Issue 10, 2018

Selective coordination of cyanate and thiocyanate in the end-on mode: synthesis, structures and properties of [Ni II2L(μ1,1-NCO)]+ and [Ni II2L(μ1,1-NCS)]+ (L2− = macrocyclic N6S2 ligand)

Abstract

The ability of the dinickel complex [Ni2L]2+ supported by the binucleating hexaaza-dithiophenolate macrocycle (L)2− to bind linear (OCN, SCN) and bent triatomic anions (NO2) has been examined. The complexes [NiII2L(μ1,1-NCO)]BPh4 (3) and [NiII2L(μ1,1-NCS)]BPh4 (4) have been synthesized by addition of KOCN or KSCN to [NiII2L](ClO4)2 (1) and characterized by IR, ESI-MS, UV-vis, SQUID magnetometry, X-ray crystallography (3) and computational studies. [Ni2L][ClO4]2 (1) binds cyanate and thiocyanate ions specifically end-on via their N atoms yielding face-sharing bis(octahedral) N3Ni(μ-S2)(μ1,1-X)NiN3 core structures (X = NCO or NCS), while no reactions occur with NO2. The X-ray structure of 3* and accompanying DFT calculations imply that the selective binding of the pseudohalide ions is governed by repulsive host–guest CH⋯(anion)π interactions. 3 and 4 exhibit an S = 2 ground state that is attained by competing antiferromagnetic and ferromagnetic exchange interactions via the thiolato and cyanato (or thiocyanato) bridges, respectively, with a value for the magnetic exchange coupling constant J of 12.6 and 9.8 cm−1 (H = −2JS1S2). The affinity of 1 for cyanate determined by absorption spectrometry in MeCN/MeOH (1/1 v/v) at I = 0.01 M is ca. two orders of magnitude higher than for thiocyanate (log K11 = 3.92(1) (3), 2.16(1) (4)). The value for 3 was found to compare favorably well with the equilibrium constant derived by isothermal titration calorimetry.

Graphical abstract: Selective coordination of cyanate and thiocyanate in the end-on mode: synthesis, structures and properties of [NiII2L(μ1,1-NCO)]+ and [NiII2L(μ1,1-NCS)]+ (L2− = macrocyclic N6S2 ligand)

Supplementary files

Article information

Article type
Paper
Submitted
08 jan. 2018
Accepted
16 mar. 2018
First published
21 mar. 2018

New J. Chem., 2018,42, 7630-7639

Selective coordination of cyanate and thiocyanate in the end-on mode: synthesis, structures and properties of [NiII2L(μ1,1-NCO)]+ and [NiII2L(μ1,1-NCS)]+ (L2− = macrocyclic N6S2 ligand)

A. Jeremies, S. Gruschinski, S. Schmorl, T. Severin and B. Kersting, New J. Chem., 2018, 42, 7630 DOI: 10.1039/C8NJ00114F

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.

Social activity

Spotlight

Advertisements