The making of mechanically interlocked molecular compounds [1] has evolved from a statistical beginning [2] to the use of molecular-recognition-driven, self-assembly protocols [3] that rely upon the operation of covalent, [4] metal, [5] or noncovalent [6] templates, [7] prior to the formation of the mechanical bond(s) by either kinetically or thermodynamically controlled processes, involving either dative [8] or covalent [9] bond formation. Previously, we have speculated [10] about the existence of another class of interlocked molecule beyond the archetypal catenanes [11] and rotaxanes, [12] which are not all that dissimilar from carceplexes [13] and yet are distinguishable from them. [14] In searching for some simple term for this class of mechanically interlocked molecule (Figure 1), which consists of two separate components-a body with two or more limbs that are rigid and protrude outwards, the torso of which carries a close-fitting, all-in-one suit, such that it encompasses the torso of the body-we have come up with the term suitane, in which a number is inserted between "suit" and "ane" to indicate the number of protruding limbs. Thus, the simplest member of the series would be suit Let us consider the specific example (Scheme 1) of a linear body template [15] LBT-H 2 2+ carrying two -CH 2 -NH 2 + CH 2 -recognition sites separated from each other by a bulky midriff [16] such that the double linking up of two matching [24]crown-8 rings in the shape of (CHO) 2 -DP24C8 units [17] can be achieved reversibly by forming four imine bonds with a diaminobenzene spacer, such as p-phenylenediamine (PPD). The virtue of employing reversible imine bond formation [18] to clothe the LBT-H 2 2+ dication with two (CHO) 2 -DP24C8 units and two PPD spacers is that errors can be corrected [19] before the final structure is fixed by

A sensitive and reagentless electrochemical aptatoxisensor was developed on cobalt (II) salicylaldiimine metallodendrimer (SDD–Co(II)) doped with electro-synthesized silver nanoparticles (AgNPs) for microcystin-LR (L, l-leucine; R, l-arginine), or MC-LR, detection in the nanomolar range. The GCE|SDD–Co(II)|AgNPs aptatoxisensor was fabricated with 5’ thiolated aptamer through self-assembly on the modified surface of the glassy carbon electrode (GCE) and the electronic response was measured using cyclic voltammetry (CV). Specific binding of MC-LR with the aptamer on GCE|SDD–Co(II)|AgNPs aptatoxisensor caused the formation of a complex that resulted in steric hindrance and electrostatic repulsion culminating in variation of the corresponding peak current of the electrochemical probe. The aptatoxisensor showed a linear response for MC-LR between 0.1 and 1.1 µg·L−1 and the calculated limit of detection (LOD) was 0.04 µg·L−1. In the detection of MC-LR in water samples, the aptatoxisensor proved to be highly sensitive and stable, performed well in the presence of interfering analog and was comparable to the conventional analytical techniques. The results demonstrate that the constructed MC-LR aptatoxisensor is a suitable device for routine quantification of MC-LR in freshwater and environmental samples.

No abstract

No abstract