Investigation of Distant Inductive Effects on Electronic Donation into Group VI Metals in Tris(phosphinomethyl)phenylborate Complexes

Authors

Shuruthi Senthil, Macalester CollegeFollow

Document Type

Honors Project On-Campus Access Only

Comments

Advisor: Dr. Paul J. Fischer (Macalester College)

Abstract

New d⁶ zerovalent group VI metal (Cr, Mo, and W) tricarbonyls supported by monoanionic tris(diisopropylphosphinomethyl)phenylborate ligands [PhBP^iPr₃]^- ([PhBP^iPr₃]^- = [PhB(CH₂PⁱPr₂)₃]^-) have been synthesized and characterized. Two new ligands featuring 3,5-dimethylphenyl and 3,5-bis(trifluoromethyl)phenyl borate substituents were isolated as thallium salts, and metallated to assess the impact of these 3,5-substituents on the electronic donation of PhBP^Ph₃ ligands towards zerovalent metals. A spectrochemical series of these ligands formulated with IR ν(CO) data and electrochemical half-wave potentials associated with the κ³-phosphine bound M(CO)₃ units suggests that tris(phosphinomethyl)phenylborate ligands do not function as “strongly donating scorpionates” towards zerovalent metals. The zerovalent chromium tris(diarylphosphinomethyl)phenylborate tricarbonyl anions were oxidized by ferrocenium to isolate the first structurally characterized paramagnetic d⁵ zwitterions containing P₃Cr(CO)₃ units (P = any neutral phosphine). Previously synthesized 17-electron [P₃Cr(CO)₃]⁺ species were insufficiently stable under ambient conditions to allow their full characterization.

Recommended Citation

Senthil, Shuruthi, "Investigation of Distant Inductive Effects on Electronic Donation into Group VI Metals in Tris(phosphinomethyl)phenylborate Complexes" (2018). Chemistry Honors Projects. 32.
https://digitalcommons.macalester.edu/chem_honors/32