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1.
Chem Commun (Camb) ; 2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33735342

RESUMO

The reactions of SbH3 with one or two equivalents of (Dipp2NacNac)Ga (Dipp2NacNac = HC{C(Me)N(Dipp)}2; Dipp = 2,6-iPr2C6H3) yield the primary and secondary stibanes (Dipp2NacNac)GaH(SbH2) (3) and {(Dipp2NacNac)GaH}2(SbH) (5). Their lighter homologs were obtained from the analogous reactions with phosphine and arsine. All compounds were characterized using heteronuclear NMR-spectroscopy, IR-spectroscopy and single-crystal X-ray diffraction.

2.
Artigo em Inglês | MEDLINE | ID: mdl-33591587

RESUMO

We herein report the synthesis, structures, coordination ability, and mechanism of formation of silicon analogs of crown ethers. An oligomerization of 2 D2 (I) (2 Dn ,=(Me4 Si2 O)n ) was achieved by the reaction with GaI3 and MIx (M=Li, Na, Mg, Ca, Sr). In these reactions the metal cations serve as template and the anions (I- /[GaI4 ]- ) are required as nucleophiles. In case of MIx =LiI, [Li(2 D3 )GaI4 ] (1) is formed. In case of MIx =NaI, MgI2 , CaI2 , and SrI2 the compounds [M(2 D4 )(GaI4 )x ] (M=Mg2+ (3), Ca2+ (4), Sr2+ (5) are obtained. Furthermore the proton complex [H(2 D3 )][Ga2 I7 ] (6) was isolated and structurally characterized. All complexes were characterized by means of multinuclear NMR spectroscopy, DOSY experiments and, except for compound 3, also by single crystal X-ray diffraction. Quantum chemical calculations were carried out to compare the affinity of M+ to 2 Dn and other ligands and to shed light on the formation of larger rings from smaller ones.

3.
Inorg Chem ; 59(23): 16783-16788, 2020 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-33185106

RESUMO

The synthesis of a second beryllium bromide modification, ß-BeBr2, was accomplished through recrystallization of α-BeBr2 from benzene in the presence of cyclo-decamethylpentasiloxane. This phase was analyzed via single-crystal X-ray diffraction and IR and Raman spectroscopy as well as density functional theory calculations. This enabled a comparison to α-BeBr2 and the α and ß phases of beryllium chloride and iodide.

4.
Chemistry ; 26(39): 8536-8540, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32428313

RESUMO

The first molecular compound with all five pnictogens was obtained by a multi-step reaction. Lithiation of the (bisamido)diazadiarsetidine (tBuNAs)2 (tBuNH)2 in aliphatic solvents leads to the dimeric metallated species [(tBuNAs)2 (tBuNLi)2 ]2 (12 ). Upon reactions with AsCl3 , SbCl3 and BiCl3 the polycyclic compounds [(tBuNAs)2 (tBuN)2 ]PnCl (Pn=As (2), Sb (3), Bi (4)) can be obtained. Conversion of 2-4 with [tBu2 SbP(tBu)Li(OEt2 )]2 leads to the remarkable interpnictogens [(tBuNAs)2 (tBuN)2 ]PnP(tBu)SbtBu2 (Pn=As (5), Sb (6), Bi (7)), whereby 7 is the first example of a molecule containing all five Group 15 elements. The compound with adjacent AsNBiPSb-chains is surprisingly stable and does not show high sensibility against light as the labile Bi-P bond might suggest.

5.
Dalton Trans ; 49(18): 5787-5790, 2020 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-32314766

RESUMO

The reaction of O(Si2Me4Cl)2 with ammonia yielded the cyclic siloxazane O(Si2Me4)2NH (1), which was used as a precursor for the synthesis of siloxazanide-type alkali metal salts. The metalation of 1 with the strong bases BzA (A = Na, K, Rb, Cs and Bz = benzyl) results in different dimensional structures depending on the alkali metal ion used. These results give new insights into framework design with inorganic building blocks and the coordination ability of siloxanes.

6.
Chemistry ; 26(1): 192-197, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31702848

RESUMO

Herein, the synthesis of new low-valent Group 14 phosphinidenide complexes [({SIDipp}P)2 M] exhibiting P-M pπ-pπ interactions (SIDipp=1,3-bis(2,6-diisopropylphenyl)-imidazolidin-2-ylidene, M=Ge, Sn, Pb), is presented. These compounds were investigated by means of structural, spectroscopic, and quantum-chemical methods. Furthermore, the monosubstituted compounds [(SIDippP)MX]2 (M=Sn, X=Cl; M=Pb, X=Br) are presented, which show dimeric structures instead of multiple bonding interaction.

7.
Inorg Chem ; 58(22): 15417-15422, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31661251

RESUMO

We present the coordination chemistry of the cyclodimethylsiloxanes D6 and D7 toward alkaline earth metal salts. The coordination chemistry of these macrocycles toward alkaline earth metals has been unprecedented to date, and we could show that these ligands coordinate better than previously thought. Direct reaction of alkaline earth metal salts with these ligands yields stable complexes even with a relatively strongly coordinating iodide anion. A handful of counterintuitive coordination compounds could be characterized by single-crystal X-ray diffraction analysis. Quantum chemical calculations of suited Born-Haber cycles showed that these complexes are indeed stable, for Mg2+ and Ca2+ even with iodide employed as the anion and for Sr2+ and Ba2+ in the presence of GaI3.

8.
Chemistry ; 25(69): 15934-15943, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31596978

RESUMO

Alkaline earth metal iodides were used as templates for the synthesis of novel silicon-based ligands. Siloxane moieties were (cross-)coupled and ion-specific, silicon-rich crown ether analogues were obtained. The reaction of 1,2,7,8-tetrasila[12]crown-4 (I) and 1,2-disila[9]crown-3 (II) with MgI2 yielded exclusively [Mg(1,2,7,8-tetrasila[12]crown-4)I2 ] (1). The larger Ca2+ ion was then employed for cross-coupling of I and II and yielded the complex [Ca(1,2,7,8-tetrasila[15]crown-5)I2 ] (2). Cross-coupling of I and 1,2,4,5-tetrasila[9]crown-3 (III) with SrI2 enables the synthesis of the silicon-dominant 1,2,4,5,10,11-hexasila[15]crown-5 ether complex of SrI2 (3). Further, the compounds [Sr(1,2,10,11-tetrasila[18]crown-6)I2 ] (4), [Sr(1,2,13,14-tetrasila[24]crown-8)I2 ] (5), and [Sr(1,2,13,14-tetrasila-dibenzo[24]crown-8)I2 ] (6) were obtained by coupling I, 1,2-disila[12]crown-4 (IV) or 1,2-disila-benzo[12]crown-4 (V), respectively. Using various anions, the (cross-)coupled ligands were also observed in an X-ray structure within the mentioned complexes. These template-assisted (cross-)couplings of various ligands are the first of their kind and a novel method to obtain macrocycles and/or their metal complexes to be established. Further, the Si-O bond activations presented herein might be of importance for silane or even organic functionalization.

9.
Dalton Trans ; 48(16): 5253-5262, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30945712

RESUMO

Herein we present the synthesis and characterization of di-tertiary butyl substituted (pseudo-)halogen bismuthanes tBu2BiX (X = Cl (1), Br (2), I (3), CN (4), N3 (5), SCN (6)). These compounds were obtained via different reaction paths. Compound 1 was obtained by a Grignard reaction of BiCl3 with two equivalents of tBuMgCl, whereas compounds 2, 3, 4 and 6 were synthesised by a oxidative addition/reductive elimination pathway starting from tBu3Bi and X2 (X = Br, I, CN, SCN). Finally, azide 5 was obtained by the reaction of 1 and NaN3. Secondary bonding interactions in the solid state within all the investigated compounds (1-6) cause additional stabilisation. Starting from tBu2BiCl, the completely tbutyl substituted ternary interpnictogen compound tBu2Bi(tBuP)SbtBu2 (7) was synthesized through the reaction with [tBu2SbP(tBu)Li(Et2O)]2. All new compounds were characterized by means of X-ray diffraction and mass spectrometry as well as NMR and IR spectroscopy.

10.
Chemistry ; 25(19): 4914-4919, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30888091

RESUMO

The N-heterocyclic carbene (NHC)-stabilized phosphinidenide, SIMesPK [SIMes=1,3-bis(2,4,6-trimethylphenyl)imidazolidine-2-ylidene], was used as an (NHC)P-transfer reagent for the synthesis of the low-valent Group 14 ate complexes K[(SIMesP)3 E] (E=Ge: 2, Sn: 3, Pb: 4), which were characterized by 1 H NMR, 31 P NMR, IR spectroscopy as well as elemental and X-ray analysis. Furthermore, SIMesPK was used in reactions with potassium amides and alkoxides to form the molecular phosphorus-potassium clusters [K4 (SIMesP)2 (hmds)2 ] [5, hmds=N(SiMe3 )2 ] and [K6 (SIMesP)2 (OtBu)4 ] (6). Finally, the reaction of SIMesPK with Li[Al(OC4 F9 )4 ] led to the potassium-rich ionic compound [(SIMesP)4 K5 ][Al(OC4 F9 )4 ] (7).

11.
Inorg Chem ; 58(5): 3518-3526, 2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-30789258

RESUMO

Herein we present the synthesis and coordination chemistry of the partially silicon based crown ether analogues 1,2,4,5-tetrasila-benzo[15]crown-5 (1) and 1,2,4,5-tetrasila[18]crown-6 (7). Stable complexes of alkali and alkaline earth metal iodides could be obtained showing the good coordination ability of these ligands. The complexes [M A(1,2,4,5-tetrasila-benzo[15]crown-5)I] (M A = Li+ (2), Na+ (4)) and [M EA(1,2,4,5-tetrasila-benzo[15]crown-5)I2] (M EA = Mg2+ (3), Ca2+ (5), Sr2+ (6)) were obtained by equimolar reaction of 1 with the respective alkali or alkaline earth metal iodide. Depending on the ionic radii of the respective cations, the coordination modes of the siloxane backbone are significantly different and could be well-represented by means of 29Si NMR spectroscopy. In addition, we were able to generate the unusual dinuclear complex [Ba2(1,2,4,5-tetrasila[18]crown-6)2I4] (8) by reaction of 7 with BaI2. All compounds were characterized via single crystal X-ray diffraction (XRD) analysis.

12.
Dalton Trans ; 47(46): 16393-16397, 2018 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-30328861

RESUMO

Through reactions of 1,2-disila[12]crown-4 or 1,2-disila-benzo[12]crown-4 ethers with BeCl2 eight-membered Be-O-heterocycles, which are annulated by two six-membered Be-O-cycles were obtained and characterised. The reactions leading to these unusual ring systems have been investigated by NMR and IR spectroscopy as well as reactions with further ligand derivatives.

13.
Dalton Trans ; 47(24): 7875-7878, 2018 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-29796512

RESUMO

Herein we present the synthesis and characterisation of the seven-membered group 13/15 chain compound HB{N(H)PtBu2BH3}2 (3) obtained from the reaction of tBu2PNH2 (1) with Me2S·BH3. Furthermore, we describe the synthesis of the aluminium and gallium compounds tBu2PN(H)AltBu2N(H)P(H)tBu2 (4) and tBu2(H)PN(H)GatBu3 (5) derived from the reaction of tBu2PNH2 (1) with MtBu3 (M = Al, Ga).

14.
Chem Commun (Camb) ; 54(21): 2659-2661, 2018 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-29479606

RESUMO

Herein, we present the synthesis and characterisation of new group 15 element compounds with low valent phosphorus atoms as substituents. This new series of compounds includes the heavier group 15 elements and represents the rare group of compounds with a direct P-E bond (E = P, As, Sb and Bi).

15.
Inorg Chem ; 57(1): 351-359, 2018 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-29232126

RESUMO

Within this study, the synthesis and coordination chemistry of open-chain ligands bearing disila-units is presented. Instead of basic 1:1 complexes, structural diversity was discovered in the variety of ligand and salt. Stable complexes of alkali and alkaline earth metal complexes were obtained by equimolar reactions of different salts with the disila-bridged podands 8,9-disila-EO5 (1) and 11,12-disila-EO7 (2) (EO5 = pentaethylene glycol; EO7 = heptaethylene glycol). The respective alkaline earth metal complexes of the type [Ca(8,9-disila-EO5)(OTf)2] (3), [Sr(8,9-disila-EO5)I2] (5), [Sr(11,12-disila-EO7)I]I (6), and [Ba(11,12-disila-EO7)OTf2] (7) (OTf = CF3SO3-) were characterized via single-crystal X-ray diffraction analyses. Within the reaction of the alkali metal salt NaPF6 with 1, the sodium ion acts as a template during the complexation process. Under elimination of one molecule of diethylene glycol, the dinuclear species [Na2(8,9,17,18-tetrasila-EO8)(PF6)2]·EO2 (4) (EO8 = octaethylen glycol, EO2 = diethylene glycol) is obtained, in which the sodium cations are 7-fold coordinated within a disilane-bearing framework. The reaction of 2 with CsOTf failed, leading to recrystallization of anhydrous CsOTf. By means of DFT calculations it was shown that the disila-bearing ligands are burdened with negative hyperconjugation interactions between the silicon and the oxygen atoms, but the coordination by sufficiently hard cations can easily overcompensate the competing polarization. In contrast, soft Lewis acids barely share interactions with silicon-bonded oxygen atoms. All findings are consistent with observations made in solution according to 29Si NMR spectroscopical studies.

16.
Chem Commun (Camb) ; 53(54): 7620-7623, 2017 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-28639632

RESUMO

The parent phosphinidene SIMesPH (1) (SIMes = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) was treated with benzyl potassium to form the metalated species SIMesPK (2), which was used as a synthon for the new group 13/15 cycles and cage compounds [SIMesPGatBu2]2 (3), [SIMesP(GatBu2)2Cl] (4) and [K(SIMesP)3AltBu] (5).

17.
Dalton Trans ; 46(21): 7074-7081, 2017 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-28518202

RESUMO

Herein we present the synthesis and characterization of the new four-membered Ga/P cycle [tBu2GaP(H)SitBu2Ph]2, which shows a cis/trans isomerization at ambient temperatures via a ring opening mechanism. The sterically demanding substituents on the phosphorus (-SitBu2Ph) and gallium (tBu) atoms lead to an unexpected reactivity towards bulky NHC ligands (IMes and IDipp). The resulting Lewis base stabilized monomeric 13/15 compounds feature an unusual binding mode of the carbene ligand. The ring opened state also enables a masked flp reactivity, which is shown by a reaction with the polar multiple bond in Ph-NCO.

18.
Chemistry ; 23(40): 9607-9617, 2017 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-28464436

RESUMO

The structures of alkali-metal chloride SO2 solvates (Li-Cs) in conjunction with 12-crown-4 or 1,2-disila-12-crown-4 show strong discrepancies, despite the structural similarity of the ligands. Both types of crown ethers form 1:1 complexes with LiCl to give [Li(1,2-disila-12-crown-4)(SO2 Cl)] (1) and [Li(12-crown-4)Cl]⋅4 SO2 (2). However, 1,2-disila-12-crown-4 proved unable to coordinate cations too large for the cavity diameter, for example, by the formation of sandwich-type complexes. As a result, 12-crown-4 reacts exclusively with the heavier alkali-metal chlorides NaCl, KCl and RbCl. Compounds [Na(12-crown-4)2 ]Cl⋅4 SO2 (3) and [M(12-crown-4)2 (SO2 )]Cl⋅4 SO2 (4: M=K; 5: M=Rb) all showed S-coordination to the chloride ions through four SO2 molecules. Compounds 4 and 5 additionally exhibit the first crystallographically confirmed non-bridging O,O'-coordination mode of SO2 . Unexpectedly, the disila-crown ether supports the dissolution of RbCl and CsCl in the solvent and gives the homoleptic SO2 -solvated alkali-metal chlorides [MCl⋅3 SO2 ] (6: M=Rb; 7: M=Cs), which incorporate bridging µ-O,O'-coordinating moieties and the unprecedented side-on O,O'-coordination mode. All compounds were characterised by single-crystal X-ray diffraction. The crown ether complexes were additionally studied by using NMR spectroscopy, and the presence of SO2 at ambient temperature was revealed by IR spectroscopy of the neat compounds.

19.
Dalton Trans ; 46(27): 8727-8735, 2017 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-27901158

RESUMO

Compounds consisting of [M(1,2-disila-[3n]crown-n)]2+ (M = Mg, Ca, Sr, Ba; n = 5, 6) and [Ba(1,2-disila-benzo[18]crown-6)]2+ cations and different anions were obtained by equimolar reaction of the hybrid disila-crown ethers 1,2-disila[15]crown-5 (1), 1,2-disila[18]crown-6 (2) and 1,2-disila-benzo[18]crown-6 (7) with alkaline earth metal salts. Even with strongly coordinating anions such as Br- or I- stable complexes could be obtained, showing the good coordination ability of these ligands. The structures of all coordination compounds were determined via single crystal X-ray diffraction (XRD). By means of DFT calculations, the complexation ability of 1,2-disila[15]crown-5 (1) towards magnesium bromide was determined to be considerably higher compared to [15]crown-5. The opposite case was observed in solution as the exchange of calcium cations between [18]crown-6 and 1,2-disila[18]crown-6 (2) was studied via dynamic proton nuclear magnetic resonance (NMR) spectroscopy.

20.
Chem Commun (Camb) ; 52(90): 13265-13268, 2016 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-27775108

RESUMO

The first hybrid crown ether with two adjacent disilane fragments was synthesized through reaction of O(Si2Me4Cl)2 (3) with O(C2H4OH)2. By means of DFT calculations, the complexation ability of 1,2,4,5-tetrasila[12]crown-4 (7) towards Li+ was determined to be considerably higher compared to [12]crown-4.

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