(Trimethylphosphine)gold(I) nitrate was prepared from the reaction of (Me3P
)AuCl and AgNO3 in MeOH-CH2Cl2. Single crystals from CH2Cl2-pentane contain
trimers [(Me3P)Au(ONO2)](3) as sub-units of polymeric chains. The organiza
tion is based on short aurophilic Au-Au contacts. A discussion considering
all other known (Me3P)AuX structures leads to the conclusion that small, el
ectronegative anions X favour aurophilic multi-coordination with longer Au
. . . Au contacts, while less electronegative, bulky groups X induce dimeri
zation with short Au . . . Au contacts. In all cases neighbouring molecules
are arranged with their principal axes roughly perpendicular (staggered).
Crystals of ((BuNC)-Bu-t)Au(ONO2) grown from CH2Cl2-pentane at -25 degreesC
were shown to be a 2:1 dichloromethane solvate with a new meander-type str
ucture, which is stable only at low temperature and under the standard pres
sure of a dichloromethane atmosphere. The structure is based on aurophilic
interactions of a similar nature as in the solvent-free phase (obtained at
5 degreesC) as judged from the bond distance parameters, but the solvent mo
lecules are accommodated in cavities formed through a different puckering o
f the chains. A comparison with other structures of (RNC)AuX molecules sugg
ests that the parallel (eclipsed) head-to-tail alignment of the molecules i
s the preferred organization in the absence of other structure-determining
effects.