Solomon Link

In conclusion, donor-acceptor tt-tt stacking interactions were utilized in synergy with metal coordination in the preparation of the described Solomon link 

SCHEME 17.7 Formation of Solomon link by self-assembly of two diazapyrene-based ligands coordinated to two Pd(II) cations and intertwined with tetraphenylenecyclophane 

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Another class of dynamic topology is a knotted macromolecule (Fig. 39b) [266-268]. Here we limit our discussion to open knots that can be untied without breaking the covalent bonds (resembling shoelaces and neckties). We do not consider knots formed by closed strings such as Borromean ring and Solomon link (Fig. 39c, d). The knot imposes constraints on the backbone, leading to a potentially different mechanochemical response compared to unknotted cousins. 

FIGURE 17.1 Most common knots and links and theirmathematical descriptions. Left to right [2]catenane, trefoil knot, Solomon link, pentafoil (or Solomon s seal) knot, and Borromean ring. 

The intent of metal coordination is to provide both a robust tanplate platform and a large diversity of stereochonical geometries defined by the coordination properties of the metal. In addition to tetrahedral and octahedral coordination geometries obtained, for example, with Cu(I) or Zn(II), respectively, linear arrangements can be obtained using Au(I) centers coordinated to alkyne- and phosphine-terminated strands to prepare different types of catenates. 2 Square planar coordination around Pd(II) was also used to generate a doubly interlocked [2]catenane, known as a Solomon link. ... 

The structure of the trefoil knot was demonstrated by a combination of high resolution mass spectrometry, NMR experiments, and computational modeling. Interestingly, the synthesis of the trefoil knot was accomplished with a consequent 56% yield, but it was shown to be accompanied by the formation of a [2]catenane species isolated in 22% yield as well as by the larger Solomon link structure detected only in minor amounts by mass spectrometry during the course of the reaction. 

A step forward in the complexity of topological molecular objects is reached with the synthesis of molecular Solomon links that are composed of two distinct strands intertwined with four alternate crossings (Figure 17.1). As a probable consequence of their increased complexity, examples of Solomon links are less common than catenates or trefoil knots. Peinador et al. reported a series of three Solomon links obtained in a single step by the self-assembly of five components two diazapyrene based strands two Pd(en)(OTf)2 coordination complexes (en = ethylene diamine, OTf = triflate) and an electron rich cyclophane containing four phenylene groups (Scheme 11)P... 

Despite the numerous molecular topologies reported to date, it is clear that very few of the intrinsic properties of these assemblies such as the topologically unconditional chirality of trefoil knots and Solomon links or the incredible kinetic inertness of Cu(I)-based [2]catenates have been exploited. A step forward for a better understanding and use of these supramolecular assemblies resides in the availability of researchers to exploit such properties. 

The finding that the heterogeneous chemistry that occurs on polar stratospheric clouds also occurs in and on liquid solutions in the form of liquid aerosol particles and droplets in the atmosphere provided a key link in understanding the effects of volcanic eruptions on stratospheric ozone in both the polar regions and midlatitudes. As discussed herein, the liquid particles formed from volcanic emissions are typically 60-80 wt% H2S04-H20, and hence the chemistry discussed in the previous section can also occur in these particles (Hofmann and Solomon, 1989). We discuss briefly in this section the contribution of volcanic emissions to the chemistry of the stratosphere and to ozone depletion on a global scale. For a brief review of this area, see McCormick et al. (1995). 

Dysidea avara from the Solomon Islands contained the melemeleones A (339) and B (340), which were identified by spectroscopic analyses [305]. They consist of a sesquiterpene linked to a quinone with an attached taurine residue [22]. 

Gentile JH, Solomon KR, Butcher JB, Harrass M, Landis WG, Power M, Rattner BA, Warren-Hicks WJ, Wenger R. 1999. Linking stressors and ecological responses. In Foran JA, Ferenc SA, editors. Multiple stressors in ecological risk and impact assessment. Pensacola, FL SETAC Press, p 27-50. 

Solomon B (2001) In Exley C (ed), Aluminum and Alzheimer s disease. The science that describes the link. Elsevier Science B.V. Amsterdam 95... 

Lazai ov-Spiegler O, Solomon AS, Schwartz M (1999) Link between opdc nerve regrowdi failui e and macrophage sdmuladon in mammals. Vision Res 39 169—175. 

Emotional experiences with positive valence ("positive emotions/ for short) may serve as the goal of behavior The link between behavior and outcome may be provided either by intentional choice or by the reinforcement properties of the experience. Example Solomon s case of a woman who was willing to take a financial loss in order to get the pleasant feeling of righteous indignation. 

Comparable in many respects to the H- He method, the tracer pair H- Kr removes many of the difficulties inherent to the use of alone. However, in contrast to the H- He method, a knowledge of the H-input function is always needed, because Kr is not linked to the H-decay. Another difference between He and Kr lies in their transport behavior through the unsaturated zone. Weise et al. (1992a) showed that while the fast diffusing He was at the atmospheric level in the soil air down to 25 m depth, the Kr activity in the soil gas decreased significantly at depths larger than about 10 m. A time lag between the atmospheric input function and the concentrations in the soil air at the water table in deep unsaturated zones affects not only Kr but also the dating methods based on CFCs (Cook and Solomon 1995) and SFe (Zoellmann et al. 2001). 

A majority of the proposed models suggest coals to consist of several ring aromatic and hydroaromatic structural units, cross-linked through aliphatic and ether bridges to form the three dimensional structure and in the pores and cavities of this structure reside weakly linked smaller molecules which are easily extracted by solvents. The model proposed by Solomon and Shinn are representative examples of this macromolecular model. 

King Solomon is also reputed to have written a book about the Philosophers Stone called HaMa en or The Compass He writes of obtaining the Philosophers Stone from the Queen of Sheba, who had previously received it from her husband Seman." Seman was a great sage amongst the Copt or Nabateans. In Chapter 8, we shall have more to say about the Nabateans as an integral link between the Sabians of Yemen and the Sabians of Harran. 

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