Multidentate Phenols


Alkoxide and aryloxide ligands have been employed extensively in inorganic chemistry due to their ability to stabilize a variety of coordination environments.  Specifically, alkoxide and aryloxide ligands are electronically versatile due to the availability of two lone pairs on the oxygen atom that allow them to function as one–electron (X), three–electron (LX), or five–electron (L2X) donors depending upon the electronic needs of the metal center.  We are interested in developing the application of multidentate aryloxide ligands, such as those derived from the below phenols, to the chemistry of main group and transition metals.




Applications of Multidentate Aryloxide Ligands to Tungsten Chemistry

With respect to bis(aryloxide) ligands, the majority of studies have been devoted to biphenolate or binaphtholate derivatives in which the two aryloxide moieties are directly linked together, but more recently attention has been given to derivatives in which the aryloxide groups are attached by a linker.  For this reason, we are interested in the application of the phenylimino-bridged diphenol PhN(o–C6H4OH)2.



For example, treatment of W(PMe3)4(h2–CH2PMe2)H with PhN(o–C6H4OH)2 results in a series of O–H and C–H bond activation reactions to give products that feature a variety of interesting coordination modes.  In particular, the complex [k4–N(C6H4)(C6H4O)2]W(PMe3)3H demonstrates that tetradentate tripodal ligand derived from C–H bond cleavage of the phenyl group.





We have also applied multidentate phenoxide ligands shown above to antimony chemistry.  For example, the antimony aryloxide compound [k4–N(CH2ArBut2O)3]Sb may be readily obtained via the reaction of Sb(OEt)3 with tris(3,5-di-t-butyl-2-hydroxybenzyl)amine, N(CH2ArBut2OH)3. 



Treatment of [k4–N(CH2ArBut2O)3]Sb with AcOH cleaves one of the Sb–O bonds to give [k3–N(CH2ArBut2O)2(CH2ArBut2OH)]Sb(k1–O2CMe), while Br2 undergoes oxidative addition to give N(CH2ArBut2O)3]SbBr2, and Me3NO2H2O yields the oxo and hydroxo complexes {[k4–N(CH2ArBut2O)3]Sb(m–O)}2, [k4–N(CH2ArBut2O)3]Sb(OH)2, and {[k4–N(CH2ArBut2O)3]SbVO}4{SbIII4O6}.





Selected References

“Synthesis and Structural Characterization of Tris(phenolate)amine Complexes of Antimony Derived from [k4–N(CH2ArBut2O)3]Sb.”  Bryte V. Kelly, Edward C. Weintrob, Daniela Buccella, Joseph M. Tanski, and Gerard Parkin Inorg. Chem. Commun. 2007, 10, 699-704.


“C–H versus O–H Bond Cleavage Reactions of Bis(2–hydroxyphenyl)phenylamine, PhN(o–C6H4OH)2:  Synthesis and Structural Characterization of Mononuclear and Dinuclear Tungsten Aryloxide Complexes Which Exhibit Bidentate, Tridentate and Tetradentate Coordination Modes.”  Bryte V. Kelly, Joseph M. Tanski, Kevin E. Janak and Gerard Parkin Organometallics 2006, 25, 5839-5842.


“Multidentate Aryloxide and Oxo–Aryloxide Complexes of Antimony:  Synthesis and Structural Characterization of [h4–N(o–C6H4O)3]Sb(OSMe2), {{[ h3–N(o–C6H4OH)(o–C6H4O)2]Sb}2(m2–O)}2 and {[h3–PhN(o–C6H4O)2]Sb}4(m3–O)2.”  Joseph M. Tanski, Bryte V. Kelly and Gerard Parkin Dalton Trans. 2005, 2442-2447.


“Synthesis and Structural Analysis of Bis(2–hydroxyphenyl)phenylamine, PhN(o–C6H4OH)2: Comparison with Tris(2-hydroxyphenyl)amine N(o–C6H4OH)3.”  Bryte V. Kelly, Joseph M. Tanski, Mary Beth Anzovino and Gerard Parkin J. Chem. Crystallogr. 2005, 35, 969-981.


“Antimony Ethylene Glycolate and Catecholate Compounds: The Structural Characterization of Polyesterification Catalysts.”  Shannon M. Biros, Brian M. Bridgewater, Adriel Villeges-Estrada, Joseph M. Tanski and Gerard Parkin Inorg. Chem. 2002, 41, 4051-4057.