13450-95-8Relevant articles and documents
Hybrid germanium iodide perovskite semiconductors: Active lone pairs, structural distortions, direct and indirect energy gaps, and strong nonlinear optical properties
Stoumpos, Constantinos C.,Frazer, Laszlo,Clark, Daniel J.,Kim, Yong Soo,Rhim, Sonny H.,Freeman, Arthur J.,Ketterson, John B.,Jang, Joon I.,Kanatzidis, Mercouri G.
, p. 6804 - 6819 (2015)
The synthesis and properties of the hybrid organic/inorganic germanium perovskite compounds, AGeI3, are reported (A = Cs, organic cation). The systematic study of this reaction system led to the isolation of 6 new hybrid semiconductors. Using CsGeI3 (1) as the prototype compound, we have prepared methylammonium, CH3NH3GeI3 (2), formamidinium, HC(NH2)2GeI3 (3), acetamidinium, CH3C(NH2)2GeI3 (4), guanidinium, C(NH2)3GeI3 (5), trimethylammonium, (CH3)3NHGeI3 (6), and isopropylammonium, (CH3)2C(H)NH3GeI3 (7) analogues. The crystal structures of the compounds are classified based on their dimensionality with 1-4 forming 3D perovskite frameworks and 5-7 1D infinite chains. Compounds 1-7, with the exception of compounds 5 (centrosymmetric) and 7 (nonpolar acentric), crystallize in polar space groups. The 3D compounds have direct band gaps of 1.6 eV (1), 1.9 eV (2), 2.2 eV (3), and 2.5 eV (4), while the 1D compounds have indirect band gaps of 2.7 eV (5), 2.5 eV (6), and 2.8 eV (7). Herein, we report on the second harmonic generation (SHG) properties of the compounds, which display remarkably strong, type I phase-matchable SHG response with high laser-induced damage thresholds (up to 3 GW/cm2). The second-order nonlinear susceptibility, S(2), was determined to be 125.3 ± 10.5 pm/V (1), (161.0 ± 14.5) pm/V (2), 143.0 ± 13.5 pm/V (3), and 57.2 ± 5.5 pm/V (4). First-principles density functional theory electronic structure calculations indicate that the large SHG response is attributed to the high density of states in the valence band due to sp-hybridization of the Ge and I orbitals, a consequence of the lone pair activation.
Access to metastable [GeH2]: N materials via a molecular "bottom-up" approach
Aku-Dominguez, Kwami,Ferguson, Michael J.,Kiran, Anagha,Medroa Del Pino, William,Minami, Yohei,Rivard, Eric,Sinclair, Jocelyn,Yasuda, Makoto
supporting information, p. 17688 - 17696 (2021/12/17)
We describe the application of a mild, molecular-based, hydride metathesis protocol for the preparation of metastable germanium(ii) dihydrides with compositions approaching [GeH2]n. The common starting material for this work [Ge(OtBu)2] was prepared in a
Gas-phase chemical equilibria in the Ge-I system
Zelenina,Titov,Titov,Chusova
, p. 720 - 723 (2007/10/03)
Thermodynamic function values were refined for three independent gas-phase chemical reactions in the Ge-I system.
Heat capacity of crystalline germanium tetraiodide
Zelenina,Minenkov,Stenin,Titov,Chusova
, p. 702 - 706 (2007/10/03)
The heat capacity of crystalline GeI4 was measured in the temperature range 6-305 K by the method of low-temperature adiabatic calorimetry. Temperature variations of the enthalpy of germanium tetraiodide were determined by mixing calorimetry in
Thermodynamic functions and phonon spectrum of Germanium tetraiodide
Paukov,Minenkov,Naumov,Zelenina
, p. 1222 - 1225 (2007/10/03)
The heat capacity of GeI4 was measured by the adiabatic method in the temperature range 6-305 K. The obtained data were used to calculate the entropy, the enthalpy, and the Gibbs energy of the compound. The characteristic temperatures related t
Formation of Halide Complexes of Methyl- and Inorganic Germanium(IV) in Aqueous Hydrohalogenic Acid Solutions
Sohrin, Yoshiki
, p. 3363 - 3371 (2007/10/02)
The reaction of methyl- and inorganic germanium(IV) hydroxides ((CH3)nGe(OH)4-n; n = 1, 2, or 3) with halide ions (X = Cl-, Br-, or I-) to form halide complexes ((CH3)nGeX4-n) in aqueous acidic solution has been investigated by liquid-liquid extraction, solid-liquid distribution (ion exchange), and 1H NMR spectrometry.It has been found that methylgermanium moieties are hard Lewis acids similarly to inorganic germanium(IV), because the stability constant of the halide complexes decreases in the order Cl- > Br- > I-.The stability constant for an X- ion increases as the number of methyl groups attached to the germanium atom increases.The species of inorganic-, monomethyl-, and dimethylgermanium are nonionic and have a tetrahedral structure in HX solution, and OJ- ions attached to the germanium atom are stepwise substituted by X- ions with an increase in HX activity.Trimethylgermanium alone forms a cation, when the activity of HX is not sufficiently high.These facts suggest that the transfer of a negative charge from methyl groups to the central germanium atom lowers the stability of the bond between the germanium atom (hard acid) and an OH- ion (hard base).
Bis(dimethylgermyl)alkane-iron tetracarbonyls: Synthesis, photolysis, and reactivity
Barrau, Jacques,Hamida, Najib Ben,Agrebi, Abdelhamid,Satge, Jacques
, p. 1585 - 1593 (2008/10/08)
This work concerns the synthesis, spectroscopic analysis, and reactivity of tetracarbonyliron bis(dimethylgermyl)alkanes Me2Ge(CH2)nGe(Me2)Fe(CO)4 (n = 1, 2). These heterocycles are obtained by cyclization of bis(dimethylgermyl)alkanes Me2HGe(CH2)nGeHMe2 (n = 1, 2) with Fe(CO)5 under UV irradiation. They are stable at room temperature, but the heterocycle with n = 1 decomposes under prolonged UV irradiation with formation of the heterocycle with n = 2, perhydrotetragermin, and (CO)3Fe(μ-GeMe2)3Fe(CO)3. Various CO substitution reactions with phosphines and cleavage reactions with organic and organometallic halides are described; they provide a convenient procedure for the generation of germanium or tin-carbonyl iron clusters. Reactions of tetracarbonyliron bis(dimethylgermyl)methane with sulfur and with oxygen presumably lead first to the dithia- (or dioxa-) digermolane Me2GeCH2Ge(Me2)Y-Y (Y = S or O) and after, by sulfur (or oxygen) loss, to thia- (or oxa-) digermetane Me2GeCH2GeMe2Y (Y = S or O), which are unstable, giving products suggestive of Me2GeY (Y = O or S) and Me2Ge=CH2 intermediates.
Chemistry of Germanium Atoms. II. Reactions of Thermally Evaporated Germanium Vapor with Organic Halides
Mochida, Kunio,Tashiro, Kumiko,Yoshida, Yasuhiro,Mizuno, Yasuhisa
, p. 1247 - 1250 (2007/10/02)
Thermally generated germanium atoms were found to react with organic halides by insertion into carbon-halogen bonds.The resulting germylenes abstracted halogens from organic halides to form trihalogermyl derivatives.Tetrahalogermanes were also formed by t
The Reaction of Germanium Atoms with Organic Halides
Mochida, Kunio,Tashiro, Kumiko
, p. 1105 - 1108 (2007/10/02)
Co-condensation of thermally evaporated germanium vapor with organic halides yields a mixture of trihalogermyl derivatives and tetrahalogermanes as major products.The nature of these reactions is discussed.
