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Comparative Studies with Zwitterionic Platinum(II) Bis(pyrazolyl)borate and 2,2‘-Bipyridylborate Complexes

Thomas, Christine M. and Peters, Jonas C. (2005) Comparative Studies with Zwitterionic Platinum(II) Bis(pyrazolyl)borate and 2,2‘-Bipyridylborate Complexes. Organometallics, 24 (24). pp. 5858-5867. ISSN 0276-7333. doi:10.1021/om050538j. https://resolver.caltech.edu/CaltechAUTHORS:20140729-123206635

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Abstract

A comparison between the mononuclear platinum complexes of three structurally different monoanionic borato ligands is presented:  [Ph_2B(pyrazolyl)_2]- ([Ph_2B(pz)_2], 1), [4-Ph_3B(2,2‘-bipyridine)]- ([(4-BPh_3)bpy], 2), and [Ph_2B(CH_2PPh_2)_2]- ([Ph_2BP_2], 3). The new bipyridylborate ligand 2 is introduced in this study. The relative trans influence of these ligands has been assessed by comparison of the structural and spectroscopic (NMR) data of the platinum dimethyl complexes [[Ph_2B(pz)_2]Pt(Me)_2][NBu_4] (4), [[(4-BPh_3)bpy]Pt(Me)_2][NBu_4] (5), and [[Ph_2BP_2]Pt(Me)_2][ASN] (6). The neutral complexes [Ph_2B(pz)_2]Pt(Me)(NCCH_3) (7), [Ph_2B(pz)_2]Pt(Me)(CO) (8), [Ph_2B(pz)_2]Pt(Me)(P(C_6F_5)_3) (9), [(4-BPh_3)bpy]Pt(Me)(NCCH_3) (10), [(4-BPh_3)bpy]Pt(Me)(CO) (11), and [(bpy)Pt(Me)(CO)][BPh_4] (12) were prepared, and the carbonyl complexes 8, 11, and 12 provide information pertaining to the relative electron-releasing character of each ligand type. The CO stretching frequencies suggest that the charged borate moiety renders the borato ligands more electron-donating than their neutral analogues. Of the neutral platinum methyl solvento complexes supported by ligands 1, 2, and 3, only those of 1 display very different C−H activation propensities. Upon protonation or methide abstraction in benzene at room temperature, complex 4 rapidly activates two molecules of benzene to generate [[Ph_2B(pz)_2]Pt(Ph)_2][NBu_4] (13). Isotopic scrambling of deuterium into methane in C_6D_6 solvent suggests the intermediacy of a methane σ-adduct in this reaction. The double C−H activation reaction can be halted by addition of acetonitrile to trap the intermediate [Ph_2B(pz)_2]Pt(Ph)(NCCH_3) (14). Complex 3 also displays reactivity toward the benzylic C−H bonds of mesitylene at room temperature to form [Ph_2B(pz)_2]Pt(pzH)(CH_2C_6H_3(CH_3)_2) (15) in modest yield.


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Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/om050538jDOIArticle
http://pubs.acs.org/doi/abs/10.1021/om050538jPublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/om050538jPublisherSupporting Information
ORCID:
AuthorORCID
Peters, Jonas C.0000-0002-6610-4414
Additional Information:© 2005 American Chemical Society. Received June 28, 2005. Publication on Web 10/22/2005. The authors acknowledge J. Christopher Thomas for insightful discussions. BP (Methane Conversion Cooperative) and the NSF (CHE-01232216) are acknowledged for funding. Larry Henling and Theodore A. Betley are acknowledged for crystallographic assistance.
Funders:
Funding AgencyGrant Number
BP Methane Conversion CooperativeUNSPECIFIED
NSFCHE-01232216
Issue or Number:24
DOI:10.1021/om050538j
Record Number:CaltechAUTHORS:20140729-123206635
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140729-123206635
Official Citation:Thomas, C. M., & Peters, J. C. (2005). Comparative Studies with Zwitterionic Platinum(II) Bis(pyrazolyl)borate and 2,2‘-Bipyridylborate Complexes. Organometallics, 24(24), 5858-5867. doi: 10.1021/om050538j
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47559
Collection:CaltechAUTHORS
Deposited By: Joanne McCole
Deposited On:29 Jul 2014 23:01
Last Modified:10 Nov 2021 17:48

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