Gold complexes of ditelluridoimidodiphosphinate ligands — Reversible oxidation of Au(I) to Au(III) via insertion of gold into a phosphorus–tellurium bond

2009 ◽  
Vol 87 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Dana J Eisler ◽  
Stuart D Robertson ◽  
Tristram Chivers

The reaction of (THT)AuCl with (TMEDA)Na[N(TePR2)2] (R = Ph, i-Pr, t-Bu) produces a series of gold (III) complexes of the type [{R2PNP(Te)R2}Au(µ-Te)]2 (4a, R = i-Pr; 4b, R = Ph; 4c, R = t-Bu) rather than the expected homoleptic Au(I) complexes of the ditelluridoimidodiphosphinate ligands. A combination of solution- and solid-state NMR studies shows that both cis and trans isomers of 4a–4c are formed in these reactions. X-ray structural determinations of the trans isomers of 4a–4c reveal a centrosymmetric arrangement with a central four-membered Au2Te2 ring formed by the formal insertion of gold into a P–Te bond; this insertion process was shown to be reversible upon addition of PPh3 to 4a to give the monomeric gold(I) complex Ph3PAu[N{TeP(i-Pr)2}2]. The X-ray structure of cis-4b is also described.Key words: gold, tellurium, redox, X-ray structures, imidodiphosphinate.

1992 ◽  
Vol 65 (2) ◽  
pp. 427-443 ◽  
Author(s):  
M. R. Krejsa ◽  
J. L. Koenig

Abstract Accelerated sulfur vulcanized cis-polyisoprene was analyzed using C-13 solid-state NMR to determine the chemical microstructure of the network. Three formulations were analyzed consisting of varying accelerator/sulfur ratios. All formulations yielded similar network structures, but the amount of sulfurization varied with sulfur concentration. At low percent cure, only polysulfidic A-type cis-structures were found. For longer cure times, the A-type structures shortened to monosulfldic, and B-type polysulfidic structures, both cis and trans, were formed. The amount of trans-sulfurized product was constant with cure once this resonance appeared. No isomerization, chain scission, saturation, or double bond migration was detected. The NMR measurements appeared to show fairly good agreement with equilibrium swelling measurements.


ChemInform ◽  
2010 ◽  
Vol 24 (41) ◽  
pp. no-no
Author(s):  
R. TACKE ◽  
J. BECHT ◽  
A. LOPEZ-MRAS ◽  
W. S. SHELDRICK ◽  
A. SEBALD

2000 ◽  
Vol 104 (9) ◽  
pp. 1921-1926 ◽  
Author(s):  
Marek Pietraszkiewicz ◽  
Oksana Pietraszkiewicz ◽  
Waclaw Kolodziejski ◽  
Krzysztof Wozniak ◽  
Neil Feeder ◽  
...  

1994 ◽  
Vol 33 (21) ◽  
pp. 4688-4695 ◽  
Author(s):  
Marek J. Potrzebowski ◽  
Gisbert Grossmann ◽  
Jaroslaw Blaszczyk ◽  
Michal W. Wieczorek ◽  
Joachim Sieler ◽  
...  

Polyhedron ◽  
2000 ◽  
Vol 19 (15) ◽  
pp. 1803-1807 ◽  
Author(s):  
Inamur Rahaman Laskar ◽  
Tapas Kumar Maji ◽  
Siddhartha Chaudhuri ◽  
Ashutosh Ghosh ◽  
Nirmalendu Ray Chaudhuri

2010 ◽  
Vol 65 (2) ◽  
pp. 119-127 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Ezzat Khan ◽  
Amin Badshah ◽  
Elias Molla ◽  
Peter Thoma ◽  
...  

The molecular structures of three alkynylsilanes, tetrakis(ethynyl-p-tolyl)silane, 3,3,6,6,-tetramethyl- 3,6-disila-triyne, 3,3,6,6,9,9,-hexamethyl-3,6,9-trisila-tetrayne, and of bis(trimethylstannyl)- ethyne have been determined by X-ray diffraction. The same alkynylsilanes, and in addition 1,2- bis(trimethylsilylethynyl)-1,1,2,2-tetramethyldisliane, were studied by solid-state 13C and 29Si MAS NMR spectroscopy. The results of these measurements were compared with crystallographic evidence and also with relevant solution-state NMR data.


2008 ◽  
Vol 63 (10) ◽  
pp. 1149-1154 ◽  
Author(s):  
Werner Uhl ◽  
Andreas Vogelpohl

AbstractThe reaction of diethylaluminum hydride with the hydrazine derivatives 1-aminopyrrole and 1- aminopiperidine afforded the corresponding dialkylaluminum hydrazides (1 and 2) by the release of elemental hydrogen. Both products are dimeric in the solid state. While 1 adopts a cis arrangement of the pyrrole groups, a trans configuration was determined for the piperidine compound 2. Only 1 gives an equilibrium mixture of cis and trans isomers in solution. Similar compounds (3 and 4) were obtained by the treatment of the same hydrazines with di(tert-butyl)gallium hydride. Both products exhibit the trans configuration in the solid state, but interestingly only the piperidine derivative 4 shows a cis/trans equilibrium in solution.


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