A novel photochemical, pH-controlled synthesis of organochromium complexes

Journal Article · Wed Mar 18 00:00:00 EST 1992 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00032a032· OSTI ID:7011801

Bakac, A; Janni, J A; Espenson, J H ^[1]

---

1. Ames Lab., IA (United States)

The irradiation of aqueous solutions of Cr{sup 2+} and RX (R = primary, secondary, and tertiary alkyl; X = Br, Cl) at 254 nm and pH 3 yields the organochromium cations (H{sub 2}O){sub 5}CrR{sup 2+}. The method is based on the photochemical generation of hydrated electrons and subsequent reduction of the alkyl halides to carbon-centered radicals. The colligation with Cr{sup 2+} then yields the desired organochromium complexes. In the presence of alcohols as cosolvents, the nature of the group R in (H{sub 2}O){sub 5}CrR{sup 2+} depends on the pH. At pH 3, R is derived from RX, and at pH 0, from the alcohol. The photochemical method was used to prepare, among others, the novel tert-butylchromium(III) ion (H{sub 2}O){sub 5}CrC(CH{sub 3}){sub 3}{sup 2+}. In the presence of scavengers for Cr{sup 2+} and/or {sm bullet}C(CH{sub 3}){sub 3} this complex decomposes rapidly by homolysis of the Cr-C bond, k{sub h} = 0.60 s{sup {minus}1} at 25C.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 7011801
• Journal Information: Inorganic Chemistry; (United States), Vol. 31:6; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CHROMIUM COMPLEXES
CHEMICAL PREPARATION
ALCOHOLS
AMBIENT TEMPERATURE
AQUEOUS SOLUTIONS
BROMINE COMPOUNDS
CHEMICAL REACTION KINETICS
CHLORINE COMPOUNDS
GAS CHROMATOGRAPHY
HYDROXYL RADICALS
LIGANDS
ORGANOMETALLIC COMPOUNDS
PH VALUE
PHOTOCHEMISTRY
PHOTOLYSIS
RADICALS
ULTRAVIOLET RADIATION
CHEMICAL REACTIONS
CHEMISTRY
CHROMATOGRAPHY
COMPLEXES
DECOMPOSITION
DISPERSIONS
ELECTROMAGNETIC RADIATION
HALOGEN COMPOUNDS
HYDROXY COMPOUNDS
KINETICS
MIXTURES
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
REACTION KINETICS
SEPARATION PROCESSES
SOLUTIONS
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
400500* - Photochemistry