The solid state aggregation of two gold(I) nitrate complexes †

Abstract

Trimethylphosphine)gold() nitrate was prepared from the reaction of (Me 3 P)AuCl and AgNO 3 in MeOH-CH 2 Cl 2 . Single crystals from CH 2 Cl 2 -pentane contain trimers [(Me 3 P)Au(ONO 2 )] 3 as sub-units of polymeric chains. The organization is based on short aurophilic Au-Au contacts. A discussion considering all other known (Me 3 P)AuX structures leads to the conclusion that small, electronegative anions X favour aurophilic multi-coordination with longer Au ؒ ؒ ؒ Au contacts, while less electronegative, bulky groups X induce dimerization with short Au ؒ ؒ ؒ Au contacts. In all cases neighbouring molecules are arranged with their principal axes roughly perpendicular (staggered). Crystals of ( t BuNC)Au(ONO 2 ) grown from CH 2 Cl 2 -pentane at Ϫ25 ЊC were shown to be a 2 : 1 dichloromethane solvate with a new meander-type structure, which is stable only at low temperature and under the standard pressure of a dichloromethane atmosphere. The structure is based on aurophilic interactions of a similar nature as in the solvent-free phase (obtained at 5 ЊC) as judged from the bond distance parameters, but the solvent molecules are accommodated in cavities formed through a different puckering of the chains. A comparison with other structures of (RNC)AuX molecules suggests that the parallel (eclipsed) head-to-tail alignment of the molecules is the preferred organization in the absence of other structure-determining effects.

[{(H3C)3NB(H)2NC}2Au][AuI2]: a linear chain polymer of gold(I) iodide with an unusual isocyanoborane ligand showing aurophilic behaviour

“…The term aurophilicity is used to describe observed AuÁ Á ÁAu interactions. These intermolecular contacts have been shown to have bond energies and distances similar to those observed for classical hydrogen-bonding interactions (7.5±12.5 kcal mol À1 and 2.7±3.5 A Ê , respectively) (Schmidbaur, 1990(Schmidbaur, , 2000Mathieson et al, 2000). Hence, aurophilic behaviour is considered to be a major factor in determining the particular supramolecular motif which a series of monomers is observed to adopt.…”

Supramolecular chemistry of gold(I) thiocyanate complexes with thiophene, phosphine and isocyanide ligands, and the structure of 2,6-dimethylphenyl isocyanide

“…Other (Me 3 P)AuX complexes are known to form their own isostructural set (X = Cl, Br, CN, NO 3 or CF 3 CO 2 ), in this case polymeric. 14 Crystals of the ligand 2,6-Me 2 C 6 H 3 NC are triclinic, space group P1 ¯, with Z = 4 formula units in the unit cell. There are two independent molecules in the unit cell which differ only marginally in their structural details.…”

The Nature of Intermolecular CuI⋅⋅⋅CuIInteractions: A Combined Theoretical and Structural Database Analysis

“…The previous energetic results are consistent with those reported by Poblet et al for a specific ion pair,80 as well as with those from a previous LMP2 analysis for neutral dimers46, 47 (with regard to the LMP2 work, we should note that, although some terms have the same name as in the present IMPT study, the two methods use different approaches and such terms do not always represent the same physical effect). The combination of different contributions and their dependence on the intermolecular distance (see, for example, Figure 2) may explain why no correlation has been found between the experimental distance and the electronegativity of the X ligand in the [{AuX(PMe 2 Ph)} 2 ] and [{AuX(CN t Bu)} 2 ] series, as reported by Schmidbaur et al4 When varying the ligands in [{CuX(EH 3 )} 2 ] (X = Cl, Br; E = N, P), we observe that the dispersion term becomes more stabilizing as the electronegativity of the donor atoms is decreased (Table 3). The exchange–repulsion and the Coulomb terms are also sensitive to the nature of the ligands, whereas the charge‐transfer and polarization terms are practically unchanged.…”