Synthesis, Structure, and Magnetic and Electrochemical Properties of Quasi-linear and Linear Iron(I), Cobalt(I), and Nickel(I) Amido Complexes

Abstract

Three potassium crown ether salts, [K(Et2O)2(18-crown-6)][Fe{N(SiMe3)Dipp}2] (1a; Dipp = C6H3-2,6-Pri2), [K(18-crown-6)][Fe{N(SiMe3)Dipp}2]·0.5PhMe (1b), and [K(18-crown-6)][M{N(SiMe3)Dipp}2] (M = Co, 2; M = Ni, 3), of the two-coordinate linear or near-linear bis-amido monoanions [M{N(SiMe3)Dipp}2]- (M = Fe, Co, Ni) were synthesized by one-electron reduction of the neutral precursors M{N(SiMe3)Dipp}2 with KC8 in the presence of 18-crown-6. They were characterized by X-ray crystallography, UV–vis spectroscopy, cyclic voltammetry, and magnetic measurements. The anions feature lengthened M–N bonds in comparison with their neutral precursors, with slightly bent coordination (N–Fe–N = ca. 172°) for the iron(I) complex, but linear coordination for the cobalt(I) and nickel(I) complexes. Fits of the temperature dependence of XMT of 1 and 2 reveal that the iron(I) and cobalt(I) complexes have large negative D zero-field splittings and a substantial orbital contribution to their magnetic moments with L = 2, whereas the nickel(I) complex has at most a small orbital contribution to its magnetic moment. The magnetic results have been used to propose an ordering of the 3d orbitals in each of the complexes.

Department(s)

Chemistry

Sponsor(s)

National Science Foundation (U.S.)

Comments

Financial support by National Science Foundation (U.S.), Grant No. CHE-1263760

International Standard Serial Number (ISSN)

0020-1669

Electronic OCLC #

37637103

Print OCLC #

1753164

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2014 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Sep 2014

Link to Full Text

Share

 
COinS