ISSN:
0018-019X
Schlagwort(e):
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The complexation of 1-methyl-2-hydroxymethyl-imidazole (L) with Cu(I) and Cu(II) has been studied in aqueous acetonitrile (AN). Cu(I) forms three complexes, Cu(AN)L+, CuL2+, and Cu(AN)H-1L, with stability constants logK(Cu(AN)+ + L ⇌ Cu(AN)L+) = 4.60 ± 0.02, logβ2 = 11.31 ± 0.04, and logK(Cu(AN)H-1L+H+ ⇌ Cu(AN)L+) = 10.43 ± 0.08 in 0.15M AN. The main species for Cu(II) are CuL2+, CuH-1L+, CuH-1L2+, and CuH-2L2.The autoxidation of CuL2+ was followed with an oxygen sensor and spectrophotometrically. Competition between the formation of superoxide in a one-electron reduction of O2 and a path leading to H2O2 via binuclear (CuL2)2O22+ was inferred from the rate law \documentclass{article}\pagestyle{empty}\begin{document}$${{ - {\rm d}\left[{{\rm O}_2 } \right]} \mathord{\left/ {\vphantom {{ - {\rm d}\left[{{\rm O}_2 } \right]} {{\rm dt}}}} \right. \kern-\nulldelimiterspace} {{\rm dt}}} = \left[{{\rm CuL}_2^ + } \right]^2 \left[{{\rm O}_2 } \right]\left({\frac{{k_{\rm a} }}{{1 + k_{\rm b} \left[{{\rm CuL}^ + } \right]}} + \frac{{k_{\rm c} \left[{\rm L} \right] + k_{\rm d} + {{\left({{{k_{\rm f} } \mathord{\left/ {\vphantom {{k_{\rm f} } {\left[{\rm L} \right]}}} \right. \kern-\nulldelimiterspace} {\left[{\rm L} \right]}} + k_{\rm g} + k_{\rm h} \left[{\rm L} \right]} \right)} \mathord{\left/ {\vphantom {{\left({{{k_{\rm f} } \mathord{\left/ {\vphantom {{k_{\rm f} } {\left[{\rm L} \right]}}} \right. \kern-\nulldelimiterspace} {\left[{\rm L} \right]}} + k_{\rm g} + k_{\rm h} \left[{\rm L} \right]} \right)} {\left[{{\rm H}^ + } \right]}}} \right. \kern-\nulldelimiterspace} {\left[{{\rm H}^ + } \right]}}}}{{\left[{{\rm CuL}_2 ^ + } \right] + k_{\rm e} \left[{{\rm Cu}\left({{\rm II}} \right)} \right]_{{\rm tot}} }}} \right)$$\end{document} with ka = (2.31 ± 0.12) · 104M-2S-1, kb = (1.0 ± 0.2) · 103M-1, kc = (2.85 ± 0.07) · 102M-2S-1, kd = 3.89 ± 0.14M-1S-1, ke = 0.112 ± 0.004, kf = (2.06 ± 0.24) · 10-10M S-1, kg = (1.35 ± 0.07) · 10-7 S-1, and kh = (6.8 ± 1.4) · 10-7M-1 S-1.
Zusätzliches Material:
6 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/hlca.19760590506
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