ABSTRACT
Pseudo-tetrahedral units of p-block atoms proved to be excellent building blocks for novel molecular architectures and for introducing new elemental combinations which are not otherwise accessible. In this work, we present a series of clusters obtained by reactions of binary Ge/As anions with [MPh2 ] (M=Zn, Cd, Hg; Ph=phenyl). The study is grounded on the fact that the binary reactant gained by extracting the solid 'K2 GeAs' with ethane-1,2-diamine (en) co-exists as (Ge2 As2 )2- and (Ge3 As)3- in solution. This allows for a larger variety of products by 'selecting' the most suitable species for the final ternary complex to crystallize. The reactions afforded the unprecedented first step of the corresponding interaction, thus attachment of (MPh)+ to a pseudo-tetrahedral unit in [PhZn(Ge3 As)]2- (1) and [PhHg(Ge3 As)]2- (2), and complex anions with two, three, or four units, [(Ge3 As)Zn(Ge2 As2 )]3- (3), [Cd3 (Ge3 As)3 ]3- (4), and [Zn3 (Ge3 As)4 ]6- (5). Quantum chemistry confirmed the compositions and the positions of the Ge or As atoms, beside explaining structural peculiarities. The subtle impact of different [MR2 ] reactants was additionally studied by corresponding reactions using [ZnMes2 ] (Mes=mesityl), which showed success in selectively crystallizing [MesZn(Ge3 As)]2- (6). Based on our findings, we derive a suggestion of the underlying reaction cascade.
ABSTRACT
Bismuth-rich polyanions show a unique potential in constructing nanostructured bismuth-based materials, but they are still poorly investigated. We use a ternary precursor of the nominal composition "K5Ga2Bi4" for the formation of [K(crypt-222)]+ salts of novel Bi-rich polyanions [Bi@Ga8(Bi2)6]q- (q = 3, 5; in 1), (Ga2Bi16)4- (in 2), and [{Ru(cod)}4Bi18]4- (in 3). Their bismuth contents exceed that of the largest homoatomic polyanion, Bi113-. The numbers of bismuth atoms in the anions in 2 and 3 furthermore surmount that of the Bi-richest binary main-group anion, (Ge4Bi14)4-, and they equal (2) or surmount (3) that reported for the anion and the cations with the largest number of Bi atoms so far, [K2Zn20Bi16]6-, [(Bi8)Ru(Bi8)]6+, and [(Bi8)Au(Bi8)]5+. Compounds 1 and 2 were obtained from reaction mixtures that contain [La(C5Me4H)3], apparently assisting in the network formation without being included in the products. In the presence of [Ru(cod)(H2CC(Me)CH2)2], yet another reaction pathway leads to the formation of the anions in 3 (conformers 3a and 3b), which are Bi-Bi linked dimers of two "[{Ru(cod)}2Bi9]2-" subunits. They comprise the largest connected assemblies of Bi atoms within one molecule and may be viewed as snapshots on the way toward even larger polybismuthide units and, ultimately, new bismuth modifications. Mass spectrometry allowed insight into the processes in solution that precede the cluster formation. In-depth quantum chemical studies were applied to explain structural peculiarities, stabilities of the observed isomers, and bonding characteristics of these bismuth-rich nanoarchitectures. The work demonstrates the high potential of the method for the access of new Bi-based materials.
ABSTRACT
Orange, transparent crystals of [BMIm]2[Mn(CO)3(GeI3)3] (BMIm: 1-butyl-3-methylimidazolium) are obtained by reacting GeI4, [Mn(CO)6][AlCl4], and Ph3GeH in the ionic liquid [BMIm][NTf2]. [Mn(CO)6][AlCl4] and triphenylgermane turn out to be essential as reactive carbonyl precursors and for the reduction of GeI4. According to X-ray structure analysis based on single crystals, the title compound exhibits a novel {MnGe3} cluster unit with Mn-Ge single bonds and surprisingly short distances (236-241 pm). Although sensitive to oxygen/moisture, the carbonyl compound is stable up to a temperature of 150 °C. Mass spectrometry (MS) shows [Mn(CO)3(GeI3)2]-, [Mn(CO)3(GeI3)I]-, and [GeI3]- as decomposition fragments in the gas phase. In addition to crystal structure analysis and MS, the title compound is characterized by energy-dispersive X-ray spectroscopy (EDXS), thermogravimetry (TG), optical spectroscopy (UV-visible), infrared spectroscopy (FT-IR), and density functional theory (DFT) calculations.
