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1.
Inorg Chem ; 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33764781

RESUMO

The crystalline selenido germanates [Li4(H2O)16][Ge4Se10]·4.3H2O (1), [{Li4(thf)12}Ge4Se10] (2), and [Li2(H2O)8][MnGe4Se10] (3) (thf = THF = tetrahydrofuran) were obtained by an extraction of a glassy ternary phase of the nominal composition Li4Ge4Se10 (=Li2S·2GeSe2) with water (1) or THF (2) and slow evaporation of the solvent or by being layered with MnBr2 in H2O/MeOH (3), respectively. The compounds contain known selenido germanate anions, however, for the first time with Li+ counterions. This is especially remarkable for the prominent ∞3{[MnGe4Se10]2-} open-framework structure, which was reported to crystallize with (NMe4)+, Cs+, Rb+, and K+ counterions, but it has not yet been realized with the smallest alkali metal cation. Impedance spectroscopic studies on Li4Ge4Se10 classify the glassy solid as a moderate Li+ ion conductor.

2.
Nat Chem ; 2020 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-33288891

RESUMO

The concept of aromaticity was originally defined as a property of unsaturated, cyclic planar organic molecules like benzene, which gain stability by the inherent delocalization of 4n + 2 π-electrons over the ring atoms. Since then, π-aromaticity has been observed for a large variety of organic and inorganic non-metal compounds, yet, for molecules consisting only of metal atoms, it has remained restricted to systems with three to five atoms. Here, we present the straightforward synthesis of a metal 12-ring that exhibits 2π-aromaticity and has a ring current much stronger than that of benzene (6π) and equivalent to that of porphine (26π), despite these organic molecules having (much) larger numbers of π-electrons. Highly reducing reaction conditions allowed access to the heterometallic anion [Th@Bi12]4-, with interstitial Th4+ stabilizing a Bi128- moiety. Our results show that it is possible to design and generate substantial π-aromaticity in large metal rings, and we hope that such π-aromatic heavy-metal cycles will eventually find use in cluster-based reactions.

4.
Artigo em Inglês | MEDLINE | ID: mdl-33006797

RESUMO

We report about the successful extension of the class of organogtetrel sulfide clusters by further examples of the still rare silicon-based species, synthesized from RSiCl 3 with R = phenyl (Ph, I ), naphthyl (Np, II ), and styryl (Sty, III ) with Na 2 S. Besides known [(PhSi) 4 S 6 ] ( IV ), new compounds [(NpSi) 4 S 6 ] ( 1 ) and [(StySi) 4 S 6 ] ( 2 ) were obtained, the first two of which underwent follow-up reactions with [AuCl(PPh 3 )] to form ternary complexes. Density functional theory (DFT) studies of cluster dimers helped to understand fundamental differences between the habitus of {Si 4 S 6 }-based vs. {Sn 4 S 6 }-based compounds. Investigations of the optical properties of crystalline compound 1 and intrinsically amorphous 2 indicated the former to show a pronounced nonlinear optical response, i.e. , second-harmonic generation, while for the latter, the chemical damage threshold seems to inhibit a corresponding observation that can be clearly put down to nonlinear optical effects. Calculations within the independent particle approximation (IPA) served to rationalize and compare electronic and optical excitations of [(RSi) 4 S 6 ] clusters (R = Ph, Np). The calculations reproduced the measured data and allowed for the interpretation of the main spectroscopic features.

5.
Nat Commun ; 11(1): 5122, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33046705

RESUMO

The access to molecules comprising direct Zn-Zn bonds has become very topical in recent years for various reasons. Low-valent organozinc compounds show remarkable reactivities, and larger Zn-Zn-bonded gas-phase species exhibit a very unusual coexistence of insulating and metallic properties. However, as Zn atoms do not show a high tendency to form clusters in condensed phases, synthetic approaches for generating purely inorganic metalloid Znx units under ambient conditions have been lacking so far. Here we show that the reaction of a highly reductive solid with the nominal composition K5Ga2Bi4 with ZnPh2 at room temperature yields the heterometallic cluster anion [K2Zn20Bi16]6-. A 24-atom polymetallide ring embeds a metalloid {Zn12} unit. Density functional theory calculations reveal multicenter bonding, an essentially zero-valent situation in the cluster center, and weak aromaticity. The heterometallic character, the notable electron-delocalization, and the uncommon nano-architecture points at a high potential for nano-heterocatalysis.

6.
Chemistry ; 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32936477

RESUMO

Herein, we present the synthesis of two pyrene-functionalized clusters, [(R pyr Sn) 4 S 6 ]·2CH 2 Cl 2 ( 4 ) and [(R pyr Sn) 4 Sn 2 S 10 ]·nCH 2 Cl 2 (n = 4, 5a ; n = 2, 5b ; R pyr  = CMe 2 CH 2 C(Me)N-NC(H)C 16 H 9 ), both of which form in reactions of the organotin sulfide cluster [(R N Sn) 4 S 6 ] ( C ; R N = CMe 2 CH 2 C(Me)N-NH 2 ) with the well-known fluorescent dye 1-pyrenecarboxaldehyde ( B ). In contrast, reactions using an organotin sulfide cluster with another core structure, [(R N Sn) 3 S 4 Cl] ( A ), leads to formation of small molecular fragments, [(R pyr Cl 2 Sn) 2 S] ( 1 ), (pyren-1-ylmethylene)hydrazine ( 2 ), and 1,2-bis(pyren-1-ylmethylene)hydrazine ( 3 ). Besides synthesis and structures of the new compounds, we report the influence of the inorganic core on the optical properties of the dye, which was analyzed exemplarily for compound 5a via absorption and fluorescence spectroscopy. This cluster was also used for exploring the potential of such non-volatile clusters for deposition on a metal surface under vacuum conditions.

7.
Chemistry ; 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32876359

RESUMO

Multinary chalcogenido (semi)metalate salts exhibit finely tunable optical properties based on the combination of metal and chalcogenide ions in their polyanionic substructure. Here, we present the structural expansion of chalcogenido germanate(IV) or stannate(IV) architectures with SbIII , which clearly affects the vibrational and optical absorption properties of the solid compounds. For the synthesis of the title compounds, [K4 (H2 O)4 ][Ge4 S10 ] or [K4 (H2 O)4 ][SnS4 ] were reacted with SbCl3 under ionothermal conditions in imidazolium-based ionic liquids. Salt metathesis at relatively low temperatures (120 °C or 150 °C) enabled the incorporation of (formally) Sb3+ ions into the anionic substructure of the precursors, and their modification to form (Cat)16 [Ge2 Sb2 S7 ]6 [GeS4 ] (1) and (Cat)6 [Sn10 O4 S20 ][Sb3 S4 ]2 (2 a and 2 b), wherein Cat=(C4 C1 C1 Im)+ (1 and 2 a) or (C4 C1 C2 Im)+ (2 b). In 1, germanium and antimony atoms are combined to form a rare noradamantane-type ternary molecular anion, six of which surround an {GeS4 } unit in a highly symmetric secondary structure, and finally crystallize in a diamond-like superstructure. In 2, supertetrahedral oxo-sulfido stannate clusters are generated, as known from the ionothermal treatment of the stannate precursor alone, yet, linked here into unprecedented one-dimensional strands with {Sb3 S4 } units as linkers. We discuss the single-crystal structures of these uncommon salts of ternary and quaternary chalcogenido (semi)metalate anions, as well as their Raman and UV-visible spectra.

8.
Inorg Chem ; 59(17): 12895-12902, 2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32845616

RESUMO

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.

9.
Angew Chem Int Ed Engl ; 59(38): 16638-16643, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32648322

RESUMO

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.

11.
Angew Chem Int Ed Engl ; 59(34): 14251-14255, 2020 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-32449980

RESUMO

The pseudo-element concept, in its most general formulation, states that isoelectronic atoms form equal numbers of bonds. Hence, clusters such as Zintl ions usually retain their structure upon isoelectronic replacement of some or all atoms. Here, a deviation from this common observation is presented, namely the formation of (Sn5 Sb3 )3- (1), a rare example of an eight-vertex Zintl ion, and an unprecedented example of a Zintl ion synthesized by solution means that has an arachno-type structure according to the Wade-Mingos rules. Three structure-types of interest for (Sn5 Sb3 )3- were identified by DFT calculations: one that matched the X-ray diffraction data, and two that that were reminiscent of fragments of known clusters. A study on the isoelectronic series of clusters, (Snx Sb8-x )2-x (x=0-8), showed that the relative energies of these three isomers vary significantly with composition (independent of electron count) and that each is the global minimum at least once within the series.

12.
Chem Commun (Camb) ; 56(35): 4769-4772, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32281999

RESUMO

We report the syntheses of two new organotin sulfide clusters with heteroaromatic substituents. A phenanthroline-functionalized tin sulfide cluster [(RPhenSn)4S6] (1; RPhen = CMe2CH2C(Me)N-NC(H)C12H7N2) and a bipyridyl-terminated cluster [(R4-bipySn)4S6] (2; R4-bipy = CMe2CH2C(Me)N-NC(H)-4-C10H7N2) were obtained from reactions of the hydrazone-functionalized organotin sulfide cluster [(RNSn)4S6] (RN = CMe2CH2C(Me)N-NH2) with 1,10-phenanthroline-5-carboxaldehyde or 2,2'-bipyridine-4-carbaldehyde. 1 and 2 were tested towards their capability of trapping metal ions by means of the terminal chelating ligands. The reaction of 2 with ZnCl2 afforded the cluster compound [(R4-bipyZnCl2Sn)4S6] (5), in which four ZnCl2 units are coordinated by the heteroaromatic organic groups. We discuss the structures and demonstrate the effect of ZnCl2 trapping on optical absorption and luminescence properties.

14.
Chemistry ; 26(51): 11819-11828, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32285972

RESUMO

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.

15.
Inorg Chem ; 59(6): 3341-3343, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32172571
16.
Chem Sci ; 11(1): 16-26, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-32110355

RESUMO

This perspective summarizes highlights and most recent advances in tin cluster chemistry, thereby addressing the whole diversity of (mostly) discrete units containing tin atoms. Although being a (semi-)metallic element, tin is in the position to occur both in formally positive or negative oxidation states in these molecules, which causes a broad range of fundamentally different properties of the corresponding compounds. Tin(iv) compounds are not as oxophilic and not as prone to hydrolysis as related Si or Ge compounds, hence allowing for easier handling and potential application. Nevertheless, their reactivity is high due to an overall reduction of bond energies, which makes tin clusters interesting candidates for functional compounds. Beside aspects that point towards bioactivity or even medical applications, materials composed of naked or ligand-protected tin clusters, with or without bridging ligands, show interesting optical, and ion/molecule-trapping properties.

17.
Inorg Chem ; 59(1): 198-202, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31876146

RESUMO

We report the formation and structures of two new organotin-copper selenide clusters that were obtained in a two-step procedure. First, [(R1Sn)4Se6] [R1 = CMe2CH2C(O)Me] is reacted with [Cu(PPh3)3Cl] and (SiMe3)2Se to form a bright-orange powder, the nature of which could not be identified in detail, yet a suspension of it in CH2Cl2 reacts with N2H4·H2O to afford single crystals of two cluster compounds, either [(Cu3Sn){(R2Sn)2Se4}2{(R2Sn2)Se3}] (1) or [(N2H4)(Cu4Sn){(R2Sn)2Se4}3] [2; R2 = CMe2CH2C(NNH2)Me]. Both are based on an intermetallic CuxSn cluster core (x = 3, 4), which is surrounded by organotin selenide units in different fashions. The results foster the assumption of a complex equilibrium to be present in according reaction mixtures.

18.
Angew Chem Int Ed Engl ; 58(47): 17041-17046, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31509340

RESUMO

Adamantane-type organotin chalcogenide clusters of the general composition [(RT)4 S6 ] (R=aromatic substituent, T=Si, Ge, Sn) have extreme non-linear optical properties that lead to highly directional white-light generation (WLG) upon irradiation with an IR laser diode. However, the mechanism is not yet understood. Now, a series of compounds [(RSn)4 E6 ] (R=phenyl, cyclopentadienyl, cyclohexyl, benzyl, CH2 CH2 (C6 H4 )CO2 Et; E=S, Se), were prepared, characterized, and investigated for their nonlinear optical properties. With the exception of crystalline [(BnSn)4 S6 ], all these compounds exhibit WLG with similar emission spectra; slight blue-shifts are observed by introduction of cyclopentadienyl substituents, while the introduction of Se in the inorganic core can provoke a red-shift. These investigations disprove the initial assumption of an aromatic substituent being a necessary precondition; the precondition seems to be the presence of (cyclic) substituents providing enough electron density.

19.
J Am Chem Soc ; 141(41): 16494-16500, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31549829

RESUMO

With the aim to mimic the yet unknown covalent deposition of metal chalcogenide clusters on transition metal dichalcogenide (TMDC) MoS2 or WS2 layers, and thereby explore the interaction between the two systems and potential consequences on physical properties of the TMDC material, we synthesized heterobimetallic model systems. The heterocubane-type cluster [(SnCl3)(WCp)3S4] (1), the organotin-sulfidomolybdate cluster [{(PhSn)3SnS6}{(MoCp)3S4}] (2), and the corresponding tungstate [(PhSn)3SnS6{(WCp)3S4}] (3) were obtained in ligand exchange reactions from [(PhSn)4S6] and [M(CO)3CpCl]. Indeed, the {M3S4} cages in 1-3 resemble a section of the respective TMDC monolayers, altogether representing minimal molecular model systems for the adsorption of organotin sulfide clusters on MoS2 or WS2. The interaction between the {(MCp)3S4} and {(PhSn)3SnS6} subunits is characterized by multicenter bonding, rendering the respective Sn atom as Sn(II), hence driving the clusters into a mixed-valence Sn(IV)/Sn(II) situation, and the M atoms as M(IV) upon an in situ redox process. The attachment is thus weaker than via regular covalent M-S bonds, but definitely stronger than via van der Waals interactions that have been characteristic for all known interactions of clusters on TMDC surfaces so far. Computational analyses of an extended model mimicking the electronic situation in the cluster prove the analogy to a covalent attachment on TMDCs.

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