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Multinuclear NMR Studies and Spin System Analyses on Dibenzo(c.e)(1,2)Oxaphosphorine 2‐Oxides

Multinuclear NMR Studies and Spin System Analyses on Dibenzo(c.e)(1,2)Oxaphosphorine 2‐Oxides ABSTRACT 2H‐Dibenzo(c.e)(1,2)oxaphosphorine 2‐oxide (HDOPO), 2‐(N,N‐diethylamino)‐dibenzo(c.e)(1,2)oxaphosphorine 2‐oxide (DEADOPO), and 2‐ethoxy‐dibenzo(c.e)(1,2)oxaphosphorine 2‐oxide (EtODOPO) are fully characterized in CDCl3 by 1H, 13C, 31P, and 15N NMR spectroscopy on 800‐ and 500‐MHz instruments. A strategy enabling their unambiguous signal assignment is presented, with special emphasis on 2D 1H,13C HMBC spectra. Additional line‐shape iterations of the aromatic 1H multiplets (ABCDX and ABCDEX spin systems) provided all long‐range nJH,H and nJP,H coupling constants with utmost precision. The experimental results augmented with those of the model compound phenylphosphonous acid clearly demonstrate that nJH,H couplings of the PH proton as well as the nJP,C values do not decrease in a monotonic manner with the number of intervening bonds from the phosphorus atom. This fact may potentially lead signal misassignments, if the analysis starts out from the coupling constants, as it occurred for HDOPO in the recent publication by Wagner et al. (Phosphorus, Sulfur and Silicon, 187, 2012, 781–798). The corrected assignment will be given in the present paper. Finally, the A2M3X or ABM3X type 1H spectral patterns of ethyl groups are also analyzed and explicit equations are derived to evaluate the strongly coupled ABM3X multiplets in EtODOPO. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Heteroatom Chemistry Wiley

Multinuclear NMR Studies and Spin System Analyses on Dibenzo(c.e)(1,2)Oxaphosphorine 2‐Oxides

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References (27)

Publisher
Wiley
Copyright
Copyright © 2016 Wiley Periodicals, Inc.
ISSN
1042-7163
eISSN
1098-1071
DOI
10.1002/hc.21313
Publisher site
See Article on Publisher Site

Abstract

ABSTRACT 2H‐Dibenzo(c.e)(1,2)oxaphosphorine 2‐oxide (HDOPO), 2‐(N,N‐diethylamino)‐dibenzo(c.e)(1,2)oxaphosphorine 2‐oxide (DEADOPO), and 2‐ethoxy‐dibenzo(c.e)(1,2)oxaphosphorine 2‐oxide (EtODOPO) are fully characterized in CDCl3 by 1H, 13C, 31P, and 15N NMR spectroscopy on 800‐ and 500‐MHz instruments. A strategy enabling their unambiguous signal assignment is presented, with special emphasis on 2D 1H,13C HMBC spectra. Additional line‐shape iterations of the aromatic 1H multiplets (ABCDX and ABCDEX spin systems) provided all long‐range nJH,H and nJP,H coupling constants with utmost precision. The experimental results augmented with those of the model compound phenylphosphonous acid clearly demonstrate that nJH,H couplings of the PH proton as well as the nJP,C values do not decrease in a monotonic manner with the number of intervening bonds from the phosphorus atom. This fact may potentially lead signal misassignments, if the analysis starts out from the coupling constants, as it occurred for HDOPO in the recent publication by Wagner et al. (Phosphorus, Sulfur and Silicon, 187, 2012, 781–798). The corrected assignment will be given in the present paper. Finally, the A2M3X or ABM3X type 1H spectral patterns of ethyl groups are also analyzed and explicit equations are derived to evaluate the strongly coupled ABM3X multiplets in EtODOPO.

Journal

Heteroatom ChemistryWiley

Published: May 1, 2016

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