be fine-tuned by a synergistic effect identified by DFT calculations as ligand-ligand cooperativity via non-covalent interactions. This finding is supported by electrochemical studies combined with UV/Vis spectroscopy and temperature-dependent NMR spectroscopy. The observed behavior is reminiscent of enzymatic redox modulation using second ligand sphere effects.

Effects of different dithiolate ligands on electrocatalytic hydrogen production of nickel complexes in acetic acid or water

In order to solve the problems of fossil energy depletion and environmental pollution, it is necessary to find new energy sources that are recyclable and environmentally friendly. Among them, hydrogen is a high calorific value, clean and sustainable energy. At present, hydrogen is mainly obtained by electrolysis of water. The use of electrocatalysts in this process can effectively reduce the consumption of electrical energy. In this study, three molecular electrocatalysts based on nickel complexes, [BzTPP]2[Ni(mnt)2](1), [BzTPP]2[Ni(i-mnt)2](2), and [BzTPP]2[Ni(tdas)2](3) ([BzTPP]+ = 1-benzyltriphenylphosphinium, mnt = 1,2-dicyanoethylene-1,2-dithiolate, i-mnt = 1,1-dicyanoethylene-2,2-dithiolate and, and tdas = 1,2,5-thiadiazole-3,4-dithiolate), were systemically investigated. Electrochemical study showed three complexes can electrocatalyze hydrogen generation from acetic acid or aqueous buffer solution, and afford a turnover frequency (TOF) of 504.76, 591.52 and 1022.93 mol of hydrogen per mole of catalyst per hour at an overpotential (OP) of 0.838 V from a neutral buffer. It is shown that [NiII(tdas)2]2−exhibits higher electro-catalytic hydrogen production activity than [NiII(mnt)2]2− and [NiII(i-mnt)2]2−. This provides a new chemical paradigm for the design and fabrication of efficient molecular catalysts for water reduction.

VdW Mediated Strong Magnetic Exchange Interactions in Chains of Hydrogen-Free Sublimable Molecular Qubits.

Sulfur-rich molecular complexes of dithiolene-like ligands are appealing candidates as molecular spin qubits because spin coherence properties are enhanced in hydrogen-free environments. Herein, we employ the hydrogen-free mononegative 1,3,2-dithiazole-4-thione-5-thiolate (dttt-) ligand as an alternative to common dinegative dithiolate ligands. We report the first synthesis and structural characterization of its Cu2+, Ni2+, and Pt2+ neutral complexes. The XPS analysis of thermal deposition of [Cu(dttt)2] in UHV conditions indicates that films of intact molecules can be deposited on surfaces by sublimation. Thanks to a combined approach employing DC magnetometry and DFT calculations, we highlighted AF exchange interactions of 108 cm-1 and 36 cm-1 attributed to the two different polymorph phases. These couplings are exclusively mediated by S···S VdW interactions, which are facilitated by the absence of counterions and made particularly efficient by the diffuse electron density on S atoms. Furthermore, the spin dynamics of solid-state magnetically diluted samples was investigated. The longest observed T m is 2.3 μs at 30 K, which significantly diverges from the predicted T m > 100 μs. These results point to the diluting matrix severely affecting the coherence lifetime of Cu2+ species via different factors, such as the contributions of neighboring 14N nuclei and the formation of radical impurities in a non-completely controllable way. However, the ease of processing [Cu(dttt)2] via thermal sublimation can allow dispersion in matrices better suited for coherent spin manipulation of isolated molecules and the realization of AF-coupled VdW structures on surfaces.

Supramolecular Co(II) complexes based on dithiolate and dicarboxylate ligands: Crystal structures, theoretical studies, magnetic properties, and catalytic activity studies in photocatalytic hydrogen evolution

Two supramolecular Co(II)-based coordination compounds have been harvested from dithiolate and dicarboxylate ligands. They have been structurally characterized by FT-IR, elemental analysis, and single crystal X-ray diffraction. Salt 1 consists of two ([tris (2-aminoethyl) amine Co] 1,1-dicyano-2,2-ethylenedithiolate)+ per thiosulphate ion linked through intermolecular hydrogen bonds. Compound 2, (pyridine-2,6-dicarboxylate)2Co-5H2OCo).2H2O, is stabilized by intramolecular O−H···O hydrogen bonds, building ribbons that propagate along the [100] direction in the crystals. From HS analysis, it is observed that the major non-covalent interactions present in 1 are C−H···O, N−H···N, N−H···S, and N−H···O hydrogen bonds, which play an important role in stabilizing the crystal structure. In 2, out of all the non-covalent interactions, O···H/H···O interactions have major contributions to stabilize the crystal structure. Theoretical investigation on the molecular structures of the crystals also revealed that the major stabilizing factor for 1 is H-bonding along with π-π stacking while that for 2 is co-ordinate bond between water and cobalt(II) ion. Direct current variable-temperature magnetic susceptibility measurements carried out on polycrystalline samples of 1 and 2 in the temperature range of 1.8–300 K shows the presence of magnetic anisotropy of the cobalt(II) ion in 1 and weak intermolecular exchange in 2. Further, both the compounds 1 and 2 are found to be highly efficient water reduction catalysts in terms of per Co turn-over-numbers at lower concentrations.

Unique Thermal Structural Phase Transitions Exhibited by Unsymmetrical Organometallic Gold(III)‐Dithiolene Complexes with Pentylthio and Hexylthio Groups

AbstractUnsymmetrical gold(III)‐dithiolene complexes are potential candidates for molecular materials that exhibit thermal structural phase transitions. In this study, unsymmetrical ppy‐gold(III) (ppy−=C‐deprotonated‐2‐phenylpyridine(−)) complexes [AuC5] and [AuC6] coordinated by dithiolene ligands containing tetrathiafulvalene (TTF) skeletons with pentylthio (2‐{bis(pentylthio)‐1,3‐dithiol‐2‐ylidene}‐1,3‐dithiol‐4,5‐dithiolate(2−)) and hexylthio groups (2‐{bis(hexylthio)‐1,3‐dithiol‐2‐ylidene}‐1,3‐dithiol‐4,5‐dithiolate(2−)) were synthesized. Both complexes exhibited a large absorption band at approximately 508 nm, owing to intramolecular ligand‐to‐ligand charge transfer. One‐dimensional columnar structures with head‐to‐tail molecular arrangements around the metal ions were constructed in the crystals. The flexible alkylthio groups were intercalated into crystalline spaces between dithiolene ligands in the columns. [AuC5] exhibits a simple phase transition at 198 °C between crystalline and isotropic phases irreversibly. The crystalline phase of [AuC6] observed at 25 °C melted at 148 °C. Another crystalline phase grew above 148 °C with a very slow crystallization rate from the liquid phase and was completely transformed into an isotropic phase at 200 °C.

Bis[1,2-bis-(4-tert-butyl-phen-yl)ethyl-ene-1,2-di-thiol-ato(1-)]nickel(II) pentane 0.25-solvate.

The title compound, [Ni(C22H26S2)2], 1, is a square-planar D 2h -symmetric compound that occurs on a general position in non-centrosymmetric tetra-gonal P41212 (No. 92) with ¼ eq of n-pentane (C5H12) as co-crystallite. Intra-ligand bond lengths show the di-thiol-ene ligands to be in their half-oxidized radical monoanionic form. Inter-molecular t Bu-C-H⋯arenecentroid and t Bu-C-H⋯NiS2C2 centroid close contacts guide the packing arrangement for 1.

A highly conducting mixed-valence nickel bis(dithiolene) salt [Et4N][Ni(Me-thiazSe-dt)2]2 with selone substitution.

The prototypical [Ni(dmit)2] complex (dmit: 1,3-dithiole-2-thione-4,5-dithiolate) is modified here by combining the N-R substitution found in [Ni(R-thiazdt)2] complexes (R-thiazdt: N-alkyl-thiazoline-2-thione-4,5-dithiolate) and the selone substitution found in [Ni(dmiSe)2] complex (dmiSe: 1,3-dithiole-2-selone-4,5-dithiolate) to give a novel N-methyl substituted, radical anionic complex formulated as [Ni(Me-thiazSe-dt)2]1- (Me-thiazSe-dt: N-methyl-thiazoline-2-selone-4,5-dithiolate). Both this anionic complex and its mixed-valence Et4N+ salt crystallize with a rare cis arrangement of the two dithiolene ligands around the Ni atom. In the 1 : 2 [Et4N][Ni(Me-thiazSe-dt)2]2 salt, the complexes organize into dimerized chains well isolated from each other, giving the salt a strong one-dimensional character. It shows however a high RT conductivity of 4.6 S cm-1 and small activation energy of 33 meV, indicating a possible Mott insulator behavior, which is not suppressed under pressures up to 10 GPa.

Synthesis, structure, and mechanism of the isomers of ruthenium complexes based on HC≡CC(OH)(CH3)2 and ortho-Carborane dithiolate ligands

Treatment of 16-electron complex ( p -cymene)Ru(S 2 C 2 B 10 H 10 ) ( 1 ) with HC≡CC(OH)(CH 3 ) 2 in chloroform at −10 °C leads to two isomers ( p -cymene)Ru(S 2 C 2 B 10 H 9 )(CH 2 CC(OH)(CH 3 ) 2 ) ( 2 and 3 ), which are converted to the corresponding complexes ( p -cymene)Ru(S 2 C 2 B 10 H 9 )(CH 2 CC(CH 3 )CH 2 ) ( 4 and 5 ) by loss of a water molecule at 62 °C, respectively. These complexes were characterized by elemental analysis, mass, IR and NMR spectroscopy. X-ray structural analysis were performed on 4 and 5 . The formation mechanisms for the title complexes were also studied. • ● In chloroform, treatment of 16e complex ( p -cymene)Ru(S 2 C 2 B 10 H 10 ) with HC≡CC(OH)(CH 3 ) 2 at − 10 °C leads to two isomers ( p -cymene)Ru(S 2 C 2 B 10 H 9 )(CH 2 CC(OH)(CH 3 ) 2 ), which are converted to the corresponding complexes ( p -cymene)Ru(S 2 C 2 B 10 H 9 )(CH 2 CC(CH 3 )CH 2 ) by loss of a water molecule at 62 °C, respectively. • ● Both isomers ( p -cymene)Ru(S 2 C 2 B 10 H 9 )(CH 2 CC(CH 3 )CH 2 ) have been characterized by IR, NMR, MS, elemental analysis and single-crystal X-ray diffraction. • ● The formation mechanisms for the title complexes were studied. Treatment of 16-electron complex ( p -cymene)Ru(S 2 C 2 B 10 H 10 ) ( 1 ) with HC≡CC(OH)(CH 3 ) 2 in chloroform at − 10 °C leads to two isomers ( p -cymene)Ru(S 2 C 2 B 10 H 9 )(CH 2 CC(OH)(CH 3 ) 2 ) ( 2 and 3 ), which are converted readily to the corresponding complexes ( p -cymene)Ru(S 2 C 2 B 10 H 9 )(CH 2 CC(CH 3 )CH 2 ) ( 4 and 5 ) by loss of a water molecule at 62 °C. These complexes were characterized by elemental analysis, mass, IR and NMR spectroscopy. X-ray structural analysis were performed on 4 and 5 . The formation mechanisms for the title complexes were also studied. The complex 4 crystallizes in monoclinic system, space group P 2 1 /n with a = 11.082(2), b = 14.529(3), c = 15.230(3) Å , α = 90, β = 101.022(2), γ = 90°, C 17 H 30 B 10 RuS 2 , Mr = 507.70, V = 2407.1(9) Å 3 , Dc = 1.401 g/cm 3 , Z = 4, F (0 0 0) = 1032, µ (Mo Kα ) = 0.828 mm −1 , R = 0.0424 and ωR = 0.1089 for 4470 observed reflections ( I > 2 σ ( I )). The complex 5 crystallizes in monoclinic system, space group P 2 1 /c with a = 16.0543(16), b = 10.5758(11), c = 14.0954(14) Å , α = 90, β = 99.0430(10), γ = 90°, C 17 H 30 B 10 RuS 2 , Mr = 507.70, V = 2363.5(4) Å 3 , Dc = 1.427 g/cm 3 , Z = 4, F (0 0 0) = 1032, µ (Mo Kα ) = 0.844 mm −1 , R = 0.0444 and ωR = 0.1076 for 3745 observed reflections ( I > 2 σ ( I )).