The chemistry and complexes of small cyano anions

Abstract

The chemistry of the anions dicyanamide and tricyanomethanide (dca and tcm, respectively) has produced a plethora of discoveries over the past few decades, particularly in relation to transition-metal coordination polymers with magnetic coupling. Over recent years there have been an increasing number of reports of heterofunctionalised cyano-containing anions, typically derivatives of dicyanomethanide. Our own group has been particularly concerned with the amide- and nitroso-functionalised anions carbamoyldicyanomethanide (cdm) and dicyanonitrosomethanide (dcnm), respectively. This feature article examines the fascinating diversity of materials and complexes that can be obtained using small cyano anions, ranging from coordination polymers to heterometallic clusters and hydrogen bonding networks. In particular, we focus on results from our own laboratories in the past few years. The magnetic properties of these materials are briefly discussed.

Vibrational–Structural Combined Study into Luminescent Mixed Copper(I)/Copper(II) Cyanide Coordination Polymers

“…Therefore, the self-assembly of copper cyanide can generate long-lived and highly efficient luminescent materials with variable structures, which sometimes exhibit intriguing topological architectures. [29,30] CuCN is not a common inorganic salt from the structural point of view. Its 1D chain structure, which is based on twocoordinate metal centers and bridging cyanido ligands, means that CuCN differs from many other inorganic salts characterized by 2D or 3D arrays.…”

Lanthanoid‐Based Ionic Liquids Incorporating the Dicyanonitrosomethanide Anion

“…The dcnm anion has been shown to coordinate to lanthanoids through its nitroso group, [25] and in the absence of sterically hindering co-ligands the 12-coordinate homoleptic trianions [LnA C H T U N G T R E N N U N G (dcnm) 6 ] 3À (Ln = La-Gd) are formed (Figure 1b). [26] The trianions [LnA C H T U N G T R E N N U N G (dcnm) 6 ] 3À may be synthesised in high yield, and the previously reported low melting points of their tetraethylammonium salts suggested that an IL may be synthesised when such an anion is coupled with a judiciously selected countercation. Recently, we reported the synthesis of the first series of lanthanoid-based ILs to contain the dicyanonitrosomethanide ligand, (N 4444 ) 3 [LnA C H T U N G T R E N N U N G (dcnm) 6 ] (Ln= La, Ce, Pr, Nd), which displayed polymorph-dependent melting points, as proven by a novel in situ synchrotron-based X-ray powder diffraction technique.…”

A Family of Lanthanoid Dimers with Nitroanilato Bridges

“…The most habitual strategies to reach this objective are: (i) using simple bridging ligands as cyanide (CN − ) [12], dicyanamide (N(CN) 2 − ) [13][14][15], azide (N 3 − ) [16][17][18][19][20], oxalato (C 2 O 4 2− ) [21], = 3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone dianion, see Scheme 1). These ligands contain an aromatic ring replacing the central C=C skeleton of oxalato and can also act as bis-bidentate ligands coupling the metal centers they bridge [25].…”