Platinum(II)-directed condensation of ethane-1,2-diamine with nitroethane and
formaldehyde yields the colourless macrocyclic complex
(trans-6,13-dimethyl-6,13-dinitro-1,4,8,11-tetraazacyclotetradecane)plat-
inum(II), [Pt(1)]2+, in good yield. This
parallels chemistry reported earlier around other triad members nickel(II) and
palladium(II). The pendant nitro groups in the major isomer are disposed on
opposite sides of the macrocycle in a trans geometry, as
confirmed by the X-ray crystal structure analysis of [Pt(1)]
(ClO4)2, which crystallizes in the
triclinic space group P-1,
a 8·041(4), b
8·482(4), c 9·443(3) Å, α
69·44(3), β 67·66(4), γ
71·73(4)°,Z1, and was refined to an
R value of 0·027 on 1920 F.
The platinum ion lies in a square planar environment of four nitrogen donors,
with typical Pt–N distances; comparisons between the platinum(II) and
palladium(II) complexes of (1) and its analogue (2), with diammonio groups in
place of dinitro groups, are discussed
Template Synthesis of [2]Rotaxanes with Large Ring Components and Tris(biphenyl)methyl Group as the Blocking Group. The Relationship between the Ring Size and the Stability of the Rotaxanes.