Bis[(2-pyridyl)bis(trimethylsilyl)methyl-C,N]germanium(II):  A Base-Stabilized Germylene and the Corresponding Germanethione, Germaneselenone, and Germanetellurone

Abstract

Bis[(2-pyridyl)bis(trimethylsilyl)methyl-C,N]germanium(II) (1) reacts with elemental chalcogens (sulfur, selenium, tellurium) to give the corresponding thione (2), selenone (3), and tellurone (4) at room temperature. At elevated temperatures, the dihydropyridinato compounds 5 and 6 are formed by a 1,3-trimethylsilyl shift from one of the methyl bridges to the sulfur and selenium atoms in 2 and 3, respectively. The compounds were characterized by NMR spectroscopy (1H, 13C, 29Si, 77Se, 125Te), MS (EI), and elemental analysis. X-ray crystal structure determinations are presented for 1, 3, 4, and 5.

Taming the germyliumylidene [CIGe:]+ and germathionium [CIGeS]+ ions by donor–acceptor stabilization using 1,8-bis(tributylphosphazenyl)naphthalene

“…The same is true for the mean Ge-N distance (1.899 Å ) in 3 compared with that in 2 (1.971 Å ). The Ge-S bond distance (2.066(1) Å ) in 3 is close to those of GeQS bonds stabilized by an intramolecular donor (ranging from 2.049(3) Å to 2.063(3) Å ), [11][12][13] but shorter than the reported Ge-S single bond distance (2.239(1) Å ), 14 implying the ylide nature of the GeQS moiety as depicted in Scheme 3. Similarly, the mean P-N distance of 1.668 Å in 3 lies between those of the P-N single bonds (1.75-1.80 Å ) 9 and PQN double bonds (1.51-1.57 Å ), 10 reflecting also the ylide nature of the PQN moieties.…”

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.…”

“…Significant advances have now been encountered in this field, as illustrated by the various successful isolations and structural characterizations of such metallanechalcogenones. But, up until recently,92,93 only four germanethiones, 94 -98 seven germaneselones 95,98 -101 and four germanetellones 37,91,95,102 had been isolated at room temperature and characterized structurally. These compounds are either thermodynamically stabilized 37,94,95,97,99,100 by coordination of Lewis base to the germanium, or kinetically stabilized by bulky protecting groups on the germanium.…”

“…But, up until recently,92,93 only four germanethiones, 94 -98 seven germaneselones 95,98 -101 and four germanetellones 37,91,95,102 had been isolated at room temperature and characterized structurally. These compounds are either thermodynamically stabilized 37,94,95,97,99,100 by coordination of Lewis base to the germanium, or kinetically stabilized by bulky protecting groups on the germanium. 91,96,101,102 Moreover, to our knowledge, no halogenated and also no nitrogen-substituted germanechalcogenones had been characterized until the recent work by our group.…”

Heavier alkali metal complexes of the bulky alkyl ligand 2-(bis(trimethylsilyl)methyl)-6-methylpyridine: Crystal structures of [{6-Me(2 Pyr)}(Me3Si)2CNa(pmdta)] and [{6-Me(2-Pyr)}(Me3Si)2CK]∞

“…Due to their ability to deliver stable organometallic complexes displaying unusual metal oxidation states and bonding modes, amongst significant structural diversity, bulky ligands derived from trimethylsilyl substituted methylpyridines have been widely used in exploring the chemistry of both main group and transition metals [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. The basic template of these ligands provides several attractive features for the synthetic and structural chemist; in conjunction with either 2-or 2,6-substitution of the pyridyl ring the number of Me 3 Si groups can be varied altering the steric bulk and degree of kinetic protection afforded metal centres, the pyridyl nitrogen can provide stabilisation through internal coordination, and the ligand can electronically re-arrange to accommodate both r and p metal-ligand bonding modes.…”