LUDI

J1992. LUDI - Rule-Based Automatic Design of New Substituents for Enzyme Inhibitor Leads. mal of Computer-Aided Molecular Design 6 593-606. 

Ruthenium aqua ions — their comparison to ruthenium ammines. P. Bernhard, H. Lehmann and A. Ludi, Comments Inorg. Chem., 1983, 2, 145-156 (22),... 

Structural chemistry of polynuclear transition metal cvanides. A. Ludi and H. U. Giidel, Struct. Bonding (Berlin), 1973,14, 1-21 (71). 

We have found that the observed X-ray intensities for trisilver cobalticyanide are incompatible with the structure suggested by Ludi et al., and correspond instead to a structure in which each cobalticyanide group is connected through covalently bonded silver atoms to cobalticyanide groups that are related to it by translation by the amount a + c, rather than by c. 

Derivation of the Structure.—The observed intensities reported by Ludi et al. for the silver salt have been converted to / -values by dividing by the multiplicity of the form or pair of forms and the Lorentz and polarization factors (Table 1). With these / -values we have calculated the section z = 0 of the Patterson function. Maxima are found at the positions y2 0, 0 1/2, and 1/21/2. These maxima represent the silver-silver vectors, and require that silver atoms lie at or near the positions l/2 0 2,0 y2 z, V2 V2 z. The section z = l/2 of the Patterson function also shows pronounced maxima at l/2 0,0 y2, and y2 x/2, with no maximum in the neighborhood of y6 ys. These maxima are to be attributed to the silver-cobalt vectors, and they require that the cobalt atom lie at the position 0 0 0, if z for the silver atoms is assigned the value /. Thus the Patterson section for z = /2 eliminates the structure proposed by Ludi et al. 

Ludi A, Gudel HU (1973) Structural Chemistry of Polynuclear Transition Metal Cyanides. 14 1-21... 

Bohm HJ. The computer program LUDI a new method for the de novo design of enzyme inhibitors. J Comput Aided Mol Design 1992 6 61-78. 

Acknowledgement. The author has taken advantage from discussions on MMCT states with many colleagues. Especially useful were those with Prof. Christian K. Jorgensen (Geneva), Prof Andreas Ludi (Bern), and Prof. Nanda Sabbatini (Bologna). 

Joss S, Hasselbach KM, Biirgi HB, Wordel R, Wagner FE, Ludi A (1989) Inorg Chem 28 1815... 

---