Unexpected formation of cis- and trans-Ph2PCH:CHPPh2 by reaction of lithiobis(diphenylphosphino)methane and dichloromethane. Carbon-13 NMR studies of the products

1984 ◽  
Vol 23 (2) ◽  
pp. 258-260 ◽  
Author(s):  
Sibbele Hietkamp ◽  
Othmar Stelzer
Keyword(s):  
Nmr Studies ◽  
Unexpected Formation ◽  
Cis And Trans

scholarly journals Angular Regioselectivity in the Reactions of 2-Thioxopyrimidin-4-ones and Hydrazonoyl Chlorides: Synthesis of Novel Stereoisomeric Octahydro[1,2,4]triazolo[4,3-a]quinazolin-5-ones

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5673
Author(s):  
Awad I. Said ◽  
Márta Palkó ◽  
Matti Haukka ◽  
Ferenc Fülöp
Keyword(s):  
Regioselective Synthesis ◽  
Synthesis Process ◽  
Two Dimensional ◽  
Electronic Control ◽  
Nmr Studies ◽  
X Ray ◽  
Hydrazonoyl Chlorides ◽  
Cis And Trans

The regioselective synthesis of cis and trans stereoisomers of variously functionalized octahydro[1,2,4]triazolo[4,3-a]quinazolin-5-ones was performed. The 2-thioxopyrimidin-4-ones used in the synthesis reacted with hydrazonoyl chlorides in a regioselective manner to produce the angular regioisomers [1,2,4]triazolo[4,3-a]quinazolin-5-ones rather than the linear isomers [1,2,4]triazolo[4,3-a]quinazolin-5-ones. The synthesis process took place with electronic control. The angular regiochemistry of the products was confirmed by X-ray experiments and two-dimensional NMR studies.

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
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Trans Isomers ◽  
Nmr Studies ◽  
Gold Complexes ◽  
X Ray ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Insertion Process

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.

Solid-State C-13 NMR Studies of Vulcanized Elastomers X. N-t-Butyl-2-Benzothiazole Sulfenamide Accelerated Sulfur Vulcanization of cis-Polyisoprene at 75.5 MHz

1992 ◽  
Vol 65 (2) ◽  
pp. 427-443 ◽  
Author(s):  
M. R. Krejsa ◽  
J. L. Koenig
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Chain Scission ◽  
Sulfur Concentration ◽  
Nmr Studies ◽  
Double Bond Migration ◽  
Sulfur Vulcanization ◽  
Equilibrium Swelling ◽  
Cis And Trans ◽  
Good Agreement

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.

pKa values of aqua ligands of platinum(II) anticancer complexes: [1H, 15N and 195Pt NMR studies of cis- and trans-[PtCl2(NH3)(cyclohexylamine)

1998 ◽  
Vol 273 (1-2) ◽  
pp. 8-13 ◽  
Author(s):  
Sarah J. Barton ◽  
Kevin J. Barnham ◽  
Abraha Habtemariam ◽  
Rodney E. Sue ◽  
Peter J. Sadler
Keyword(s):  
Nmr Studies ◽  
Pka Values ◽  
Anticancer Complexes ◽  
Cis And Trans

Platinum and palladium complexes of [R2PCH2P(Y)R′2] and [R2PCHP(Y)R′2]− ligands, Y = O,S, or Se: 13C, 31P, 77Se, and 195Pt nuclear magnetic resonance studies and the crystal and molecular structures of trans-[PtCl(PEt3){But2PCH2P(O)Me2}][ClO4] and trans-PtCl(PEt3){Ph2PCH2P(S)But2}|[ClO4]

1988 ◽  
Vol 66 (5) ◽  
pp. 1272-1282 ◽  
Author(s):  
David Eric Berry ◽  
Jane Browning ◽  
Keith Roger Dixon ◽  
Robert Wayne Hilts
Keyword(s):  
Palladium Complexes ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Nmr Studies ◽  
Isomer Distribution ◽  
Cis And Trans Isomers ◽  
Platinum And Palladium Complexes ◽  
Cell Dimensions ◽  
Structure Determinations ◽  
Cis And Trans

Reactions of the bisphosphine monochalcogenides, [Ph2PCH2P(Y)R2], Y = O, S, or Se, R = Ph, Pri, or But, with the chloro-bridged dimers [M2Cl4(PR′3)2], M = Pd or Pt, R′ = Et or Bun, in the presence of either NaClO4 or NaBF4 yield perchlorate and fluoroborate salts of the complex cations cis- and trans-[PtCl(PR′3){Ph2PCH2P(Y)R2}]+. In many cases both cis and trans isomers (defined by the relative orientation of the two M—P bonds) are obtained and the precise isomer distribution is a sensitive function of the substituents. Corresponding neutral complexes, cis- and trans-[PtCl(PR′3){Ph2PCHP(Y)R2}], can be synthesized either by deprotonation of the cations using NaH or by use of the salts Li[Ph2PCHP(Y)R2] in the initial bridge cleavage reactions. These and related complexes are characterized by complete 13C, 31P, 77Se, and 195Pt NMR studies and by two crystal structure determinations. The complexes I, trans-[PtCl(PEt3){But2PCH2P(O)Me2}][ClO4], and II, trans-[PtCl(PEt3){Ph2PCH2P(S)But2}][ClO4], crystallize in the monoclinic space group P21/c, respective cell dimensions: a = 15.579(2), b = 13.590(3), c = 13.578(1) Å;β= 105.96(1)°; and a = 14.002(4), b = 16.366(5), c = 15.524(5) Å; β = 106.01 (3)°. Complete X-ray diffraction studies show that both complexes contain closely square planar platinum centres with the R2PCH2P(Y)R′2 ligands coordinated via phosphorus and the Y atom so as to form five-membered chelate rings. The molecular dimensions suggest that the bond to sulphur is stronger than that to oxygen and exerts a larger trans influence.

scholarly journals NMR Studies on Cyclic Arsenites. Analysis of the NMR Spectra of cis- and trans-2-Phenyl-4,5-dimethyl-1,3,2-dioxarsolane.

1972 ◽  
Vol 26 ◽  
pp. 2532-2535 ◽  
Author(s):  
Dagfinn W. Aksnes ◽  
Olav Vikane ◽  
S. Liaaen-Jensen ◽  
M. J. Tricker ◽  
Sigfrid Svensson
Keyword(s):  
Nmr Spectra ◽  
Nmr Studies ◽  
Cis And Trans
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