Klaus Eichele Publication Abstracts 2019

---

[UP]	J.-J. Maudrich, F. Diab, S. Weiß, M. Widemann, T. Dema, H. Schubert, K. M. Krebs, K. Eichele, L. Wesemann: Deprotonation of Organogermanium and Organotin Trihydrides Inorg. Chem. 2019, 58(23), 15758-15768. DOI: 10.1021/acs.inorgchem.9b01822

Terphenyltin and terphenylgermanium trihydrides were deprotonated in reaction with strong bases, such as LiMe, LDA, or KBn. In the solid state, the Li salts of the germate anion 4 and 4a exhibit a Li-Ge contact. In the Li salt of the dihydridostannate anion 6a, the Li cation is not coordinated at the tin atom instead an interaction of the Li cation with the hydride substituents was found. Evidenced by (HLi)-H-1-Li-7-HOESY NMR spectroscopy the Li-salt of the deprotonated tin hydride 6a exhibits in toluene solution a contact between Li cation and hydride substituents, whereas in the (HLi)-H-1-Li-7-HOESY NMR spectrum of the homologous germate salt 4a, no crosspeak between hydride and Li signals was found. The organodihydridogermate and -stannate react as nucleophiles with low-valent Group 14 electrophiles. Thus, three compounds were synthesized: Ar-(sic)'-EH2-Ar (E', E = Sn, Ge; Pb, Ge; Pb, Sn; Ar = Ar', Ar*). Following an alternative synthesis Ar'SnH2PbAr* was synthesized in reaction between [(Ar*PbH)(2)] and [(Ar'SnH)(4)] generated in situ. In reaction between low-valent organotin hydride [(Ar*SnH)(2)] and organdihydridostannate [Ar*SnH2](-) formation of distannate [Ar*2Sn2H3](-) was found.

---

[UP]	S. Weiß, M. Auer, K. Eichele, H. Schubert, L. Wesemann: eta3-Allyl Coordination at Pb(II) Organometallics 2019, 38(2), 417-423. DOI: 10.1021/acs.organomet.8b00766

Allylmagnesium chloride and methyl-propenyl-magnesium bromide were reacted with bulky substituted organolead and organotin halides (Ar*PbBr)2, (Ar'PbBr)2, (Ar*SnCl)2 (Ar* = 2,6-trip2C6H3-, trip = 2,4,6-triisopropylphenyl, Ar' = 2,6-mes2C6H3-, mes = 2,4,6-trimethylphenyl). The allyl ligand coordinates in an eta3-coordination mode at organoplumbylene fragments. In the solid state as well as in solution, eta3-coordination was characterized by crystal structure analysis and Saunders' isotopic perturbation technique. For the plumbylene Ar*Pb(C3H5), a solid state 207Pb magic angle spinning (MAS) NMR spectrum could be obtained. The isotropic chemical shift is -435 ppm, and the magnitude of the 207Pb chemical shift tensor of 7000(500) ppm is among the greatest observed experimentally. The methylallyl ligand coordinated at a plumbylene fragment exhibits two short and one long Pb-C interaction. In reaction with aniline, the allyl ligand reacts as a leaving group to give amidoplumbylenes.

---

[UP]

C. O. Hollfelder, L. N. Jende, H.-M. Dietrich, K. Eichele, C. Maichle-Mössmer, R. Anwander: 1,3-Diene Polymerization Promoted by Half-Sandwich Rare-Earth-Metal Dimethyl Complexes: Active Species Clustering and Cationization/Deactivation Processes Chem. Eur. J. 2019, 25(30), 7298-7302. DOI: 10.1002/chem.201901269

When activated with fluorinated borate cocatalysts the trimetallic complexes [Cp*LnMe2]3 (Ln=Y, Lu; Cp*=C5Me5) promote efficiently the formation of high-cis polybutadiene. Respective polyisoprenes instead bear much less pronounced microstructures, but reveal crosslinked products at lower polymerization temperatures. Varying the amount of cocatalyst, the emerging active species were examined by NMR spectroscopic techniques (incl. 1H DOSY). The occurrence of donor-solvent and thermally induced degradation products of the highly reactive precatalyst [Cp*YMe2]3 and derived catalyst species was revealed by the elucidation of methylidene clusters [Cp*3Y3Me4(CH2)(thf)2] and [Cp*6Y6Me4(CH2)4], as well as [(Cp*Y)2Me2(N(Me)2(C6H4)]n[B(C6F5)4]n, implying a multimetallic active species.

---

[UP]	F. Diab, F. S. W. Aicher, C. P. Sindlinger, K. Eichele, H. Schubert, L. Wesemann: Reductive Elimination and Oxidative Addition of Hydrogen at Organostannylium and Organogermylium Cations Chem. Eur. J. 2019, 25(17), 4426-4434. DOI: 10.1002/chem.201805770

Bulkily substituted organodihydrogermylium and -stannylium cations [Ar*EH2](+) (E=Ge, Sn; Ar*=2,6-Trip(2)C(6)H(3), Trip=2,4,6-triisopropylphenyl) were characterized as salts of the weakly coordinating perfluorinated alkoxyaluminate anion [Al{OC(CF3)(3)}(4)](-). At room temperature, the stannylium cation liberates hydrogen to generate the low valent organotin cation [Ar*Sn](+). In contrast, the dihydrogermylium cation transfers the hydrogen atoms to an aryl moiety of the terphenyl ligand and oxidatively adds either hydrogen under an atmosphere of hydrogen or a sp(2) CH unit of the 1,2-difluorobenzene solvent.

---

[UP]	R. Schmidt, M. Strobele, K. Eichele, H.-J. Meyer: Lithium Ion Motion in Lithium Nitridoborate Chalcogenides Li-5(BN2)Ch (Ch = Se, Te) Z. Anorg. Allg. Chem. 2019, 645(4), 461-465. DOI: 10.1002/zaac.201800432

The compounds Li-5(BN2)Se and Li-5(BN2)Te were synthesized at 900 degrees C in a closed system utilizing weld shut niobium ampoules and obtained as white microcrystalline powders. Their crystal structures were solved and refined on the basis of single-crystal X-ray diffraction data with the space group I4(1)md [a = 6.3983(4) angstrom, c = 11.1072(9) angstrom for Li-5(BN2)Se and a = 6.5878(3) angstrom, c = 11.4382(7) angstrom for Li-5(BN2)Te]. The temperature dependent Li+ motion was investigated by Li-7 MAS NMR spectroscopy.