Silanylidene and Germanylidene Anions: Valence‐Isoelectronic Species to the Well‐Studied Phosphinidene

The reduction of TipMCl₃ (Tip=2,4,6‐triisopropylphenyl) (M=Si, Ge) with KC₈ in the presence of cyclic alkyl(amino) carbene (cAAC) afforded the acyclic silanylidene and germanylidene anions in the form of potassium salt [K(cAAC)MTip]₂ (M=Si ( 1 ); Ge ( 2 )). The silanylidene and germanylidene anions are valence‐isoelectronic to the well‐studied phosphinidene and are a new class of acyclic anions of Group 14. Compounds 1 and 2 were isolated and well characterized by NMR and single‐crystal X‐ray structure analysis. Furthermore, the structure and bonding of compounds 1 and 2 was investigated by computational methods.     

trans-Bis(3-aminoflavone-κ2N,O)bis(perchlorato-κO)copper(II), a new potential antitumour agent

The title compound, trans-bis(3-amino-2-phenyl-4H-1-benzopyran-4-one-κ²N,O⁴)bis(perchlorato-κO)copper(II), [Cu(ClO₄)₂(C₁₅H₁₁NO₂)₂], is composed of mononuclear units wherein the central Cu^II cation occupies a crystallographic inversion centre. The cation is coordinated by two bidentate 3-aminoflavone ligands occupying the equatorial sites and by two perchlorate anions in the apical positions, thereby giving rise to a markedly elongated octahedral coordination geometry. Two symmetry-related intermolecular N—H...O hydrogen bonds link the molecules into chains of rings running parallel to the [100] direction, while intramolecular N—H...O hydrogen bonds help to determine the orientation of the apical perchlorate anions.     

Asymmetric Synthesis and Configurational Stability of C2‐Symmetric Hexacoordinated Phosphate Anions (TARPHATs) with Predetermined Chirality from Tartrate Esters

C₂‐Symmetric TARPHAT anions 5 made of a central P^V atom, one tartrato (=dialkyl 2,3‐di(hydroxy‐κO)butanedioato(2−)), and two tetrachloropyrocatecholato (=3,4,5,6‐tetrachlorobenzene‐1,2‐diolato(2−)‐κO,κO′) ligands can be easily prepared in decent to high yields (50–86%) as their dimethylammonium salt by using a one‐pot process and simple commercially available starting materials. The presence of the chiral tartrato ligands (usually (2R,3R)) leads to the formation of diastereoisomeric anions ((Δ,2R,3R)/(Λ,2R,3R)). Decent to good control by the chiral ligands – under equilibration conditions – over the Λ or Δ configuration of the adducts was observed (d.r. 84 : 16 in CHCl₃ for the di(tert‐butyl) tartrate derivative), the selectivity depending on the nature of the ester chains as well as on the solvent.     

N,N,N′-Tri­methyl­ethyl­enediammonium dichloride

The title compound, C₅H₁₆N₂²⁺·2Cl⁻, was isolated as a by-product from the reaction between trimethylethyl­enedi­amine and germanium tetrachloride in the presence of triethyl­amine. The asymmetric unit contains two cations, one in the gauche and the other in the trans conformation; these conformations are stabilized by hydrogen-bonding interactions between the N—H moieties and the chloride anions.     

Molecular Ln(III)−H−E(II) Linkages (Ln=Y,Lu; E=Ge,Sn, Pb)

Following the alkane-elimination route, the reaction between tetravalent aryl tintrihydride Ar*SnH₃ and trivalent rare-earth-metallocene alkyls [Cp*₂Ln(CH{SiMe₃}₂)] gave complexes [Cp*₂Ln(μ-H)₂SnAr*] implementing a low-valent tin hydride (Ln=Y, Lu; Ar*=2,6-Trip₂C₆H₃, Trip=2,4,6-triisopropylphenyl). The homologous complexes of germanium and lead, [Cp*₂Ln(μ-H)₂EAr*] (E = Ge, Pb), were accessed via addition of low-valent [(Ar*EH)₂] to the rare-earth-metal hydrides [(Cp*₂LnH)₂]. The lead compounds [Cp*₂Ln(μ-H)₂PbAr*] exhibit H/D exchange in reactions with deuterated solvents or dihydrogen.     

The Insertion of EII and EIV Chlorides (E=Si,Ge) into the Si−Si Bond of Disilylene

Reactions of silicon and germanium dichlorides L ⋅ ECl₂ (E=Si, L=IPr; E=Ge, L=dioxane) with the phosphinoamidinato-supported disilylene ({κ²(N,P)-NNP}Si)₂ resulted in formal tetrylene insertions into the Si−Si bond. In the case of the reaction with silylene, two products were isolated. The first product ({κ²(N,P)-NNP}Si)₂SiCl₂, is the formal product of direct SiCl₂ insertion into the Si−Si bond of ({κ²(N,P)-NNP}Si)₂ and thus features two separated silylamido silylene centers. Over time, migration of the SiCl₂ group to a lateral position afforded the second product, the disilylene {κ²(Si,P)−SiCl₂NNP}Si−Si{κ²(N,P)-NNP}. In contrast, insertion of GeCl₂ resulted only in the isolation of the germanium analogue of {κ²(Si,P)−SiCl₂NNP}Si−Si{κ²(N,P)-NNP}, containing a Ge atom in the central position namely, compound {κ²(Si,P)−SiCl₂NNP}Ge−Si{κ²(N,P)-NNP}, which is a rare example of a silylene-germylene. Finally, reaction of disilylene ({κ²(N,P)−NNP}Si)₂ with SiCl₄ and SiHCl₃ led to the formation of the new bis(silyl)silylene, ({NNP}SiCl₂)₂Si:. All four new products from these insertion reactions have been characterized by multinuclear NMR and single-crystal X-ray diffraction studies.     

Synthesis of Low-Valent Dinuclear Group 14 Compounds with Element–Element Bonds by Transylidation

Dinuclear low-valent compounds of the heavy main group elements are rare species owing to their intrinsic reactivity. However, they represent desirable target molecules due to their unusual bonding situations as well as applications in bond activations and materials synthesis. The isolation of such compounds usually requires the use of substituents that provide sufficient stability and synthetic access. Herein, we report on the use of strongly donating ylide-substituents to access low-valent dinuclear group 14 compounds. The ylides not only impart steric and electronic stabilization, but also allow facile synthesis via transfer of an ylide from tetrylene precursors of type ^RY₂E to ECl₂ (E=Ge, Sn; ^RY=TolSO₂(PR₃)C with R=Ph, Cy). This method allowed the isolation of dinuclear complexes amongst a germanium analogue of a vinyl cation, [(^PhY)₂GeGe(^PhY)]⁺ with an electronic structure best described as a germylene-stabilized Ge^II cation and a ylide(chloro)digermene [^CyY(Cl)GeGe(Cl)^CyY] with an unusually unsymmetrical structure.     

The Unprecedented Tetrakis‐(disulfato)‐silicate Anion [Si(S2O7)4]4−, its Germanium Congener [Ge(S2O7)4]4−, and the Tris‐(disulfato)‐metallates [M(S2O7)3]2− (M=Si,Ge, Ti), Stabilized by Divalent Counter Cations B2+ (B=Sr,Ba, Pb)

The reaction of oleum (65 % SO₃) with the tetrachlorides of silicon, germanium, and titanium, respectively, led to the complex disulfates Sr₂[M(S₂O₇)₄] (M=Si, Ge), Ba[M(S₂O₇)₃] (M=Si, Ge, Ti) and Pb[M(S₂O₇)₃] (M=Ge, Ti) if strontium, barium, and lead were used as divalent counter cations. The strontium compounds exhibit the unique tetrakis‐(disulfato)‐metallate anions [M(S₂O₇)₄]^4? with the silicon and germanium atoms in octahedral coordination of two chelating and two monodentate disulfate groups. All of the other compounds display tris‐(disulfato)‐metallate anions [M(S₂O₇)₃]^2? with three chelating disulfate groups surrounding the M atoms. Thermoanalytical investigations on the germanium compounds Sr₂[Ge(S₂O₇)₄] and Ba[Ge(S₂O₇)₃] revealed their decomposition in multi‐step processes leading to a mixture of BSO₄ and BGe₄O₉ (B=Sr, Ba), while the thermal degradation of Pb[Ti(S₂O₇)₃] yields PbTiO₃. For selected examples, IR data are additionally presented.     

BDH-TTP as a Structural Isomer of BEDT-TTF,and Its Two-Dimensional Hexafluorophosphate Salt

Metallic behavior down to low temperature is shown by charge transfer salts of BDH-TTP ( 1 ), a structural isomer of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF). In the case of (BDH-TTP)₂PF₆ this behavior is attributed to the structure, which is made up of κ-type sheets of BDH-TTP donor molecules and sheets of PF₆⁻ anions.     

Accessing Ta/Cu Architectures via Metal-Metal Salt Metatheses: Heterobimetallic C−H Bond Activation Affords μ-Hydrides

We employ a metal-metal salt metathesis strategy to access low-valent tantalum-copper heterometallic architectures (Ta−μ₂-H₂−Cu and Ta−μ₃-H₂−Cu₃) that emulate structural elements proposed for surface alloyed nanomaterials. Whereas cluster assembly with carbonylmetalates is well precedented, the use of the corresponding polyarene transition metal anions is underexplored, despite recognition of these highly reactive fragments as storable sources of atomic Mⁿ⁻. Our application of this strategy provides structurally unique early-late bimetallic species. These complexes incorporate bridging hydride ligands during their syntheses, the origin of which is elucidated via detailed isotopic labelling studies. Modification of ancillary ligand sterics and electronics alters the mechanism of bimetallic assembly; a trinuclear complex resulting from dinuclear C−H activation is demonstrated as an intermediate en route to formation of the bimetallic. Further validating the promise of this rational, bottom-up approach, a unique tetranuclear species was synthesized, featuring a Ta centre bearing three Ta−Cu interactions.     

Enhanced Anion Binding from Unusual Coordination Modes of Bis(thiourea) Ligands in Platinum Group Metal Complexes

Treatment of a range of bis(thiourea) ligands with inert organometallic transition‐metal ions gives a number of novel complexes that exhibit unusual ligand binding modes and significantly enhanced anion binding ability. The ruthenium(II) complex [Ru(η⁶‐p‐cymene)(κS,S′,N‐ L³ ?H)]⁺ ( 2 b ) possesses juxtaposed four‐ and seven‐membered chelate rings and binds anions as both 1:1 and 2:1 host guest complexes. The pyridyl bis(thiourea) complex [Ru(η⁶‐p‐cymeme)(κS,S′,N_py‐ L⁴ )]²⁺ ( 4 ) binds anions in both 1:1 and 1:2 species, whereas the free ligand is ineffective because of intramolecular NH???N hydrogen bonding. Novel palladium(II) complexes with nine‐ and ten‐membered chelate rings are also reported.     

Diamondoid framework solid with Sn(OCH3)2–tetrapyridylporphyrin linkers,CuI nodes and [CuICl2]− counter‐ions

We report on the synthesis of a new metal–organic framework (MOF) composed of Sn(OCH₃)₂–tetrakis(pyridin‐4‐yl)porphyrin linkers, Cu⁺ connecting nodes and [CuCl₂]⁻ counter‐ions, namely poly[[bis(methanolato‐κO)[μ₅‐5,10,15,20‐tetrakis(pyridin‐4‐yl)porphyrin‐κ⁸1κN⁵:1′κN¹⁰:1′′κN¹⁵:1′′′κN²⁰:2κ⁴N²¹,N²²,N²³,N²⁴]copper(I)tin(II)] dichloridocuprate(I)], [CuSn(C₄₀H₂₄N₈)(CH₃O)₂][CuCl₂]. Its crystal structure consists of a single‐framework coordination polymer of the organic ligand and the Cu^I ions. The latter are characterized by a tetrahedral coordination geometry [with CN (coordination number) = 4], linking to the pyridyl N‐atom sites of four different ligands and imparting to the positively charged polymeric assembly a diamondoid PtS‐type topology. Correspondingly, every porphyrin unit is coordinated to four different Cu^I connectors. The [CuCl₂]⁻ anions occupy the intra‐lattice voids, along with disordered molecules of the water crystallization solvent. The asymmetric unit of this structure consists of two halves of the porphyrin scaffold, located on centres of crystallographic inversion, and the Cu⁺ and [CuCl₂]⁻ ions. This report provides unique structural evidence for the formation of tetrapyridylporphyrin‐based three‐dimensional MOFs with a diamondoid architecture that have been observed earlier only on rare occasions.     

The one‐dimensional structure of Cu(dmen)2Pd(CN)4 (dmen is N,N‐di­methyl­ethyl­enedi­amine)

The title compound, catena‐poly­[[μ‐cyano‐1:2κ²C:N‐dicyano‐1κ²C‐bis(N,N‐di­methyl­ethyl­enedi­amine‐2κ²N,N′)­pallad­ium(II)­copper(II)]‐μ‐cyano‐1:2′κ²C:N], [CuPd(CN)₄(C₄H₁₂N₂)₂]_n, consists of infinite quasi‐linear chains with all metal positions on centers of symmetry. The paramagnetic [Cu(dmen)₂]²⁺ cations are linked by diamagnetic [Pd(CN)₄]²⁻ anions via bridging cyano groups, which occupy trans positions in both cation and anion, giving rise to 2,2‐TT‐type chains. The coordination polyhedron of the paramagnetic Cu atom is an octahedron exhibiting typical elongation due to the Jahn–Teller effect, with two longer Cu—N([triple‐bond]C) bonds in the axial positions [2.5528 (13) Å] and four shorter Cu—N_dmen bonds (dmen is N,N‐dimethylethylenediamine) in the equatorial plane [1.9926 (11) and 2.1149 (12) Å]. The Cu—N[triple‐bond]C angle is 138.03 (12)°. Neighboring chains form weak N—H⋯NC hydrogen bonds.     

New Rare‐Earth Metal Germanides RE2Ge9 (RE = Nd,Sm) by Thermal Decomposition of High‐Pressure Phases REGe5

The rare‐earth metal germanides RE₂Ge₉ (RE = Nd, Sm) have been prepared by thermal decomposition of the metastable high‐pressure phases REGe₅ at ambient pressure. The compounds adopt an orthorhombic unit cell with a = 396.34(4) pm; b = 954.05(8) pm and c = 1238.4(1) pm for Nd₂Ge₉ and a = 395.46(7) pm; b = 946.4(2) pm and c = 1232.1(3) pm for Sm₂Ge₉. Crystal structure refinements reveal space group Pmmn (No. 59) for Nd₂Ge₉. The atomic pattern resembles an ordered defect variety of the pentagermanide motif REGe₅ (RE = La; Nd, Sm, Gd, Tb) comprising corrugated germanium layers. These condense into a three‐dimensional network interconnected by eight‐coordinated germanium atoms. The resulting framework channels along [100] enclose the neodymium atoms. With respect to the atomic arrangement of the pentagermanides, half of the interlayer germanium atoms are eliminated in an ordered way so that occupied and empty germanium columns alternate along [001]. The rare‐earth metal atoms of both types of compounds, REGe₅ and RE₂Ge₉, exhibit the electronic states 4f ³ and 4f ⁵ (oxidation state +3) for neodymium and samarium, respectively, evidencing that the modification of the germanium network leaves the electron configuration of the metal atoms unaffected.     

Zinc(II) and cadmium(II) chloride complexes with 4,4′‐bi‐1,2,4‐triazole

New coordination compounds with the 4,4′‐bi‐1,2,4‐triazole ligand (btr), namely tetraaqua‐2κ⁴O‐di‐μ₂‐4,4′‐bi‐1,2,4‐triazole‐1:2κ²N¹:N^1′;2:3κ²N¹:N^1′‐hexachlorido‐1κ³Cl,3κ³Cl‐trizinc(II), [Zn₃Cl₆(C₄H₄N₆)₂(H₂O)₄], (I), and poly[cadmium(II)‐μ₂‐4,4′‐bi‐1,2,4‐triazole‐κ²N¹:N²‐di‐μ₂‐chlorido], [CdCl₂(C₄H₄N₆)]_n, (II), reveal an unprecedented molecular zwitterionic structure for (I) and a polymeric two‐dimensional layer structure for (II). Differences between these products, which involve the formation of either charge‐separated chlorometallate/aquametal fragments or complementary organic and inorganic bridges, are attributable to the hardness–softness characters of the metal cations. In (I), two N¹,N^1′‐bidentate btr molecules connect one [Zn(H₂O)₄]²⁺ cation and two [ZnCl₃]⁻ anions into a linear trizinc motif (the Zn atom of the cation occupies a centre of inversion in an N₂O₄ coordination octahedron, whereas the Zn atom of the anion possesses a distorted tetrahedral Cl₃N environment). In (II), the distorted vertex‐sharing CdCl₄N₂ octahedra are linked into binuclear [Cd₂(μ₂‐Cl)(μ₂‐btr)₂]³⁺ fragments by unprecedented N¹:N²‐bidentate btr double bridges and bridging chloride ligands, while the additional chloride anions are also bridging, providing further propagation of the fragments into a two‐dimensional network [Cd—Cl = 2.5869 (2)–2.6248 (7) Å].     

Synthesis,Crystal, and Electronic Structure of the New Ternary Zintl Phase Eu2–xMg2–yGe3 (x = 0.1; y = 0.5)

The new ternary phase Eu_2–xMg_2–yGe₃ (x = 0.1, y = 0.5) was obtained by solid‐state synthesis and the structure determined by means of Single Crystal X‐ray Diffraction. The compound crystallizes with the orthorhombic space group Cmcm (no. 63) having structural features of the low‐temperature modification of LaSi. The crystal structure contains two different types of germanium anions: isolated Ge^4– and $\rm^{2}_{\infty}$ [Ge^2–x–y] chains. The cation substructure is partially disordered and is best represented assuming a split position. The chemical bonding is well represented by the Zintl‐Klemm concept. Resistivity measurements reveal that the compound is metallic. DFT band structure calculations were carried out on the ideal stoichiometric compound Eu₂Mg₂Ge₃, showing that this model (x = 0; y = 0) would be also metallic as a consequence of the ecliptic stacking of anions. Susceptibility and specific heat measurements evidence the presence of weak, and probably frustrated, antiferromagnetic interactions between disordered europium atoms.     

Micropattern of GeO2/GeC lines prepared by UV irradiation and heat treatment of polygermane copolymers of methylphenylgermylene/phenylgermyne units

Upon ultraviolet irradiation of polygermane copolymers of methylphenylgermylene/phenylgermyne units (PhMeGe)_n(PhGe)_m in air, the germanium–germanium bond in the copolymer film changed into a digermoxane chain. Laser flash photolysis of the copolymer film showed the intermediacy of polygermyl radicals generated by Ge–Ge bond homolysis. The XPS showed the formation of germanium carbide (GeC) and germanium dioxide (GeO₂) upon heating the unirradiated and irradiated copolymer (PhMeGe)_n(PhGe)_m films, respectively. A relatively high-resolution micro- pattern of GeC/GeO₂ was obtained by combining the photochemical and thermal properties of the copolymers of methylphenylgermylene/phenylgermyne units. © 1997 John Wiley & Sons, Ltd.     

Tetrameric indium trichloride,a new modification of a widely used compound

The title compound, hexa‐μ‐chloro‐1:2κ⁴Cl;2:3κ⁴Cl;3:4κ⁴Cl‐hexachloro‐1κ²Cl,2κCl,3κCl,4κ²Cl‐hexakis­(diethyl­amine)‐1κ²N,2κN,3κN,4κ²N‐tetraindium(III), [(InCl₃)₄(Et₂NH)₆] or [In₄Cl₁₂(C₄H₁₁N)₆], lies about an inversion centre and consists of four octahedrally coordinated In centres linked by bridging Cl atoms to form three four‐membered In₂Cl₂ rings.     

A Potential Method Using Ge{iPrNC[N(SiMe3)2]NiPr}2, (Et3Si)2Te and Anhydrous Hydrazine for Germanium Tellurides

A germanium(II)‐guanidine derivative of formula Ge{iPrNC[N(SiMe₃)₂]NiPr}₂ ( 1 ) was synthesized and characterized by ¹H NMR, ¹³C NMR, elemental analysis, and X‐ray diffraction method. Thermal property was also studied to identify its thermal stability and volatility. More importantly, compound 1 was synthesized to develop a new method for germanium tellurides, where anhydrous hydrazine was introduced to prompt the activity of germanium(II) guanidines (or derivatives) towards (Et₃Si)₂Te. Solution reaction of compound 1 , (Et₃Si)₂Te, and anhydrous hydrazine was investigated to pre‐identify the feasibility of this combination for ALD process. The EDS data of the black precipitate from this reaction verified the potential of this method to manufacture germanium tellurides.     

catena‐Poly[potassium [copper(II)‐μ‐isothiocyanato‐μ‐N‐salicylidene‐β‐alaninato(2–)]]

The title polymeric compound, catena‐poly­[dipotassium [bis­[μ‐N‐salicyl­idene‐β‐alaninato(2−)]‐κ⁴O,N,O′:O′′;κ⁴O′′:O,N,O′‐dicopper(II)]‐di‐μ‐iso­thio­cyanato‐κ²N:S;κ²S:N], {K[Cu(NCS)(C₁₀H₉NO₃)]}_n, consists of [iso­thio­cyanato(N‐salicyl­idene‐β‐alaninato)copper(II)]⁻ anions connected through the two three‐atom thio­cyanate (μ‐NCS) and the two anti,anti‐μ‐­carboxyl­ate bridges into infinite one‐dimensional polymeric anions, with coulombically interacting K⁺ counter‐ions with coordination number 7 constrained between the chains. The Cu^II atoms adopt a distorted tetragonal–bipyramidal coordination, with three donor atoms of the tridentate Schiff base and one N atom of the bridging μ‐NCS ligand in the basal plane. The first axial position is occupied by a thio­cyanate S atom of a symmetry‐related μ‐NCS ligand at an apical distance of 2.9770 (8) Å, and the second position is occupied by an O atom of a bridging carboxyl­ate group from an adjacent coordination unit at a distance of 2.639 (2) Å.