Le 2018-09-19 11:59, Frank von Delft a écrit :
> I believe medicinal chemists do indeed talk about "enthalpic interactions". > Frank Not a good choice either (à mon avis ...) THE REAL REASON WHY OIL AND WATER DON'T MIX Todd P. Silverstein Journal of Chemical Education 1998 _75_ (1), 116 DOI: 10.1021/ed075p116 https://pubs.acs.org/doi/abs/10.1021/ed075p116 [6] Stefano > On 19/09/2018 10:40, Stefano Trapani wrote: > > Le 2018-09-18 19:31, Daniel M. Himmel, Ph. D. a écrit : > > (where hydrophobic interactions result from van der Waals forces in an > aqueous environment). > > Hi > > I am not sure that, if one is to give a concise definition of hydrophobic > "interactions", this would be a convenient one, because it may lead someone > to identify vdW forces as the main factor that maintains apolar aggregated > molecules together in aqueous environment. I have seen many students (and > PhD's) believing to the equality: hydrophobic 'forces'=vdW forces (and not > understanding, for example, that the side chains of a Ser and an Ile can also > establish vdW interactions). > > It is true that apolar groups that aggregate establish van der Waals > interactions (like any molecule in contact with another one) but these > microscopic (real) forces are not (as far as I know) the main reason of > aggregation in aqueous environment. > > The hydrophobic effect seem to be of a mainly entropic nature (and it has > much more to do with hydrogen bonds than van der Waals forces): > > https://en.wikipedia.org/wiki/Hydrophobic_effect#Cause [2] > > https://en.wikipedia.org/wiki/Entropic_force#Hydrophobic_force [3] > > Being mainly of an entropic nature, hydrophobic "contacts" are not the direct > result of real microscopic "forces" that act between apolar groups. The terms > "forces" and "interactions" in widely used expressions like "hydrophobic > forces" and "hydrophobic interactions" are somehow misleading. > > Best > > --- > Stefano Trapani > > Maître de Conférences > http://www.cbs.cnrs.fr/index.php/fr/personnel?PERS=Stefano%20Trapani [1] > ------------------------------------- > Centre de Biochimie Structurale (CBS) > 29 rue de Navacelles > 34090 MONTPELLIER Cedex, France > > Tel : +33 (0)4 67 41 77 29 > Fax : +33 (0)4 67 41 79 13 > ------------------------------------- > Université de Montpellier > CNRS UMR 5048 > INSERM UMR 1054 > ------------------------------------- > > -- > This message has been scanned for viruses and > dangerous content by MAILSCANNER [4], and is > believed to be clean. > > ------------------------- > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 [5] -- This message has been scanned for viruses and dangerous content by MAILSCANNER [4], and is believed to be clean. Links: ------ [1] http://www.cbs.cnrs.fr/index.php/fr/personnel?PERS=Stefano%20Trapani [2] https://en.wikipedia.org/wiki/Hydrophobic_effect#Cause [3] https://en.wikipedia.org/wiki/Entropic_force#Hydrophobic_force [4] http://www.mailscanner.info/ [5] https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 [6] https://pubs.acs.org/doi/abs/10.1021/ed075p116 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
