[Ge9{Si(SiMe3)3}2{Ge(SiMe3)3}]–: The Mixed Substituted Metalloid Germanium Cluster and the Intermetalloid Cluster [ZnGe18{Si(SiMe3)3}4{Ge(SiMe3)3}2]

The novel metalloid germanium cluster [Ge₉(Hyp)₂Hyp^Ge]^– ( 1 ) was synthesized, exhibiting two different bulky groups [Hyp = Si(SiMe₃)₃; Hyp^Ge = Ge(SiMe₃)₃]. Further reaction of 1 with ZnCl₂ gives the derivative [ZnGe₁₈(Hyp)₄(Hyp^Ge)₂] ( 2 ) in good yield, showing that the substitution of Si(SiMe₃)₃ by Ge(SiMe₃)₃ within a metalloid Ge₉R₃^– compound leads to a comparable reactivity. 1 and 2 are characterized by NMR spectroscopy, mass spectrometry ( 1 ) and single crystal structure analyses ( 2 ). 1 and 2 are the first metalloid germanium clusters bearing germyl groups.     

Probing the aromaticity in 2,3-pyrido-annulated N-heterocyclic carbene and its heavier analogues

The aromaticity in 2,3-pyrido-annulated 1,3,2λ²-diazatetroles C₅H₃N(NR)₂E^II (E^II = C, Si, Ge, Sn, Pb) was studied using a set of experimental and calculated criteria: UV-VIS, Raman, ISE, NICS, GIMIC and EDDB. The data obtained indicate either a slight decrease in aromaticity (NICS, GIMIC, ISE methods) or equal aromaticity (UV-VIS, ISE methods) compared to benzo-annulated analogues C₆H₄(NR)₂E. The π-aromaticity increases down the group from Si to Pb.     

Gemischtligandkomplexe des Nickel(0) und Kobalt(I) mit anionischen Liganden des Typs E(C6H5)3− (E  Ge,Sn, Pb)

Mixed Ligand Complexes of Nickel(0) and Cobalt(I) with the Anionic Ligands E(C₆H₅)₃^? (E ? Ge, Sn, Pb) Complexes of the general formula M^INi(PPh₃)₃(EPh₃)(THF)_x (E ? Ge[Ia], Sn[Ib], Pb[Ic]) and M^I₃Ni(PPh₃)(EPh₃)₃(THF)_x (E ? Ge[IIa], Sn[IIb]) are formed from (Ph₃P)₂Ni(C₂H₄) by substitution with M^IEPh₃. The analogous complexes of the ligand SiPh₃^? could not be prepared, because of the formation of SiPh₄ from LiSiPh₃ and coordinated PPh₃. Attempts to synthesize a nickel(II) complex of the ligand SnPh₃^? had no success, only possible decomposition products of these compounds, like (nBu₂PPh)₂Ni^II(Ph)Cl and Na_xNi°(PPh₃)_4?x(SnP₄)_x(THF)_Y, were isolated. NaCo^I(PPh₃)₂(SnPh₃)₂(THF)₇ (IV) was prepared by the reaction of Co(PPh₃)₃Cl and NaSnPh₃. ¹H-NMR and ¹¹⁹Sn Mössbauer spectra show a higher donor action of SnPh₃^? in IIb than in Ib. This causes a stronger π-back donation Ni → P in the case of IIb. IV is a paramagnetic compound, the vis-spectrum is discussed using simple crystal field theory.     

On the Reactivity of Silylated Ge9 Clusters: Synthesis and Characterization of [ZnCp*(Ge9{Si(SiMe3)3}3)], [CuPiPr3(Ge9{Si(SiMe3)3}3)], and [(CuPiPr3)4{Ge9(SiPh3)2}2]

We report on the synthesis of new derivatives of silylated clusters of the type [Ge₉(SiR₃)₃]^? (R = SiMe₃, Me = CH₃; R = Ph, Ph = C₆H₅) as well as on their reactivity towards copper and zinc compounds. The silylated cluster compounds were synthesized by heterogeneous reactions starting from the Zintl phase K₄Ge₉. Reaction of K[Ge₉{Si(SiMe₃)₃}₃] with ZnCl₂ leads to the already known dimeric compound [Zn(Ge₉{Si(SiMe₃)₃}₃)₂] ( 1 ), whereas upon the reaction with [ZnCp*₂] the coordination of [ZnCp*]⁺ to the cluster takes place (Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) under the formation of [ZnCp*(Ge₉{Si(SiMe₃)₃}₃)] ( 2 ). A similar reaction leads to [CuPiPr₃(Ge₉{Si(SiMe₃)₃}₃)] ( 3 ) from [CuPiPr₃Cl] (iPr=isopropyl). Further we investigated the novel silylated cluster units [Ge₉(SiPh₃)₃]^? ( 4 ) and [Ge₉(SiPh₃)₂]^? ( 5 ), which could be identified by mass spectroscopy. Bis‐ and tris‐silylated species can be synthesized by the respective stoichiometric reactions, and the products were characterized by ESI‐MS and NMR experiments. These clusters show rather different reactivity. The reaction of the tris‐silylated anion 4 with [CuPiPr₃Cl] leads to [(CuPiPr₃)₃Ge₉(SiPh₃)₂]⁺ as shown from NMR experiments and to [(CuPiPr₃)₄{Ge₉(SiPh₃)₂}₂] ( 6 ), which was characterized by single‐crystal X‐ray diffraction. Compound 6 shows a new type of coordination of the Cu atoms to the silylated Zintl clusters.     

Stabilization Studies on Divalent Five‐Membered Rings C4H4C,C4H4Si,C4H4Ge,C4H4Sn,and C4H4Pb

Energy differences, ΔX_S‐t (X = E, H and G) (ΔX_S‐t = X_(singlet)‐X_(triplet)) between singlet (s) and triplet (t) states are calculated at B3LYP/6‐311++G (3df,2p). The DFT calculations show that the triplet state of C₄H₄C is a ground state with planar conformer respect to its corresponding nonplanar singlet state. Both singlet and triplet states of C₄H₄M (M = Si, Ge, Sn and Pb) have a planar conformer with the singlet ground state. Four isodesmic reactions are presented for determining the stability energies, SE. NICS calculations are carried out for C₄H₄M to determine the aromatic character.     

The Largest Metalloid Group 14 Cluster,Ge18[Si(SiMe3)3]6: An Intermediate on the Way to Elemental Germanium

The oxidation of [Ge₉(Hyp)₃]^? (Hyp=Si(SiMe₃)₃) with an Fe^II salt leads to Ge₁₈(Hyp)₆ ( 1 ), the largest Group 14 metalloid cluster that has been structurally characterized to date. The arrangement of the 18 germanium atoms in 1 shows similarities to that found in the solid‐state structure Ge(cF136). Furthermore, 1 can be described as a macropolyhedral cluster of two Ge₉ units. Quantum‐chemical calculations further hint at a strained arrangement so that 1 can be considered as a first trapped intermediate on the way from Ge₉ units to elemental germanium with the clathrate‐II structure (Ge(cF136)).     

Reactivity of a N-Coordinated Germylene-Borane Complex: From Ge→B to Ge→Ga Coordination

Reactivity studies of the Ge^II→B complex L(Cl)Ge⋅BH₃ ( 1 ; L=2-Et₂NCH₂-4,6-tBu₂-C₆H₂) were performed to determine the effect on the Ge^II→B donation. N-coordinated compounds L(OtBu)Ge⋅BH₃ ( 2 ) and [LGe⋅BH₃]₂ ( 3 ) were prepared. The possible tuning of the Ge^II→B interaction was proved experimentally, yielding compounds 1-PPh₂-8-(LGe)-C₁₀H₆ ( 4 ) and L(Cl)Ge⋅GaCl₃ ( 5 ) without a Ge^II→B interaction. In 5 , an unprecedented Ge^II→Ga coordination was revealed. The experimental results were complemented by a theoretical study focusing on the bonding in 1 − 5 . The different strength of the Ge^II→E (E=B, Ga) donation was evaluated by using energy decomposition analysis. The basicity of different L(X)Ge groups through proton affinity is also assessed.     

[Ge4O6Te4]4—, an Adamantanoid Oxotellurido Germanate(IV) with a Central Ge4O6 Core

[Mn(en)₃]₂[Ge₄O₆Te₄]·1.5en ( 1 ) and (enH)₃[Mn(en)₃]₃[Ge₄O₆Te₄]₂I·4.7en ( 2 ) may be prepared at 150 °C by solvothermal reaction of elemental Ge and Te with Mn(OOCCH₃)₂ ·4H₂O in the presence of [CH₃)₄N]I as a mineralizer in respectively superheated ethylenediamine (en) or an en/CH₃OH (3:2) mixture. Both contain the novel [Ge₄O₆Te₄]^4— anion with a central adamantanoid Ge₄O₆ core and four terminal Te atoms and represent the first examples of such a mixed [M₄E₆E₄′]^4— anion (M = Si‐Sn; E = O‐Te). As a result of their increased polarity, the Ge‐Te bonds of 2 are markedly shorter (2.438 — 2.462Å) than those previously reported for telluridogermanates(IV).     

Neue ternäre Germanide: Die Verbindungen Ln4Zn5Ge6 (Ln: Gd,Tm, Lu)

New Ternary Germanides: The Compounds Ln ₄Zn₅Ge₆ ( Ln : Gd, Tm, Lu) Three new ternary germanides were prepared by heating mixtures of the elements. Gd₄Zn₅Ge₆ (a = 4.249(3), b = 18.663(17), c = 15.423(6) Å), Tm₄Zn₅Ge₆ (a = 4.190(1), b = 18.410(5), c = 15.105(5) Å), and Lu₄Zn₅Ge₆ (a = 4.179(1), b = 18.368(4), c = 15.050(3) Å) are isotypic and crystallize in a new structure type (Cmc2₁; Z = 4), composed of edge‐ and corner‐sharing ZnGe₄ tetrahedra. The rare‐earth atoms fill channels of the Zn,Ge network running along the a axis and predominantly have an octahedral coordination of Ge atoms or a pentagonal prismatic environment of Zn and Ge atoms. The ZnGe₄ tetrahedra are orientated to each other so that two of six Ge atoms form pairs, while the other ones have no homonuclear contacts. This is in accord with an ionic splitting of the formula: (Ln³⁺)₄(Zn²⁺)₅(Ge^3–)₂(Ge^4–)₄. LMTO band structure calculations support the interpretation of bondings derived from interatomic distances. The metallic conductivity of these compounds expected from the electronic band structure was confirmed by measurements of the electrical resistance of Tm₄Zn₅Ge₆.     

On the Nature of Bridging Metal Atoms in Intermetalloid Clusters: Synthesis and Structure of the Metal‐Atom‐Bridged Zintl Clusters [Sn(Ge9)2]4− and [Zn(Ge9)2)]6−

The addition of Sn and Zn ions to [Ge₉] clusters by reaction of [Ge₉]^4? with SnPh₂Cl₂, ZnCp*₂ (Cp*=pentamethylcyclopentadienyl), or Zn₂[HC(Ph₂P=NPh)₂]₂ is reported. The resulting Sn‐ and Zn‐bridged clusters [(Ge₉)M(Ge₉)]^q? (M=Sn, q=4; M=Zn, q=6) display various coordination modes. The M atoms that coordinate to the open square of a C_4v‐symmetric [Ge₉] cluster form strong covalent multicenter M?Ge bonds, in contrast to the M atoms coordinating to triangular cluster faces. Molecular orbital analyses show that the M atoms of the Ge₉M fragments coordinate to a second [Ge₉] cluster with similar orbitals but in different ways. The [Ge₉Sn]^2?unit donates two electrons to the triangular face of a second [Ge₉]^2? cluster with D_3h symmetry, whereas [Ge₉Zn]^2?acts as an electron acceptor when interacting with the triangular face of a D_3h‐symmetric [Ge₉]^4? unit.     

Atom Exchange Versus Reconstruction: (GexAs4−x)x− (x=2, 3) as Building Blocks for the Supertetrahedral Zintl Cluster [Au6(Ge3As)(Ge2As2)3]3−

The Zintl anion (Ge₂As₂)^2? represents an isostructural and isoelectronic binary counterpart of yellow arsenic, yet without being studied with the same intensity so far. Upon introducing [(PPh₃)AuMe] into the 1,2‐diaminoethane (en) solution of (Ge₂As₂)^2?, the heterometallic cluster anion [Au₆(Ge₃As)(Ge₂As₂)₃]^3? is obtained as its salt [K(crypt‐222)]₃[Au₆(Ge₃As)(Ge₂As₂)₃]?en?2 tol ( 1 ). The anion represents a rare example of a superpolyhedral Zintl cluster, and it comprises the largest number of Au atoms relative to main group (semi)metal atoms in such clusters. The overall supertetrahedral structure is based on a (non‐bonding) octahedron of six Au atoms that is face‐capped by four (Ge_xAs_4?x)^x? (x=2, 3) units. The Au atoms bind to four main group atoms in a rectangular manner, and this way hold the four units together to form this unprecedented architecture. The presence of one (Ge₃As)^3? unit besides three (Ge₂As₂)^2? units as a consequence of an exchange reaction in solution was verified by detailed quantum chemical (DFT) calculations, which ruled out all other compositions besides [Au₆(Ge₃As)(Ge₂As₂)₃]^3?. Reactions of the heavier homologues (Tt₂Pn₂)^2? (Tt=Sn, Pb; Pn=Sb, Bi) did not yield clusters corresponding to that in 1 , but dimers of ternary nine‐vertex clusters, {[AuTt₅Pn₃]₂}^4? (in 2 – 4 ; Tt/Pn=Sn/Sb, Sn/Bi, Pb/Sb), since the underlying pseudo‐tetrahedral units comprising heavier atoms do not tend to undergo the said exchange reactions as readily as (Ge₂As₂)^2?, according to the DFT calculations.     

Nickel(O)-Komplexe mit anionischen Liganden des Typs E(C6H5) (E = Si,Ge, Sn)

Nickel(O) Complexes with the Anionic Ligands E (C₆H₅)^?₃ (E = Si, Ge, Sn) Complexes of the type Me^I_XNi(EPH₃)_X(THF)_Y are formed from Ni(COD)₂ by substitution with Me^IEPh₃ (E = Si, Ge, Sn) in THF (COD = Cyclooctadiene-1,5). In the case of the ligands GePh^?₃ and SnPh^?₃ nickel(O) is fourfold coordinated, but in the case of SiPh^?₃ it is only two-fold or threefold coordinated. Products of the reaction between Ni(COD)₂ and LiPbPh₃ are Li₂Ni(COD)Ph₂(THF)₅ and Ph₃PbPbPh₃. The ¹H-n.m.r., ²⁹Si-n.m.r., and ¹¹⁹Sn-Mössbauer spectra of the complexes Me^I_XNi(EPh₃)_X(THF)_Y are compared with the spectra of the corresponding alkali compounds Me^IEPh₃. The magnetic anisotropy effects of the atomes Ge, Sn, Pb and Ni are of high importance for ¹H- and ²⁹Si-chemical shifts. The donor action of SnPh^?₃ is shown by the Mössbauer spectrum of Na₄Ni(SnPh₃)₄(THF)₄. But there is no direct evidence of π-back donation in the compound.     

通过核独立化学位移(NICS)计算研究二价三、五、七元环C2H2M, C4H4M and C6H6M(M=C, Si, Ge, Sn and Pb)的芳香族特性

The aromatic character of divalent three, five and seven-membered rings C₂H₂M, C₄H₄M and C₆H₆M(M=C, Si, Ge, Sn and Pb) is investigated through magnetic and geometric criteria by Density Functional Theory (DFT)method using 6^-311++G(3df,2p) basis set of the GAUSSIAN 98 program. The result of Nucleus-independent Chemical Shifts (NICS)(0.5) calculations show an aromatic character for singlet state of C₂H₂M(M=C, Si, Ge, Sn and Sn) and nonaromatic character for triplet states of C₂H₂M(except M=Ge and Pb). NICS (0.5) calculations show nonaromatic character for the singlet state of C₄H₄C and antiaromatic character for C₄H₄M(M=Si, Ge, Sn and Pb). In contrast, NICS (0.5) calculations indicate antiaromatic character for the triplet state of C₄H₄C and nonaromatic character to C₄H₄M(M=Si, Ge, Sn and Pb). NICS (0.5) calculations show a slightly homoaromatic character for the singlet state of C₆H₆M and anti-aromatic character for triplet state of C₆H₆M.     

Die inneren Schwingungen der Tetrahetero-Tetrahedran-Anionen Ge44, Sn44- und Pb44

The Internal Vibration of the Tetrahetero-Tetrahedrane Anions Ge₄^4?, Sn₄⁴-, and Pb₄⁴ The Frequencies of the internal vibrations ν₁ (A₁), ν₂(E), ν₃(T₂) of the tetrahetero-tetrahedrane an ions Ge₄⁴- and Sn₄⁴- are determined from the infrared and Raman spectra of K₇LiGe₈ and KSn, respectively. A comparison of the characteristic vibration of tetrahedrane anions X₄⁴- (X = Si, Ge, Sn)and the isoelectronic neutral tetrahedranes Y₄ of the neighbouring elements (Y = P, As, Sb) shows a rather constant ratio of the corresponding frequencies k = v^?(X₄⁴-) = 0,77. This allows for an estimate of v^?(Pb₄⁴-) from the known Bi₄data. In the inflated spectrum of KPb bands are observed in the predicted frequency range.     

Low-Valent Group 14 NHC-Stabilized Phosphinidenide ate Complexes and NHC-Stabilized K/P-Clusters

The N-heterocyclic carbene (NHC)-stabilized phosphinidenide, SIMesPK [SIMes=1,3-bis(2,4,6-trimethylphenyl)imidazolidine-2-ylidene], was used as an (NHC)P-transfer reagent for the synthesis of the low-valent Group 14 ate complexes K[(SIMesP)₃E] (E=Ge: 2 , Sn: 3 , Pb: 4 ), which were characterized by ¹H NMR, ³¹P NMR, IR spectroscopy as well as elemental and X-ray analysis. Furthermore, SIMesPK was used in reactions with potassium amides and alkoxides to form the molecular phosphorus–potassium clusters [K₄(SIMesP)₂(hmds)₂] [ 5 , hmds=N(SiMe₃)₂] and [K₆(SIMesP)₂(OtBu)₄] ( 6 ). Finally, the reaction of SIMesPK with Li[Al(OC₄F₉)₄] led to the potassium-rich ionic compound [(SIMesP)₄K₅][Al(OC₄F₉)₄] ( 7 ).     

Interaction between cobaltocenium and decamethylcobaltocenium salts and Ph3ELi (E = Si,Ge, Sn)

Reactions of cobaltocenium salts [(C₅R₅)₂Co]PF₆ (R = H, Me) with Ph3ELi (E = Si, Ge, Sn) and with Ph₂SbLi mainly follow two pathways (nucleophilic addition and one-electron reduction), yielding cobalt cyclopentadiene-cyclope ntadienyl complexes (⁴-Ph₃EC₅R₅)(⁵-C₅R₅)Co (R = H, E = Si, Ge, Sn; R = Me, E = Si) and cobaltocenes (C₅R₅)₂Co (R = H, Me), respectively. The contribution of nucleophilic addition of Ph₃ELi decreases in the order of elements Si > Ge > Sn and when hydrogen atoms are replaced by methyl groups in the initial cobaltocenium salt. Thermal decomposition of cobalt cyclopentadiene-cyclopentadienyl complexes results in substituted cobaltocenes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 10, pp. 2557–2560, October, 1996.     

Synthesis and Thermal Decomposition of Heavy Tetrylenes Bearing N-Aminocarbazolyl Substituents

The synthesis of the N-aminocarbazole R-NH₂ ( 2 ) is reported. Subsequent reaction with bis[bis(trimethylsilyl)amido]tetrylenes E[N(SiMe₃)₂]₂ (E=Ge, Sn, or Pb) allowed the isolation of formal hydrazidotetrylene derivatives, R−N(H)EN(SiMe₃)₂ ( 3 ) that includes the first example of a hydrazidoplumbylene to date. Thermal decomposition of these compounds resulted in the elimination of “NH” and afforded the tetrylenes R-EN(SiMe₃)₂ ( 4 ).     

Reaktionen von Zink- und Cadmiumhalogeniden mit Tris(trimethylsilyl)phosphan und Tris(trimethylsilyl)arsan

Reactions of Zinc and Cadmium Halides with Tris(trimethylsilyl)phosphane and Tris(trimethylsilyl)arsane ZnCl₂ reacts with E(SiMe₃)₃ (E = P, As) in toluene in the presence of PⁿPr₃ to give the binuclear complexes [Zn₂Cl₂{E(SiMe₃)₂}₂(PⁿPr₃)₂] · C₇H₈ (E = P 1 , As 2 ). Therefore by the use of PⁱPr₃ clusters consisting of ten metal atoms are obtained, [Zn₁₀Cl₁₂(ESiMe₃)₄(PⁱPr₃)₄] (E = P 3 , As 4 ). As a result of the reaction of CdBr₂ with P(SiMe₃)₃ the compound [CdBr₂{P(SiMe₃)₃}]₂ ( 5 ) can be isolated at –40 °C. In the presence of PⁿPr₃ CdBr₂ reacts with P(SiMe₃)₃ forming the binuclear complex [Cd₂Br₂{P(SiMe₃)₂}₂(PⁿPr₃)₂] · thf ( 6 ). The same reaction with PⁱPr₃ yields to the cluster [Cd₁₀Br₁₂(PSiMe₃)₄{P(SiMe₃)₃}₄] · 2 C₇H₈ ( 7 ). ZnI₂ and CdI₂ react with As(SiMe₃)₃ to yield the complexes [MI₂{As(SiMe₃)₃}]₂ (M = Zn 8 , Cd 9 ). In the case of CdI₂ additionally the cluster [Cd₁₀I₁₂(AsSiMe₃)₄ · {As(SiMe₃)₃}₄] · 4,5 C₇H₈ ( 10 ) is formed which is analogous to the compounds 3 , 4 and 7 . In the presence of [PⁿBu₄]I 8  reacts in THF to give the ionic compound [PⁿBu₄]₂[Zn₆I₆(AsSiMe₃)₄(thf)₂] · C₆H₆ ( 11 ).     

Phosphine-Stabilized Pnictinidenes

The reaction of the intramolecular germylene-phosphine Lewis pair (o-PPh₂)C₆H₄GeAr* ( 1 ) with Group 15 element trichlorides ECl₃ (E=P, As, Sb) was investigated. After oxidative addition, the resulting compounds (o-PPh₂)C₆H₄(Ar*)Ge(Cl)ECl₂ ( 2 : E=P, 3 : E=As, 4 : E=Sb) were reduced by using sodium metal or LiHBEt₃. The molecular structures of the phosphine-stabilized phosphinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)P ( 5 ), arsinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)As ( 6 ) and stibinidene (o-PPh₂)C₆H₄(Ar*)Ge(Cl)Sb ( 7 ) are presented; they feature a two-coordinate low-valent Group 15 element. After chloride abstraction, a cyclic germaphosphene [(o-PPh₂)C₆H₄(Ar*)GeP] [B(C₆H₃(CF₃)₂)₄] ( 8 ) was isolated. The ³¹P NMR data of the germaphosphene were compared with literature examples and analyzed by quantum chemical calculations. The phosphinidene was treated with [iBu₂AlH]₂, and the product of an Al−H addition to the low-valent phosphorus atom (o-PPh₂)C₆H₄(Ar*)Ge(H)P(H)Al(C₄H₉)₂ ( 9 ) was characterized.     

(Ge4Bi14)4−: A Case of “Element Segregation” on the Molecular Level

Extraction of a solid with the nominal composition “K₂GeBi” with 1,2‐diaminoethane (en) in the presence of 4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane (crypt‐222) afforded the salt [K(crypt‐222)]₄(Ge₄Bi₁₄). The 18‐atom Zintl anion (Ge₄Bi₁₄)⁴⁻ has a heretofore unknown molecular topology, which can be thought of as the formal condensation product of two E₁₁³⁻ cages along a shared Ge₄ waist. In this way, (Ge₄Bi₁₄)⁴⁻ represents the largest and most structurally complex Bi‐containing polyanion. We describe its stepwise formation, its geometric and electronic structure, and comment on relative stabilities of isomers with different distributions of the four Ge atoms on the 18 positions that were investigated using DFT calculations.