scholarly journals How metallation affects solid-state conformation and assembly of hexameric cyclic peptoids

2013 ◽  
Vol 69 (a1) ◽  
pp. s238-s238
Author(s):  
Consiglia Tedesco ◽  
Loredana Erra ◽  
Brunello Nardone ◽  
Gavin Vaughan ◽  
Irene Izzo ◽  
...  
Tetrahedron ◽  
1992 ◽  
Vol 48 (20) ◽  
pp. 4209-4230 ◽  
Author(s):  
Marian Mikołajczyk ◽  
Piotr P. Graczyk ◽  
Michał W. Wiecorek ◽  
Grzegorz Bujacz

Biopolymers ◽  
1990 ◽  
Vol 30 (5-6) ◽  
pp. 509-516 ◽  
Author(s):  
Benedetto Di Blasio ◽  
Ettore Benedetti ◽  
Vincenzo Pavone ◽  
Carlo Pedone ◽  
Michele Saviano ◽  
...  

1989 ◽  
Vol 44 (5) ◽  
pp. 575-581 ◽  
Author(s):  
Giuliano Bandoli ◽  
Umberto Casellato ◽  
Mario Gleria ◽  
Antonio Grassi ◽  
Enzo Montoneri ◽  
...  

The crystal and molecular structure of [NP(OC10H7)2]3 was determined by X-ray analysis.The dipole moments of this compound and of the hexa(phenoxo)cyclotriphosphazatrienes of formula [NP(OC6H3XX′Y)2]3 (X = X′ = H, Y = p-Br; X = m-CH3,. X′ = H. Y = p-Cl; X = X′ = m-CH3, Y = p-Cl; X = X′ = m-CH3, Y = H; X = X′ = H, Y = p-CH(CH3)2; X = X′ = H, Y = p-C(CH3)3) were measured in benzene at 25°C. Crystals of [NP(OC10H7)2]3 are monoclinic with unit cell dimensions a = 24.870(15), b = 7.712(8), c = 27.687(14) Å, β = 115.85(7)°; space group P21/c. The structure was refined to an agreement factor of 0.09. The phosphazene ring deviates (max. deviation 17°) from planarity. and mean distances (A) and angles (°) are P-N 1.58(1). P-O 1.58(1), O-C 1.41(2); P-N-P 120(1), N-P-N 119(1), P-O-C 124(2). The conformations of the naphthyloxo groups at P(2) and P(3) are similar, and different from the group at P(1).Dipole moment analysis showed that the solid state conformation changes in the solution state. The measured value was in agreement with a symmetric conformation in which at the O-P-O plane each naphthyloxo group is rotated by ca. 40-50° from the anti-coplanar arrangement relative to this plane. The dipole moment data for the p-substituted phenoxo derivatives agree with such a conformation, but the analysis of the dipole moment values of phosphazenes having phenoxo groups bearing more than one substituent group and p-CH(CH3)2 substituent failed to do so due to the inherent limitations of the method.


2005 ◽  
Vol 61 (5) ◽  
pp. 585-594 ◽  
Author(s):  
J. Pérez ◽  
K. Nolsøe ◽  
M. Kessler ◽  
L. García ◽  
E. Pérez ◽  
...  

Two methods for the classification of eight-membered rings based on a Bayesian analysis are presented. The two methods share the same probabilistic model for the measurement of torsion angles, but while the first method uses the canonical forms of cyclooctane and, given an empirical sequence of eight torsion angles, yields the probability that the associated structure corresponds to each of the ten canonical conformations, the second method does not assume previous knowledge of existing conformations and yields a clustering classification of a data set, allowing new conformations to be detected. Both methods have been tested using the conformational classification of Csp 3 eight-membered rings described in the literature. The methods have also been employed to classify the solid-state conformation in Csp 3 eight-membered rings using data retrieved from an updated version of the Cambridge Structural Database (CSD).


2001 ◽  
Vol 12 (3) ◽  
pp. 146-150 ◽  
Author(s):  
Rafal Kruszynski ◽  
Tadeusz J. Bartczak ◽  
Piotr Majewski

1979 ◽  
Vol 44 (20) ◽  
pp. 3496-3500 ◽  
Author(s):  
Louis D. Quin ◽  
John Leimert ◽  
Eric D. Middlemas ◽  
Richard W. Miller ◽  
Andrew T. McPhail

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