This book contains an overview of complex formation by macrocyclic ligand systems. The study of macrocyclic chemistry represents a major area of activity which impinges on a range of other areas in both chemistry and biochemistry. The field has characteristically yielded many interesting and unusual compounds. The text discusses the structures and properties of macrocyclic compounds; the synthesis of macrocycles; polyether crown and related systems; metal-ion and molecular recognition (host-guest chemistry); as well as kinetic, thermodynamic and electrochemical aspects of a range of macrocyclic systems. A discussion of the different categories of naturally occurring macrocycles is also included. Specialist and non-specialist alike will find this a useful text. Apart from serving as a convenient reference for established workers in the field, it should also prove useful to new graduate students as well as to researchers from other areas who seek a general introduction to the subject. The topics discussed also provide a suitable basis for a senior undergraduate or graduate course in macrocyclic chemistry and inorganic complexes.

Cucurbit[n]uril chemistry has become an important part of contemporary supramolecular chemistry since cucurbit[n]urils (Q[n]s) are not only able to encapsulate various guests, but are also capable of coordinating to a wide range of metal ions, leading to the establishment of Q[n]-based host-guest chemistry and coordination chemistry. Each of these impressive developments can be attributed to the growth of protocols for obtaining Q[n]s. In this review, we survey synthetic procedures for obtaining cucurbit[n]urils and their substituted derivatives together with the separation and purification of these remarkable compounds. The coverage is aimed at both existing workers in the field as well as at those requiring an "entry" into Q[n]-based research.

Two new twisted cucurbiturils, cucurbit[13]uril (tQ[13]) and cucurbit[15]uril (tQ[15]), have been synthesized and separated, and their structures have been confirmed by NMR spectroscopy and MALDI-TOF mass spectrometry together with the X-ray structures of two new complexes, {Dy(H2O)4Cd(H2O)4tQ[13]}·2.5[CdCl4]·65H2O and {Cd0.5(H2O)2tQ[15]}·[CdCl4]·47H2O. tQ[15] is the largest cucurbit[n]uril (Q[n]) in the Q[n] family reported to date. The X-ray diffraction studies of both complexes indicated that these large tQ[n]s effectively exhibit two different cavities-a central cavity and two side cavities. Preliminary host-guest behavior by each of the new systems was investigated by NMR studies.

In this tutorial review the use of macrocyclic complexes as building blocks in a selection of supramolecular systems is discussed with emphasis on the properties, such as enhanced stabilities, that cyclic ligands and their complexes may impart on the resulting assemblies. An aim of the review is to exemplify the versatility of macrocyclic ligand complexes for use as components in a range of both discrete and polymeric systems. The use of macrocyclic systems for controlling CuI aggregation, as scaffolds for metal-cluster formation, as the cyclic components in interlocked catenane and rotaxane structures, for constructing assemblies based on macrocycle exo-coordination, for forming columnar stacks, as well as their roles as both structural and redox centres in a range of coordination polymer types are all presented.

In the realm of supramolecular chemistry, a small number of intricately interwoven structures that bridge the boundaries between art and science have been reported. These motifs, which typically form on the nanometre scale, display both considerable beauty and complexity. However, the generation of new topologies of this type has remained a very significant synthetic challenge. Here, we describe the synthesis of a discrete highly intertwined metal losupramolecular assembly based on a universal 3 ravel motif-a topology as yet unprecedented in supramolecular chemistry. The exotic, 20 component, [Fe 8 L 12 ] ravel entanglement may be considered as a 'branched knot', with individual molecules displaying either left or right handed chirality. The formation of this cluster was demonstrated by single crystal and powder X ray diffraction. The arrangement is stabilized by a favourable combination of π-π interactions and Nature's tendency to minimize voids in molecular architectures.