Q linker

Pon RT, Yu S. Hydroquinone-0,0 -diacetic acid (Q-linker) as a replacement for succinyl and oxalyl linker arms in solid-phase oligonucleotide synthesis. Nucleic Acids Res 25 3629-3635, 1997. 

Hyun et al. [345] prepared PbS Q-dots in a suspension and tethered them to Ti02 nanoparticles with a bifunctional thiol-carboxyl linker molecule. Strong size dependence due to quantum confinement was inferred from cyclic voltammetry measurements, for the electron affinity and ionization potential of the attached Q-dots. On the basis of the measured energy levels, the authors claimed that pho-toexcited electrons should transfer efficiently from PbS into T1O2 only for dot diameters below 4.3 nm. Continuous-wave fluorescence spectra and fluorescence transients of the PbS/Ti02 assembly were consistent with electron transfer from small Q-dots. The measured charge transfer time was surprisingly slow ( 100 ns). Implications of this fact for future photovoltaics were discussed, while initial results from as-fabricated sensitized solar cells were presented. 

SIMe.q sllyl linker (28) COOH TBAF or CsF COOH... 

Metal salen complexes can adopt non-planar conformations as a result of the conformations of the ethane-1,2-diyl bridge. The conformations may have Cs or C2 symmetry, but the mixtures are racemic. Replacement of the ethylenediamine linker by chiral 1,2-diamines leads to chiral distortions and a C2 chiral symmetry of the complex due to the half-chair conformation of the 5-membered ring of the chelate. Depending on substitution at the axial positions of the salen complex, the symmetry may be reduced to Q, but as we have seen before in diphosphine complexes of rhodium (Chapter 4) and bisindenyl complexes of Group 4 metals (Chapter 10) substitution at either side leads to the same chiral complex. Figure 14.10 sketches the view from above the complex and a front view. 

Like their para isomers, 43,47, and 53 have open-shell singlet (M ) ground states (Table 4). The triplet ( A ) and quintet ( A ) states are predicted to be about 2 and 20-25 kcal/mol higher in energy, respectively. Thus, the S-Q splittings are approximately 5 kcal/mol smaller than the corresponding ones of the para isomers (13, 16 and 8, respectively), but qualitatively very similar, as expected due to the similar electronic properties of the o- and p-phenylene linkers. 

In many respects, the linker LI can be likened to a flexible hinge, a role consistent with a swinging head model proposed for IFs. In this model, segment 1A can (under appropriate conditions) split into two separate Q-helical strands, thereby maximizing the range of movement of the head domains and hence increasing their capacity to interact with various other cellular entities (Parry et al, 2002). 

Yang, Y., Dowling, J., Yu, Q.-C., Kouklis, P., Cleveland, D. W., and Fuchs, E. (1996). An essential cytoskeletal linker protein connecting actin microfilaments to intermediate filaments. Cell 86, 655-665. 

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