Cis effect

In inorganic chemistry, the cis effect is defined as the labilization (or destabilization) of CO ligands that are cis to other ligands. CO is a well-known strong pi-accepting ligand in organometallic chemistry that will labilize in the cis position when adjacent to ligands due to steric and electronic effects. The system most often studied for the cis effect is an octahedral complex M(CO)
5X where X is the ligand that will labilize a CO ligand cis to it. Unlike the trans effect, which is most often observed in 4-coordinate square planar complexes, the cis effect is observed in 6-coordinate octahedral transition metal complexes. It has been determined that ligands that are weak sigma donors and non-pi acceptors seem to have the strongest cis-labilizing effects. Therefore, the cis effect has the opposite trend of the trans-effect, which effectively labilizes ligands that are trans to strong pi accepting and sigma donating ligands.[1][2][3]

  1. ^ Miessler, Gary O. Spessard, Gary L. (2010). Organometallic chemistry (2nd ed.). New York: Oxford University Press. ISBN 978-0195330991.{{cite book}}: CS1 maint: multiple names: authors list (link)
  2. ^ Atwood, Jim D. (1997). Inorganic and organometallic reaction mechanisms (2. ed.). New York [u.a.]: Wiley-VCH. ISBN 978-0471188971.
  3. ^ Atkins, Peter (2010). Shriver & Atkins' inorganic chemistry (5th ed.). New York: W. H. Freeman and Co. ISBN 978-1429218207.