RESUMEN

The aminotroponiminate (ATI) ligand stabilized germylene cation [(i-Bu)2ATIGe][B(C6F5)4] (2) is found to be an efficient low-valent main-group catalyst for the cyanosilylation of aldehydes and ketones (ATI=aminotroponiminate). It was synthesized by reacting [(i-Bu)2ATIGeCl] (1) with Na[B(C6F5)4]. The catalytic cyanosilylation of diverse aliphatic and aromatic carbonyl compounds (aldehydes and ketones) using 0.075-0.75 mol% of compound 2 was completed within 5-45 min. The catalytic efficiency seen with aliphatic aldehydes was around 15,800 h-1, making compound 2 a capable low-valent main-group catalyst for the aldehyde and ketone cyanosilylation reactions. Further, DFT calculations reveal a pronounced charge localization at the germanium atom of compound 2, leading to its superior catalytic performance.

RESUMEN

Low-valent main group compounds that fluoresce in the solid-state were previously unknown. To address this, we investigated room-temperature photoluminescence from a series of crystals of germylenes 3-8 in this article; they exhibited emissions nearly reaching the NIR. Germylene carboxylates (3-8) were synthesized by reacting dipyrromethene stabilized germylene pyrrolide (2) with carboxylic acids such as acetic acid, trifluoroacetic acid, benzoic acid, p-cyanobenzoic acid, p-nitrobenzoic acid, and acetylsalicylic acid.

RESUMEN

The possibility of using aza-dipyrromethene (a-DPM) ligands to stabilize compounds containing low-valent main group elements is demonstrated through the isolation of germylenes, a-DPM(p-tol)GeCl (2), a-DPM(Naph)GeCl (6), and a-DPM(Naph)GeN(TMS)2 (7) (tol=tolyl, Naph=naphthyl). Because of the presence of the a-DPM ligand, these germylenes exhibit an absorption maximum at around 640 nm, a highly red-shifted value previously unknown for germylenes.

RESUMEN

Germacarbonyl compounds are the germanium analogs of carbonyl compounds requiring an inert atmosphere for stability. Making these compounds survive the ambient conditions was not feasible given the lability of the Ge[double bond, length as m-dash]E bonds (E = O, S, Se, Te). However, the first examples of germacarbonyl compounds synthesized under ambient conditions by taking advantage of dipyrromethene ligand stabilization are detailed here; the isolated compounds are thiogermanone 3, selenogermanone 4, thiogermacarboxylic acid 6, selenogermacarboxylic acid 7, thiogermaester 9, selenogermaester 10, thiogermaamide 12, and selenogermaamide 13 with Ge[double bond, length as m-dash]E bonds (E = S, Se). Compounds 12 and 13 can react under atmospheric conditions with copper(i) halides offering air and water stable monomeric 14-15 and dimeric 16-19 copper(i) complexes (halide = Cl, Br, I). Apart from just binding, selectivity was also observed; thiogermaamide 12 and selenogermaamide 13 bind CuCl and CuBr, respectively, when treated with a mixture of copper(i) halides.

RESUMEN

Two routes can offer the first stannylene cyanide [(L)SnCN] (5); the substitution reaction of either stannylene amide [(i-Bu)2ATISnN(SiMe3)2] (3) or stannylene pyrrolide [(i-Bu)2ATISn(NC4H4)] (4) using an excess of trimethylsilyl cyanide (L = aminotroponiminate (ATI)). Using 0.1-2.0 mol% of compound 5, catalytic cyanosilylation of a variety of aliphatic and aromatic aldehydes was achieved at rt-50 °C in 0.33-2.0 h. The mechanism of this catalytic reaction is authenticated by the isolation of a structurally characterized intermediate.

RESUMEN

The biological applications of germylenes remain unrealised owing to their unstable nature. We report the isolation of air-, water-, and culture-medium-stable germylene DPMGeOH (3; DPM=dipyrromethene ligand) and its potential biological application. Compound 3 exhibits antiproliferative effects comparable to that of cisplatin in human cancer cells. The cytotoxicity of compound 3 on normal epithelial cells is minimal and is similar to that of the currently used anticancer drugs. These findings provide a framework for a plethora of biological studies using germylenes and have important implications for low-valent main-group chemistry.

Asunto(s)

Complejos de Coordinación/química , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Chlorocebus aethiops , Complejos de Coordinación/farmacología , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Ligandos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Células Vero

RESUMEN

This manuscript reports the first examples of germylene stabilized cadmium complexes {[{(i-Bu)2ATIGe(i-Pr)}2(CdI2)] (3, monomeric), [{(i-Bu)2ATIGe(i-Pr)(CdCl2)}2] (6, dimeric), [{(i-Bu)2ATIGe(i-Pr)(CdI2)}2] (7, dimeric)} and novel germylene zinc complexes {[{(i-Bu)2ATIGe(i-Pr)}2(ZnCl2)] (2, monomeric), [{(i-Bu)2ATIGe(i-Pr)(ZnI2)}2] (5, dimeric)} (ATI = aminotroponiminate). The reactions of germylene zinc complex [{(i-Bu)2ATIGe(i-Pr)(ZnCl2)}2] (4) with elemental sulphur and selenium resulted in the first examples of germathione and germaselenone stabilized ZnCl2 complexes [{(i-Bu)2ATIGe(i-Pr)(S)(ZnCl2)}2] (8) and [{(i-Bu)2ATIGe(i-Pr)(Se)(ZnCl2)}2] (9), respectively. Compound 4 was obtained through the reaction of compound 2 with ZnCl2. Interconversions between the monomeric and dimeric zinc/cadmium complexes (2 ↔ 4/3 ↔ 7) are shown. Compounds 2-3 and 5-9 are characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction studies are performed on compounds 2-3, 5-7, and 9. To understand the nature of bonding in the first examples of germylene cadmium complexes, ab initio calculations are also carried out on compounds 3 and 7.

RESUMEN

Germaacid chloride, germaester, and N-germaacyl pyrrole compounds were not known previously. Therefore, donor-acceptor-stabilised germaacid chloride (i-Bu)2ATIGe(O)(Cl) → B(C6F5)3 (1), germaester (i-Bu)2ATIGe(O)(OSiPh3) → B(C6F5)3 (2), and N-germaacyl pyrrole (i-Bu)2ATIGe(O)(NC4H4) → B(C6F5)3 (3) compounds, with Cl-Ge[double bond, length as m-dash]O, Ph3SiO-Ge[double bond, length as m-dash]O, and C4H4N-Ge[double bond, length as m-dash]O moieties, respectively, are reported here. Germaacid chloride 1 reacts with PhCCLi, KOt-Bu, and RLi (R = Ph, Me) to afford donor-acceptor-stabilised germaynone (i-Bu)2ATIGe(O)(CCPh) → B(C6F5)3 (4), germaester (i-Bu)2ATIGe(O)(Ot-Bu) → B(C6F5)3 (5), and germanone (i-Bu)2ATIGe(O)(R) → B(C6F5)3 (R = Ph 6, Me 7) compounds, respectively. Interconversion between a germaester and a germaacid chloride is achieved; reaction of germaesters 2 and 5 with TMSCl gave germaacid chloride 1, and 1 reacted with Ph3SiOLi and KOt-Bu to produce germaesters 2 and 5. Reaction of N-germaacyl pyrrole 3 with thiophenol produced a donor-acceptor-stabilised germaacyl thioester (i-Bu)2ATIGe(O)(SPh) → B(C6F5)3 (10). Furthermore, the attempted syntheses of germaamides and germacarboxylic acids are also discussed.

RESUMEN

Well-defined germylene cations [(i-Bu)2ATI]GeOTf (4) and [(i-Bu)2ATIGe][GaCl4] (5) are isolated, and the catalytic utility of compound 4 for the hydroboration of a variety of aldehydes and ketones is reported (ATI = aminotroponiminate).

RESUMEN

A triflatostannylene [L†Sn(ii)][OTf] (2) is reported here as an efficient catalyst with low-valent main-group element for the hydroboration of aldehydes and ketones (L† = aminotroponate). Using 0.025-0.25 mol% of compound 2, hydroboration of various aldehydes and ketones is accomplished in 0.13-1.25 h at room temperature; the aliphatic aldehydes show an impressive TOF of around 30 000 h-1. DFT calculations are performed to explore the mechanistic aspects of this reaction suggesting that the reaction proceeds via a stepwise pathway with hydridostannylene [L†Sn(ii)H] (2a) as the active catalyst and the H atom transfer from the Sn-H bond to the carbonyl carbon being the rate determining step.

RESUMEN

Pseudohalogenogermylenes [(iBu)2 ATI]GeY (Y=NCO 4, NCS 5) show different coordination behavior towards group 6 metal carbonyls in comparison to the corresponding halogenogermylenes [(iBu)2 ATI]GeX (X=F 1, Cl 2, Br 3) (ATI=aminotroponiminate). The reactions of compounds 4-5 and 1-3 with cis-[M(CO)4 (COD)] (M=Mo, W, COD=cyclooctadiene) gave trans-germylene metal complexes {[(iBu)2 ATI]GeY}2 M(CO)4 (Y=NCO, M=Mo 6, W 11; Y=NCS, M=Mo 7) and cis-germylene metal complexes {[(iBu)2 ATI]GeX}2 M(CO)4 (M=Mo, X=F 8, Cl 9, Br 10; M=W, X=Cl 12), respectively. Theoretical studies on compounds 7 and 9 reveal that donor-acceptor interactions from Mo to Ge atoms are better stabilized in the observed trans and cis geometries than in the hypothetical cis and trans structures, respectively.

RESUMEN

The ability of a platinum compound to act as a catalyst for the cyanosilylation of carbonyl compounds is demonstrated through a well-defined germylene stabilized Pt(ii) dicyanide, trans-{(iBu)2ATIGe(iPr)}2Pt(CN)2.

RESUMEN

A structurally characterized cationic aluminium complex [(AT)Al(DMAP)]+[OTf]- (3) stabilized through a relatively nonbulky aminotroponate (AT) ligand is reported (DMAP = 4-(dimethylamino)pyridine). This compound was found to work as an excellent mononuclear main-group catalyst of the cyanosilylation of a variety of aldehydes and ketones. Loadings of 1 to 2 mol% of this catalyst consumed these substrates in just 5 to 30 min at room temperature.

RESUMEN

Complexes of germanone containing formal Ge=O→M bonds (M=Zn, B, Ge, Sn) were isolated and characterized. The compounds were prepared through a novel synthetic route using a germanium µ-oxo dimer 3 as the starting material. This method circumvents the need to employ germanones to prepare complexes of germanones.

RESUMEN

Commercially available N-oxide (2-mercaptopyridine-N-oxide) is used as a ligand instead of an oxidizing agent to stabilize the compounds of main group elements in low-valent states. The isolated compounds [(C5H4NOS)2Sn (), (C5H4NOS)SnCl () and (C5H4NOS)GeCl ()] are the first structurally characterized examples of O,S-heterocyclic stannylenes and germylenes with interesting bonding features. Further, the reaction of compound with SbCl3 afforded the rare dichlorodiantimony oxide [{(C5H4NOS)SbCl}2O] () unprecedentedly.

RESUMEN

Use of a substituted digermylene oxide as a ligand has been demonstrated through the isolation of a series of group 11 metal(I) iodide complexes. Accordingly, the reactions of digermylene oxide [{(i-Bu)2ATIGe}2O] (ATI = aminotroponiminate) (1) with CuI under different conditions afforded [({(i-Bu)2ATIGe}2O)2(Cu4I4)] (2) with a Cu4I4 octahedral core, [({(i-Bu)2ATIGe}2O)2(Cu3I3)] (3) with a Cu3I3 core, and [{(i-Bu)2ATIGe}2O(Cu2I2)(C5H5N)2] (4) with a butterfly-type Cu2I2 core. The reactions of compound 1 with AgI and AuI produced [({(i-Bu)2ATIGe}2O)2(Ag4I4)] (5) with a Ag4I4 octahedral core and [{(i-Bu)2ATIGe}2O(Au2I2)] (6) with a Au2I2 core, respectively. The presence of metallophilic interactions in these compounds is shown through the single-crystal X-ray diffraction and atom-in-molecule (AIM) studies. Preliminary photophysical studies on compound 6 are also carried out.

RESUMEN

A novel silathiogermylene [Bu(I)2(ATI)GeSSiMe3] (2) containing a reactive Ge(II)-SSiMe3 moiety showed an unusual reaction when treated with elemental selenium and sulfur to afford the germaacid anhydrides [{Bu(I)2(ATI)Ge(Se)}2Se] (3) and [{Bu(I)2(ATI)Ge(S)}2S] (4) in excellent yields, respectively. This single-step conversion of compound 2 to compounds 3 and 4 involves condensation along with insertion and oxidative addition reactions and such reactivity of a germylene with elemental chalcogens is observed for the first time.

RESUMEN

The first example of a germanium(II) cyanide complex [GeCN(L)] (2) (L=aminotroponiminate (ATI)) has been synthesized through a novel and relatively benign route that involves the reaction of a digermylene oxide [(L)Ge-O-Ge(L)] (1) with trimethylsilylcyanide (TMSCN). Interestingly, compound 2 activates several aldehydes (RCHO) at room temperature and results in the corresponding cyanogermylated products [RC{OGe(L)}(CN)H] (R=H 3, iPr 4, tBu 5, CH(Ph)Me 6). Reaction of one of the cyanogermylated products (4) with TMSCN affords the cyanosilylated product [(iPr)C(OSiMe3 )(CN)H] (7) along with [GeCN(L)] quantitatively, and insinuates the possible utility of [GeCN(L)] as a catalyst for the cyanosilylation reactions of aldehydes with TMSCN. Accordingly, the quantitative formation of several cyanosilylated products [RC(OSiMe3 )(CN)H] (7-9) in the reaction between RCHO and TMSCN by using 1 mol % of [GeCN(L)] as a catalyst is also reported for the first time.

RESUMEN

The potential of thio and seleno germanones [LPhGe═E] (L = aminotroponiminate (ATI) ligand, E = S 3, Se 4) to function as ligands has been demonstrated through the isolation of their silver(I) iodide complexes [{(t-Bu)2ATIGe(E)Ph}2(Ag2I2)] (E = S 5, Se 6) with a planar and discrete Ag2I2 core. Compounds 5 and 6 possess the hitherto unknown Ge═E→Ag-I moieties and the crystallographic data reveals the presence of a strong argentophilic interaction (2.950(1) Å) in complex 6, but is inconclusive in complex 5 (3.470(1) Å). Using theoretical studies, proof for the presence and absence of argentophilic interactions in complexes 6 and 5 was obtained, respectively. Further, it is disclosed that the donor ability of the chalcogen atoms in the Ge═E→Ag-I moieties dictate the Ag···Ag interaction in these complexes.

RESUMEN

A germylene monochloride complex ((DPM)GeCl, 1) that is water stable was isolated for the first time. Interestingly, it reacts with cesium fluoride under ambient conditions (non-inert atmosphere and water-containing solvent) to afford water stable germylene monofluoride complex ((DPM)GeF, 2). Due to the usage of DPM (dipyrrinate) ligand, germylene monohalides 1 and 2 show fluorescence in the visible region at 555 and 538 nm, respectively. Compounds 1 and 2 are the first fluorescent germylene complexes and were characterized by multinuclear NMR spectroscopy. The structure of compound 1 was also proved by single crystal X-ray diffraction studies.