Dimers and 2D Networks of Adamantane-Related Ternary Organosilicon Coinage Metal Sulfide Clusters.

Adamantane-type organotin sulfide clusters were recently shown to react with coinage metal phosphine complexes under replacement of an organic substituent by a metal-phosphine unit. An extension of such studies involving the silicon-based congener [(PhSi)4S6] (A) revealed that the cluster core will be partly disassembled and a {PhSi} moiety is replaced by a coinage metal phosphine complex to form [(Et3PAg)3(PhSi)3S6] (B) and [Na2(thf)2.33][(Me3PCu)(PhSi)3S6] (C). Herein, we present an extension of this work upon variation of the reactants and reaction conditions. Besides the isolation of crystalline precursor complexes [CuCl(PMe2Ph)3] (1) and [AgCl(PMe2Ph)2]2 (2), the study addresses reactions of A with AgCl and a phosphine ligand in CH2Cl2, upon which A is completely disassembled to form [(Ph3P)3Ag(µ-S)SiCl2Ph] (3). In another case a CH2 group, most likely stemming from CH2Cl2, was attached to the ligand, thus generating [{PhCl(S)SiSCH2P(Ph2)CH2CH2}2] (4). Upon using CuCl and 1,4­bis(diphenylphosphino)butane (dppb) we isolated the phosphine-bridged analog of B, [{(dppbCu2)CuP(Ph2)(CH2CH2)(PhSi)3S6}2] (5). In order to receive the yet elusive silver homolog of C, we used PMe2Ph as a bulkier ligand. This way we generated a 2D coordination polymer of the desired composition, [Na2(thf)1.5][(Me2PhPAg)(PhSi)3S6] (6). UV-visible spectra of 6 indicated a bandgap of 3.89 eV, thus blue-shifted in regards to B and C.

Assembly of One to Four As4 Analogues, (Ge2 As2 )2- or (Ge3 As)3- , in the Coordination Sphere of [PhM]+ , [MesM]+ , or M2+ (M=Zn, Cd, Hg).

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.

Between Elemental Match and Mismatch: From K12 Ge3.5 Sb6 to Salts of (Ge2 Sb2 )2- , (Ge4 Sb12 )4- , and (Ge4 Sb14 )4.

The solid mixture "K2 GeSb" was shown to comprise single-crystalline K12 Ge3.5 Sb6 (1), a double salt of K5 [GeSb3 ] with carbonate-like [GeSb3 ]5- anions, and the metallic Zintl phase K2 Ge1.5 . Extraction of 1 with ethane-1,2-diamine in the presence of crypt-222 afforded [K(crypt-222)]+ salts of several novel binary Zintl anions: (Ge2 Sb2 )2- (in 2), (Ge4 Sb12 )4- (in 3), and in the presence of [AuMePPh3 ] also (Ge4 Sb14 )4- (in 4). The anion in 2 represents a predicted, yet heretofore missing pseudo-tetrahedral anion. 4 comprises a cluster analogous to (Ge4 Bi14 )4- and (Ga2 Bi16 )4- , and thus one of the most Sb-rich binary p-block anions. The unprecedented cluster topology in 3 can be viewed as a defect-version of the one in 4 upon following a "dead end" of cluster growth. The findings indicate that Ge and Sb atoms are at the border of a well-matching and a mismatch elemental combination. We discuss the syntheses, the geometric structures, and the electronic structures of the new compounds.

High-spin carbonyl complexes of iron(I) and cobalt(I).

Metal carbonyl complexes are almost exclusively found in a low-spin state due to the strong-field nature of the CO ligand. Here the characterisation of highly labile three-coordinate metal(I) monocarbonyl complexes of iron and cobalt is presented. Experimental and quantum chemical examinations reveal their high-spin configuration.

Systematic Access of Ternary Organotetrel-Copper Chalcogenide Clusters by [PhTE3 ]3- Anions (T=Si, Sn; E=S, Se).

Fragmentation reactions of organotetrel chalcogenide heteroadamantane-type clusters [(PhT)4 E6 ] (T/E=Si/S (1); Si/Se; Sn/S, and Sn/Se) by addition of the corresponding sodium chalcogenide gave salts of the general formula Na3 [PhTE3 ], with T/E=Si/S (2); Si/Se (3); Sn/S (A); Sn/Se (4). Reaction of these salts with [Cu(PPh3 )3 Cl] gave a series of organotetrel-copper chalcogenide clusters [(CuPPh3 )6 (PhTE3 )2 ] with T/E=Si/S; (5), Si/Se (6), Sn/S (7) and Sn/Se (8). Compounds 5-8 share a common structural motif with two intact {PhTE3 } units coordinating a Cu6 moiety, which was previously reported with other ligands, and for the Sn and Ge congeners only. If the Sn/Se reaction system was allowed to crystallize more slowly, single crystals of compound [(CuPPh3 )6 (PhSnSe3 )3 Cu3 SnSe] (9) were obtained, which are based on a larger cluster structure. Hence, 9 might form from 8 through incorporation of additional cluster fragments. The experimentally and quantum chemically determined optical properties were compared to related clusters.

Insights into Formation and Relationship of Multimetallic Clusters: On the Way toward Bi-Rich Nanostructures.

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.

Atom Exchange Versus Reconstruction: (Gex As4-x )x- (x=2, 3) as Building Blocks for the Supertetrahedral Zintl Cluster [Au6 (Ge3 As)(Ge2 As2 )3 ]3.

The Zintl anion (Ge2 As2 )2- represents an isostructural and isoelectronic binary counterpart of yellow arsenic, yet without being studied with the same intensity so far. Upon introducing [(PPh3 )AuMe] into the 1,2-diaminoethane (en) solution of (Ge2 As2 )2- , the heterometallic cluster anion [Au6 (Ge3 As)(Ge2 As2 )3 ]3- is obtained as its salt [K(crypt-222)]3 [Au6 (Ge3 As)(Ge2 As2 )3 ]⋅en⋅2 tol (1). The anion represents a rare example of a superpolyhedral Zintl cluster, and it comprises the largest number of Au atoms relative to main group (semi)metal atoms in such clusters. The overall supertetrahedral structure is based on a (non-bonding) octahedron of six Au atoms that is face-capped by four (Gex As4-x )x- (x=2, 3) units. The Au atoms bind to four main group atoms in a rectangular manner, and this way hold the four units together to form this unprecedented architecture. The presence of one (Ge3 As)3- unit besides three (Ge2 As2 )2- units as a consequence of an exchange reaction in solution was verified by detailed quantum chemical (DFT) calculations, which ruled out all other compositions besides [Au6 (Ge3 As)(Ge2 As2 )3 ]3- . Reactions of the heavier homologues (Tt2 Pn2 )2- (Tt=Sn, Pb; Pn=Sb, Bi) did not yield clusters corresponding to that in 1, but dimers of ternary nine-vertex clusters, {[AuTt5 Pn3 ]2 }4- (in 2-4; Tt/Pn=Sn/Sb, Sn/Bi, Pb/Sb), since the underlying pseudo-tetrahedral units comprising heavier atoms do not tend to undergo the said exchange reactions as readily as (Ge2 As2 )2- , according to the DFT calculations.

Systematic DFT Studies on Binary Pseudo-tetrahedral Zintl Anions: Relative Stabilities and Reactivities towards Protons, Trimethylsilyl Groups, and Iron Complex Fragments.

Binary pseudo-tetrahedral Zintl anions composed of (semi)metal atoms of the p-block elements have proven to be excellent starting materials for the synthesis of a variety of heterometallic and intermetalloid transition metal-main group metal cluster anions. However, only ten of the theoretically possible 48 anions have been experimentally accessed to date as isolable salts. This brings up the question whether the other species are generally not achievable, or whether synthetic chemists just have not succeeded in their preparation so far. To contribute to a possible answer to this question, global minimum structures were calculated for all anions of the type (TrTt3 )5- , (TrPn3 )2- , and (Tt2 Pn2 )2- , comprising elements of periods 3 to 6 (Tr: triel, Al⋅⋅⋅Tl; Tt: tetrel, Si⋅⋅⋅Pb; Pn: pnictogen, P⋅⋅⋅Bi). By analyzing the computational results, a concept was developed to predict which of the yet missing anions should be synthesizable and why. Additionally, the results of an electrophilic attack by protons or trimethylsilyl groups or a nucleophilic attack by transition metal complex fragments are described. The latter yields butterfly-like structures that can be viewed as a new form of adaptable tridentate chelating ligands.

Ternary Mixed-Valence Organotin Copper Selenide Clusters.

Reactions of the organotin selenide chloride clusters [(R1 SnIV )3 Se4 Cl] (A, R1 =CMe2 CH2 C(O)Me) or [(R1 SnIV )4 Se6 ] (B) with [Cu(PPh3 )3-x Clx ] yield cluster compounds with different inorganic, mixed-valence core structures: [Cu4 SnII SnIV6 Se12 ], [Cu2 SnII2 SnIV4 Se8 Cl2 ], [Cu2 SnII SnIV4 Se8 ], [Cu2 SnII2 SnIV2 Se4 Cl4 ], and [Cu2 SnIV2 Se4 ]. Five of the compounds, namely [(CuPPh3 )2 {(R1 SnIV )2 Se4 }] (1), [(CuPPh3 )2 SnII {(R2 SnIV )2 Se4 }2 ] (2), [(CuPPh3 )2 (SnII Cl)2 {(RSnIV )2 Se4 }2 ] (3) [(CuPPh3 )2 (SnII Cu2 ){(R1 SnIV )2 Se4 }3 ] (4), and [Cu(CuPPh3 )(SnII Cu2 ){(R1 SnIV )2 Se4 }3 ] (5) are structurally closely related. They are based on [(CuPPh3 )2 {(RSnIV )2 Se4 }n ] aggregates comprising [(RSnIV )2 Se4 ] and [CuPPh3 ] building units, which are linked by further metal atoms. A sixth compound, [(CuPPh3 )2 (SnII Cl)2 {(R1 SnIV Cl)Se2 }2 ] (6), differs from the others by containing [(RSnIV Cl)Se2 ] units instead, which affects the absorption properties. The compounds were analyzed by single-crystal X-ray diffraction, NMR and 119 Sn Mössbauer spectroscopy, DFT calculations as well as optical absorption experiments.

Formation and Structural Diversity of Organo-Functionalized Tin-Silver Selenide Clusters.

When reacting the organic functionalized tin selenide clusters [(SnR1 )3 Se4 Cl] (A, R1 =CMe2 CH2 C(O)Me) or [(SnR1 )4 Se6 ] (B) with (SiMe3 )2 Se and [Ag(PPh3 )3 Cl] at -78 °C in CH2 Cl2 , a microcrystalline intermediate (compound 1) precipitates, which was investigated by magic angle spinning (MAS) NMR spectroscopy, powder X-ray diffraction (PXRD), energy dispersive X-ray (EDX) spectroscopy, and quantum chemistry calculations, to derive information about its composition and structure. Compound 1 re-dissolves under reorganization into the organo-functionalized Ag/Sn/Se cluster compound [Ag6 (µ6 -Se)(Ag8 Se12 ){(R1 Sn)2 Se2 }6 ] (2), or the mixed-valence cluster [(AgPPh3 )2 (SnII Cl)2 Se2 {(R1 SnIV )2 Se2 }2 ] (3), depending on the presence or the exclusion of daylight, respectively. The addition of N2 H4 ⋅H2 O to a solution of 1 yields selectively [Ag7 (µ7 -Se)(Ag7 Se12 ){(R2 Sn)2 Se2 }6 ] (4, R2 =CMe2 CH2 C(N2 H2 )Me), the Ag/Sn/Se core of which is isomeric to that of 2. 2-4 were characterized by X-ray diffraction. NMR spectroscopic studies on solutions of 1 indicate the co-existence of different species.

Syntheses, structures and theoretical investigations of [Au10S2(PPh2)2(dppma2)4(dppma3)]·[Au6S2(dppma2)2(dppma3)].

The synthesis, crystal structure and theoretical studies of a high-nuclear gold(i) complex stabilized by bridging aromatic phosphane ligands are reported. The complex is composed of a neutral Au10 complex unit with a horseshoe-like structure around a neutral Au6 complex unit with a distorted cubane-like structure.