Synthesis and structural characterization of metal–organic frameworks with the mellitate linker M2(OH)2[C12O12H2]·2H2O (M = Al,Ga, In) MIL-116

A new series of isostructural MOF-type carboxylates called MIL-116 (M₂(OH)₂[C₁₂O₁₂H₂]·2H₂O), was synthesized from the combination of mellitic acid and trivalent p cations M = Al³⁺, Ga³⁺ or In³⁺. Their structures were analyzed either by single-crystal microdiffraction using the synchrotron radiation beamline (ID13 station at ESRF, Grenoble) or solved from powder X-ray diffraction. The 3D hybrid framework is built up from the connection of infinite straight chains of metal-centered octahedra sharing trans corners linked to each other through the mellitate ligands. Here the ligand acts as octadentate linker with four of the carboxylic groups involved in the M–O–C bondings. The two other carboxylate arms remain non-bonded under their protonated form. This represents a rare case of the occurrence of both non-bonding and bonding organic functionalities in a MOF-type solid. Within the tunnels are located water species that interact with the non-coordinated –COOH groups pointing towards the channel.     

A One-Pot Procedure to Prepare S-Protected 4-Iodothiophenols

By means of non-aqueous reduction of pipsyl chloride followed by treatment with K₂CO₃ and then reacting with acetyl chloride or benzyl chloride, S-acetyl/benzyl -4-iodothiophenols were obtained in a one-pot procedure with yield as high as 90%. These S-protected arenethiols are very important intermediates to synthesize self-assembled molecular wires.     

A New High Pressure - Low Temperature Process for the Synthesis and the Crystal Growth of Gallium Nitride

Gallium nitride can be synthesized by a solvothermal route using ammonia as solvent and a nitriding additive (such as hydrazine hydrochloride NH 2 NH 3 Cl or sodium azide NaN 3 ) encapsulated in melt gallium as chemical reagents. The involved temperature and pressure are respectively 600 °C and 150 MPa. The synthesized products are then characterized by X-Ray Diffraction and Scanning Electron Microscopy. The synthesis parameters influence the powder morphology and purity.     

Theoretical investigation of the GaF molecule and its positive ion

Coupled pair approximation and configuration interaction calculations were carried out on the gallium fluoride molecule and its positive ion with flexible basis sets. Spectroscopic constants of these species were examined in detail through step-wise extensions of correlating space. The contribution from correlations of the semi-core 3d electrons in Ga was found to be sizable. The bonding character was revealed to be highly ionic even for the positive ion. Received: 13 June 1998/Accepted: 28 August 1998 / Published online: 7 December 1998     

REGaSi的合成、结构及Ga-Si成键网络

用电弧熔炼法合成了系列化合物ＲＥＧａＳｉ,采用粉末Ｘ射线衍射方法测定了化合物ＳｍＧａＳｉ的晶体结构,获得其晶体学及结构修正参数为;四方晶系,ＬａＰｔＳｉ类型,（１０９）Ｉ４１ｍｄ,Ｍｒ＝２５０．０,ａ＝０．４１３４（３）ｎｍ,ｃ＝１．４２２（２）ｎｍ,Ｖ＝０．２４３０（５）ｎｍ＾３,Ｚ＝４,Ｄｘ＝６．４６４ｇ．ｃｍ＾－３,Ｆ（０００）＝４２８,Ｔ＝２９６Ｋ。     

X‐Ray Photoemission Studies of the Ternary Intermetallic Compounds Li2MGa and LiMGa2 (M = Rh,Pd, Ir,Pt)

X‐ray photoelectron and x‐ray excited Auger spectra were measured for the intermetallic compounds LiMGa₂ and Li₂MGa (M = Rh, Pd, Ir, Pt). The valence band spectra exhibit characteristic differences in the location of the M d‐band between group 9 elements (Rh, Ir) and group 10 elements (Pd, Pt) on one side and between LiMGa₂ and Li₂MGa on the other. The experimentally observed differences are in excellent agreement with results from band structure calculations. The combination of binding energy shifts with Auger kinetic energy shifts allowed a separation of initial and final state contributions. Core hole screening is very efficient in accordance with the metallic character of the investigated phases. The magnitude of the screening correlates with the theoretically predicted composition of the density of states at the Fermi level. Application of Wertheim's electrostatic model allowed to estimate the charge distribution for LiRhGa₂ and Li₂RhGa. The sign of the charges agrees with expectations that result from the Extended Zintl Concept. The results show, how dangerous it is to draw conclusions on the chemistry of such systems from photoemission data alone.     

Synthese und Kristallstruktur von iso‐Butylimidogalliummethyl, [CH3Ga–NCH2CH(CH3)2]6

Synthesis and X‐Ray Structure Determination of iso ‐Butylimido Galliummethyl, [CH₃Ga–NCH₂CH(CH₃)₂]₆ The thermal decomposition of [Me₂Ga–N(ⁱBu)SnMe₃]₂ (prepared by the reaction of [Me₂SnNⁱBu]₃ with GaMe₃ in a 1:3 molar ratio) in an evacuated, sealed tube at 160°C forms [MeGaNⁱBu]₆ in high yield and SnMe₄. Mass, ¹H and ¹³C NMR as well as some IR and Raman spectroscopic data are given and the crystal structure of this cage molecule with a hexagonal prismatic Ga₆N₆ skeleton has been determined.