Carbon−Nitrogen Bond Construction and Carbon−Oxygen Double Bond Cleavage on a Molecular Titanium Oxonitride: A Combined Experimental and Computational Study
Authors
Carbó, Jorge J.; García López, Diego; González del Moral, OctavioIdentifiers
Permanent link (URI): http://hdl.handle.net/10017/63037DOI: 10.1021/acs.inorgchem.5b00943
ISSN: 0020-1669
Date
2015-10-05Academic Departments
Universidad de Alcalá. Departamento de Química Orgánica y Química Inorgánica
Teaching unit
Unidad Docente Química Inorgánica
Funders
Ministerio de Economía y Competitividad
Universidad de Alcalá
Generalitat de Catalunya
Bibliographic citation
Inorganic Chemistry, 2015, v. 54, n. 19, p. 9401-9412
Project
info:eu-repo/grantAgreement/MINECO//CTQ2013-44625- R/ES/
info:eu-repo/grantAgreement/MINECO//CTQ2011-29054-C02-01/ES/
info:eu-repo/grantAgreement/Generalitat de Catalunya//2014SGR199/CAT/
info:eu-repo/grantAgreement/UAH//CCG2014%2FEXP-022/ES/
Document type
info:eu-repo/semantics/article
Version
info:eu-repo/semantics/aceptedVersion
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
© 2015 American Chemical Society
Access rights
info:eu-repo/semantics/openAccess
Abstract
New carbon nitrogen bonds were formed on addition of isocyanide and ketone reagents to the oxonitride species [{Ti(eta(5)-C5Me5)(mu-O)}(3)(mu(3)-N)] (1). Reaction of 1 with XylNC (Xyl = 2,6-Me2C6H3) in a 1:3 molar ratio at room temperature leads to compound [{Ti(eta(5)-C5Me5)(mu-O)}(3)(mu-XylNCCNXyl)(NCNXyl)] (2), after the addition of the nitrido group to one coordinated isocyanide and the carbon carbon coupling of the other two isocyanide molecules have taken place. Therrnolysis of 2 gives [{Ti(eta(5)-C5Me5)(mu-O)}(3)(XylNCNXyl)(CN)] (3) where the heterocumulene [XylNCCNXyl] moiety and the carbodiimido [NCNXyl] fragment in 2 have undergone net transformations. Similarly, tert-butyl isocyanide (tBuNC) reacts with the starting material 1 under mild conditions to give the paramagnetic derivative [{Ti-3(eta(5)-C5Me5)3(mu-O)(3)(NCNtBu)}(2)(mu-CN)(2)] (4). However, compound 1 provides the oxo ketimide derivatives [{Ti-3(eta(5)-C5Me5)(3)(mu-O)(4)}(NCRPh)] [R = Ph (5), p-Me(C6H4) (6), o-Me(C6H4) (7)] upon reaction with benzophenone, p-methylbenzophenone, and o-methylbenzophenone, respectively. In these reactions, the carbon oxygen double bond is completely ruptured, leading to the formation of a carbon nitrogen and two metal oxygen bonds. The molecular structures of complexes 2-4, 6, and 7 were determined by single-crystal X-ray diffraction analyses. Density functional theory calculations were performed on the incorporation of isocyanides and ketones to the model complex [{Ti(eta(5)-C6H3)(mu-O)}(3)(mu(3)-N)] (1H). The mechanism involves the coordination of the substrates to one of the titanium metal centers, followed by an isomerization to place those substrates cis with respect to the apical nitrogen of 1H, where carbon nitrogen bond formation occurs with a low-energy barrier. In the case of aryl isocyanides, the resulting complex incorporates additional isocyanide molecules leading to a carbon carbon coupling. With ketones, the high oxophilicity of titanium promotes the unusual total cleavage of the carbon oxygen double bond.
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Carbo_CarbonNitrogen_InorgChem ... | 1.778Mb |
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