Chalcogenido-Dimethylgallates and -Indates DMPyr2[Me2M(μ2−E)]2 (M=Ga,In; E=S,Se): Building Blocks for Higher and Lower Order Chalcogenidoindates

Metalation of the anions in the ionic liquids DMPyr[SH] and DMPyr[SeH] (DMPyr=1,1-dimethylpyrrolidinium) by trimethylgallium and trimethylindium is investigated. The reaction proceeds via pre-coordination of [EH]⁻, methane elimination and formation of an unprecedented series of chalcogenido metalates DMPyr₂[Me₂M(μ₂−E)]₂ (M=Ga, In; E=S, Se). These show the presences of dinuclear dianions with four-membered ring structures displaying highly nucleophilic bridging chalcogenide ligands in their crystallographically determined molecular structures. Some representative reactions of these building blocks with amphoteric electrophiles were studied: Addition of two equivalents of E(SiMe₃)₂ (E=S, Se) to the indates DMPyr₂[Me₂In(μ₂−S)]₂ and DMPyr₂[Me₂In(μ₂−Se)]₂ leads to a cleavage of the ring, E silylation and formation of mononuclear, monoanionic indates DMPyr[Me₂In(SSiMe₃)₂], DMPyr[Me₂In(SeSiMe₃)₂], and even a mixed sulfido-selenido dimethylindate DMPyr[Me₂In(SSiMe₃)(SeSiMe₃)]. Reaction of DMPyr₂[Me₂In(μ₂−S)]₂ with two equivalents of Lewis acid Me₃In leads to charge delocalization, ring expansion and formation of six-membered ring DMPyr₃[Me₂In(μ₂−S−InMe₃)]₃. The latter is a key intermediate in the formation of dianionic sulfidoindate DMPyr₂[(Me₂In)₆(μ₃−S)₄] displaying an unusual inverse heteroadamantane cage structure with four capping sulfido ligands.     

Homoleptic Isocyanide Metalates

Novelties and surprises in the chemistry of metal isocyanides : The synthesis and structure determination of homoleptic isocyanide metalates [M(CNXyl)_m]⁻ (M=Co, m=4; M=Mn, m=5; Xyl=2,6-Me₂C₆H₃) indicate that we need to revise our understanding of transition metal–isocyanide interactions. Further investigations will be required to determine whether these salts with isocyanide metalate ions display a chemistry as rich as that of the analogous carbonyl metalates.     

Structural Expansion of Chalcogenido Tetrelates in Ionic Liquids by Incorporation of Sulfido Antimonate Units

Multinary chalcogenido (semi)metalate salts exhibit finely tunable optical properties based on the combination of metal and chalcogenide ions in their polyanionic substructure. Here, we present the structural expansion of chalcogenido germanate(IV) or stannate(IV) architectures with Sb^III, which clearly affects the vibrational and optical absorption properties of the solid compounds. For the synthesis of the title compounds, [K₄(H₂O)₄][Ge₄S₁₀] or [K₄(H₂O)₄][SnS₄] were reacted with SbCl₃ under ionothermal conditions in imidazolium-based ionic liquids. Salt metathesis at relatively low temperatures (120 °C or 150 °C) enabled the incorporation of (formally) Sb³⁺ ions into the anionic substructure of the precursors, and their modification to form (Cat)₁₆[Ge₂Sb₂S₇]₆[GeS₄] ( 1 ) and (Cat)₆[Sn₁₀O₄S₂₀][Sb₃S₄]₂ ( 2 a and 2 b ), wherein Cat=(C₄C₁C₁Im)⁺ ( 1 and 2 a ) or (C₄C₁C₂Im)⁺ ( 2 b ). In 1 , germanium and antimony atoms are combined to form a rare noradamantane-type ternary molecular anion, six of which surround an {GeS₄} unit in a highly symmetric secondary structure, and finally crystallize in a diamond-like superstructure. In 2 , supertetrahedral oxo-sulfido stannate clusters are generated, as known from the ionothermal treatment of the stannate precursor alone, yet, linked here into unprecedented one-dimensional strands with {Sb₃S₄} units as linkers. We discuss the single-crystal structures of these uncommon salts of ternary and quaternary chalcogenido (semi)metalate anions, as well as their Raman and UV-visible spectra.     

Radical Anions,Radical-Anion Salts,and Anionic Complexes of 2,1,3-Benzochalcogenadiazoles

By means of cyclic voltammetry (CV) and DFT calculations, it was found that the electron-acceptor ability of 2,1,3-benzochalcogenadiazoles 1 – 3 (chalcogen: S, Se, and Te, respectively) increases with increasing atomic number of the chalcogen. This trend is nontrivial, since it contradicts the electronegativity and atomic electron affinity of the chalcogens. In contrast to radical anions (RAs) [ 1 ]^.− and [ 2 ]^.−, RA [ 3 ]^.− was not detected by EPR spectroscopy under CV conditions. Chemical reduction of 1 – 3 was performed and new thermally stable RA salts [K(THF)]⁺[ 2 ]^.− ( 8 ) and [K(18-crown-6)]⁺[ 2 ]^.− ( 9 ) were isolated in addition to known salt [K(THF)]⁺[ 1 ]^.− ( 7 ). On contact with air, RAs [ 1 ]^.− and [ 2 ]^.− underwent fast decomposition in solution with the formation of anions [ECN]⁻, which were isolated in the form of salts [K(18-crown-6)]⁺[ECN]⁻ ( 10 , E=S; 11 , E=Se). In the case of 3 , RA [ 3 ]^.− was detected by EPR spectroscopy as the first representative of tellurium–nitrogen π-heterocyclic RAs but not isolated. Instead, salt [K(18-crown-6)]⁺₂[ 3 -Te₂]²⁻ ( 12 ) featuring a new anionic complex with coordinate Te−Te bond was obtained. On contact with air, salt 12 transformed into salt [K(18-crown-6)]⁺₂[ 3 -Te₄- 3 ]²⁻ ( 13 ) containing an anionic complex with two coordinate Te−Te bonds. The structures of 8 – 13 were confirmed by XRD, and the nature of the Te−Te coordinate bond in [ 3 -Te₂]²⁻ and [ 3 -Te₄- 3 ]²⁻ was studied by DFT calculations and QTAIM analysis.     

Mössbauer study of some Fe-containing M6 and M5 clusters

Isomer shift (δ) and quadrupole splitting (Δ) parameters have been assigned to the iron sites in [FeRh₅(CO)₁₆]⁻, trans- and cis-[Fe₂Rh₄(CO)₁₆]²⁻, [Fe₃-Rh₃(CO)₁₇]³⁻, [FeRh₄(CO)₁₅]²⁻, [Fe₃Pt₃(CO)₁₅]²⁻ and [Fe₄M(CO)₁₆]²⁻ (M = Pd or Pt) from ⁵⁷Fe Mössbauer spectra recorded at 78 K. The data for the closo compounds [FeRh₅(CO)₁₆]⁻ and [Fe₂Rh₄(CO)₁₆]²⁻ are compared with those for [Fe₆(CO)₁₆C]²⁻. In [Fe₃Rh₃(CO)₁₇]³⁻, the three major Fe sites were identified. For both [Fe₄M(CO)₁₆]²⁻ compounds two isomers were shown to be present in the solid state.     

trans-[Pt(BCat')Me(PCy3)2]: an experimental case study of reductive elimination processes in Pt-Boryls through associative mechanisms

A stable trans‐(alkyl)(boryl) platinum complex trans‐[Pt(BCat′)Me(PCy₃)₂] (Cat′=Cat‐4‐tBu; Cy=cyclohexyl=C₆H₁₁) was synthesised by salt metathesis reaction of trans‐[Pt(BCat′)Br(PCy₃)₂] with LiMe and was fully characterised. Investigation of the reactivity of the title compound showed complete reductive elimination of Cat′BMe at 80 °C within four weeks. This process may be accelerated by the addition of a variety of alkynes, thereby leading to the formation of the corresponding η²‐alkyne platinum complexes, of which [Pt(η²‐MeCCMe)(PCy₃)₂] was characterised by X‐ray crystallography. Conversion of the trans‐configured title compound to a cis derivative remained unsuccessful due to an instantaneous reductive elimination process during the reaction with chelating phosphines. Treatment of trans‐[Pt(BCat′)Me(PCy₃)₂] with Cat₂B₂ led to the formation of CatBMe and Cat′BMe. In the course of further investigations into this reaction, indications for two indistinguishable reaction mechanisms were found: 1) associative formation of a six‐coordinate platinum centre prior to reductive elimination and 2) σ‐bond metathesis of B? B and C? Pt bonds. Mechanism 1 provides a straightforward explanation for the formation of both methylboranes. Scrambling of diboranes(4) Cat₂B₂ and Cat′₂B₂ in the presence of [Pt(PCy₃)₂], fully reductive elimination of CatBMe or Cat′BMe from trans‐[Pt(BCat′)Me(PCy₃)₂] in the presence of sub‐stoichiometric amounts of Cat₂B₂, and evidence for the reversibility of the oxidative addition of Cat₂B₂ to [Pt(PCy₃)₂] all support mechanism 2, which consists of sequential equilibria reactions. Furthermore, the solid‐state molecular structure of cis‐[Pt(BCat)₂(PCy₃)₂] and cis‐[Pt(BCat′)₂(PCy₃)₂] were investigated. The remarkably short B? B separations in both bis(boryl) complexes suggest that the two boryl ligands in each case are more loosely bound to the Pt^II centre than in related bis(boryl) species.     

Cationic complexes of trimethylplatinum(IV) with tridentate ligands—I. Preparation and characterization of complexes from a range of thio,seleno, thio-seleno,amino-thio and amino-seleno ligands

The new ionic complexes [PtMe₃{MeE(CH₂)_nE′(CH₂)_nEMe}]⁺X⁻ [n = 3; E = E′ = S : n = 2; E = Se or S; E′ = O, S, Se or SS: X = I, BPh₄ or BF₄] and [PtMe₃(H₂NCH₂CH₂)₂E′]+BF⁻₄ [E′ = O or SS] have been prepared and characterized by molar-conductivity measurements and ¹H NMR spectroscopy. The hitherto unreported ligands [(MeE(CH₂)_n)₂E′] (n = 3; E = E′ = S: n = 2; E = Se; E′ = O or S or Se: n = 2; E = S; E′ = Se] have been characterized by ¹H NMR and ⁷⁷Se NMR (where appropriate), and by mass spectroscopy.     

Treatment of Silylene–Phosphinidene with Chalcogens Resulted Exclusively in the Formation of Silicon-Bonded Chalcogens

Chalcogen-bonded silicon phosphinidenes LSi(E)−P−^MecAAC (E=S ( 1 ); Se ( 2 ); Te ( 3 ); L=PhC(NtBu)₂; ^MecAAC=C(CH₂)(CMe₂)₂N-2,6-iPr₂C₆H₃)) were synthesized from the reactions of silylene–phosphinidene LSi−P−^MecAAC ( A ) with elemental chalcogens. All the compounds reported herein have been characterized by multinuclear NMR, elemental analyses, LIFDI-MS, and single-crystal X-ray diffraction techniques. Furthermore, the regeneration of silylene–phosphinidene ( A ) was achieved from the reactions of 2 – 3 with L′Al (L′=HC{(CMe)(2,6-iPr₂C₆H₃N)}₂). Theoretical studies on chalcogen-bonded silicon phosphinidenes indicate that the Si−E (E=S, Se, Te) bond can be best represented as charge-separated electron-sharing σ-bonding interaction between [LSi−P−^MecAAC]⁺ and E⁻. The partial double-bond character of Si−E is attributed to significant hyperconjugative donation from the lone pair on E⁻ to the Si−N and Si−P σ*-molecular orbitals.     

Calculation of force constants and vibrational frequencies of octahedral MX6 molecules

The vibrational frequencies of some octahedral species ([SbX₆]⁻, [SbX₆]³⁻, [NbX₆]⁻, [NbX₆]²⁻, [TaX₆]⁻, [TaX₆]²⁻; X = F, Cl, Br, I) have been calculated by means of six extrapolated molecular force constants using some linear relations between the force constants and the reciprocal radii of the ligands. A statistical treatment of these correlations allowed the calculation of error limits for a probability of 90%. The computations of the force constants and vibrational frequencies were based on the GF-matrix method.     

Elucidating the Mechanism of Simultaneous Activation of CH4 and CO2 Mediated by Single Group 10 Metal Anions in Gas Phase

Quantum chemistry calculations predict that besides the reported single metal anion Pt⁻, Ni⁻ can also mediate the co-conversion of CO₂ and CH₄ to form [CH₃−M(CO₂)−H]^– complex, followed by transformation to C−C coupling product [H₃CCOO−M−H]⁻ ( A ), hydrogenation products [H₃C−M−OCOH]⁻ ( B ) and [H₃C−M−COOH]⁻. For Pd⁻, a fourth product channel leading to PdCO₂⁻…CH₄ becomes more competitive. For Ni⁻, the feed order must be CO₂ first, as the weaker donor-acceptor interaction between Ni⁻ and CH₄ increases the C−H activation barrier, which is reduced by [Ni−CO₂]⁻. For Ni⁻/Pt⁻, the highly exothermic products A and B are similarly stable with submerged barrier that favors B . The smaller barrier difference between A and B for Ni⁻ suggests the C−C coupling product is more competitive in the presence of Ni⁻ than Pt⁻. The charge redistribution from M⁻ is the driving force for product B channel. This study adds our understanding of single atomic anions to activate CH₄ and CO₂ simultaneously.     

B−B Bond Nucleophilicity in a Tetraaryl μ-Hydridodiborane(4) Anion

The tetraaryl μ-hydridodiborane(4) anion [ 2 H]⁻ possesses nucleophilic B−B and B−H bonds. Treatment of K[ 2 H] with the electrophilic 9-H-9-borafluorene (HBFlu) furnishes the B₃ cluster K[ 3 ], with a triangular boron core linked through two BHB two-electron, three-center bonds and one electron-precise B−B bond, reminiscent of the prominent [B₃H₈]⁻ anion. Upon heating or prolonged stirring at room temperature, K[ 3 ] rearranges to a slightly more stable isomer K[ 3 a ]. The reaction of M[ 2 H] (M⁺=Li⁺, K⁺) with MeI or Me₃SiCl leads to equimolar amounts of 9-R-9-borafluorene and HBFlu (R=Me or Me₃Si). Thus, [ 2 H]⁻ behaves as a masked [:BFlu]⁻ nucleophile. The HBFlu by-product was used in situ to establish a tandem substitution-hydroboration reaction: a 1:1 mixture of M[ 2 H] and allyl bromide gave the 1,3-propylene-linked ditopic 9-borafluorene 5 as sole product. M[ 2 H] also participates in unprecedented [4+1] cycloadditions with dienes to furnish dialkyl diaryl spiroborates, M[R₂BFlu].     

Origin of the different reactivity of the high-valent coinage-metal complexes [RCuiiiMe3]− and [RAgiiiMe3]− (R=allyl)**

High-valent tetraalkylcuprates(iii ) and -argentates(iii ) are key intermediates of copper- and silver-mediated C−C coupling reactions. Here, we investigate the previously reported contrasting reactivity of [RMⁱⁱⁱ Me₃]⁻ complexes (M=Cu, Ag and R=allyl) with energy-dependent collision-induced dissociation experiments, advanced quantum-chemical calculations and kinetic computations. The gas-phase fragmentation experiments confirmed the preferred formation of the [RCuMe]⁻ anion upon collisional activation of the cuprate(iii ) species, consistent with a homo-coupling reaction, whereas the silver analogue primarily yielded [AgMe₂]⁻, consistent with a cross-coupling reaction. For both complexes, density functional theory calculations identified one mechanism for homo coupling and four different ones for cross coupling. Of these pathways, an unprecedented concerted outer-sphere cross coupling is of particular interest, because it can explain the formation of [AgMe₂]⁻ from the argentate(iii ) species. Remarkably, the different C−C coupling propensities of the two [RMⁱⁱⁱ Me₃]⁻ complexes become only apparent when properly accounting for the multi-configurational character of the wave function for the key transition state of [RAgMe₃]⁻. Backed by the obtained detailed mechanistic insight for the gas-phase reactions, we propose that the previously observed cross-coupling reaction of the silver complex in solution proceeds via the outer-sphere mechanism.     

New PF3 and Carbonyl Chemistry of Tantalum

Reduction of [TaCl₅] by six equivalents of alkali metal naphthalenide in 1,2-dimethoxyethane at −60°C followed by treatment with gaseous PF₃ provides the first homoleptic phosphane complex containing tantalum in the −1 oxidation state, [Ta(PF₃)₆]⁻. This can be protonated by concentrated sulfuric acid to yield the previously unknown highly acidic and volatile hydride [HTa(PF₃)₆]. An improved normal-pressure synthesis of [Ta(CO)₆]⁻ is described. Reduction of the latter species by sodium in liquid ammonia gives the carbonyl trianion [Ta(CO)₅]³⁻ which undergoes monoprotonation and stannylation to form [HTa(CO)₅]²⁻ and [Ph₃SnTa(CO)₅]²⁻, respectively. The hydride is a useful precursor to [(Ph₃PAu)₃Ta(CO)₅], the only known gold cluster of tantalum.     

Darstellung und Eigenschaften der Diphthalocyaninate des Yttriums und Indiums

Synthesis and Properties of the Diphthalocyaninates of Yttrium and Indium Blue di(phthalocyaninato(2–))metalates of tervalent yttrium and indium are obtained by the reaction of yttrium acetate or anhydrous indium chloride with molten phthalodinitrile in the presence of potassium methylate and isolated as complex salts with organic cations. Anodic oxidation of (ⁿBu₄N)[M(Pc^2?)₂] (M = Y, In) yields crystals of green paramagnetic di(phthalocyaninato)metal(III)-dichloromethane solvate, [M(Pc)₂] · CH₂Cl₂ (μ_eff = 1.8/1.9 B.M. (Y/In)). Red brown di(phthalocyaninato)metal(III)-polybromide, [M(Pc^?)₂]Br_x is prepared by oxidation with bromine in excess. The redox properties of the di(phthalocyaninato)metalates(III) are investigated by cyclic voltammetry and difference pulse polarography. A quasi reversible (ΔE ? 60 mV) one electron process at 0.09 V (Y) and ?0.07 V (In) is assigned to the redox couple [M(Pc^2?)₂]^?/[M(Pc)₂]. Electronic absorption spectra as well as MIR/FIR and resonance Raman spectra are reported. The characteristic features of the three oxidation states and the influence of the ionic radius and the electron configuration of the metal ion are discussed.     

Potentiometric and spectroscopic study of copper(II) complexes with glycyl-glycyl-l-histidyl-l-alanine in aqueous solution

The complex formation between copper(II) and the tetrapeptide glycyl-glycyl-l-histidyl-l-alanine ([H₃L]²⁺) has been studied in aqueous solution at t = 25°C and I = 0.1 mol dm⁻³ by potentiometric, visible spectrophotometric and circular dichroism measurements. All the experimental techniques show that the complex [CuLH₋₂]⁻ is predominant over a wide pH range, while the monodentate [CuLH]²⁺ is formed in the acidic region and a further deprotonated [CuLH₋₃]²⁻ species exists at pH higher than 10. The formation constants of the three above complexes are reported and a structure is proposed on the basis of spectroscopic results. The structure of [CuLH₋₂]⁻ species very probably involves four nitrogen donors in the plane, excluding coordination by the l-alanine residue, while it seems likely that [CuLH₋₃]²⁻ is formed by simple dissociation of the N-1 pyrrole hydrogen.     

Chemistry of Palladium and Platinum with Selenium and Tellurium Ligands

Reactions of NaER (E = Se, Te; R = Ph, substituted Ph or 2-pyridyl) with a number of mono- and bi-nuclear palladium and platinum complexes have been investigated. Complexes of the type [M(Sepy)₂], [M(ER)₂(PR₃)₂], [M₂Cl₂(μ-ER)₂(PR₃)₂] and [M₂Cl₂(μ-Cl)(μ-ER)(PR₃)₂] (M = Pd, Pt) were isolated. They were characterized by elemental analysis, NMR (¹H, ¹³C, ³¹P, ⁷⁷Se, ¹²⁵Te, ¹⁹⁵Pt) data and in a few cases by X-ray diffraction studies. The [M(Sepy)₂(PPh₃)₂] dissociates into PPh₃ and [M(Sepy)(η²-Sepy)(PPh₃)] in solution. 2-Selenopyridine in its complexes acts in a monodentate (bonding through selenium) as well as in chelating (Se?N) or bridging fashion. The mononuclear complexes [M(ER)₂(PR₃)₂] are useful precursors for stepwise synthesis of cationic bi- and tri-nuclear derivatives.     

Synthesis and Characterization of Heteropolynuclear Redox Active Materials[FerCuCl]4YY′; Y?=?Y′?=?O, Y?=?Y′?=?Cat and Y?=?O, Y′?=?Cat, Fer?=?N,N-dimethylaminomethylferrocene and Cat?=?3,4,5,6-tetrachlorocatecholato Ligand

This paper describes the synthesis and characterization of heteropolynuclear redox active materials [FerCuCl]₄YY′, Y = Y′ = O, Y = Y′ = Cat and Y = O, Y′ = Cat, Fer = N,N-dimethylaminomethylferrocene and Cat = 3,4, 5,6-tetrachlorocatecholato ligand. Manometric O₂ uptake measurements in PhNO₂ show that tetranuclear [FerCuCl]₄ and [FerCuCl]₄Cat give the tetranuclear oxocopper(II) products [FerCuCl]₄O₂ and [FerCuCl]₄CatO, respectively. The absence of carbonyl stretching vibrational bands in [FerCuCl]₄Cat₂ and [FerCuCl]₄CatO suggest that tetrachloro-1,2-benzoquinone (TClBQ) is reduced to the corresponding catecholete during the oxidation of copper(I) centers in [FerCuCl]₄. The near i.r. electronic spectra for [FerCuCl]₄O₂, [FerCuCl]₄CatO and [FerCuCl]₄Cat₂ exhibit broad intense split maxima in the 750–875 nm range, attributed to a minimum of three halide ligands per Cu. Room temperature solid state e.p.r. spectra for [FerCuCl]₄CatO and [FerCuCl]₄Cat₂ are of the axial type, suggesting a square pyramidal geometry around Cu^II.     

Chalkogenoniobate als Ausgangsverbindungen zur Darstellung neuer heterobimetallischer Niobium‐Münzmetall‐Chalkogenido‐Cluster

Chalcogenoniobates as Reagents for the Synthesis of New Heterobimetallic Niobium Coinage Metal Chalcogenide Clusters In the presence of phosphine chalcogenoniobates such as Li₃[NbS₄] · 4 CH₃CN ( I ), (NEt₄)₄[Nb₆S₁₇] · 3 CH₃CN ( II ) and (NEt₄)₂[NbE′₃(E^tBu)] ( III a : E′ = E = S; III b : E = Se, E′ = S; III c : E = E′ = Se) respectively react with copper and gold salts to give a number of new heterobimetallic niobium copper(gold) chalcogenide clusters. These clusters show metal chalcogenide units already known from the complex chemistry of the tetrachalcogenometalates [ME₄]^n– (M = V, n = 3, E = S; M = Mo, W, n = 2, E = S, Se). The compounds 1 – 8 owe a central tetrahedral [NbE₄] structural unit, which coordinates η² from two to five coinage metal atoms, employing the chalcogenide atoms of the [NbE₄] edges. The compounds 9 – 11 have a [M′₂Nb₂E₄] (M′ = Cu, Au) heterocubane unit in common, involving a metal metal bond between the niobium atoms, while the compounds 12 and 13 show a complete and 14 an incomplete [M′₃NbE₃X] heterocubane structure (X = Cl, Br). 15 consists of a Cu₆Nb₂ cube with the six planes capped by μ₄ bridging selenide ligands forming an octahedra. The compounds 1 – 15 are listed below: (NEt₄) [Cu₂NbSe₂S₂(dppe)₂] · 2 DMF ( 1 ), [Cu₃NbS₄(PPh₃)₄] ( 2 ), [Au₃NbSe₄(PPh₃)₄] · Et₂O ( 3 ), [Cu₄NbS₄Cl(PCy₃)₄] ( 4 ), [Cu₄NbS₄Cl(P^tBu₃)₄] · 0,5 DMF ( 5 ), [Cu₄NbSe₄(NCS)(P^tBu₃)₄] · DMF ( 6 ), [Cu₄NbS₄(NCS)(dppm)₄] · Et₂O ( 7 ), [Cu₅NbSe₄Cl₂‐ (dppm)₄] · 3 DMF ( 8 ), [Cu₂Nb₂S₄Cl₂(PMe₃)₆] · DMF ( 9 ), [Au₂Nb₂Se₄Cl₂(PMe₃)₆] · DMF ( 10 ), (NEt₄)₂[Cu₃Nb₂S₄(NCS)₅(dppm)₂(dmf)] · 4 DMF ( 11 ), [Cu₃NbS₃Br(PPh₃)₃(dmf)₃]Br · [CuBr(PPh₃)₃] · PPh₃ · OPPh₃ · 3 DMF ( 12 ), [Cu₃NbS₃Cl₂(PPh₃)₃(dmf)₂] · 1.5 DMF ( 13 ), (NEt₄)[Cu₃NbSe₃Cl₃(dmf)₃] ( 14 ), [Cu₆Nb₂Se₆O₂(PMe₃)₆] ( 15 ). The structures of these compounds were obtained by X‐ray single crystal structure analysis.     

Structural Consequences of S → Se Substitution in some Symmetrical [M(S2CNR2)3] Complexes

The consequences of replacement of the symmetrically chelate ligands in [M(E₂CNR₂)₃] (E = S, Se) complexes of potential 32 symmetry by analogous mixed S,Se unsymmetrical chelates are explored for both small (M = Co) and large (M = In) metal atoms, and R = primary (Et) and secondary (ⁱPr) alkyl substituents by way of low‐temperature single crystal X‐ray studies of [(Co(SSeCNEt₂)₃] ([Co(Se₂CNEt₂)₃] also determined as datum), and [In(SSeCNR₂)₃], R = Et, ⁱPr. The structure of [(ⁱPr₂N·CS·Se)₂] is also recorded.