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Dual Coordination Modes of Ethylene-Linked NP2 Ligands in Cobalt(II) and Nickel(II) Iodides

Dong, Qingchen and Rose, Michael J. and Wong, Wai-Yeung and Gray, Harry B. (2011) Dual Coordination Modes of Ethylene-Linked NP2 Ligands in Cobalt(II) and Nickel(II) Iodides. Inorganic Chemistry, 50 (20). pp. 10213-10224. ISSN 0020-1669.

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Here we report the syntheses and crystal structures of a series of cobalt(II) and nickel(II) complexes derived from _RNP2 ligands (where R = OMe_(Bz), H_(Bz), Br_(Bz), Ph) bearing ethylene linkers between a single N and two P donors. The Co^(II) complexes generally adopt a tetrahedral configuration of general formula [(NP2)Co(I)_2], wherein the two phosphorus donors are bound to the metal center but the central N-donor remains unbound. We have found one case of structural isomerism within a single crystal structure. The Co^(II) complex derived from _(Bz)NP2 displays dual coordination modes: one in the tetrahedral complex [(_(Bz)NP2)Co(I)_2]; and the other in a square pyramidal variant, [(_(Bz)NP2)Co(I)_2]. In contrast, the Ni^(II) complexes adopt a square planar geometry in which the P(Et)N(Et)P donors in the ligand backbone are coordinated to the metal center, resulting in cationic species of formula [(_RNP2)Ni(I)]^+ with iodide as counterion. All Ni^(II) complexes exhibit sharp ^1H and ^(31)P spectra in the diamagnetic region. The Co^(II) complexes are high-spin (S = 3/2) in the solid state as determined by SQUID measurements from 4 to 300 K. Solution electron paramagnetic resonance (EPR) experiments reveal a high-spin/low-spin Co^(II) equilibrium that is dependent on solvent and ligand substituent.

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Gray, Harry B.0000-0002-7937-7876
Additional Information:© 2011 American Chemical Society. Received: June 7, 2011. Publication Date (Web): September 13, 2011. This work was supported by the NSF CCI Solar Fuels Research Program (CHE-0802907). M.J.R. also received support from an NSF ACC-F postdoctoral fellowship (NSF CHE-1042009). W.Y.W. and Q.C.D. thank the Hong Kong Research Grants Council (HKBU202508), the University Grants Committee of HKSAR, China (Project No. [AoE/P-03/08]) and Hong Kong Baptist University for support. We thank Drs. Larry Henling and Michael Day for assistance in solving crystal structures, and Dr. Angelo Di Bilio for assistance in recording EPR spectra. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to the California Institute of Technology (CHE-0639094).
Group:CCI Solar Fuels
Funding AgencyGrant Number
NSF CCI Solar Fuels Research ProgramCHE-0802907
NSF ACC-F postdoctoral fellowshipCHE-1042009
Hong Kong ResearchHKBU202508
University Grants Committee of HKSAR, ChinaAoE/P-03/08
Hong Kong Baptist UniversityUNSPECIFIED
Issue or Number:20
Record Number:CaltechAUTHORS:20111115-152532868
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Official Citation:Dual Coordination Modes of Ethylene-Linked NP2 Ligands in Cobalt(II) and Nickel(II) Iodides Qingchen Dong, Michael J. Rose, Wai-Yeung Wong, and Harry B. Gray Inorganic Chemistry 2011 50 (20), 10213-10224
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:27791
Deposited By: Ruth Sustaita
Deposited On:15 Nov 2011 23:55
Last Modified:22 Nov 2019 09:58

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