Aurophilicity−Coordination Interplay in the Design of Cyano-Bridged Nickel(II)−Gold(I) Bimetallic Assemblies:  Structural and Computational Studies of the Gold(I)−Gold(I) Interactions

Abstract

Two polymorphic cyano-bridged Au(I)-Ni(II) bimetallic complexes of formulas [Ni(en)2Au(CN)2][Au(CN)2] (1) and [Ni(en)2[Au(CN)2]2] (2) have been prepared from the 1:2 reaction between [Au(CN)2]- and either [Ni(en)2Cl2]Cl or [Ni(en)3]Cl2.2H2O, respectively. The structure of 1 consists of polymeric cationic chains of alternating [Au(CN)2]- and [Ni(en)2]2+ units running along the a axis and [Au(CN)2]- anions lying between the chains. The noncoordinated dicyanoaurate anions are aligned perpendicular to the ac plane and involved in aurophilic interactions with the bridging dicyanoaurate groups, ultimately leading to a 2D bimetallic grid. The structure of 2 consists of trinuclear molecules made of two [Au(CN)2]- anions linked to [Ni(en)2]2+ unit in trans configuration. Trinuclear units are joined by aurophilic interactions to form 1D zigzag chains. The magnetic properties of these compounds are strongly dominated by the local anisotropy of the octahedral Ni(II) ions, thus indicating that the magnetic exchange interaction mediated by dicyanoaurate bridging groups, if it exists, is very weak. To get insight into the electronic properties of the inter- and intramolecular interactions of the [Au(CN)2]- building blocks, the structures of different aggregates of dicyanogold units were optimized and then analyzed by making use of atoms-in-molecules (AIM) theory. Moreover, bond indices were calculated by methods based upon nonlinear population analysis.

Access to Metal Complexes of the Elusive Imidobis(phosphaalkene) Anion by N–Si Bond Cleavage of a N‐Silylimino‐Bridged Bis(phosphaalkene)

“…The electron density at this CP is quite low (0.02-0.03 e Å -3 , see ESI), however, it is comparable to those observed for hydrogen bonded interactions and is slightly larger than the value reported for Au-CNNi compounds. [19] Scheme 3. Isodesmic reactions (see text).…”

Two Mn(II)–Au(I) supramolecular assemblies bonded by coordination, aurophilicity and hydrogen-bonding, π–π interactions and their magnetic properties

“…The m(CN) band at 2144 cm À1 for 1 is due to free [Au(CN) 2 ] À anion and the other m(CN) bands 2161 cm À1 for 1, 2157 cm À1 for 2 are due to coordinated [Au(CN) 2 ] À groups [22]. Fig.…”

“…The luminescence in aqueous solution is of special importance, because this may allow for monitoring and probing biological processes associated with the luminescent material [18][19][20]. Using [Au(CN) 2 ] À anion and metal ions as tectons, new supramolecular assemblies with novel topologic structures and properties are expected to be obtained [21][22][23][24][25][26][27][28]. Since the self-assembly of supramolecular architectures is highly influenced by factors such as the solvent system, templates and counterion, the exploration of synthetic routes is a long-term challenge [29].…”

Synthesis and crystal structure of a 3D copper(II)–silver(I) coordination polymer assembled through hydrogen bonding, π–π stacking and metal–π interactions, {[Cu(phen)2(CN)][Ag(CN)2] · 3H2O} n (phen = 1,10-phenanthroline)

“…Transition metal cyanides such as [Fe(CN) 6 ] 3− [1][2][3][4][5][6], [Ni(CN) 4 ] 2− [7][8][9][10][11], [Au(CN) 2 ] − [12][13][14][15][16][17], and [Ag(CN) 2 ] − [18][19][20][21][22][23][24][25][26][27][28][29] are widely used as building blocks for the preparation of supramolecular coordination systems. The rigidity of such frameworks may allow shape and size selective inclusion of organic solvents, water molecules, and aromatic compounds for potential applications in the area of catalysis [1,12,29,30].…”