Germanium-Containing Heterobicyclic 10-π-Electron Ring Systems. Synthesis and Characterization of Neutral and Cationic Germanium(II) Derivatives of Aminotroponiminates

Abstract

The neutral and cationic aminotroponiminate derivatives of germanium(II) have been investigated. The treatment of GeCl 2 ‚(1,4-dioxane) with [(i-Pr) 2 ATI]Li or [(Me) 2 ATI]Li in a 1:1 molar ratio gave the corresponding monochloro germanium(II) complex. Substitution of the chloride ion of [(i-Pr) 2 ATI]GeCl with weakly coordinating anions [CF 3 SO 3 ] -and [(η 5 -C 5 H 5 )ZrCl 2 (µ-Cl) 3 ZrCl 2 (η 5 -C 5 H 5 )] -led to cationic germanium(II) species containing {[(i-Pr) 2 ATI]Ge} + ion. Although NMR data of the cationic species show notable differences relative to their neutral analog, the solid state data show only minor changes in the C 7 N 2 Ge moiety. The Ge-N bond distances of the cations are not indicative of significant Ge-N π-bonding. These compounds feature some of the smallest N-Ge-N angles known for Ge(II) compounds. Attempted synthesis of the tetraphenylborate salt of {[(Me) 2 ATI]Ge} + led to a phenyl group transfer product [(Me) 2 ATI]GePh‚BPh 3 with a Ge(II)-B bond. Details of the 1 H, 13 C NMR spectroscopy and X-ray crystal structures of all these compounds are described.

Isolation of a germanium(ii) cation and a germylene iron carbonyl complex utilizing an imidazolin-2-iminato ligand

“…1c However, it is clearly reduced as compared to I and II in which the Ge-N bond lengths range from 1.894(2) Å to 1.917(5) Å. 4,5 In contrast, the Ge1-N1 distance of 1.9694(14) Å is significantly increased with respect to that in I and II. Note that the germanium(II) cation III also exhibits a longer Ge-N distance to the imino nitrogen-atom (1.9884(18) Å) and a shorter Ge-N contact to the amino nitrogen-atom (1.8286(21) Å).…”

“…For example, Dias and co-workers implemented an aminotroponiminate ligand to stabilise the highly reactive Ge(II) cation species (I, Fig. 1), 4 whereas a β-diketiminate ligand was introduced by Power (II, Fig. 1).…”

“…Notably, most related iron carbonyls exhibit a germanium center that is either tetracoordinate (germylene-iron complexes) 22 or found at the apex of a trigonal pyramid (ferrogermylenes). 23 From our literature search 24 we retrieved the germylene complex (2,6-tBu 2 -4-Me-C 6 H 2 O) 2 GeFe(CO) 4 as the only respective example with a trigonal planar-coordinate germanium center. 25 The Fe1-Ge1 bond length in 3 was determined to be 2.3026(5) Å [2.3041(5) Å] which is longer than that reported for (2,6-tBu 2 -4-Me-C 6 H 2 O) 2 GeFe(CO) 4 (2.240(2) Å) 25 but does not exceed the range found for the majority of related iron carbonyls (germylene-iron complexes: 2.298(2)-2.348(1) Å; ferrogermylenes: 2.4415(11) Å, 2.496(2) Å).…”

Weak Arene Stabilization of Bulky Amido‐Germanium(II) and Tin(II) Monocations

“…[3] Although truly one-coordinate cations of the type RED + are unknown, a variety of kinetic and/or electronic stabilization strategies have been employed to allow an entry to higher-coordinate examples. These include the use of anionic [4] or neutral [5] arene donors (as in 1 and 2), and bi- [6][7][8] or polydentate [9] N-donor ligands (as in 3 and 4). Other notable stabilization strategies involve electronic saturation of RE:…”

Three‐coordinate divalent Group 14 element derivatives and related compounds

“…Thus, the presence of ligands with donor side arms on the germanium or the tin element can (by transfer of electron density) reduce the deficit on 37 is, to our knowledge, the first example of an intramolecular base stabilized homoleptic dialkylgermylene. Various amino-, phosphino-, thioalkoxy-, alkoxy-and aryloxy-divalent species have also been isolated in monomeric form owing to this method of stabilization; one should mention in particular the studies of Jutzi and co-workers, 28,32,54,71 Veith and coworkers, 15,18,40,66 Parkin and co-workers, 67 Jurkschat and co-workers, 77,78 Dias and co-workers 31,35,42,69,80,81 and Roesky and co-workers. …”