Determination of the magnitude and sign of the 2JPt-P coupling constants in dinuclear platinum(I) phosphine complexes by two-dimensional phosphorus-31 NMR spectroscopy

1992 ◽  
Vol 31 (2) ◽  
pp. 312-317 ◽  
Author(s):  
Jane V. Zeile Krevor ◽  
Ursula Simonis ◽  
Annette Karson ◽  
Claire Castro ◽  
Mohammed Aliakbar
Keyword(s):  
Nmr Spectroscopy ◽  
Coupling Constants ◽  
Two Dimensional ◽  
Phosphine Complexes ◽  
Dinuclear Platinum

Convenient Sign Determination of Various Coupling Constants in Alkynylplatinum(II) Phosphine Complexes

1991 ◽  
Vol 46 (1) ◽  
pp. 35-38 ◽  
Author(s):  
Bernd Wrackmeyer
Keyword(s):  
Coupling Constants ◽  
Two Dimensional ◽  
Model Compounds ◽  
Standard Equipment ◽  
Phosphine Complexes ◽  
Sign Determination

(1)The utilization of two-dimensional (2 D) 13C /1H , 31P/1H and 195Pt/1H heteronuclear shift correlations for the sign determination of various coupling constants [e.g., 2J(31PPt13C) > 0 (trans), 2J(31PPt13C) < 0 (cis), 3J( 31PPtC13C) > 0 (cis, trans), 4J(31PPtCC1H ) > 0 (trans), 4J(31PCC1H ) < 0 (cis), 3J(195PtCC1H ) > 0, 2J(31PC1H ) < 0, etc.] is demonstrated, using standard equipment. The complexes [trans-(Bu3P)2Pt(C ≡ C -H)2] and [cis-(Et2PCH2CH2PEt2)Pt(C ≡ C - H)2] (2) serve as model compounds.

Structural studies of digitoxin and related cardenolides by two-dimensional NMR

1990 ◽  
Vol 68 (2) ◽  
pp. 272-277 ◽  
Author(s):  
Torbjörn Drakenberg ◽  
Peter Brodelius ◽  
Deane D. McIntyre ◽  
Hans J Vogel
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chair Conformation ◽  
Coupling Constants ◽  
Two Dimensional ◽  
Structural Studies ◽  
Solution Conformation ◽  
Phase Sensitive ◽  
Multiple Relay ◽  
C Nmr

The 1H and 13C NMR spectra of the cardenolides digitoxigenin, digoxigenin, digitoxin, and mono- and bis-digitoxigenin digitoxosides have been completely assigned by two-dimensional NMR spectroscopy. The techniques used include phase-sensitive COSY, multiple relay COSY, and carbon–proton correlation (HETCOR and HMQC) spectra. Various aspects of the solution conformation of the steroid moiety of digitoxin and digoxigenin could be determined from coupling constants and NOE difference experiments and they are indicative of an all-chair conformation. The carbohydrate rings in digitoxin and the mono- and bis-digitoxigenin digitoxosides are also in the chair conformation. Keywords: cardenolides, digitoxigenin, digitoxin, 2-dimensional NMR, conformational analysis.

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