Rhenium polyhydride complexes that contain phosphine ligands and the anions of 2-hydroxyquinoline or 2-mercaptoquinoline
Abstract
An examination of the reactions of ReH7(PPh3) 2 with Hhq (2-hydroxyquinoline) and Hmq (2-mercaptoquinoline) has established that the reaction course is solvent dependent, and the monohydridorhenium(III) complexes ReH(hq)2(PPh3)2 and ReH(mq) 2(PPh3)2 can be produced in addition to ReH 4(hq)(PPh3)2 and ReH4(mq)(PPh 3)2. Since steric hindrance at the metal center does not prohibit complex formation, reactions of the tetrahydride complexes ReH 4(hq)(PPh3)2 and ReH4(mq)(PPh 3)2 with tertiary phosphines have been investigated. This study has led to the production of a new class of dihydridorhenium(III) mixed-phosphine complexes of the type ReH2(hq)(PPh3)2(PR 3) and ReH2(mq)(PPh3)2(PR3) (where R3 is Me3, Me2Ph, or MePh2). Similar reactions of ReH4(hq)(PPh3)2 with PPh3 have produced different complexes depending on the reaction conditions. The complex ReH2(hq)(PPh3)3 is produced at room temperature in benzene while ReH2(hq)(PPh 3)2(PHPh2) is generated in refluxing benzene. Thermolysis of ReH2(hq)(PPh3)3 also leads to the formation of ReH2(hq)(PPh3)2(PHPh 2). The structures of ReH2(hq)(PPh3)2(PMe 3), ReH2(hq)(PPh3)3, and ReH2 (hq)(PPh3)2(PHPh2) were established by X-ray crystallography. Deuterium labeling experiments have been conducted in an attempt to determine the source of the H in the PHPh2 ligand of ReH2(hq)(PPh 3)2(PHPh2). During the study of these reactions in C6D6, it was established that ortho-deuterated triphenylphosphine is also produced. Possible pathways for the formation of ReH2(hq)(PPh 3)2(PHPh2) and ortho-deuterated PPh3 are proposed.
Degree
Ph.D.
Advisors
Walton, Purdue University.
Subject Area
Chemistry
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