Karl Klinkhammer | Johannes Gutenberg-Universität Mainz (original) (raw)
Papers by Karl Klinkhammer
Chemical Science, 2011
ABSTRACT In this report we present data from hyperfine sublevel correlation spectroscopy (HYSCORE... more ABSTRACT In this report we present data from hyperfine sublevel correlation spectroscopy (HYSCORE), an electron paramagnetic resonance (EPR) spectroscopic technique, that reveals weak but distinct interactions between several main group element radicals and physically dissolved dinitrogen in solution. These interactions are the basis for a well-defined coordination of N2 to the paramagnetic centers. The complexes formed are primarily of the van der Waals-type but also feature a non-negligible orbital overlap between dinitrogen and the radicals' SOMO. Our spectroscopic findings are strongly supported by experiments with isotope-labeled 15N2, spectral simulations and quantum chemical and density functional theory (DFT) calculations. Formation of such complexes is unexpected when considering the small polarizability of dinitrogen but steric effects like formation of a binding “pocket” may facilitate their formation. The sensitivity, selectivity, and resolution of HYSCORE with respect to the detection of weak hyperfine couplings is needed to identify such complexes that are probably the result of a subtle interplay of induced van der Waals forces between N2, the solvent and the dissolved radicals.
Organometallics, 1997
3 ]HCl} yields, depending on X, one of the following: (a) novel branched polysilyllithium compoun... more 3 ]HCl} yields, depending on X, one of the following: (a) novel branched polysilyllithium compounds; (b) the known (Me 3 Si) 3 SiLi; (c) various mixtures. The cleavage of family 1 can be understood in terms of steric effects, i.e., assuming that MeLi attacks preferentially the sterically less hindered Si atom leading to the formation of new polysilyllithium compounds, e.g., t-BuMe 2 -Si(Me 3 Si) 2 SiLi‚3THF and t-BuMe 2 SiSiMe 2 (Me 3 Si) 2 SiLi‚3THF, which were isolated in a crystalline form. The X-ray structure of the former is presented. In contrast to 1 the lithiation of the branched polysilanes 2 leads exclusively (mostly with (Me 3 Si) 3 SiSiMe-(SiMe 3 ) 2 ) to the known (Me 3 Si) 3 SiLi. Lithiation of 3 leads to a number of novel polysilyllithium compounds. We tentatively propose that the lithiation of 3 proceeds by a two step reaction in which a disilene is formed as an intermediate, and this is followed by fast addition of a second molecule of MeLi to produce the final silyllithium product.
Nachrichten aus der Chemie, 2000
Nachrichten aus der Chemie, 2000
![Research paper thumbnail of Cyclooctadienemethylplatinum complexes: synthesis, reactivity, molecular structure and spectroscopic properties of the organometallic hydroxoplatinum(II) complex [(COD)PtMe(OH)]](https://attachments.academia-assets.com/43690690/thumbnails/1.jpg)
](Journal of Organometallic Chemistry, 1999
Organometallic complexes of the type [(COD)PtMeL] (COD = 1,5-cyclooctadiene, L = Cl, I, OH, Me, C... more Organometallic complexes of the type [(COD)PtMeL] (COD = 1,5-cyclooctadiene, L = Cl, I, OH, Me, CH 2 C(O)CH 3 , C C Ph, pyridine, N-methyl pyrazinium) and the dinuclear complex [{(COD)PtMe} 2 (m-C C C C)] were prepared and characterised by 1 H-NMR spectroscopy. The crystal structures for the complexes with L =Cl, OH and Me are reported. The complex [(COD)PtMe(OH)] is a unique example of a platinum complex containing an olefin and a hydroxy ligand on the same metal centre. It reacts with C H acidic substrates to form Pt C bonds. Representative reactions with acetone, phenylacetylene and 1,3-butadiyne and the corresponding products are reported.
Inorganica Chimica Acta, 2001
Aggregation control of copper(I) thiolates through substituent size and ancillary chelate ligands... more Aggregation control of copper(I) thiolates through substituent size and ancillary chelate ligands: closely related mono-, di-, tri-and tetranuclear complexes
Inorganic Chemistry, 2012
The expanded ligand N,N'-dimethyl-N,N&... more The expanded ligand N,N'-dimethyl-N,N'-dipyridin-2-yl-pyridin-2,6-diamine (ddpd) coordinates to copper(II) ions in a meridional fashion giving the dicationic complex mer-[Cu(ddpd)(2)](BF(4))(2) (1). In the solid state at temperatures below 100 K the cations of 1 localize in Jahn-Teller elongated CuN(6) polyhedra with the longest Cu-N bond pointing in the molecular x or y directions while the z axis is constrained by the tridentate ddpd ligand. The elongated polyhedra are ordered in an antiferrodistortive way giving an idealized zincblende structure. At higher temperature dynamically averaged (fluxional) polyhedra in the molecular x/y directions are observed by multifrequency variable temperature electron paramagnetic resonance (EPR) and by variable temperature X-ray diffraction studies. Compared to [Cu(tpy)(2)](2+) (tpy = 2,2';6',2″-terpyridine) the Jahn-Teller splitting 4δ(1) of 1 is larger. This is very probably caused by the much more favorable orbital overlap in the Cu-N bonds in 1 which results from the larger bite angle of ddpd as compared to tpy. The "freezing-in" of the Jahn-Teller dynamics of 1 (T ≈ 100 K) occurs at higher temperature than observed for [Cu(tpy)(2)](2+) (T < 77 K) which is also probably due to the larger Jahn-Teller distortion of 1 resulting in a larger activation barrier.
Inorganic Chemistry, 2009
The kinetic and thermodynamic stabilities of the group 13 hydrides EH 3 (E = B, Al, Ga, In, Tl, E... more The kinetic and thermodynamic stabilities of the group 13 hydrides EH 3 (E = B, Al, Ga, In, Tl, E113) are investigated by relativistic density functional and wave function based theories. The unimolecular decomposition of EH 3 f EH þ H 2 becomes energetically more favorable going down the Group 13 elements, with the H 2 -abstraction of InH 3 , TlH 3 , and (E113)H 3 (E113: element with nuclear charge 113) being exothermic. In accordance with the Hammond-Leffler postulate, the activation barrier for the dissociation process decreases accordingly going down the group 13 elements in the periodic table shifting to an early transition state, with activation energies ranging from 88.4 kcal/mol for BH 3 to 41.3 kcal/mol for TlH 3 and only 21.6 kcal/mol for (E113)H 3 at the scalar relativistic coupled cluster level of theory. For both TlH 3 and (E113)H 3 we investigated spin-orbit effects using Dirac-Hartree-Fock and second-order Møller-Plesset theory to account for electron correlation. For (E113)H, spin-orbit coupling results in a chemically inert closed 7p 1/2 -shell, thus reducing the stability of the higher oxidation state even further. We also investigated the known organothallium compound Tl(CH 3 ) 3 , which is thermodynamically unstable similar to TlH 3 , but kinetically very stable with an activation barrier of 57.1 kcal/mol.
![Research paper thumbnail of Bis[bis(trimethylsilyl)methyl]galliumbromid und monomeres {Bis[bis(trimethylsilyl)methyl]gallium}[tris(trimethylsilyl)silyl]tellurid [(Me3Si)2CH]2Ga–TeSi(SiMe3)3](https://attachments.academia-assets.com/43690695/thumbnails/1.jpg)
](Chemische Berichte, 1992
I~ 1547 Bis[bis( trimethylsilyl)methyl]galliumbromid und monomeres {Bis[bis( trimethylsilyl)methy... more I~ 1547 Bis[bis( trimethylsilyl)methyl]galliumbromid und monomeres {Bis[bis( trimethylsilyl)methyl] gallium} [tris( trimethylsilyl)silyl] tellurid [(MeJSihCHhGa -TeSi(SiMeJ)J between a digallium(4) and a ditellane derivative I Gallium-tellurium 1t interaction, Tellurium compounds BlslblS(trlrnethylstlyl)methyl]galllum Bromide and MonomerJe {BIs(b1s(lrlmelhylsllyl)methyl]galllum} rrr1s(lrJmethylsllyl)sllyliielluride [(Me~lhCHhGa -TeSI Bis(bis(trimethylsilyl)methyljgallium bromide GaBrICH(SiM~hh (4), prepared from Ga,Br .. . 2 dioxane and bis(trlmethylsilyl)methyllithium in the molar ratio of 1:3, reacts with the sterlcally bigh-shielded lithium tris(trimethylsilyl}silyltelluride . DME to yield I(MelSibCHbGa-TeSi(SiM~h (5). 5 can also be synthesized by a metathetic reaction between tetrakis-(bis(trimethylsi1yl)methylldigaUium and bis(tris{trimelhylsilyl)silyllditellane in toluene at tOO·C. A erystal strueture de-Unseren Arbeitsgruppen gelang kürzlich die Synthese des Tetrakis[bis(trimethylsilyl)methyl]digalliums(4) (1) mit Gallium -Gallium-Ell und des Bis[tris(trimetbylsilyl)silyl]ditellans (3) mit Tellur -Tellur-Bindungrzl: Die Verbindung 1 entsteht in hoher Ausbeute bei der Umsetmng von GalBr • . 2 Dioxan mit vier Äquivalenten des sterisch anspruchsvollen Bis(trimethylsilyl)metbyllithiums (GI. 1) und weist nacb den Ergebnissen einer Kristallstrukturanalyse ein nahezu Dioxan Br \ / Br-(ja-(ja-Br t 4 UCHISiJ,hl'2 Syntbese von GaBr[CH(SiMe3h:h (4) Intensive Bemühungen zur Synthese von Bis[bis(trimethylsilyl)methyl]galliumbromid sowie des entsprechen-Clum. BeT.
Dalton Transactions, 2010
In this report we present the synthesis and the detailed electron paramagnetic resonance (EPR) sp... more In this report we present the synthesis and the detailed electron paramagnetic resonance (EPR) spectroscopic characterization of novel trivalent lead- and tin-based radicals comprising sterically demanding germyl substituents. The investigated radicals are derived from the recently reported trihypersilyl-substituted tetryl radicals *PbHyp3 and *SnHyp3. The tetryl radicals *Pb(Ge(SiMe3)3)3 (8), *Pb(Ge(SiMe3)3)2Si(SiMe3)3 (9), *PbGe(SiMe3)3(Si(SiMe3)3)2 (10), and *Sn(Ge(SiMe3)3)3 (11) show substitution patterns derived from stepwise (9, 10) or complete (8, 11) substitution of hypersilyl groups (Hyp = Si(SiMe3)3) in *PbHyp3 and *SnHyp3 by homologous hypergermyl groups (Hge = Ge(SiMe3)3). They were generated through oxidation of the corresponding potassium tetranides KPbR3 and KSnR3 (R = Hyp, Hge), which in turn had been synthesized employing nucleophilic addition of KHyp or KHge to PbHyp2 or to the novel tetrylenes PbHge2 (1) and SnHge2 (12). The gained EPR spectroscopic data give insights into the influence of the substitution pattern on the geometric and electronic properties of the lead-centered species. With an increasing number of germyl substituents, the spin-orbit coupling to the central atom increases resulting in larger g(iso)-values and larger g-anisotropies while the 209Pb hyperfine splitting constants A(iso) decrease. These decreasing splitting constants are indicative of a diminished s-character of the singly occupied molecular orbital (SOMO) and to a molecular geometry running from slightly pyramidal to almost planar. Interestingly, already one germyl substituent (for radical 10) dominates most of the mentioned properties. For stannyl radical 11 a similar trend is seen for the spin-orbit coupling, while the (117/119)Sn hyperfine splittings unexpectedly increase from SnHyp3 to SnHge3.
![Research paper thumbnail of New sulfide-bridged heterocubanes [MVI(S)ReI3(CO)9(μ3-S)4]−, M = Mo or W, with transition metals in very different oxidation states](https://attachments.academia-assets.com/43690693/thumbnails/1.jpg)
](Chemical Communications, 1998
The cluster anions [M VI (S)Re I 3 (CO) 9 (m 3 -S) 4 ] 2 , M = Mo or W, contain three six-coordin... more The cluster anions [M VI (S)Re I 3 (CO) 9 (m 3 -S) 4 ] 2 , M = Mo or W, contain three six-coordinate tricarbonylrhenium(I) fragments, held together by one m 3 -sulfide ion and by one reducible and charge transfer-active m 3 -M VI S 4 22 unit.
Angewandte Chemie, 1999
ABSTRACT Eine lineare Si-Hg-Hg-Si-Anordnung und einen Hg-Hg-Abstand von 265.69 pm weist die erste... more ABSTRACT Eine lineare Si-Hg-Hg-Si-Anordnung und einen Hg-Hg-Abstand von 265.69 pm weist die erste zweikernige, σ-gebundene Quecksilber(I)-Verbindung mit zweifach koordinierten Hg-Zentren (1) auf. Sie entsteht unerwartet bei der Umsetzung von zwei Äquivalenten des Silans (Me3SiMe2Si)3SiH mit tBu2Hg. Setzt man die Reagentien dagegen im Verhältnis 1:1 ein, so entsteht erwartungsgemäß die Quecksilber(II)-Verbindung (Me3SiMe2Si)3SiHgtBu.
Angewandte Chemie, 1994
... Tetrakis(hypersilyl)dithallium(Tf - TI) - eine Verbindung des zweiwertigen Thallium ** Sonja ... more ... Tetrakis(hypersilyl)dithallium(Tf - TI) - eine Verbindung des zweiwertigen Thallium ** Sonja Henkel, Karl Wilhelm Klinkhammer* und Wolfgang Schwarz Wahrend Molekiilverbindungen mit zweiwerligem Bor in Form von Diboranen(4) schon seit langer Zeit bekannt sind, gelang ...
Angewandte Chemie International Edition in English, 1997
... code +(441)7983329 Dr. KW Klinkhammer, Dr. W. Schwarz Institut fur Anorganische Chemie der Un... more ... code +(441)7983329 Dr. KW Klinkhammer, Dr. W. Schwarz Institut fur Anorganische Chemie der Universitit Stuttgart (Germany) [**I We are ... In contrast, in the analogous compounds with Ga, and In, tetrahedra we observed almost indistinguishable Ga-Ga and In-In distances ...
Angewandte Chemie International Edition, 1999
Most of the known mercury compounds have a formal 2 oxidation state. [1±5] s-Bonded organomercury... more Most of the known mercury compounds have a formal 2 oxidation state. [1±5] s-Bonded organomercury(i) compounds with a 1 oxidation state for example RHgHgR, R organic substituent, have been frequently cited in the literature as
![Research paper thumbnail of The Synthesis of the First Compound with Li-Si-Hg Bonding: [{Li(iPr3Si)2Si}2Hg]—a Source for the [Li(iPr3Si)2Si]. Radical](https://attachments.academia-assets.com/43690687/thumbnails/1.jpg)
](Angewandte Chemie International Edition, 2002
Organometallics, 1998
The diarylplumbylene R 2 Pb: (3), R ) 2-tBu-4,5,6-Me 3 C 6 H, and the rearranged alkylarylplumbyl... more The diarylplumbylene R 2 Pb: (3), R ) 2-tBu-4,5,6-Me 3 C 6 H, and the rearranged alkylarylplumbylene RR′Pb:, R ) 2,4,6-tBu 3 C 6 H 2 , R′ ) CH 2 C(CH 3 ) 2 -3,5-tBu 2 C 6 H 3 , were synthesized and characterized by NMR and UV/vis spectroscopy, as well as by X-ray crystallography. Treatment of 3 with the disilylplumbylene R′′ 2 Pb:, R′′ ) Si(SiMe 3 ) 3 , furnished the heteroleptic plumbylene RR′′Pb: (8), which, in the solid state, forms the plumbylene dimer RR′′PbPbRR′′ (9). The X-ray structure analysis of 9 reveals a trans-bent angle of 46.5°and a Pb ... Pb separation of 3.37 Å, the shortest observed so far between the lead atoms of two plumbylenes.
Chemical Science, 2011
ABSTRACT In this report we present data from hyperfine sublevel correlation spectroscopy (HYSCORE... more ABSTRACT In this report we present data from hyperfine sublevel correlation spectroscopy (HYSCORE), an electron paramagnetic resonance (EPR) spectroscopic technique, that reveals weak but distinct interactions between several main group element radicals and physically dissolved dinitrogen in solution. These interactions are the basis for a well-defined coordination of N2 to the paramagnetic centers. The complexes formed are primarily of the van der Waals-type but also feature a non-negligible orbital overlap between dinitrogen and the radicals' SOMO. Our spectroscopic findings are strongly supported by experiments with isotope-labeled 15N2, spectral simulations and quantum chemical and density functional theory (DFT) calculations. Formation of such complexes is unexpected when considering the small polarizability of dinitrogen but steric effects like formation of a binding “pocket” may facilitate their formation. The sensitivity, selectivity, and resolution of HYSCORE with respect to the detection of weak hyperfine couplings is needed to identify such complexes that are probably the result of a subtle interplay of induced van der Waals forces between N2, the solvent and the dissolved radicals.
Organometallics, 1997
3 ]HCl} yields, depending on X, one of the following: (a) novel branched polysilyllithium compoun... more 3 ]HCl} yields, depending on X, one of the following: (a) novel branched polysilyllithium compounds; (b) the known (Me 3 Si) 3 SiLi; (c) various mixtures. The cleavage of family 1 can be understood in terms of steric effects, i.e., assuming that MeLi attacks preferentially the sterically less hindered Si atom leading to the formation of new polysilyllithium compounds, e.g., t-BuMe 2 -Si(Me 3 Si) 2 SiLi‚3THF and t-BuMe 2 SiSiMe 2 (Me 3 Si) 2 SiLi‚3THF, which were isolated in a crystalline form. The X-ray structure of the former is presented. In contrast to 1 the lithiation of the branched polysilanes 2 leads exclusively (mostly with (Me 3 Si) 3 SiSiMe-(SiMe 3 ) 2 ) to the known (Me 3 Si) 3 SiLi. Lithiation of 3 leads to a number of novel polysilyllithium compounds. We tentatively propose that the lithiation of 3 proceeds by a two step reaction in which a disilene is formed as an intermediate, and this is followed by fast addition of a second molecule of MeLi to produce the final silyllithium product.
Nachrichten aus der Chemie, 2000
Nachrichten aus der Chemie, 2000
Journal of Organometallic Chemistry, 1999
Organometallic complexes of the type [(COD)PtMeL] (COD = 1,5-cyclooctadiene, L = Cl, I, OH, Me, C... more Organometallic complexes of the type [(COD)PtMeL] (COD = 1,5-cyclooctadiene, L = Cl, I, OH, Me, CH 2 C(O)CH 3 , C C Ph, pyridine, N-methyl pyrazinium) and the dinuclear complex [{(COD)PtMe} 2 (m-C C C C)] were prepared and characterised by 1 H-NMR spectroscopy. The crystal structures for the complexes with L =Cl, OH and Me are reported. The complex [(COD)PtMe(OH)] is a unique example of a platinum complex containing an olefin and a hydroxy ligand on the same metal centre. It reacts with C H acidic substrates to form Pt C bonds. Representative reactions with acetone, phenylacetylene and 1,3-butadiyne and the corresponding products are reported.
Inorganica Chimica Acta, 2001
Aggregation control of copper(I) thiolates through substituent size and ancillary chelate ligands... more Aggregation control of copper(I) thiolates through substituent size and ancillary chelate ligands: closely related mono-, di-, tri-and tetranuclear complexes
Inorganic Chemistry, 2012
The expanded ligand N,N'-dimethyl-N,N&... more The expanded ligand N,N'-dimethyl-N,N'-dipyridin-2-yl-pyridin-2,6-diamine (ddpd) coordinates to copper(II) ions in a meridional fashion giving the dicationic complex mer-[Cu(ddpd)(2)](BF(4))(2) (1). In the solid state at temperatures below 100 K the cations of 1 localize in Jahn-Teller elongated CuN(6) polyhedra with the longest Cu-N bond pointing in the molecular x or y directions while the z axis is constrained by the tridentate ddpd ligand. The elongated polyhedra are ordered in an antiferrodistortive way giving an idealized zincblende structure. At higher temperature dynamically averaged (fluxional) polyhedra in the molecular x/y directions are observed by multifrequency variable temperature electron paramagnetic resonance (EPR) and by variable temperature X-ray diffraction studies. Compared to [Cu(tpy)(2)](2+) (tpy = 2,2';6',2″-terpyridine) the Jahn-Teller splitting 4δ(1) of 1 is larger. This is very probably caused by the much more favorable orbital overlap in the Cu-N bonds in 1 which results from the larger bite angle of ddpd as compared to tpy. The "freezing-in" of the Jahn-Teller dynamics of 1 (T ≈ 100 K) occurs at higher temperature than observed for [Cu(tpy)(2)](2+) (T < 77 K) which is also probably due to the larger Jahn-Teller distortion of 1 resulting in a larger activation barrier.
Inorganic Chemistry, 2009
The kinetic and thermodynamic stabilities of the group 13 hydrides EH 3 (E = B, Al, Ga, In, Tl, E... more The kinetic and thermodynamic stabilities of the group 13 hydrides EH 3 (E = B, Al, Ga, In, Tl, E113) are investigated by relativistic density functional and wave function based theories. The unimolecular decomposition of EH 3 f EH þ H 2 becomes energetically more favorable going down the Group 13 elements, with the H 2 -abstraction of InH 3 , TlH 3 , and (E113)H 3 (E113: element with nuclear charge 113) being exothermic. In accordance with the Hammond-Leffler postulate, the activation barrier for the dissociation process decreases accordingly going down the group 13 elements in the periodic table shifting to an early transition state, with activation energies ranging from 88.4 kcal/mol for BH 3 to 41.3 kcal/mol for TlH 3 and only 21.6 kcal/mol for (E113)H 3 at the scalar relativistic coupled cluster level of theory. For both TlH 3 and (E113)H 3 we investigated spin-orbit effects using Dirac-Hartree-Fock and second-order Møller-Plesset theory to account for electron correlation. For (E113)H, spin-orbit coupling results in a chemically inert closed 7p 1/2 -shell, thus reducing the stability of the higher oxidation state even further. We also investigated the known organothallium compound Tl(CH 3 ) 3 , which is thermodynamically unstable similar to TlH 3 , but kinetically very stable with an activation barrier of 57.1 kcal/mol.
Chemische Berichte, 1992
I~ 1547 Bis[bis( trimethylsilyl)methyl]galliumbromid und monomeres {Bis[bis( trimethylsilyl)methy... more I~ 1547 Bis[bis( trimethylsilyl)methyl]galliumbromid und monomeres {Bis[bis( trimethylsilyl)methyl] gallium} [tris( trimethylsilyl)silyl] tellurid [(MeJSihCHhGa -TeSi(SiMeJ)J between a digallium(4) and a ditellane derivative I Gallium-tellurium 1t interaction, Tellurium compounds BlslblS(trlrnethylstlyl)methyl]galllum Bromide and MonomerJe {BIs(b1s(lrlmelhylsllyl)methyl]galllum} rrr1s(lrJmethylsllyl)sllyliielluride [(Me~lhCHhGa -TeSI Bis(bis(trimethylsilyl)methyljgallium bromide GaBrICH(SiM~hh (4), prepared from Ga,Br .. . 2 dioxane and bis(trlmethylsilyl)methyllithium in the molar ratio of 1:3, reacts with the sterlcally bigh-shielded lithium tris(trimethylsilyl}silyltelluride . DME to yield I(MelSibCHbGa-TeSi(SiM~h (5). 5 can also be synthesized by a metathetic reaction between tetrakis-(bis(trimethylsi1yl)methylldigaUium and bis(tris{trimelhylsilyl)silyllditellane in toluene at tOO·C. A erystal strueture de-Unseren Arbeitsgruppen gelang kürzlich die Synthese des Tetrakis[bis(trimethylsilyl)methyl]digalliums(4) (1) mit Gallium -Gallium-Ell und des Bis[tris(trimetbylsilyl)silyl]ditellans (3) mit Tellur -Tellur-Bindungrzl: Die Verbindung 1 entsteht in hoher Ausbeute bei der Umsetmng von GalBr • . 2 Dioxan mit vier Äquivalenten des sterisch anspruchsvollen Bis(trimethylsilyl)metbyllithiums (GI. 1) und weist nacb den Ergebnissen einer Kristallstrukturanalyse ein nahezu Dioxan Br \ / Br-(ja-(ja-Br t 4 UCHISiJ,hl'2 Syntbese von GaBr[CH(SiMe3h:h (4) Intensive Bemühungen zur Synthese von Bis[bis(trimethylsilyl)methyl]galliumbromid sowie des entsprechen-Clum. BeT.
Dalton Transactions, 2010
In this report we present the synthesis and the detailed electron paramagnetic resonance (EPR) sp... more In this report we present the synthesis and the detailed electron paramagnetic resonance (EPR) spectroscopic characterization of novel trivalent lead- and tin-based radicals comprising sterically demanding germyl substituents. The investigated radicals are derived from the recently reported trihypersilyl-substituted tetryl radicals *PbHyp3 and *SnHyp3. The tetryl radicals *Pb(Ge(SiMe3)3)3 (8), *Pb(Ge(SiMe3)3)2Si(SiMe3)3 (9), *PbGe(SiMe3)3(Si(SiMe3)3)2 (10), and *Sn(Ge(SiMe3)3)3 (11) show substitution patterns derived from stepwise (9, 10) or complete (8, 11) substitution of hypersilyl groups (Hyp = Si(SiMe3)3) in *PbHyp3 and *SnHyp3 by homologous hypergermyl groups (Hge = Ge(SiMe3)3). They were generated through oxidation of the corresponding potassium tetranides KPbR3 and KSnR3 (R = Hyp, Hge), which in turn had been synthesized employing nucleophilic addition of KHyp or KHge to PbHyp2 or to the novel tetrylenes PbHge2 (1) and SnHge2 (12). The gained EPR spectroscopic data give insights into the influence of the substitution pattern on the geometric and electronic properties of the lead-centered species. With an increasing number of germyl substituents, the spin-orbit coupling to the central atom increases resulting in larger g(iso)-values and larger g-anisotropies while the 209Pb hyperfine splitting constants A(iso) decrease. These decreasing splitting constants are indicative of a diminished s-character of the singly occupied molecular orbital (SOMO) and to a molecular geometry running from slightly pyramidal to almost planar. Interestingly, already one germyl substituent (for radical 10) dominates most of the mentioned properties. For stannyl radical 11 a similar trend is seen for the spin-orbit coupling, while the (117/119)Sn hyperfine splittings unexpectedly increase from SnHyp3 to SnHge3.
Chemical Communications, 1998
The cluster anions [M VI (S)Re I 3 (CO) 9 (m 3 -S) 4 ] 2 , M = Mo or W, contain three six-coordin... more The cluster anions [M VI (S)Re I 3 (CO) 9 (m 3 -S) 4 ] 2 , M = Mo or W, contain three six-coordinate tricarbonylrhenium(I) fragments, held together by one m 3 -sulfide ion and by one reducible and charge transfer-active m 3 -M VI S 4 22 unit.
Angewandte Chemie, 1999
ABSTRACT Eine lineare Si-Hg-Hg-Si-Anordnung und einen Hg-Hg-Abstand von 265.69 pm weist die erste... more ABSTRACT Eine lineare Si-Hg-Hg-Si-Anordnung und einen Hg-Hg-Abstand von 265.69 pm weist die erste zweikernige, σ-gebundene Quecksilber(I)-Verbindung mit zweifach koordinierten Hg-Zentren (1) auf. Sie entsteht unerwartet bei der Umsetzung von zwei Äquivalenten des Silans (Me3SiMe2Si)3SiH mit tBu2Hg. Setzt man die Reagentien dagegen im Verhältnis 1:1 ein, so entsteht erwartungsgemäß die Quecksilber(II)-Verbindung (Me3SiMe2Si)3SiHgtBu.
Angewandte Chemie, 1994
... Tetrakis(hypersilyl)dithallium(Tf - TI) - eine Verbindung des zweiwertigen Thallium ** Sonja ... more ... Tetrakis(hypersilyl)dithallium(Tf - TI) - eine Verbindung des zweiwertigen Thallium ** Sonja Henkel, Karl Wilhelm Klinkhammer* und Wolfgang Schwarz Wahrend Molekiilverbindungen mit zweiwerligem Bor in Form von Diboranen(4) schon seit langer Zeit bekannt sind, gelang ...
Angewandte Chemie International Edition in English, 1997
... code +(441)7983329 Dr. KW Klinkhammer, Dr. W. Schwarz Institut fur Anorganische Chemie der Un... more ... code +(441)7983329 Dr. KW Klinkhammer, Dr. W. Schwarz Institut fur Anorganische Chemie der Universitit Stuttgart (Germany) [**I We are ... In contrast, in the analogous compounds with Ga, and In, tetrahedra we observed almost indistinguishable Ga-Ga and In-In distances ...
Angewandte Chemie International Edition, 1999
Most of the known mercury compounds have a formal 2 oxidation state. [1±5] s-Bonded organomercury... more Most of the known mercury compounds have a formal 2 oxidation state. [1±5] s-Bonded organomercury(i) compounds with a 1 oxidation state for example RHgHgR, R organic substituent, have been frequently cited in the literature as
Angewandte Chemie International Edition, 2002
Organometallics, 1998
The diarylplumbylene R 2 Pb: (3), R ) 2-tBu-4,5,6-Me 3 C 6 H, and the rearranged alkylarylplumbyl... more The diarylplumbylene R 2 Pb: (3), R ) 2-tBu-4,5,6-Me 3 C 6 H, and the rearranged alkylarylplumbylene RR′Pb:, R ) 2,4,6-tBu 3 C 6 H 2 , R′ ) CH 2 C(CH 3 ) 2 -3,5-tBu 2 C 6 H 3 , were synthesized and characterized by NMR and UV/vis spectroscopy, as well as by X-ray crystallography. Treatment of 3 with the disilylplumbylene R′′ 2 Pb:, R′′ ) Si(SiMe 3 ) 3 , furnished the heteroleptic plumbylene RR′′Pb: (8), which, in the solid state, forms the plumbylene dimer RR′′PbPbRR′′ (9). The X-ray structure analysis of 9 reveals a trans-bent angle of 46.5°and a Pb ... Pb separation of 3.37 Å, the shortest observed so far between the lead atoms of two plumbylenes.