Karl Wilhelm Klinkhammer

Thallium(I) -bis(trimethylsilyl) amid

The reaction of LiN(SiMe3)2 With TlCl in toluene yields the bis(trimethylsilyl)amino derivative of thallium(I) (1). In the gaseous phase and in benzene solution the compound is mainly monomeric, whereas in the solid state the amide 1 consists of cyclic dimers, which are linked to infinite chains by intermolecular Tl ⋯ Tl contacts.

Boryl and Bridged Borylene Complexes of Iron and Ruthenium

The reactivity of aminodihaloboranes R2NBX2 (R = Me, SiMe3; × = Cl, Br) towards transition metal complexes of the type Na[(η5-C5R′5)M(CO)2)] (M = Fe, Ru; R′ = H, Me) was investigated. In the case of Me2NBBr2 and M = Fe the borylcomplexes [(η5-C5R′5)(CO)2Fe{BBr(NMe2)}] (C5R′5 = C5H59a; C5R′5 = C5H4Me 9b; C5R′5 = C5Me510) were obtained. The compounds 9aand 9bwere formed together with the corresponding bridged borylene complexes [μ-BNMe2(μ-CO){(η5-C5R′5)Fe(CO)}2] (C5R′5 = C5H511a; C5R′5 = C5H4Me 11b) in a 1:1 ratio, the latter, however, could be isolated from these mixtures as pure materials. In addition the novel boryl and borylene ruthenium complexes [(η5-C5H5)(CO)2Ru{BX(NMe2)}] (X = Cl 12a; × = Br 12b), [(η5-C5H5)(CO)2Ru{BCl{NSiMe3{BClN(SiMe3)2}}}] (13) and [μ-BN(SiMe3)2(μ-CO){(η5-C5H5)Ru(CO)}2] (14) were obtained by similar methods. All compounds were characterized by multinuclear NMR and IR spectroscopy. The structure of 13 in the solid state was determined by a single-crystal X-ray diffraction study.

A Heteroleptic Diplumbene and a Magnesium Dibromide Stabilized Plumbylene Dimer

Treatment of the diarylplumbylene R2Pb: (R = 2,4,6-iPr3C6H2) with the disilylplumbylene R′2Pb: [R′ = Si(SiMe3)3] furnishes the heteroleptic plumbylene RR′Pb: which exists as the diplumbene RR′Pb=PbRR′ (7) in the solid state. The X-ray structure analysis of 7 reveals a trans-bent angle of 42.7° and a Pb–Pb bond length of 298.99(5) pm, the shortest observed so far for diplumbenes with a lead–lead double bond. Reaction of mesitylmagnesium bromide with PbCl2 yielded black crystals of an MgBr2 stabilized dimesitylplumbylene dimer with a large trans-bent angle of 71°, a lead–lead separation of 335.49(6) pm, and long Pb···Br contacts of 315.71(8) pm.

Synthesis and Crystal Structure of the two Lithium Hypersilylcuprates LiCu2[Si(SiMe3)3]3 and [Li7(OtBu)6][Cu2{Si(SiMe3)3}3]

The two hypersilylcuprates LiCu2Hyp3 (2) and [Li7(OtBu)6][Cu2Hyp3] (3) (Hyp = Si(SiMe3)3) were synthesized by reactions of unsolvated lithium hypersilanide, LiHyp with hypersilylcopper and CuOtBu, respectively. Both contain the novel A-frame trihypersilyldicuprate anion [Cu2Hyp3]–. In the former case a molecular compound is produced containing intimate ion pairs. In the latter case the cuprate anion and the unique large [Li7(OtBu)6]+ cation form a salt-like compound, only sparingly soluble in unpolar solvents. According to NBO analyses the bonding within the trihypersilyldicuprate moiety is best described by interaction of a bridging lewis-basic hypersilanide anion with two lewis-acidic hypersilyl copper fragments. Synthese und Kristallstrukturen der Hypersilylcuprate LiCu2[Si(SiMe3)3]3 und [Li7(OtBu)6][Cu2{Si(SiMe3)3}3] Die beiden Hypersilylcuprate LiCu2Hyp3 (2) and [Li7(OtBu)6][Cu2Hyp3] (3) (Hyp = Si(SiMe3)3) entstehen durch die Reaktion von unsolvatisiertem Lithiumhypersilanid, LiHyp, mit Hypersilylkupfer bzw. CuOtBu. Beide enthalten das neuartige Trihypersilyldicuprat-Anion [Cu2Hyp3]–. Wahrend im ersten Fall eine aus Kontaktionenpaaren bestehende molekulare Substanz vorliegt, treten in 3 Cupratanionen und die grosen einzigartigen [Li7(OtBu)6]+- Kationen zu einer salzartigen, in unpolaren Losungsmitteln unloslichen Verbindung zusammen. Die Bindungsverhaltnisse werden, wie NBO-Analysen belegen, am besten durch die Wechselwirkung eines verbruckenden, lewis-basischen Hypersilylanions mit zwei lewis-sauren Hypersilylkupfer-Fragmenten beschrieben.

Calcium-bis { [tris(trimethylsilyl)silyl]tellanid } · 4 THF-Synthese, spektroskopische Charakterisierung und Struktur / Calcium-bis{[tris(trimethylsilyl)silyl]tellanide} · 4THF-Synthesis, Spectroscopic Characterization and Structure

Calcium bis{[tris(trimethylsilyl)silyl]tellanide} · 4THF is obtained by metallation of [tris(trimethylsilyl)silyl]tellane using dimeric calcium bis[bis(trimethylsilyl)amide] in toluene, followed by recrystallisation from tetrahydrofuran. The compound is characterized by a remarkable highfield shift of the 125Te{1H}-NMR resonance (-2204 ppm vs. Me2Te). The X-ray structure determination (triclinic, P1; Z = 1; a = 1042.6(2), b = 995.7(2), c = 1379.6(3) pm; α = 90.06(2), β = 92.76(2), γ = 94,03(2)° at -100 °C) shows a distorted octahedral coordination sphere of the calcium atom (Ca-Te 319; Ca-O 236 and 241 pm). The two [tris(trimethylsilyl)silyl]-tellanide ligands are in a trans position; the angle Ca-Te-Si is widened to 129°.

Die Kristallstruktur von Diethylaluminiumhypersilanid, [(C2H5)2Al–Si{Si(CH3)3}3]2

The Crystal Structure of Diethylaluminium Hypersilanide [(C2H5)2Al–Si{Si(CH3)3}3]2 [Et2Al–Hsi]2 (Et = C2H5, Hsi = –Si(SiMe3)3), prepared from [Et2AlCl]2 and equimolar amounts of base-free Li–Hsi in n-pentane, crystallizes in the triclinic space group P 1 with two independent dimers per unit cell. One of these molecules is disordered. The dimers consist of planar Al2C2-skeletons with Al–C–Al bridging bonds of 212,9(2) and 221,2(2) pm, respectively, and with intramolecular C–H…Al contacts of 202(2) pm.

New sulfide-bridged heterocubanes [MVI(S)ReI3(CO)9(µ3-S)4]–, M = Mo or W, with transition metals in very different oxidation states

The cluster anions [MVI(S)ReI3(CO)9(µ3-S)4]–, M = Mo or W, contain three six-coordinate tricarbonylrhenium(I) fragments, held together by one µ3-sulfide ion and by one reducible and charge transfer-active µ3-MVIS42– unit.

Synthese, Struktur und Reaktivität des Lithium[tris-(trimethylsilyl)silyl]tellanids · DME (Metallderivate von Molekülverbindungen ; 4)

Lithium-tris(trimethylsilyl)silanid · 1,5 DME [3] reagiert mit Tellur in 1,2-Dimethoxyethan zu farblosem Lithium-[tris(trimethylsilyl)silyi]tellanid · DME (1). Nach der Rontgenstrukturanalyse {-150 ± 3°C; P21/c; a = 1346,6(4); b = 1497,0(4); c = 1274,5(3) pm; β = 99,22(2)°; Z = 2 Dimere; R = 0,030} ist Verbindung 1 im Festkorper dimer; die beiden Tris(trimethylsilyl)silyl-Gruppen sind am planaren Li-Te-Li-Te-Ring trans-standig zueinander angeordnet. Tellur erreicht durch Bindung an zwei Lithium und ein Silicium die Koordinationszahl 3, Lithium durch Bindung an zwei Tellur und den Chelatliganden DME die Koordinationszahl 4 {Li-Te 278 und 284; Si-Te 250; Li-O 200 pm (2X); Te-Li-Te 105°, Li-Te-Li 75°; O-Li-O 84°}. Der hier zu 154 pm ermittelte kovalente Radius des DME-komplexierten Lithiumatoms fallt in den auch fur andere Verbindungen typischen Bereich von 155 ± 3 pm. Charakteristische Umsetzungen des Tellanids 1 fuhren zu [Tris(trimethylsilyl)silyl]tellan (2), Methyl-[tris(trimethylsilyl)silyl]tellan (4) und Bis[tris(trimethylsilyl)silyl]ditellan (5). Lithium tris(trimethylsilyl)silanide · 1,5 DME [3] and tellurium react in 1,2-dimethoxyethane to give colourless lithium [tris(trimethylsilyl)silyl]tellanide · DME (1). An X-ray structure determination {-150 · 3·C; P21/c; a = 1346.6(4); b = 1497.0(4); c = 1274.5(3) pm; β = 99.22(2)·; Z = 2 dimers; R = 0.030} shows the compound to be dimeric forming a planar Li-Te-Li-Te ring with two tris(trimethylsilyl)silyl substituents in a trans position. Three-coordinate tellurium is bound to the central silicon of the tris(trimethylsilyl)silyl group and to two lithium atoms; the two remaining sites of each four-coordinate lithium are occupied by the chelate ligand DME {Li-Te 278 and 284; Si-Te 250; Li-O 200 pm (2X); Te-Li-Te 105°; Li-TeLi 75°; O-Li-O 84°}. The covalent radius of 154 pm as determined for the DME-complexed lithium in tellanide 1 is within the range of 155 ± 3 pm, also characteristic for similar compounds. In typical reactions of the tellanide 1 [tris(trimethylsilyl)silyl]tellane (2), methyl-[tris(trimethylsilyl)silyl]tellane (4) and bis[tris(trimethylsilyl)silyl]ditellane (5) are formed.