Crown Notices

Although section 48 of the HSW makes provision for binding the Crown to the provisions of part of the Act it excepts sections 21 to 25 which deal with prohibition and improvement notices. The Crown immunity exists because in the exercise of justice in the name of the monarch it is not constitutionally possible for one part of the Crown service to pursue another part of the service into the Courts. Nevertheless, the HSE does apply a version of prohibition and improvement notices, called Crown Notices, when deficiencies are found on Crown property. Through the National Health Service (Amendment) Act 1986, Crown immunity for both food legislation and health and safety legislation have been removed from the Health Authority. 

The story goes that when Archimedes was bathing, he noticed the water overflowed as he stepped in, and the solution to the crown problem came to him he could tell the exact volume of the crown by measuring the volume of water it displaced. If the crown was made of silver and gold together, it would displace more water than one made only of gold. He was so excited that he ran naked into the street, yelling, "Eureka which means "I ve found it ... 

Electroneutral combinations are often favored by enthalpic against entropic contributions, however with noticeable exceptions. Thus, crown ether 18-C-6 complexes with e.g. free amines in methanol show stability constants around lgK= 2.5 0.1, quite independent of the amine structure, but very sizeable differences in AH, ranging from 1 or 2 kJ/mol for secondary or tertiary amines to 30 kJ/mol for primary amines with surprisingly favorable entropic TAS values of up to 13 kJ/mol. Protonated amines show increased lg K values of up to 4.4, mainly due to enthalpic advantages, and not. as one might expect for the more polar combinations, due to entropic effects, although these are also sizeable.[38]... 

The discussion so far has centred on receptors based on the iminodiacetate element . However, even crown ethers can serve as receptors in sensors where the dicationic alkaline earths can elicit a larger fluorescence response than the alkali monocations. Charge density effects of this sort are particularly noticeable in solvents of relatively low polarity. The best examples are to be found among fluoroionophores [137] with integrated fluorophore and receptor moieties such as (53) [120] and (54) [121]. No PET sensors of this type are currently available, though case (32) [85] is an approximate example of a fluorophore-spacer-receptor system. 

In the twenty-first century, there will continue to be a noticeable trend from studies of classical crown ethers towards directed polysizamacromolecules for metal atom complexation and the introduction of multiple heteroatoms for tuned directed self-assembly, including most recently metal atom centers, as the heteroatom. 

Photochemical butterfly-like E — Z photoisomerization of a bis(crown ether) azobenzene derivative 354 was found to be thermally reversible and the stereoisomers exhibit unique contrasting behaviour in the presence of metal ions.1108 The concentration of the Z-isomer in the photostationary state was noticeably enhanced by the addition of K+, Rb + or Cs +, because the corresponding Z-complex achieved a stable sandwich geometry (Scheme 6.162). As a result, the cations could be selectively extracted by the Z-derivative from an aqueous phase to an organic solvent (o-dichlorobenzene), whereas no complexation (i.e. no transfer) took place in the case of the E-isomer. 

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