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Title: Low-temperature neutron diffraction studies of C-H-metal interactions in two tantalum-neopentylidene complexes: (Ta(CHCMe/sub 3/)(PMe/sub 3/)Cl/sub 3/)/sub 2/ (T = 110 K) and the first alkylidene/olefin complex, Ta(eta/sup 5/-C/sub 5/Me/sub 5/)(CHCMe/sub 3/)(eta/sup 2/-C/sub 2/H/sub 4/)(PMe/sub 3/) (T = 20 K)

Abstract

Neutron diffraction studies of the two title compounds in which precise hydrogen atom location was essential, have established that the neopentylidene ligands are highly distorted. In (Ta(CHCMe/sub 3/)(PMe/sub 3/)Cl/sub 3/)/sub 2/, the Ta==C/sub ..cap alpha../-C/sub ..beta../ is 161.2 (1)/sup 0/, the Ta==C/sub ..cap alpha../-H/sub ..cap alpha../ angle is 84.8 (2)/sup 0/, the Ta==C/sub ..cap alpha../ bond is short (1.898 (2) A), the C/sub ..cap alpha../-H/sub ..cap alpha../ distance is long (1.131 (3) A), and H/sub ..cap alpha../ angle is 78.1 (3)/sup 0/, the C/sub ..cap alpha../-H/sub ..cap alpha../ bond is also long (1.135 (5) A), the Ta==C/sub ..cap alpha../ bond length short (1.946 (3) A), and H/sub ..cap alpha../ is only 2.042 (5) A from Ta. We believe the neopentylidene ligand is distorted in each case primarily because the metal is attracting electron density from the C/sub ..cap alpha../-H/sub ..cap alpha../ bond. The tantalum-ethylene bonding in the second molecule is best described as that of a tantallacyclopropane ring on the basis of the long ethylene C-C bond (1.477 (4) A) and the large angle (68.5/sup 0/) between the normals to the two CH/sub 2/ planes. We believe the neopentylidene/ethylene complex does not decompose via a tantallacyclobutane complex because of themore » large separation between the neopentylidene and ethylene ligands.« less

Authors:
 [1]; ; ;
  1. (Argonne National Lab., IL)
Publication Date:
OSTI Identifier:
6876016
Alternate Identifier(s):
OSTI ID: 6876016
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Am. Chem. Soc.; (United States); Journal Volume: 103:1
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; TANTALUM COMPLEXES; STRUCTURAL CHEMICAL ANALYSIS; BOND ANGLE; BOND LENGTHS; LIGANDS; LOW TEMPERATURE; NEUTRON DIFFRACTION; ORGANIC CHLORINE COMPOUNDS; ORGANIC PHOSPHORUS COMPOUNDS; VERY LOW TEMPERATURE; COHERENT SCATTERING; COMPLEXES; DIFFRACTION; DIMENSIONS; LENGTH; ORGANIC COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; SCATTERING; TRANSITION ELEMENT COMPLEXES 400201* -- Chemical & Physicochemical Properties; 400301 -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)

Citation Formats

Schultz, A.J., Brown, R.K., Williams, J.M., and Schrock, R.R. Low-temperature neutron diffraction studies of C-H-metal interactions in two tantalum-neopentylidene complexes: (Ta(CHCMe/sub 3/)(PMe/sub 3/)Cl/sub 3/)/sub 2/ (T = 110 K) and the first alkylidene/olefin complex, Ta(eta/sup 5/-C/sub 5/Me/sub 5/)(CHCMe/sub 3/)(eta/sup 2/-C/sub 2/H/sub 4/)(PMe/sub 3/) (T = 20 K). United States: N. p., 1981. Web. doi:10.1021/ja00391a030.
Schultz, A.J., Brown, R.K., Williams, J.M., & Schrock, R.R. Low-temperature neutron diffraction studies of C-H-metal interactions in two tantalum-neopentylidene complexes: (Ta(CHCMe/sub 3/)(PMe/sub 3/)Cl/sub 3/)/sub 2/ (T = 110 K) and the first alkylidene/olefin complex, Ta(eta/sup 5/-C/sub 5/Me/sub 5/)(CHCMe/sub 3/)(eta/sup 2/-C/sub 2/H/sub 4/)(PMe/sub 3/) (T = 20 K). United States. doi:10.1021/ja00391a030.
Schultz, A.J., Brown, R.K., Williams, J.M., and Schrock, R.R. Wed . "Low-temperature neutron diffraction studies of C-H-metal interactions in two tantalum-neopentylidene complexes: (Ta(CHCMe/sub 3/)(PMe/sub 3/)Cl/sub 3/)/sub 2/ (T = 110 K) and the first alkylidene/olefin complex, Ta(eta/sup 5/-C/sub 5/Me/sub 5/)(CHCMe/sub 3/)(eta/sup 2/-C/sub 2/H/sub 4/)(PMe/sub 3/) (T = 20 K)". United States. doi:10.1021/ja00391a030.
@article{osti_6876016,
title = {Low-temperature neutron diffraction studies of C-H-metal interactions in two tantalum-neopentylidene complexes: (Ta(CHCMe/sub 3/)(PMe/sub 3/)Cl/sub 3/)/sub 2/ (T = 110 K) and the first alkylidene/olefin complex, Ta(eta/sup 5/-C/sub 5/Me/sub 5/)(CHCMe/sub 3/)(eta/sup 2/-C/sub 2/H/sub 4/)(PMe/sub 3/) (T = 20 K)},
author = {Schultz, A.J. and Brown, R.K. and Williams, J.M. and Schrock, R.R.},
abstractNote = {Neutron diffraction studies of the two title compounds in which precise hydrogen atom location was essential, have established that the neopentylidene ligands are highly distorted. In (Ta(CHCMe/sub 3/)(PMe/sub 3/)Cl/sub 3/)/sub 2/, the Ta==C/sub ..cap alpha../-C/sub ..beta../ is 161.2 (1)/sup 0/, the Ta==C/sub ..cap alpha../-H/sub ..cap alpha../ angle is 84.8 (2)/sup 0/, the Ta==C/sub ..cap alpha../ bond is short (1.898 (2) A), the C/sub ..cap alpha../-H/sub ..cap alpha../ distance is long (1.131 (3) A), and H/sub ..cap alpha../ angle is 78.1 (3)/sup 0/, the C/sub ..cap alpha../-H/sub ..cap alpha../ bond is also long (1.135 (5) A), the Ta==C/sub ..cap alpha../ bond length short (1.946 (3) A), and H/sub ..cap alpha../ is only 2.042 (5) A from Ta. We believe the neopentylidene ligand is distorted in each case primarily because the metal is attracting electron density from the C/sub ..cap alpha../-H/sub ..cap alpha../ bond. The tantalum-ethylene bonding in the second molecule is best described as that of a tantallacyclopropane ring on the basis of the long ethylene C-C bond (1.477 (4) A) and the large angle (68.5/sup 0/) between the normals to the two CH/sub 2/ planes. We believe the neopentylidene/ethylene complex does not decompose via a tantallacyclobutane complex because of the large separation between the neopentylidene and ethylene ligands.},
doi = {10.1021/ja00391a030},
journal = {J. Am. Chem. Soc.; (United States)},
number = ,
volume = 103:1,
place = {United States},
year = {Wed Jan 14 00:00:00 EST 1981},
month = {Wed Jan 14 00:00:00 EST 1981}
}