A closer look : A deeper theoretical understanding of the multifaceted periodic system of elements (PSE) has been achieved in recent years. The large energy gaps above the noble gas shells 1s2 and np6 (n=2–6) impress periodicity onto the whole PSE, which is complete with Period 7. The electron configurations of unbound atoms are chemically misleading. The common n+l rule is an example of the “invention of facts” even in the hard sciences.
Chemistry “beyond the molecule” is based on weak, noncovalent, and reversible interactions. As a consequence of these bonds being weak, structural organization by folding and self‐assembly can only be fully exploited with larger molecules that can provide multiple binding sites. Such “supramolecules” can now be synthesized and their folding into desired conformations predicted. A new level of chemistry can now be realized through the creation of non‐natural entities composed of molecular building blocks with defined secondary structures. Herein we define these building blocks as “supramolecular elements”. We anticipate that further research on such large molecules will reveal construction principles dictated by recurring motifs that govern structure formation through folding and self‐assembly. These principles are comparable to the organization of atoms in the Periodic Table of Chemical Elements and may lead to the establishment of a Periodic System of Supramolecular Elements. 相似文献
A numerical classification was performed on 69 elements with 54 chemicaland physicochemical properties. The elements fell
into clusters in closeaccord with the electron shell s-, p- andd-blocks. The f-block elements were not included forlack of sufficiently complete data. The successive periods ofs- and p-block elements appeared in an ovalconfiguration, with d-block elements lying to one side. Morethan three axes were required to give good representation of thevariation, although
the interpretation of the higher axes is difficult.Only 15 properties were scorable for the noble gases, but despite thepaucity
of properties reflecting chemical reactivity, analysis of the 69elements on these properties still showed the major features
seen fromthe full set.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
