Ligand field molecular mechanics LFMM

Although the properties which can be computed are limited, LFT has provided for over half a century a reasonably useful, semi-quantitative picture of metal-ligand bonding in Werner-type coordination complexes (3,25-27). In the present context, the advantage of LFT is its computational efficiency. Therefore, we added LFT to MM to give the ligand field molecular mechanics (LFMM) method (28). 

The angular overlap approach has also been used as a component in a more mathematically sophisticated approach to metal-ligand interactions, the ligand field molecular mechanics (LFMM) method, which has applications to a variety of concepts discussed in this chapter. ... 

Ligand Field Molecular Mechanics (LFMM). Thus, LFMM is based on a combination of a conventional force field with terms explicitly capturing electronic effects, which takes the following functional form ... 

The second solution is used in the MOMEC program and the ligand field molecular mechanics (LFMM) method as implemented in DOMMINO. In both cases, instead of using an L-M-L angle bend term, explicit ligand-ligand 1,3-nonbonded interactions are permitted which, in the spirit of VSEPR theory or points on a sphere (POS), facilitate the treatment of any coordination number. 

Computer programs for empirical force-field calculations that use other concepts have been tested, and some of these will be discussed elsewhere in this book. Among these approaches are one based on a pure central force-field model, used for simple organic compounds [208], an equipotential surface force-field model, used for carbonyl cluster complexes [99,103], and a program that includes ligand field terms, developed for transition metal complexes in the LFMM model (ligand field molecular mechanics) [21, 105, 108]. 

Abstract This chapter discusses molecular mechanics (MM)-based approaches to investigate organometallic complexes. In particular, ligand field MM (LFMM), Sum of Interactions Between Fragments Ab Initio (SIBFA), and VALBOND with its extension to VALBOND-TRANS are presented in some detail. Two particular applications of VALBOND-TRANS to an Ir(III) and a Pt(II) complex are presented. Possible future extensions, including the study of chemical reactions and polarization effects, are briefly discussed at the end. 

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