NGLC 2004-2010.National Geological Library of China All Rights Reserved. Add:29 Xueyuan Rd,Haidian District,Beijing,PRC. Mail Add: 8324 mailbox 100083 For exchange or info please contact us via email. |
NGLC 2004-2010.National Geological Library of China All Rights Reserved. Add:29 Xueyuan Rd,Haidian District,Beijing,PRC. Mail Add: 8324 mailbox 100083 For exchange or info please contact us via email. |
-1081 (1a), -1049 (fac-1b),-1015 (mer-1b)), an increase in the Mo-P coupling constant (193 Hz(1a), 264 Hz (fac-1b), 337 Hz(mer-1b)), and an increase in the line width (35 Hz(1a), 90 Hz (fac-1b), 300 Hz(mer-1b)). Theconversion offac-[(bpy)(CO)3Mo{PN(Me)CH2CH2O(OMe)}](fac-2a) intomer-[(bpy)(CO)3Mo{PN(Me)CH2CH2O}]+(mer-2b) showed a similar trend in95Mo NMR data, thoughfac-[(bpy)(CO)3Mo{PN(Me)CH2CH2O}]+was not detected in this case. mer-2bexhibits the largestMo-P coupling constant (343 Hz) among those reported so far.These changes can bereasonably attributed to a dominant contribution from the imbalance ofelectron density atthe Mo in the Ramsey equation due to a significant double-bondcharacter between themolybdenum and the phosphenium phosphorus. Comparison of couplingconstants betweenM and a phosphenium P in[(bpy)(CO)3M{PN(Me)CH2CH2NMe}]+(M = Mo, W) revealedthat the ratio1JW-P/1JMo-Pis 1.67, which is very close to the ratio (1.76) reported formanyseries of M-phosphine (or phosphite) complexes (M = Mo, W).The 95Mo NMR spectra ofcis- andtrans-[(bpy)(CO)2Mo{PN(Me)CH2CH2X(OMe)}{PN(Me)CH2CH2X}]+(X = NMe, cis-1c, trans-1c; X = O,cis-2c, trans-2c) have alsobeen measured; the chemical shifts areunderstood similarly in terms of the imbalance of electron density atMo.