Assembly of a three-dimensional polyknotted coordination polymer

The coordination polymer {[Cd-2(4,4'-pytz)3(mu-NO3)(NO3)(3)(MeOH)]}(infinity) 1, displays a unique polyknotted structure in which each Cd(II) center is coordinated by three pyridyl N-donors arranged in tin approximate T-shaped geometry to form a ladder motif. Within this structure, each ladder is interpenetrated perpendicularly by two other ladders. Significantly, each of the Cd(II) centers at the intersections of one ladder is bridged by a coordinated NO3- anion to a Cd(II) center located at the corner of a square section of one of the perpendicularly interpenetrated ladders. Thus, all the ladders are linked together to give a three-dimensional polymer where the overall architecture is constructed of one molecule in a fused ''polyknot".