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Syntheses and Structures of Buta-1,3-Diynyl Complexes from "on Complex" Cross-Coupling Reactions

DOI: 10.1021/om501186c DOI Help

Authors: Marie-christine Oerthel (Durham University) , Dmitry Yufit (Durham University) , Mark A. Fox (Durham University) , Martin R. Bryce (Durham University) , Paul J. Low (University of Western Australia)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Organometallics , VOL 34 (11) , PAGES 2395 - 2405

State: Published (Approved)
Published: June 2015
Diamond Proposal Number(s): 6749

Abstract: The Pd(PPh3)4/CuI-cocatalyzed reaction of Ru(CñMCCñMCH)(PPh3)2Cp (2) with aryl iodides, Ar-I (3, Ar = C6H4CN-4 (a); C6H4Me-4 (b); C6H4OMe-4 (c); 2,3- dihydrobenzo[b]thiophene (d); C5H4N (e)) proceeds smoothly in diisopropylamine and under an inert atmosphere to give the substituted buta-1,3-diynyl complexes Ru(CñM CCñMCAr)(PPh3)2Cp (4a-e) in moderate to good yield. The procedure allows the rapid preparation of a range of metal complexes of arylbuta-1,3-diynyl ligands without necessitating the prior synthesis of the individual buta-1,3-diynes as ligand precursors. Similar reaction of 2 with half an equivalent of 1,4- diiodobenzene affords the bimetallic derivative {Ru- (PPh3)2Cp}2(ƒÊ-CñMCCñMC-1,4-C6H4−CñMCCñMC) (5). In the presence of atmospheric oxygen, homocoupling of the diynyl reagent 2 takes place to provide the octa-1,3,5,7-tetrayndiyl complex {Ru(PPh3)2Cp}2(ƒÊ-CñMCCñMCCñMCCñMC) (6). Crystallographically determined molecular structures are reported for five complexes (4a, 4b, 4d, 5, and 6). Quantum chemical calculations indicate that the HOMOs are mainly located on the C4−C6H4−C4 and C8 bridges for 5 and 6, respectively, while spectroelectrochemical (UV−vis−NIR and IR) studies on 6 establish that oxidation takes place at the C8 bridge, likely followed by cyclodimerization reactions of the bridging ligand.

Subject Areas: Chemistry

Instruments: I19-Small Molecule Single Crystal Diffraction