Inversion symmetry and local vs. dispersive interactions in the nucleation of hydrogen bonded cyclic n-mer and tape of imidazolecarboxamidines

• Sihui Long,
• Venkatraj Muthusamy,
• Peter G. Willis,
• Sean Parkin and
• Arthur Cammers

Beilstein J. Org. Chem. 2008, 4, No. 23, doi:10.3762/bjoc.4.23

• minimization and their level of accuracy, especially in the prediction of hydrogen bonding options that are proximal in energy [28][46][47]. Prediction of the organic solid state is challenged by the fact that many crystalline phases likely result from marginal differences in large opposing effects. While the

• be made about the most popular hydrogen bond motif followed by caveats regarding the use of crystal-structure derived atomic parameters to broadly characterize hydrogen bonding energies. 1: An intuitive prediction regarding the relationship between crude hydrogen bond donor/acceptor directionality

• obvious exceptions. See text. The icon legend is identical to Figure 8 and Figure 10. The Y-axis from Figure 8 energies (θ only) and the X-axis from Figure 10 energies are compared. The high and low energies of θ are mostly responsible for the two crystalline phases that lie outside the prediction that

Tether- directed synthesis of highly substituted oxasilacycles via an intramolecular allylation employing allylsilanes

• Peter J. Jervis and
• Liam R. Cox

Beilstein J. Org. Chem. 2007, 3, No. 6, doi:10.1186/1860-5397-3-6

• all four possible oxasilacycles in addition to appreciable quantities of a diene side-product. The results with anti-aldehydes are more interesting. In line with our prediction, substrates possessing this relative stereochemistry provide results which are comparable to those from aldehydes that lack a

Effect of transannular interaction on the redox- potentials in a series of bicyclic quinones

• Grigoriy Sereda,
• Jesse Van Heukelom,
• Miles Koppang,
• Sudha Ramreddy and
• Nicole Collins

Beilstein J. Org. Chem. 2006, 2, No. 26, doi:10.1186/1860-5397-2-26

• calculated parameters and to the nature and positions of substituents in the bicyclic system. Results and Discussion Accurate computational prediction of redox-potentials requires comparison of energies for both the starting quinone and its reduced forms. The open-shell nature of the reduced species and

• often the necessity to take into account solvation makes the prediction of the redox-potentials a challenging and time consuming computational problem. However, Koopmans' theorem [4] enabled us to relate redox-potentials of bicyclic quinones with their LUMO energies, which characterize solely the

• starting compound. Despite the neglected orbital relaxation that immediately follows the reduction, such correlations have proved to be an efficient tool for prediction of redox-potentials of anthracyclines [5], substituted anthracenes [6], and oligothiophenes [7]. For all chemical species, the

EcoScale, a semi- quantitative tool to select an organic preparation based on economical and ecological parameters

• Koen Van Aken,
• Lucjan Strekowski and
• Luc Patiny

Beilstein J. Org. Chem. 2006, 2, No. 3, doi:10.1186/1860-5397-2-3

• not take into account the nature and environmental impact of the generated waste. In order to arrive at a more meaningful prediction, the E-factor is multiplied by a environmentally hazardous quotient Q. For example, a Q value of 1 can be attributed to NaCl, while heavy metals can be assigned a value