113032-62-5Relevant articles and documents
Determination of the Relative Signs of 2J((31)P-(31)P) in Complexes of Tungsten (0) and Molybdenum (0) usng Two-dimensional -COSY-45 Nuclear Magnetic Resonance Chemical Shift Correlation
Fontaine, Xavier L.R.,Kennedy, John D.,Shaw, Bernard L.,Vila, Jose M.
, p. 2401 - 2406 (2007/10/02)
Two-dimensional -COSY-45 n.m.r. spectroscopy has been used to determine the magnitudes and relative signs of J((31)-(31)P) in three- and four-spin systems.The complexes studied are of molybdenum (0) and tungsten (0) with CO and Ph2PC(=CH2)PPh2 (vdpp), Ph2PCH2PPh2 (dppm), Ph2PCH(CH2CH3)PPh2 (1,1-dppp), PEt3, or PPhEt2 as ligands.It is found that 2J((31)P-(31)P) (cis) when the P atoms are coupled via both P-M-P and P-C-P linkages and 2J(31)P-(31)P) (trans) are of the same sign, presumably positive, and both are of opposite sign to J((31)P-(31)P) (cis) when the P atoms are linked via the P-M-P pathway only.This suggests a dominant positive contribution to cisoid (31)P-(31)P coupling via the P-C-P pathway.