From owner-chemistry;at;ccl.net Fri May 14 16:36:00 2010 From: "Mahmoud A. A. Ibrahim m.ibrahim]|[compchem.net" To: CCL Subject: CCL:G: Binding Enthalpy in vacuum and solvent Message-Id: <-41856-100514112346-3145-g1+awv9xGYHVSQVScouMSA(~)server.ccl.net> X-Original-From: "Mahmoud A. A. Ibrahim" Content-Type: multipart/alternative; boundary=0016e6db2ad42418d304868f7548 Date: Fri, 14 May 2010 16:23:30 +0100 MIME-Version: 1.0 Sent to CCL by: "Mahmoud A. A. Ibrahim" [m.ibrahim*compchem.net] --0016e6db2ad42418d304868f7548 Content-Type: text/plain; charset=windows-1256 Content-Transfer-Encoding: quoted-printable Dear CCG1 You can use SCFVAC (in G03) or DOVACUMM (in G09) options in SCRF to calculate delta G solvation energy directly in one calculation. This option performs one calculation in gas phase. Note: these options are defined by "read" card in SCRF. Sincerely; M. Ibrahim 2010/5/14 CompChem Group compchemgroup1 _ gmail.com > Dear *Professor Ahmed El-Nahas and all* > Thanks for reply. According to IUPAC, the defination of solvation energy = is > "The change in Gibbs energy when an ion or molecule is transferred from a > vacuum (or the gas phase) to a solvent. The main contributions to the > solvation energy come from: (a) the cavitation energy of formation of the > hole which preserves the dissolved species in the solvent; (b) the > orientation energy of partial orientation of the dipoles; (c) the isotrop= ic > interaction energy of electrostatic and dispersion origin; and (d) the > anisotropic energy of specific interactions, e.g. hydrogen bonds, > donor-acceptor interactions etc." > However, I calculated Ni2+ cation in water, please see this part of outpu= t: > > Variational PCM results > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > (a.u.) =3D -1507.146446 > (a.u.) =3D -1507.887943 > Total free energy in solution: > with all non electrostatic terms (a.u.) =3D -1507.882504 > -------------------------------------------------------------------- > (Polarized solute)-Solvent (kcal/mol) =3D -465.30 > -------------------------------------------------------------------- > Cavitation energy (kcal/mol) =3D 3.41 > Dispersion energy (kcal/mol) =3D 0.00 > Repulsion energy (kcal/mol) =3D 0.00 > Total non electrostatic (kcal/mol) =3D 3.41 > -------------------------------------------------------------------- > > Did you mean by solvation energy the highlight one? > Thanks, > CCG1 > > =C8=CA=C7=D1=ED=CE 13 =E3=C7=ED=E6, 2010 05:08 =D5=A1 =CC=C7=C1 =E3=E4 Ah= med El-Nahas amelnahas!=3D! > hotmail.com >: > >> >> People add solvent (in term of PCM) to the reactants and products; the >> solvation of bar metal ions releases a lot of kcal/mols at the expense >> of the total reaction enthalpy. If you look at the energy of solvation o= f >> the ligand, metal ion and complex, separately, you will realize this fac= t. I >> have a similar situation with a difference of about 150-300 kcal/mol bet= ween >> gas phase and solution, depending of your metal ion, ligand and the >> resulting complex. >> >> >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D >> *Professor Ahmed El-Nahas* >> *Physical Chemistry (Quantum Chemistry)* >> *Computational Chemistry Unit (CCU)* >> *Chemistry Department* >> *Faculty of Science* >> *El-Menoufia University* >> *Shebin El-Kom* >> *Egypt* >> *Email: amelnahas:_:hotmail.com* >> *Tel: +2-016-4607974; +81-09062124377* >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D >> >> >> >> >> > From: owner-chemistry:_:ccl.net >> > To: amelnahas:_:hotmail.com >> > Subject: CCL: Binding Enthalpy in vacuum and solvent >> > Date: Wed, 12 May 2010 09:29:15 -0400 >> > >> > >> > Sent to CCL by: "Comp Chem Group " [compchemgroup1 a gmail.com] >> > Dear All, >> > By surveying on "Interaction Enthalpy" of transition metal complex in >> vacuum and solvent (PCM or other model), I found in all cases that the >> enthalpy change in vacuum is larger than that solvent. For example, if d= elta >> H in vacuum=3D -1000 kcal/mol, in solvent=3D -200 kcal/mol. Could anyone= explain >> why? >> > Regards, >> > CCG1 >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> >! ; >> > >> > >> > >> > >> >> ------------------------------ >> Hotmail: Trusted email with powerful SPAM protection. Sign up now. >> > --=20 Mahmoud A. A. Ibrahim Current Address 7.05, School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom. Home Address Chemistry Department, Faculty of Science, Minia University, Minia 61519, Egypt. Contact Information Email: m.ibrahim ~~ compchem.net Website: www.compchem.net Fax No.: +20862342601 --0016e6db2ad42418d304868f7548 Content-Type: text/html; charset=windows-1256 Content-Transfer-Encoding: quoted-printable Dear=A0CCG1
You can use SCFVAC (in G03) or DOVACUMM (in G09) options in= SCRF =A0to calculate delta G solvation energy directly in one calculation.= This option performs one calculation in gas phase.
Note: these o= ptions are defined by "read" card in SCRF.
Sincerely;
M. Ibrahim


2010/5/14 CompChem Group compchemgroup1 _ gmail.com <owner-chemistry ~~ ccl.net>
Dear Professor Ahmed El-Nahas and all
Thanks for reply. According to= IUPAC, the defination of solvation energy is "The change=20 in Gibbs energy when an ion or molecule is transferred from a=20 vacuum=20 (or the gas phase) to a solvent. The main contributions to=20 the solvation=20 energy come from: (a) the cavitation energy of formation of=20 the=20 hole which preserves the dissolved species in the solvent; (b) the=20 orientation energy of partial orientation of the dipoles; (c)=20 the isotropic=20 interaction energy of electrostatic and dispersion origin;=20 and (d)=20 the anisotropic energy of specific interactions, e.g. hydrogen =20 bonds, donor-acceptor interactions etc."
However, I c= alculated Ni2+ cation in water, please see this part of output:

Vari= ational PCM results
=A0=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D
=A0<psi(f)|=A0=A0 H=A0=A0=A0 |psi(f)>=A0=A0= =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 (a.u.) =3D=A0=A0 -15= 07.146446
=A0<psi(f)|H+V(f)/2|psi(f)>=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0=A0=A0=A0=A0 (a.u.) =3D=A0=A0 -1507.887943
=A0Total free energy in= solution:
=A0 with all non electrostatic terms=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0=A0 (a.u.) =3D=A0=A0 -1507.882504
=A0-----------------------------= ---------------------------------------
=A0(Polarized solute)-Sol= vent=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 (kcal/mol) =3D=A0=A0=A0 -465= .30
=A0----------------------------------------------------------= ----------
=A0Cavitation energy=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 (kcal/mol) =3D=A0=A0=A0=A0=A0=A0 3.41
=A0Dispersion energy=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0= =A0=A0=A0=A0=A0 (kcal/mol) =3D=A0=A0=A0=A0=A0=A0 0.00
=A0Repulsion energ= y=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 (= kcal/mol) =3D=A0=A0=A0=A0=A0=A0 0.00
=A0Total non electrostatic=A0=A0=A0= =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 (kcal/mol) =3D=A0=A0=A0=A0=A0=A0= 3.41
------------------------------------------------------------------= --

Did you mean by solvation energy the highlight one?
Thanks,
CCG1=

=C8=CA=C7=D1=ED=CE 13 = =E3=C7=ED=E6, 2010 05:08 =D5=A1 =CC=C7=C1 =E3=E4 Ahmed El-Nahas amelnahas!= =3D!hotmail.com <owner-chemistry^_^ccl.net>:
=A0
= People add solvent (in term of PCM) to the reactants and products; the solv= ation of=A0bar metal ions=A0releases=A0a lot of kcal/mols at the expense of= =A0the=A0total reaction enthalpy. If you look at the energy of solvation of= the ligand, metal ion and complex, separately, you will realize this fact.= I have a similar situation with a difference of about 150-300 kcal/mol bet= ween gas phase and solution, depending of your metal ion, ligand and the re= sulting complex.
= =A0

=A0
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Professor Ahmed El-Nahas
Physical Chemistry (Quantum Chemistry)=
Computational Chemistry= Unit (CCU)
= Chemistry Department
Faculty of Science
El-Menoufia University<= /b>
Shebin El= -Kom
Egyp= t
Email: amelnahas:_:hotmail.com
= Tel: +2-016-4607974; +81-09062124377
=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D



=A0
> From: owner-chemistry:_:ccl.net
> To: amelnahas:_:hotmail.com
> Subject: CCL: Bi= nding Enthalpy in vacuum and solvent
> Date: Wed, 12 May 2010 09:29:15 -0400
>
>
> Sent t= o CCL by: "Comp Chem Group " [compchemgroup1 a gmail.com]
> Dear All,
> By su= rveying on "Interaction Enthalpy" of transition metal complex in = vacuum and solvent (PCM or other model), I found in all cases that the enth= alpy change in vacuum is larger than that solvent. For example, if delta H = in vacuum=3D -1000 kcal/mol, in solvent=3D -200 kcal/mol. Could anyone expl= ain why?
> Regards,
> CCG1
>
>
>
>
>
&g= t;
>
>
>
>
>
>
>
>
&g= t;
>
>
>
>
>
>
>
>
>
>
&gt! ;
>
>
>
>


Hotmail: Trust= ed email with powerful SPAM protection. Sign up now.



--
=A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0Mahmoud A. A. Ibrahim =A0 =A0 =A0 =A0
=A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0 =A0 =A0 Current Address
=A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 7.05, School of Chemistry,
=A0 =A0 =A0 =A0 =A0 =A0 =A0The Universi= ty of Manchester,
=A0 =A0 =A0 =A0 Oxford Road, Manchester, M13 9PL,
=A0 =A0 =A0 =A0 =A0= =A0 =A0 =A0 =A0 =A0 =A0 United Kingdom.

=A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0 =A0Home Address
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= Chemistry Department,
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Faculty o= f Science,
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Minia Univers= ity,
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Minia 61519,
=A0 = =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Egypt.

= =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Contact Information
=A0 =A0 =A0= =A0 =A0 Email: m.ibrahim ~~ compche= m.net
=A0 =A0 =A0 =A0 =A0 =A0 =A0Website: ww= w.compchem.net
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Fax No.: +208623= 42601
--0016e6db2ad42418d304868f7548--