Tetramethylcyclopentadienylselenium derivatives

Abstract

Bis(1,2,3,4-tetramethylcyclopentadienyl)selane (1) has been prepared by the reaction of tetramethylcyclopentadienyllithium (Cp(t)Li) with selenium bis(diethyldithiocarbamate). Treatment of Cp(t)Li with elemental selenium, followed by air oxidation, led to loss of the allylic hydrogen atom, and formation of the novel tricyclic compound 1,4,5,6,7,10,11,12-octamethyltricyclo[7.3.0.0]-2,8-diselenadodeca-3,5,9,11-tetraene (2). The sulfur analogue of 2 has been obtained by a similar procedure. The X-ray crystal structures of compounds 1 and 2 have been determined, and the molecular geometry observed for has been probed using DFT calculations.

Pentamethylcyclopentadienylselenium derivatives VI: Synthesis and characterisation of ferrocenyl(pentamethylcyclopentadienyl)selenium

“…In the case of 3 this procedure gives good agreement with the experimental value (Se (C 5 Me 4 H) 2 : d = 292 [10]; SeFc 2 : d = 275 [11]; 3: d = 280). The observed resonance for 4 is, however, significantly downfield of the expected region (1: d = 324; SeFc 2 : d = 275; 4: d = 378).…”

“…The Se-C(10) distance is considerably shorter (1.868(10) Å ), as would be expected for a bond to an sp 2 hybridised carbon atom, and indeed appears to be one of the shortest carbon-selenium single bonds [15]). The C(10)-Se-C(11) angle of 101.8(4)°is considerably smaller than its equivalent in 1 (109.6(2)° [12]), where the steric requirements of the two allylic methyl groups appear to be dominant in determining the observed geometry, and resembles that in SeðC 5 Bu t 2 H 3 ÞPh (100.3(3)° [14]) and Se (C 5 Me 4 H) 2 (99.7(1)° [10]), where these methyl groups are absent.…”

Deuterated dimethyl sulfoxide as a good NMR solvent for the characterization of alkali metal cyclopentadienides, amides, alkoxides and phenoxides

“…The coordinated THFs were replaced by the stronger donor solvent and existed as free molecules as seen from their chemical shifts (d 1 H 3.61, 1.77, d 13 C 67.1, 25.2) [11]. Unlike in THFd 8 , compound 1b [12], 1c [13] gave clean spectra in DMSO-d 6 (supporting information). To the best of our knowledge, this is the first report of the NMR studies of the two compounds which have innumerable applications in organometallic chemistry.…”

“…2b was purchased from SigmaeAldrich, and used as received. 1a [10], 1b [12], 1c [13], 1d [15], 1e [16], 3a [21], 4a [17], 4b [18], 4c [19] and 4d [20] were prepared according to the literature procedures. NMR spectra were recorded in DMSO-d 6 4.2.…”

Neuartige Cyclopentadienyl‐N‐silylphosphazen‐Komplexe der Seltenerdmetalle Yttrium und Lutetium

“…Die folgenden Verbindungen wurden nach Literaturvorschriften dargestellt: Dimethylfulven (CH 3 ) 2 C=C 5 H 4 34, Li(C 5 H 4 t Bu) 35, Li(C 5 Me 4 H) 36, (C 5 H 4 t Bu)Me 2 SiCl 37, (C 5 Me 4 )Me 2 SiCl 38, Benzylkalium 39, TMSN=P(NMe 2 ) 3 40, TMSN=P t Bu 3 22, HN=P t Bu 3 20, N , N ‐Dimethylbenzylamin 41, Li(dmba) 42, [Y(dmba) 3 ] 28, [Lu(dmba) 3 ] 29. n BuLi (1.6 m Lösung in Hexan) wurde in p. A. Qualität bei den Firmen Aldrich und ACROS, bezogen.…”