Subject: MMX and all that

From: (Chemical Physics Institute)
Date: Sun, 13 Apr 1997 17:27:25 -0300 (GMT)

Dear CCLers,
lovers of molecular simulation
and supramolecular chemistry!

Some days ago, I posted a question concerning the MMX force
field.

Here, I am presenting a summary of answers to my question.
The original question was as follows:

Dear Colleagues,
users of PCModel,
I am very interested in how the MMX field
treat metal cations. Any hints or references would be greatly appreciated.
Other experience in using this force field would also be rather precious.
All answers will be summarized.

With best wishes for successful calculations
Alexander Bagatur'yants

********************************************************************
* Prof. Alexander A. Bagatur'yants   Phone: (007)-(095)-9362588    *
* Center on Photochemistry           Fax:   (007)-(095)-9361255    *
* Russian Academy of Science                (007)-(095)-4335325    *
* ul. Novatorov 7a, Moscow           E-mail  [email-masked] *
* 117421 RUSSIA                              [email-masked]  *
********************************************************************

I received the following answers:

From: "Yurii Kruglyak" <[email-masked]>
Subject: CCL:MMX for systems with metal ions

Dear Alexander,

Dr. Victor Kuzmin, Dept of Molecular Electronics, Odessa State University
[email-masked]
and his group have developed DISMOL, MMX like soft specially designed for
molecular systems with metal ions.
Some initial references to this soft may be found in
Tim Clark, A handbook of computational chemistry, "Mir", Moscow, 1990, p. 376.
Sincerely,

--
 =======================================================================
 Professor Yuri Kruglyak

 Department of Molecular Electronics            [email-masked]
 Odessa State University                        [email-masked]
 Dvoryanskaya St. 2                             FaxLine: +380-482-637785
 ODESSA 270100 UKRAINE                          Voice  : +380-482-603314

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From: [email-masked]
Subject: CCL:MMX organometallic implementation

Prof. Bagatur'yants:

     The MMX algorithm for modeling organometallic compounds is described
briefly in the documentation to the PCMODEL program, if you have that
available, and also in a book chapter which the MMX developers have published:

Gajewski, J. J.; Gilbert, K. E.; McKelvey, J. in Advances in Molecular
Modeling, Vol. 2, (ed. Liotta, D.), JAI Press, Greenwich, CT (1990), pp 65-92.

     There is also a very good recent book on the general subject of
organometallic force field modeling:

Comba, P.; Hambley, T. W. Molecular Modeling of Inorganic Compounds. VCH, New
York (1995).

     Basically, except for a few main group metals such as silicon and aluminum
(which have their own parameter sets), MMX has a "generic" metal atom type
which can be modified for specific metallic elements by such parameters as
charge and covalent radius.
     Metal-organic interactions can be modeled as "covalent" bonds, in which
case a set of force field parameters (bond stretch, angle bend, torsions, etc.)
are used, or as "coordination" bonds, in which case MMX uses an
electrostatic-based potential which operates upon the metal center and the lone
electron pairs of the ligand donor atom(s).  There are provisions for invoking
the trans effect, and high spin/low spin in different coordination geometries.

     I hope that this has been of some help to you.  My interest in the area
comes from the fact that, hopefully, I will soon finish a manuscript for an
entry-level book for VCH on force field modeling which uses MMX examples.

                                 Regards...
------------------------------
Matthew F. Schlecht
DuPont Agricultural Products
Newark, DE  19714-0030    USA
[email-masked]
------------------------------

From: Alexandre Hocquet <[email-masked]>
Subject: Re: CCL:MMX

Priviet Sasha,
The actual description of the MMX forcefield is in a book which i never
could obtain :
Gajewski, Gilbert, McKelvey, Advances in Molecular Modelling, Liotta Ed, JAI
Press,
Greenwich, CT, 1990.
If, by chance, you encounter it, i am greatly interested in a copy.
However, some information about how this forcefield treats inorganics and
organometallics
can be found in :
Mackie, Baird, Organometallics, 1992, 11, 3712-3724
Hope this helps...
Alexandre Hocquet
Laboratorio de Cristalografia
Facultad de Ciencias Fisicas
Universidad de Chile
Blanco Encalada, 2008
Santiago Centro
Chile
fono : 56 2 678 45 19
fax : 56 2 696 73 59
email : [email-masked]

From: Lars Hemmingsen <[email-masked]>

Hi Alexander !

Concerning your question about MMX and metal ions.

The review by Benjamin P. Hay (in Coordination Chemistry Reviews, 1993, 126,
177-236) is a good place to start - among other things it contains a listing
of published molecular mechanical calculations on coordination compounds,
where also some MM2 calculations are referenced.

                        good luck, yours Lars Hemmingsen

I am very grateful to all who responded to my question!

Being a rather poor lover of these topics, I kindly ask all
who knows to point to a freeware with MMX implemented.

Best Luck to everybody!

Yours
Alexander A. Bagatur'yants
********************************************************************
* Prof. Alexander A. Bagatur'yants   Phone: (007)-(095)-9362588    *
* Center on Photochemistry           Fax:   (007)-(095)-9361255    *
* Russian Academy of Science                (007)-(095)-4335325    *
* ul. Novatorov 7a, Moscow           E-mail  [email-masked] *
* 117421 RUSSIA                              [email-masked]  *
********************************************************************