Low-valent Main-group Catalysis under Ambient Conditions using a Germylene Cation.

Catalysis using low-valent main-group compounds is usually done under inert conditions; no example of such catalysis has been doable entirely in ambient conditions until now. This aspect is addressed in this work through an air- and water-stable germylene cation [DPMGe][(OH)B(CF)] (2) (DPM=dipyrromethene); it efficiently catalyzes aldehyde and ketone hydrosilylations under ambient conditions. Detailed theoretical studies reveal that compound 2's stability is bolstered by the interaction between the anion and germanium's frontier orbitals.

ATI Stabilized Germylene Cation as a Cyanosilylation Catalyst for Aldehydes and Ketones.

The aminotroponiminate (ATI) ligand stabilized germylene cation [(i-Bu)ATIGe][B(CF)] (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)ATIGeCl] (1) with Na[B(CF)]. The catalytic cyanosilylation of diverse aliphatic and aromatic carbonyl compounds (aldehydes and ketones) using 0.

Germylenes Exhibiting Solid-State Emissions that Extend to NIR.

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.

Aza-Dipyrrinate Stabilized Compounds with a Low-Valent Main Group Element.

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) (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.

Air and water stable germacarbonyl compounds.

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).

Stannylene cyanide and its use as a cyanosilylation catalyst.

Two routes can offer the first stannylene cyanide [(L)SnCN] (5); the substitution reaction of either stannylene amide [(-Bu)ATISnN(SiMe)] (3) or stannylene pyrrolide [(-Bu)ATISn(NCH)] (4) using an excess of trimethylsilyl cyanide (L = aminotroponiminate (ATI)). Using 0.1-2.

A Prelude to Biogermylene Chemistry*.

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.

Germylene stabilized group 12 metal complexes and their reactivity with chalcogens.

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.

Donor-acceptor-stabilised germanium analogues of acid chloride, ester, and acyl pyrrole compounds: synthesis and reactivity.

Germaacid chloride, germaester, and -germaacyl pyrrole compounds were not known previously. Therefore, donor-acceptor-stabilised germaacid chloride (i-Bu)ATIGe(O)(Cl) → B(CF) (), germaester (i-Bu)ATIGe(O)(OSiPh) → B(CF) (), and -germaacyl pyrrole (i-Bu)ATIGe(O)(NCH) → B(CF) () compounds, with Cl-Ge[double bond, length as m-dash]O, PhSiO-Ge[double bond, length as m-dash]O, and CHN-Ge[double bond, length as m-dash]O moieties, respectively, are reported here. Germaacid chloride reacts with PhCCLi, KO-Bu, and RLi (R = Ph, Me) to afford donor-acceptor-stabilised germaynone (i-Bu)ATIGe(O)(CCPh) → B(CF) (), germaester (i-Bu)ATIGe(O)(O-Bu) → B(CF) (), and germanone (i-Bu)ATIGe(O)(R) → B(CF) (R = Ph , Me ) compounds, respectively.

Ge(ii) cation catalyzed hydroboration of aldehydes and ketones.

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).

Expanding the limits of catalysts with low-valent main-group elements for the hydroboration of aldehydes and ketones using [LSn(ii)][OTf] (L = aminotroponate; OTf = triflate).

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.

Catalytic cyanosilylation using germylene stabilized platinum(ii) dicyanide.

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.

Pseudohalogenogermylenes versus Halogenogermylenes: Difference in their Complexation Behavior towards Group 6 Metal Carbonyls.

Pseudohalogenogermylenes [(iBu) ATI]GeY (Y=NCO 4, NCS 5) show different coordination behavior towards group 6 metal carbonyls in comparison to the corresponding halogenogermylenes [(iBu) ATI]GeX (X=F 1, Cl 2, Br 3) (ATI=aminotroponiminate). The reactions of compounds 4-5 and 1-3 with cis-[M(CO) (COD)] (M=Mo, W, COD=cyclooctadiene) gave trans-germylene metal complexes {[(iBu) ATI]GeY} M(CO) (Y=NCO, M=Mo 6, W 11; Y=NCS, M=Mo 7) and cis-germylene metal complexes {[(iBu) ATI]GeX} M(CO) (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.

A cationic aluminium complex: an efficient mononuclear main-group catalyst for the cyanosilylation of carbonyl compounds.

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.

The Preparation of Complexes of Germanone from a Germanium μ-Oxo Dimer.

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.

O,S-Heterocyclic stannylenes: synthesis and reactivity.

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.

Digermylene Oxide Stabilized Group 11 Metal Iodide Complexes.

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.

Crystal structure of (Z)-3-[5-chloro-2-(prop-2-yn-yloxy)phen-yl]-3-hy-droxy-1-[4-(tri-fluoro-meth-yl)phen-yl]-prop-2-en-1-one.

The title compound, C19H12ClF3O3, obtained by the photochemical transformation of 2-[5-chloro-2-(prop-2-yn-yloxy)benzo-yl]-3-[4-(tri-fluoro-meth-yl)phen-yl]oxirane adopts a Z conformation with respect to the enolic C=C double bond. The dihedral angle between the benzene rings is 12.25 (16)° and an intra-molecular O-H⋯O hydrogen bond closes an S(6) ring.

Single-step conversion of silathiogermylene to germaacid anhydrides: unusual reactivity.

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.

Use of thio and seleno germanones as ligands: silver(I) halide complexes with Ge═E→Ag-I (E = S, Se) moieties and chalcogen-dependent argentophilic interaction.

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.

Germylene cyanide complex: a reagent for the activation of aldehydes with catalytic significance.

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.

Can low-valent germanium chemistry be practiced under ambient conditions? A tale of a water-stable yet reactive germylene monochloride complex.

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.

Are ligand-stabilized carboxylic acid derivatives with Ge═Te bonds isolable?

The stability of ligand-stabilized carboxylic acid derivatives (such as esters, amides, anhydrides, and acid halides) with terminal Ge═Te bonds is highly questionable as there is no report on such compounds. Nevertheless, we are able to isolate germatelluroester [LGe(Te)Ot-Bu] (4), germatelluroamide [LGe(Te)N(SiMe3)2] (5), and germatelluroacid anhydride [LGe(Te)OGe(Te)L] (6) complexes (L = aminotroponiminate (ATI)) as stable species. Consequently, the synthetic details, structural characterization, and UV-vis spectroscopic and theoretical studies on them are reported for the first time.

Aminotroponiminato(chloro)germylene stabilized copper(I) iodide complexes: synthesis and structure.

Reaction of an aminotroponiminato(chloro)germylene [(i-Bu)2ATIGeCl] (1) (ATI = aminotroponiminate) with CuI in acetonitrile afforded an aminotroponiminato(chloro)germylene stabilized copper(I) iodide complex [{(i-Bu)2ATIGeCl}2(Cu4I4)(CH3CN)2] (2) with a tetrameric distorted cubane type Cu4I4 core. The reaction of compound 1 in dichloromethane with CuI in the presence of 2 equiv of pyridine resulted in the first germylene stabilized copper(I) iodide complex [{(i-Bu)2ATIGeCl}(CuI)(C5H5N)2] (3) with a monomeric CuI core. A reaction of compound 1 with equimolar amounts of CuI and pyridine in dichloromethane resulted in a copper(I) iodide complex [{(i-Bu)2ATIGeCl}2(Cu2I2)(C5H5N)2] (4) with a dimeric Cu2I2 core.

Digermylene oxide complexes: facile synthesis and reactivity.

A simple heating of aminotroponiminate (ATI) ligand stabilized germylene monochlorides [(R)2ATIGeCl] (R = t-Bu 1, i-Bu 2) with an excess of potassium hydroxide in toluene resulted in the first ATI ligand stabilized digermylene oxides [{(R)2ATIGe}2O] (R = t-Bu 3, i-Bu 4), respectively. Reaction of compound 3 with elemental sulfur and selenium gave the first germaacid anhydride complexes [{(t-Bu)2ATIGe(E)}2O] (E = S 5, Se 6) with (S)Ge-O-Ge(S) and (Se)Ge-O-Ge(Se) moieties, respectively. The digermylene oxide complexes 3 and 4 and germaacid anhydride complexes 5 and 6 were characterized by multinuclear NMR spectroscopy and single-crystal X-ray diffraction analysis.