TY - JOUR
T1 - Combined experimental and computational study of W(II), Ru(II), Pt(IV) and Cu(I) amine and amido complexes using 15N NMR spectroscopy
AU - Delp, Samuel A.
AU - Munro-Leighton, Colleen
AU - Khosla, Chetna
AU - Templeton, Joseph L.
AU - Alsop, Nikki M.
AU - Gunnoe, T. Brent
AU - Cundari, Thomas R.
N1 - Funding Information:
The National Science Foundation (CAREER Award; CHE 0238167) is acknowledged by TBG for support of this research. TRC acknowledges the partial support of this research from the National Science Foundation through grant CHE-0701247. TRC also acknowledges the Chemical Computing Group for generously providing the MOE software and the NSF-CRIF program (CHE-0741936) for their support of the computational facilities used for the calculations. The authors also wish to thank Dr. Sabapathy Sankar (North Carolina State University) for his assistance in obtaining the 15 N NMR spectra, Prof. Elon Ison (North Carolina State University) for use of his UV–Vis spectrometer, and Prof. Jochen Autschbach (SUNY-Buffalo) for advice on NMR calculations.
Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2009/4/15
Y1 - 2009/4/15
N2 - Using 2D proton-coupled gHSQC pulse sequences in addition to 1D 15N NMR experiments of 15N labeled systems, 15N NMR chemical shifts of a range of transition metal amido and amine complexes were determined. Tungsten(II), ruthenium(II), platinum(IV) and copper(I) complexes with aniline and their anilido variants were studied and compared to free aniline, lithium anilido and anilinium tetrafluoroborate. Upon coordination of aniline to transition metals, upfield chemical shifts of 20-60 ppm were observed. Deprotonation of the amine complexes to form amido complexes resulted in downfield chemical shifts of 40-60 ppm for all of the complexes except for the tungsten d4 system. For the tungsten(II) complexes, the cationic aniline complex displayed a downfield shift of approximately 56 ppm relative to the neutral anilido complex. The change in chemical shift for amine to amido conversion is proposed to depend on the ability of the amido ligand to π-bond with the metal center, which influences the magnitude of the paramagnetic screening term.
AB - Using 2D proton-coupled gHSQC pulse sequences in addition to 1D 15N NMR experiments of 15N labeled systems, 15N NMR chemical shifts of a range of transition metal amido and amine complexes were determined. Tungsten(II), ruthenium(II), platinum(IV) and copper(I) complexes with aniline and their anilido variants were studied and compared to free aniline, lithium anilido and anilinium tetrafluoroborate. Upon coordination of aniline to transition metals, upfield chemical shifts of 20-60 ppm were observed. Deprotonation of the amine complexes to form amido complexes resulted in downfield chemical shifts of 40-60 ppm for all of the complexes except for the tungsten d4 system. For the tungsten(II) complexes, the cationic aniline complex displayed a downfield shift of approximately 56 ppm relative to the neutral anilido complex. The change in chemical shift for amine to amido conversion is proposed to depend on the ability of the amido ligand to π-bond with the metal center, which influences the magnitude of the paramagnetic screening term.
KW - N NMR spectroscopy
KW - Amido
KW - Amine
KW - Transition metals
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U2 - 10.1016/j.jorganchem.2009.01.006
DO - 10.1016/j.jorganchem.2009.01.006
M3 - Article
AN - SCOPUS:62849096270
VL - 694
SP - 1549
EP - 1556
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
SN - 0022-328X
IS - 9-10
ER -