Pnictogen Dications Supported by BZIMPY Ligands.

Two homologous series of pnictogen(III) dications, stabilized by 2,6-bis(benzimidazole-2-yl)pyridine ligands have been prepared. Both series contain Pn-X moieties (Pn = P, As, Sb, Bi; X = Cl or Ph) and have been fully characterized using spectroscopic methods including X-ray crystallography. The Lewis acidity of these compounds has also been probed by computational methods; the results suggest that the dictations are strong Lewis acids, with the PnCl compounds being more acidic than the PnPh compounds, and with Lewis acidity increasing from P to Bi, in both series.

Synthesis, Characterization, and Single-Crystal X-ray Structures of Refractory Metal Compounds as Precursors for the Single-Source Chemical Vapor Deposition of Metal Nitrides.

The chemical vapor deposition of refractory metal nitrides requires volatile precursors and has previously been achieved by using metal complexes containing a variety of imide ligands. Recently, the 1,4-di--butyl-1,3-diazabutadiene (DAD) adduct of bis(-butylimide)dichloridemolybdenum(VI) was shown to be an excellent precursor for the single-source CVD of MoN thin films. Leveraging the success of this work, we prepared chromium and tungsten compounds with the same framework.

P and P Ions Supported by BZIMPY Ligands.

We report a class of compounds in which both P -X and P forms featuring the same ligand are stable and readily cycled with each other. A series of P -X (X=Cl, Br, I) dicationic triflate salts supported by benzyl- and allyl-substituted 2,6-bis(benzimidazole-2-yl)pyridine (BZIMPY) ligands is synthesized. Surprisingly, treatment of these with R PO (R=Et, Oct) results in reduction to BZIMPY-ligated P monocationic triflate salts while treatment with Ph P reduces but also substitutes the compound to produce Ph P-BZIMPY-ligated P dicationic triflate salts.

An Improved Synthesis of PN-adamantanoid Cages P (NR) and a Mechanistic Study of their Fourfold Oxidation.

Phosphorus-nitrogen (PN) adamantanoid cages are valuable precursors for materials chemistry, but their syntheses are based on harsh methods that sometimes require access to restricted reagents. We report a new and scalable synthesis of PN adamantanoid compounds by chlorosilane elimination between bis-silylated amines and phosphorus trichloride. We further study the mechanism of the recently-reported four-fold oxidation of such cages with Me SiN to yield tetravalent tetrahedral connectors for materials chemistry.

Disturbance of intermolecular forces: eutectics as a new tool for the preparation of vapor-phase deposition precursors.

The volatile bis(-butylimido)dichloromolybdenum(VI) compounds, (BuN)MoCl·dad (dad = 1,4-di--butyl-1,3-diazabutadiene) (1) and [(BuN)MoCl(-Cl)·(BuNH)] (2), form a eutectic, with a two to one composition ( = 0.33). A decrease of 40 °C in the melting temperature has been observed between the eutectic mixture and the pure compounds.

Origin of Decomposition in a Family of Molybdenum Precursor Compounds.

The bis(-butylimido)-molybdenum(VI) framework has been used successfully in the design of vapor-phase precursors for molybdenum-containing thin films, so understanding its thermal behavior is important for such applications. Here, we report the thermal decomposition mechanism for a series of volatile bis(alkylimido)-dichloromolybdenum(VI) adducts with neutral ,'-chelating ligands, to probe the stability and decomposition pathways for these molecules. The alkyl groups explored were -butyl, -pentyl, 1-adamantyl, and a cyclic imido (from 2,5-dimethylhexane-2,5-diamine).

Thermal Stability and Decomposition Pathways in Volatile Molybdenum(VI) Bis-imides.

The vapor deposition of many molybdenum-containing films relies on the delivery of volatile compounds with the general bis(butylimido)molybdenum(VI) framework, both in atomic layer deposition and chemical vapor deposition. We have prepared a series of (BuN)MoCl adducts using neutral ,'-chelates and investigated their volatility, thermal stability, and decomposition pathways. Volatility has been determined by thermogravimetric analysis, with the 1,4-di--butyl-1,3-diazabutadiene adduct () found to be the most volatile (1 Torr of vapor pressure at 135 °C).

Heavy Metals Make a Chain: A Catenated Bismuth Compound.

Catenation is common for the light main-group elements whereas it is rare for the heavy elements. Herein, we report the first example of a neutral molecule containing a Bi chain. It is prepared in a one-step reaction between bismuth trichloride and bis(diisopropylphosphino)amine in methanol suspension.

Coordination, reactivity, and structural properties of electron-rich ethoxy- and dimethylamino-substituted 1,3-diketiminate ligands and their complexes.

In this paper we describe the synthesis, characterization, and X-ray crystal structures of two ligands, diethyl-N,N'-bis(p-tolyl)malonimidate and 1,3-bis(dimethylamino)-N,N'-bis(p-tolyl)propanediimidate. Their corresponding rhodium(i) dicarbonyl, dimethylaluminium, and bis-ligated zinc complexes have also been prepared and characterized. The donor properties of the ligands have been studied and have been compared to those of the traditional anionic N,N'-chelating ligand nacnac.

Crystal structure of 2,4,6-tri-methyl-benzoic anhydride.

The title compound, CHO, was formed in the reaction between 2,4,6-tri-methyl-benzoic acid and ,-diiso-propyl-ethyl-amine in the presence of 1,3-di-chloro-1,3-bis-(di-methyl-amino)-propenium hydrogen dichloride, and was recrystallized from diethyl ether solution. It is the first exclusively alkyl-substituted benzoic anhydride to have been structurally characterized. The asymmetric unit consists of a half mol-ecule, the other half of which is generated by twofold rotation symmetry; the dihedral angle between the symmetry-related aromatic rings is 54.

Rapid, Reversible, Solid-Gas and Solution-Phase Insertion of CO2 into In-P Bonds.

The P,P-chelated heteroleptic complex bis[bis(diisopropylphosphino)amido]indium chloride [(i-Pr2P)2N]2InCl was prepared in high yield by treating InCl3 with 2 equiv of (i-Pr2P)2NLi in Et2O/tetrahydrofuran solution. Samples of [(i-Pr2P)2N]2InCl in a pentane slurry, a CH2Cl2 solution, or in the solid state were exposed to CO2, resulting in the insertion of CO2 into two of the four M-P bonds to produce [O2CP(i-Pr2)NP(i-Pr2)]2InCl in each case. Compounds were characterized by multinuclear NMR and IR spectroscopy, as well as single-crystal X-ray diffraction.

Comment on "crystallographic snapshot of an arrested intermediate in the biomimetic activation of CO2 ".

Out of focus: A recent Communication published in this journal describes the synthesis of [nBu4 N]HCO3 . The authors performed a single-crystal X-ray study that revealed a putative species described as an incipient hydroxide ion engaging in a long, and presumably weak, interaction with CO2 . Our recent exploration of the coordination chemistry of CO2 with small ions leads us to believe that such an exceptional bonding situation is unlikely.