Modeling lanthanide complexes: sparkle/AM1 parameters for ytterbium (III).

The Sparkle/AM1 model is extended to ytterbium (III) complexes. Thus, a set of 15 complexes, with various representative ligands, chosen to be representative of all complexes of high crystallographic quality (R-factor <0.05 A) in the Cambridge Crystallographic Database, and which possess oxygen and/or nitrogen as coordinating atoms, was used as the training set. In the validation procedure we added 32 more high quality crystallographic structures. For the 47 complexes, the Sparkle/AM1 unsigned mean error for all interatomic distances between the Yb(III) ion and the ligand atoms of the first sphere of coordination is 0.07 A, similar to present-day ab initio/ECP geometry prediction accuracies, and potentially useful for luminescent complex design while being hundreds of times faster.