Ligand-substitution and electron-transfer reactions of pentacoordinate copper (I) complexes

Journal Article · Wed Jan 11 04:00:00 EST 1989 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00300a011· OSTI ID:5852673

Goodwin, J A; Wilson, L J; Stanbury, D M; Scott, R A

The kinetics of the electron self-exchange for the Cu(I)/Cu(II) couple of the pentacoordinate complex of 2,6-bis(1-((2-imidazol-4-ylethyl)imino)ethyl)pyridine ((imidH)/sub 2/DAP) has been studied in CD/sub 3/CN by dynamic NMR line-broadening techniques. The rate constant, k/prime//sub 22/ is 1.31 /times/ 10/sup 4/ M/sup /minus/1/ s/sup /minus/1/ at 25/degree/C and an ionic strength of 22.3 mM (Me/sub 4/NBF/sub 4/). Correction for ion pairing gives k''/sub 22/ = 2.8 /times/ 10/sup 4/M/sup /minus/1/ s/sup /minus/1/ at /mu/ = 38 mM and 25/degree/C, which is a factor of 10 greater than that for the (Cu((py)/sub 2/DAP))/sup n+/ analogue. With the use of these two self-exchange rate constants, the Marcus cross relationship accurately predicts the measured cross-exchange rate constant. Transfer of the ligand from (Cu/sup I/((py)/sub 2/DAP))/sup +/ to (Zn/sup II/(CH/sub 3/CN)/sub 6/)/sup 2+/ at /mu/ = 20 mM was investigated at 25/degree/C in CH/sub 3/CN by using the stopped-flow technique. With excess Zn(II), saturation kinetics were observed; this behavior is attributed to rate-limiting dissociation of the copper complex with a rate constant of 310 s/sup /minus/1/. These results are considered in evaluating the possibility of an inner-sphere mechanism of electron transfer. 33 refs., 6 figs., 3 tabs..

• Research Organization: William Marsh Rice Univ., Houston, TX (USA)
• OSTI ID: 5852673
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 28:1; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKANES
COMPLEXES
COPPER COMPLEXES
CYANIDES
DATA
DEUTERIUM
ELECTRON TRANSFER
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN ISOTOPES
INFORMATION
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
STABLE ISOTOPES
TRANSITION ELEMENT COMPLEXES