19F NMR studies of the comparative electronegativity of the Ph3E groups (E=C, Si, Ge, Sn, or Pb) in Ph3E derivatives of tris(4-fluorophenyl)stannanethiol

Compounds (4-FC₆H₄)₃SnSEPh₃ (E=C, Si, Ge, Sn, or Pb) were synthesized or generated in solution. The data on the comparative electronegativity of the Ph₃E groups were obtained from the results of¹⁹F NMR spectroscopy. It was established that, except for E=C, the electronegativity changes in parallel with the absolute electronegativity of the central atom. Possible reasons for the deviation observed are discussed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1215‐1218, June, 1997.     

Rational Design of Anode Materials Based on Group IVA Elements (Si,Ge, and Sn) for Lithium‐Ion Batteries

Lithium‐ion batteries (LIBs) represent the state‐of‐the‐art technology in rechargeable energy‐storage devices and they currently occupy the prime position in the marketplace for powering an increasingly diverse range of applications. However, the fast development of these applications has led to increasing demands being placed on advanced LIBs in terms of higher energy/power densities and longer life cycles. For LIBs to meet these requirements, researchers have focused on active electrode materials, owing to their crucial roles in the electrochemical performance of batteries. For anode materials, compounds based on Group IVA (Si, Ge, and Sn) elements represent one of the directions in the development of high‐capacity anodes. Although these compounds have many significant advantages when used as anode materials for LIBs, there are still some critical problems to be solved before they can meet the high requirements for practical applications. In this Focus Review, we summarize a series of rational designs for Group IVA‐based anode materials, in terms of their chemical compositions and structures, that could address these problems, that is, huge volume variations during cycling, unstable surfaces/interfaces, and invalidation of transport pathways for electrons upon cycling. These designs should at least include one of the following structural benefits: 1) Contain a sufficient number of voids to accommodate the volume variations during cycling; 2) adopt a “plum‐pudding”‐like structure to limit the volume variations during cycling; 3) facilitate an efficient and permanent transport pathway for electrons and lithium ions; or 4) show stable surfaces/interfaces to stabilize the in situ formed SEI layers.     

The germanium(II) ate complex [Ph3PiPr][Ge(OCOMe)3]: the first structurally characterized compound containing a discrete [E14(II)O3](−) (E14(II) = Si,Ge, Sn or Pb) anion

An X‐ray diffraction study reveals an unusual structure of the new thermally stable germanium(II) ate complex [Ph₃PⁱPr][Ge(OAc)₃] (4) containing a discrete [Ge(OAc)₃]^(?) anion containing monodentate acetate ligands with a trigonal pyramidal germanium centre. Copyright © 2005 John Wiley & Sons, Ltd.     

Fluoromethyl Cations and Group XIV Congeners AHnF3‐n+ (A: Si,Ge, Sn,Pb; n = 0—2): From Covalent Structures to Ion‐Molecule Complexes

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.     

Simulation of molecular and electronic structure of η5-π-complexes of fullereneI h -C 60 with half-sandwich XCp species (X=Si, Ge, Sn)

The molecular and electronic structure of hypothetical complexes of unsubstituted fullerene C₆₀ withI _h symmetry and its cyclopentadienyl type derivatives were simulated by the MNDO/PM3 method taking the C₆₀(XC[) _n molecules (n=1, 2, 10, 12; X=Si, Ge, Sn) and η⁵-C₆₀H₅XCp (X=Ge, Sn), respectively, as example. The complexes 12η⁵-πC₆₀(XCp)₁₂ and η⁵-πC₆₀XCp withI _h andC _5v symmetry, respectively, were found to be the most stable compounds. The energies of the X−C₆₀ bonds in these complexes are close to those of X−Cp bonds in bis(cyclopentadienyl) complexes XCp₂ and are substantially higher than the energies of similar bonds in complexes of unsubstituted fullerene η¹-πC₆₀(XCp)⁻ and η⁵-πC₆₀(XCp)⁺. Geometric parameters and spin densities in radicals C₆₀XCp and biradicals C₆₀(XCp)₂ and C₆₀H₁₀ were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2155–2165, November, 1998.     

Synthesis of trinuclear silicon-, germanium-, and tin-containing tungsten carbene complexes [(ButO)2(Cl)2W=CH]2EPh2 (E = Si, Ge, or Sn). Crystal structure of [(ButO)2(Cl)2W=CH]2SiPh2 complex

New trinuclear organosilicon, organogermanium, and organotin-containing tungsten carbene complexes Ph₂E[CH=WCl₂(OBu^t)₂]₂ (E = Si, Ge, or Sn) were synthesized by the reaction of the trinuclear carbyne complexes Ph₂E[C≡W(OBu^t)₃]₂ with HCl. The tin-containing carbene complex is thermally unstable and was identified in solution by ¹H and ¹³C NMR spectroscopy. The silicon-and germanium-tungsten carbene complexes were isolated in high yields as individual crystals and were characterized by elemental analysis, IR spectroscopy, and ¹H and ¹³C NMR spectroscopy. The structure of the silicon-containing complex Ph₂Si[CH=WCl₂(OBu^t)₂]₂ was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2424–2427, November, 2005.     

ChemInform Abstract: H-Bridged Structures for Tetrahedranes A4H4 (A: C,Si, Ge,Sn, and Pb).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

Rationally functionalized deltahedral zintl ions: synthesis and characterization of [Ge9-ER3]3-, [R3E-Ge9-ER3]2-, and [R3E-Ge9-Ge9-ER3]4- (E=Ge, Sn; R=Me, Ph)

Six new derivatized deltahedral Zintl ions have been synthesized by reactions between the known Zintl ions Ge(9) (n-) with the halides R(3)EX and/or the corresponding anions R(3)E(-) for E=Ge or Sn. This rational approach is based on our previous discovery that these derivatization reactions are based on nucleophilic addition to the clusters. All species were structurally characterized as their salts with potassium countercations sequestered in 2,2,2-crypt or [18]crown-6 ether. The tin-containing anions were characterized also in solutions by (119)Sn NMR spectroscopy. The reaction types for such substitutions and the structures of the new anions are discussed.     

Reaction Mechanism of the Symmetry‐Forbidden [2+2] Addition of Ethylene and Acetylene to Amido‐Substituted Digermynes and Distannynes Ph2NEENPh2, (E=Ge,Sn): A Theoretical Study

Quantum chemical calculations of reaction mechanisms for the formal [2+2] addition of ethylene and acetylene to the amido‐substituted digermyne and distannyne Ph₂N?EE?NPh₂ (E=Ge, Sn) have been carried out by using density functional theory at the BP86/def2‐TZVPP level. The nature and bonding situations were studied with the NBO method and with the charge and energy decomposition analysis EDA‐NOCV. The addition of ethylene to Ph₂N?EE?NPh₂ takes place through an initial [2+1] addition to one metal atom and consecutive rearrangement to four‐membered cyclic species, which feature a weak E?E bond. Rotation about the C?C bond with concomitant rupture of the E?E bond leads to the 1,2‐disubstituted ethanes, which have terminal E(NPh₂) groups. The overall reaction Ph₂N?EE?NPh₂+C₂H₄→(Ph₂N)E?C₂H₄?E(NPh₂) has very low activation barriers and is slightly exergonic for E=Ge but slightly endergonic for E=Sn. The analysis of the electronic structure shows that there is charge donation of nearly one electron to the ethylene moiety already in the first part of the reaction. The energy partitioning analysis suggests that the HOMO(Ph₂N?EE?NPh₂)→LUMO(C₂H₄) interaction has a similar strength as the HOMO(C₂H₄)→LUMO(Ph₂N?EE?NPh₂) interaction. The [2+2] addition of acetylene to Ph₂N?EE?NPh₂ also takes place through an initial [2+1] approach, which eventually leads to 1,2‐disubstituted olefins (Ph₂N)E?C₂H₂?E(NPh₂). The formation of the energetically lowest lying conformations of cis‐(Ph₂N)E?C₂H₂?E(NPh₂), which occurs with very low activation barriers, is clearly exergonic for the germanium and the tin compound. The trans‐coordinated isomers of (Ph₂N)E?C₂H₂?E(NPh₂) are slightly lower in energy than the cis form but they are separated by a substantial energy barrier for the rotation about the C?C bond. The energy decomposition analysis indicates that the initial reaction takes place under formation of electron‐sharing bonds between triplet fragments rather than HOMO–LUMO interactions.     

Spektroskopische Untersuchungen an R3MF-Verbindungen (M = Si,Ge, Sn)

Spectroscopical Investigations on R₃MF Compounds (M = Si, Ge, Sn) The IR and RAMAN spectra of a number of R₃MF compounds (M? Si, Ge, Sn) have been recorded. The frequencies of the vibrational spectra were almost completely assigned. The measurements of the IR-spectra were investigated (as for as possible) in all states of aggregations. The force of the intermolecular interactions were discussed by means of the spectroscopic data.     

A Mixed Heavier Si=Ge Analogue of a Vinyl Anion

The versatile reactivities of disilenides and digermenide, heavier analogues of vinyl anions, have significantly expanded the pool of silicon and germanium compounds with various unexpected structural motifs in the past two decades. We now report the synthesis and isolation of a cyclic heteronuclear vinyl anion analogue with a Si=Ge bond, potassium silagermenide as stable thf‐solvate and 18‐c‐6 solvate by the KC₈ reduction of germylene or digermene precursors. Its suitability as synthon for the synthesis of functional silagermenes is proven by the reactions with chlorosilane and chlorophospane to yield the corresponding silyl‐ and phosphanyl‐silagermenes. X‐ray crystallographic analysis, UV/Vis spectroscopy and DFT calculations revealed a significant degree of π‐conjugation between N=C and Si=Ge double bonds in the title compound.     

Zur Kenntnis der inversen Perowskite M3TO (M = Ca,Sr, Yb; T = Si,Ge, Sn,Pb)

On the Inverse Perovskites M₃TO (M = Ca, Sr, Yb; T = Si, Ge, Sn, Pb) Ca₃SiO and seven further inverse perovskites M₃TO (M = Ca, Sr, Yb; T = Si, Ge, Sn, Pb) were prepared in iron crucibles under argon by the reactions 6 M + TO₂ + T = 2 M₃TO, and 3 M+ TO = M₃TO for Yb₃PbO, respectively, at temperatures between 1123 to 1173 K. The crystal structures of all compounds were solved and refined using X—ray powder diffraction methods. Ca₃SiO, Ca₃GeO, Sr₃SiO, Sr₃GeO, Yb₃SiO and Yb₃GeO are orthorhombic perovskites (anti—GdFeO₃—type, space group Pbnm, No. 62, Z = 4). They show slightly distorted corner—sharing OM₆ octahedra that are tilted with respect to their positions in the ideal perovskite structure. The effective radii of the T^4— vary significantly with M²⁺. Thus, these perovskites can no longer be discussed in terms of the hard—sphere model, and Goldschmidt's tolerance factor does not apply. The ideal cubic representatives Yb₃SnO and Yb₃PbO were refined in space group Pm3¯m (anti—SrTiO₃ type, Z = 1).     

ChemInform Abstract: Structural Evolution of Doped Gold Clusters: MAu‐x (M: Si,Ge, Sn; x = 5—8).

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.