Organogermanium Research Articles

Optimization study for the speciation analysis of organotin and organogermanium compounds by on-column capillary gas chromatography with flame photometric detection using quartz surface-induced luminescence

A laboratory-designed flame photometric detector (FPD) using quartz surface-induced luminescence was used for the on-column capillarychromatographic determination of organotin and organogermanium compounds. The detector response depend on gas flow-rates, detector temperature and the operation mode. The linear range is up to four orders of magnitude for oganotin and up to three orders of magnitude for oganogermanium compounds. The minimum detectable amounts, defined as the signal equal to three times the standard deviation (3σ) of the baseline noise, vary with the species detected and range from 0.7 to 2.3 pg for ethylated butyl- and phenyltin species and from 50 to 100 pg for pentylaed dimethyl-, trimethyl- and tetrabutylgermanium. The determination of butyltin compounds in water and sediments was evaluated in comparison with a GC-AAS system. The proposed method is simple, highly sensitive and reproducible.

2-Carboxyethylgermanium sesquioxide, a synthetic organogermanium compound, as an inducer of contrasuppressor T cells.

2-Carboxyethylgermanium sesquioxide (Ge-132), a synthesized organogermanium compound with immunomodulating activities, was shown to be an inducer of anti-suppressor T cells in normal mice. The suppressor cell activity of T6S cells, a clone of burn-induced CD8+ IL-4-producing suppressor T cells, was clearly inhibited when a mixed lymphocyte-tumor cell reaction of the clone was conducted with splenic mononuclear cells from mice treated orally with a 100 mg/kg dose of Ge-132. The activity of anit-suppressor cells was demonstrated in spleens of mice 2 days after treatment with Ge-132 and reached its peak on day 3. The anti-suppressor cells induced by the compound were of a contrasuppressor T cell-linage, because they were characterized as CD4+ CD28+ TCRalpha/beta+ Vicia villosa lectin-adherent T cells. These cells produced IFN-gamma but did not produce IL-2, IL-4, IL-6 or IL-10 in their culture fluids. CD4+ anti-suppressor T cells induced by Ge-132 may be different from other subsets of CD4+ T cells because Th1 and Th2 cells generated in our laboratory did not adhere to Vicia villosa lectin-coated petri dishes, and each produced specific cytokines. Th1 cells produced IFN-gamma and IL-2 while Th2 cells produce IL-4 and IL-10 in vitro. These results suggest that Ge-132 may be useful as an inducer of contrasuppressor T cells in immunocompromised individuals bearing suppressor T cells. To eliminate suppressor T cells from immunocompromised hosts may result in improved resistance from various opportunistic infections.

Effects of organogermanium compound GE-132 on differentiation and calcification of rat bone marrow stromal cells

Effects of organogermanium compound GE-132 on differentiation and calcification of rat bone marrow stromal cells

Formation of Crystalline Germanium Nanoclusters in a Silica Xerogel Matrix from an Organogermanium Precursor

Addition of the organogermanium compound, Me3GeS(CH2)3Si(OMe)3, to a modified, conventional sol−gel formulation gives a silica xerogel doped with this molecular species. Subsequent thermal treatment of this molecularly doped xerogel under oxidizing then reducing conditions affords nanoclusters of Ge highly dispersed throughout the bulk of the xerogel matrix. Under appropriate conditions, Ge nanoclusters having an average diameter of ca. 68 Å can be formed by this procedure. Characterization of this nanocomposite material by TEM, HRTEM, EDS, XRD, micro-Raman spectroscopy, electron diffraction, and UV−visible spectroscopy indicates that the Ge nanoclusters are highly crystalline and exhibit optical properties consistent with those expected when quantum confinement effects are operative.

The molecular structure of organogermanium compounds

The molecular structure of organogermanium compounds

Mass spectrometry studies of organometallic compounds: Part 1. Compounds of general formula PhnGeCl4-n

The mass spectra of organogermanium compounds of the type Ph n GeCl 4-n (where n=1-4) were investigated. Positive and negative ion spectra of these compounds were recorded using conventional electron impact (EI) conditions. In common with the analogous tetra-alkyltin compound, Ph 4 Ge produced no negative ion spectra under these conditions. Tandem mass spectrometry (MS-MS) was used to deduce fragmentation reaction pathways for these compounds. In the case of PhGeCl 3 , collision-induced dissociation studies were extended to examine the ion-molecule reactions under relatively high reactant pressures of methanol and/or water vapour in the collision cell of the MS-MS instrument.

ChemInform Abstract: Recent Developments in SET Reactions of Organogermanium Compounds

AbstractChemInform 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.

5340806 Composition containing organogermanium compound and immunity adjusting agent comprising the composition: Sawai Kiichi; Kurono Masayasu; Awaya Juichi; Kojima Akio; Ninomiya Hideaki; Ishiwata Yoshiro; Nakajima Masahir Sanwa Kagaku Kenkyusho Co Ltd

5340806 Composition containing organogermanium compound and immunity adjusting agent comprising the composition: Sawai Kiichi; Kurono Masayasu; Awaya Juichi; Kojima Akio; Ninomiya Hideaki; Ishiwata Yoshiro; Nakajima Masahir Sanwa Kagaku Kenkyusho Co Ltd

Synthesis of 1‐triphenylgermylpropiono‐4‐substituted semicarbazides, thiosemicarbazides and their heterocyclic derivatives

AbstractTwenty‐one new organogermanium compounds with the formulae Ph3GeCHR1CH2CONHNHC(X)NHR2 (1) (R1=H, Ph; = Ph, p‐CH3Ph, O‐CH3Ph, p‐ClPh, COPh, X = S, O) and magnified image (R1 = H, Ph; R2 = Ph, p‐CH3Ph, o‐CH3Ph, p‐ClPh; X=S, O) were synthesized and characterized by elemental analysis, 1H NMR, IR, MS and X‐ray diffraction techniques. Compounds l were prepared by the reactions of Ph3GeCHR1CH2CONHNH2 with R2NCX in chloroform in 77‐94% yields, and 2 were obtained by refluxing l with sodium hydroxide (8%) with yields of 55‐94%.

Germanium-containing coatings by IR laser-induced decomposition of ethoxy(trimethyl) germane and tetramethylgermane

Different germanium-based materials are produced from ethoxy(trimethyl)germane (ETG) and tetramethylgermane (TMG) by CO 2 laser radiation. The CO 2 laser SF 6-photosensitized decomposition of TMG affords germanium, the infrared multiphoton decomposition of ETG yields a material which is rich in Ge and contains small amounts of oxygen and carbon, and the SF 6-photosensitized decomposition of ETG yields a deposit containing Ge and substantial quantities of C and O.

Polygermoxanes suitable for biochemical purposes: II Linear trigermoxanes (high‐viscosity oils)

AbstractLinear trigermoxanes, R1 RGeOGe(R3)2OGeRR1, a new series of organogermanium compounds, were synthesized by reaction of a lithium organogermanolate with a suitable organogermanium dihalide. With alkyl or phenyl substituents, these trigermoxanes are structurally unstable viscous oils, due to redistribution reactions. When R3 substituents are bulky groups, such as mesityl, trigermoxanes are thermally and structurally stable oils; depending on the R1 and R2 substituents their viscosities lie in the range 240 to more than 1500 cPo (mPa s) at 20°C. When both terminal germanium atoms are substituted with two mesityl groups, trigermoxanes are stable glassy solids.

Identification of organogermanium compounds as matrix complexes in fast‐atom bombardment mass spectrometry

AbstractThe application of aqueous matrices to fast‐atom bombardment mass spectrometry enables the detection of several organogermanium compounds as specific complexes with matrices. In the positive‐ion mode, the organogermanium compounds showed a dominant ion [M+matrix‐3 · H2O+H]+ whose dehydration involved atoms attached to the germanium atom. On the other hand, two types of fragmentation were observed in the negative‐ion mode The first was a group of compounds, with a carboxy group, that formed a lactone ring and showed a dominant ion at [M+matrix ‐3 · H2O‐H]−. The other group, without carboxy, attached another matrix molecule and showed a dominant fragment ion at [M+2 · matrix‐3 · H2O‐H]−. The investigation of these complex structures was performed using various matrices and D2O treatment.

IR laser thermolysis of tetramethylgermane for CVD of germanium

The CO 2 laser photosensitized (SF 6) decomposition of tetramethylgermane (TMG) yields C 1 and C 2 hydrocarbons along with a germanium deposit which contains some amounts of carbon and oxygen. The presence of these elements is judged to be caused by the adsorption of TMG on the surface of the deposit and by the sensitivity of the deposit to air.

Correlations between process parameters, chemical structure and electronic properties of amorphous hydrogenated Ge xC 1−x films prepared by plasma-enhanced chemical vapour deposition in a three-electrode reactor

A new type of reactor for plasma deposition activated by audio frequency with three parallel electrodes is presented. The reactor was tested for deposition of amorphous hydrogenated Ge xC 1−x films frm organogermanium compounds. It was found that small changes of a coupling capacity in the system can cause a step change in the electronic structure of deposited films. Such a change, however, was not manifested by the molecular structure and only monotonic changes of Ge content and cross-linking were observed. The step change in the electronic structure was attributed to the amorphous semiconductor-amorphous dielectric transition.

The Germanium–Carbon Bond Cleavage Reaction of (Germylmethyl)amine Derivatives. Mechanism and Stereochemistry

Abstract A facile cleavage reaction of the germanium–carbon bond of (germylmethyl)amine derivatives to give a germyl anion and an azomethine derivative was developed. The effects of substituents such as phenyl, benzyl, and ethyl groups on the germanium and nitrogen atoms of the (germylmethyl)amine derivatives on the cleavage reaction, were investigated. The mechanism was also investigated based on the stereochemistry of the cleavage reaction using an optically active organogermanium compound.

Modelling of Hexacoordinated Transition States of Germanium Based on the Crystal Structures of Germanium-substituted Bis(lactamo-N-methyl)germanes L2GeX2 and L2GeXY (X, Y = Hal, OTf, BF4, l3)

X-Ray structural data on the investigation of hypervalent organogermanium compounds testify to the absence of essential differences in the structural parameters between the series of penta- and hexacoordinated compounds, regarded as models for S N -Si reactions.

特集 ゲルマニウムの化学―その独自性と類似性 熱力学的ｐＫａ計算法の有機ゲルマニウム化合物への適用

特集 ゲルマニウムの化学―その独自性と類似性 熱力学的ｐＫａ計算法の有機ゲルマニウム化合物への適用

Antifertility and biocidal activities of organometallics of silicon, germanium, titanium and zirconium derived from 2‐acetylthiophene thiosemicarbazone

AbstractA comparative biochemical study of four Group IV element compounds with specific sulphur‐containing organic substrates has been carried out and discussed. The structural characterizations of these organometallics, viz. Me2SiLCl, Me2SiL2, Me3SiL, Ph2SiLCl, Ph2SiL2, Ph3SiL, Ph3GeL, Cp2TiLCl, Cp2TiL2, Cp2ZrLCl and Cp2ZrL2 (where LH2‐acetylthiophene thiosemicarbazone) had been deduced on the basis of various physico‐chemical and instrumental techniques, viz., IR, UV, 1H NMR, 13C NMR AND 29SI NMR spectral studies. All the organometallics and the parent thiomine have been screened against a number of microbes and their sterilizing power in male mice tested. The results of these biocidal studies show that the organosilicon(IV) and organogermanium(IV) compounds are more active than the organotitanium(IV) and organozirconium(IV) derivatives. An attempt has also been made to correlate the structural aspects of the molecule with its biological activity.

Thermodynamics of antagonist binding to rat muscarinic M2 receptors: antimuscarinics of the pridinol, sila‐pridinol, diphenidol and sila‐diphenidol type

1. We studied the effect of temperature on the binding to rat heart M2 muscarinic receptors of antagonists related to the carbon/silicon pairs pridinol/sila-pridinol and diphenidol/sila-diphenidol (including three germanium compounds) and six structurally related pairs of enantiomers [(R)- and (S)-procyclidine, (R)- and (S)-trihexyphenidyl, (R)- and (S)-tricyclamol, (R)- and (S)-trihexyphenidyl methiodide, (R)- and (S)-hexahydro-diphenidol and (R)- and (S)-hexbutinol]. Binding affinities were determined in competition experiments using [3H]-N-methyl-scopolamine chloride as radioligand. The reference drugs were scopolamine and N-methyl-scopolamine bromide. 2. The affinity of the antagonists either increased or decreased with temperature. van't Hoff plots were linear in the 278-310 degrees K temperature range. Binding of all antagonists was entropy driven. Enthalpy changes varied from large negative values (down to -29 kJ mol-1) to large positive values (up to +30 kJ mol-1). 3. (R)-configurated drugs had a 10 to 100 fold greater affinity for M2 receptors than the corresponding (S)-enantiomers. Enthalpy and entropy changes of the respective enantiomers were different but no consistent pattern was observed. 4. When silanols (R3SiOH) were compared to carbinols (R3COH), the affinity increase caused by C/Si exchange varied between 3 and 10 fold for achiral drugs but was negligible in the case of chiral drugs. Silanols induced more favourable enthalpy and less favourable entropy changes than the corresponding carbinols when binding. Organogermanium compounds (R4Ge) when compared to their silicon counterparts (R4Si) showed no significant difference in affinity as well as in enthalpy and entropy changes. 5. Exchange of a cyclohexyl by a phenyl moiety was associated with an increase or a decrease in drug affinity (depending on the absolute configuration in the case of chiral drugs) and generally also with a more favourable enthalpy change and a less favourable entropy change of drug binding. 6. Replacement of a pyrrolidino by a piperidino group and increasing the length of the alkylene chain bridging the amino group and the central carbon or silicon atom were associated with either an increase or a decrease of entropy and enthalpy changes of drug binding. However, there was no clear correlation between these structural variations and the thermodynamic effects. 7. Taken together, these results suggest that hydrogen bond-forming OH groups and, to a lesser extent, polarizable phenyl groups contribute significantly to the thermodynamics of interactions between these classes of muscarinic antagonists and M2 muscarinic receptors.

NMR Spectra of Organogermanium Compounds. Part XII. 73Ge and 13C NMR Spectra and Molecular Mechanics Calculations of 3-Germabicyclo[3.1.0]hexanes and Related Compounds

Abstract 73Ge and 13C NMR spectra of several 3-germabicyclo[3.1.0]hexanes (GBCH) were determined. The results are consistent with the structure as predicted by molecular mechanics calculations. Thus, GBCH prefer the boat form as bicyclo[3.1.0]hexanes (BCH) do. GBCH finally assumes the chair form by excessive substitution.