The Nature of the Ag^I⋅⋅⋅Ag^IInteraction in Different Ag(NH₃)₂Dimers Embedded in Supramolecular Solids

Abstract

An isolated silver(I) ammonia monomer, a dimer, and a novel dimer containing an intercalated water molecule have been embedded as guests in supramolecular frameworks, [Ag(NH3)2][(H2thpe)(H3thpe)].MeCN (1), [{Ag(NH3)2}2][(H2thpe)2]4.25 H2O (2), and [{Ag(NH3)2}-H2O-{Ag(NH3)2}][(H2thpe)(2)]benzene (3) (H3THPE=tris(hydroxyphenyl)ethane). The [{Ag(NH3)2}2]2+ dimer is not stable as an isolated entity, but is stabilized by hydrogen bonding in the supramolecular framework. The water-intercalated silver(I) ammonia dimer, which constitutes a novel species, is also subject by hydrogen bonding in concentrated solutions. The destabilization energy of the dimer relative to isolated monomers is calculated to be approximately 300 kJ mol(-1) by both perturbation methods and DFT theory. For the water-intercalated dimer it is calculated to be approximately 200 kJ mol(-1) according to the BSSE-corrected MP2 calculation. The different aggregate states show a dramatic variation of absorption and emission properties, in accordance with the concentration dependent red-shift observed in solutions. Natural-bond-orbital analysis shows that the disilver-ammonium-aquo "sandwich" cation in 3 is stabilized by interaction between the pi lone pair orbital on the oxygen atom of the water molecule and Ag(I)--N sigma antibonding molecular orbital.

Supramolecular Assembly of Ag(I) Centers: Diverse Topologies Directed by Anionic Interactions

“…It has been proposed that strong repulsive electrostatic interaction contributes to the instability of Ag–Ag bond formation, validating common ligand-supported strategies to push such argentophilic interactions. 11 Structures of the present Ag(I) complexes 1 – 4 , however, arise principally from interactions with the anions and H-bonding. Catenation of the Ag(I) atoms along the c axis is stabilized by the extended long-range noncovalent interactions in structure 4 .…”

Energetic Silver Salts with 5‐Aminotetrazole Ligands

“…Figure 6 shows a view of the asymmetric unit of the compound. There exists two types of crystallographically independent and noninteracting 16 moieties, both of which show the simple linear coordination expected for the Ag + cations, similar to salts with the [Ag(NH 3 ) 2 ] + cation,45a with ∢N‐Ag‐N=169.2(1) and 176.4(1)° presenting a distorted linear geometry.…”

Bis[diamminesilver(I)] 5-nitroisophthalate monohydrate

“…(Mooibroek et al, 2006;Nishio et al, 1998). Although Ag I ion under ammoniacal conditions can form {[Ag(NH 3 ) 2 ] + } n (n = 1 or 2) (Zheng et al, 2007), which can be stabilized by supramolecular interactions, only limited [Ag(NH 3 ) 2 ]-containing compounds were documented due to the weak Ag-N ammine coordination bond Zheng et al, 2002). Recently, we have pursued systematic investigations about the self-assembly of Ag I ion with different bipodal N-donor ligands and multicarboxylates under ammoniacal conditions Sun, Luo, Xu et al, 2009;.…”

“…For general background to noncovalent interactions, see: Biswas et al (2009); Egli & Arkhel (2007); Jeffrey et al (1985); Mooibroek et al (2006); Nishio et al (1998); Rahman et al (2003). For related structures, see: ; Sun, Luo, Xu et al (2009); ; ; ; Zheng et al (2002Zheng et al ( , 2007.…”