Trans effects in octahedral complexes: substitution of chloromethyl- and dichloromethylpentaaquochromium(III) ions by thiocyanate ion

Journal Article · Tue Nov 01 04:00:00 EST 1977 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic50177a020· OSTI ID:5309241

Bushey, W R; Espenson, J H

Equilibrium and kinetic data were evaluated for formation of the 1 : 1 complexes of NCS/sup -/ with (H/sub 2/O)/sub 5/CrCh/sub 2/Cl/sup 2 +/ and (H/sub 2/O)/sub 5/CrCHCl/sub 2//sup 2 +/. Equilibrium is established within less than 100 s, which is unusually rapid for Cr(III) substitution. This corresponds to replacement of only a single H/sub 2/O molecule for both NCS/sup -/ and Ch/sub 3/OH as entering groups, verified for NCS/sup -/ by species tests and equilibrium constant determinations and for CH/sub 3/OH by chemical analysis. The formation constants for NCS/sup -/ are 10.4 and 12.8 M/sup -1/ for CrCH/sub 2/Cl/sup 2 +/ and CrCHCl/sub 2//sup 2 +/, respectively. The kinetic data for anation follow the expression k/sub an/ = A(NCS/sup -/)/(1 + C(NCS/sup -/)) and are consistent with both a limiting S/sub N/1 and an ion-pairing mechanism.

• Research Organization: Ames Lab., IA
• OSTI ID: 5309241
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 16:11; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CARBONIC ACID DERIVATIVES
CHEMICAL REACTION KINETICS
CHLORINATED ALIPHATIC HYDROCARBONS
CHROMIUM COMPLEXES
COMPLEXES
EQUILIBRIUM
HALOGENATED ALIPHATIC HYDROCARBONS
KINETICS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANOMETALLIC COMPOUNDS
REACTION KINETICS
THIOCYANATES
TRANSITION ELEMENT COMPLEXES