Issue 13, 2000

Chromium(II) complexes bearing 2,6-substituted N,N ′-diarylformamidinate ligands

Abstract

The synthesis, isolation and characterisation of several new chromium(II) complexes of the N,N ′-bis(2,6-xylyl)formamidinate ligand (DXylF ) has been undertaken. The structure of three such complexes, namely Cr(DXylF )2, 1, Cr2(μ-Cl)2(DXylF )2(THF )2, 2, and Cr2(Ac)2(DXylF )2(THF )2, 3, have been determined by X-ray crystallography. It has been shown that the steric demands of the 2,6-xylyl group effectively discourage the formation of the homoleptic paddlewheel structure Cr2(DXylF )4: instead, the mononuclear (but stoichiometrically equivalent) complex Cr(DXylF )2, 1 was obtained. It is likely that the unusual dichromium dichloride-bridged intermediate 2 also owes its stability to the presence of such bulky substituents. Although this complex does not possess a significant metal–metal bonding interaction [Cr–Cr = 2.612(1) Å], it has however, proven to be a useful starting material for the preparation of the novel quadruply bonded dichromium mixed acetate–formamidinate complex 3 [Cr–Cr (avg) = 2.339(7) Å]. In both 2 and 3, the 2,6-xylyl groups force the formamidinate ligands to oppose one another contrary to the trans effect. In addition, it was found that compound 3 can be accessed from the chromium acetate starting material and, for comparison, an attempt was also made to prepare the N,N ′-bis(o-anisyl)formamidinate (DPhOMeF ) analogue. With the formamidinates occupying positions cis to one another and with the absence of axially coordinated THF ligands, the molecular structure of the resultant Cr2(Ac)2(DPhOMeF )2, 4 [Cr–Cr = 2.037(1) Å], is different from that of 3.

Article information

Article type
Paper
Submitted
13 Jan 2000
Accepted
24 Apr 2000
First published
13 Jun 2000

J. Chem. Soc., Dalton Trans., 2000, 2001-2005

Chromium(II) complexes bearing 2,6-substituted N,N ′-diarylformamidinate ligands

F. A. Cotton, L. M. Daniels, C. A. Murillo and P. Schooler, J. Chem. Soc., Dalton Trans., 2000, 2001 DOI: 10.1039/B000326N

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements