Random incremental pulse search

Ferguson D M and D J Raber 1989. A New Approach to Probing Conformational Space with Molecular Mechanics Random Incremental Pulse Search, journal of the American Chemical Society 111 4371-4378. 

Ferguson, D. M. and Raber, D. J. (1989) A new approach to probing conformational space with molecular mechanics random incremental pulse search. J. Am. 

Ferguson and Raber s RIPS (Random Incremental Pulse Search) program also performs its stochastic search in Cartesian coordinate space. Two modes of operation are possible, the first to locate just the global minimum energy conformation and the second to perform a complete search of the conformational space. In the hunt for the global energy minimum, the lowest energy structure found to... 

D. M. Ferguson and D. j. Raber, /. Comput. Chem., 11(9), 1061 (1990). Molecular Mechanics Calculations of Several Lanthanide Complexes An Application of the Random Incremental Pulse Search. 

Non-bonded interactions [632-634] were included in the same way as was used first for the modeling of cobalt(III) complexes [130] and more recently for a wide range of transition metal compoimds [95, 104, 125]. That is, standard models with M-L harmonic bond-stretching terms were used, but the L-M-L harmonic terms were deleted and L... L non-bonded interactions were used in their place. In the first of these studies, on lanthanoid shift reagents, two seven-coordinate europium(III) and ytterbium(III) complexes, [Eu(dipivaloylmethanato)3(quinuchdine)] and [Yb (acetylacetonato)3(H20)] (Figure 15.5), were modeled [632]. The structures of these complexes were well reproduced. In a subsequent study, these complexes and [Eu (dipivaloylmethanato)3(DMSO)] were studied with the same force field, while the random incremental pulse search method was used to locate all potential coordination geometries [633]. 

PLG is believed to exist in a type II p-turn in its bioactive conformation. The random incremental pulse search (RIPS)-MM2 > conformational scanning algorithm was used to predict the manner in which the 5,5- and 5,6-bicyclic thiazolidine lactam ring systems would restrict the tli2 and < )3 torsional angles, two of the angles that define a p-turn. These studies revealed that low energy conformations of both model compounds present torsional values close... 

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