Reaction of the transient species W(CO)5(cyclohexane) with cyclo-C4HnO (n = 4, 6, 8) studied by time-resolved infrared absorption spectroscopy

Alex Lugovskoy, Riki Paur-Afshari, Richard H. Schultz

نتاج البحث: نشر في مجلةمقالةمراجعة النظراء

22 اقتباسات (Scopus)

ملخص

Time- and temperature-resolved infrared absorption spectroscopy is used to monitor the ligand substitution reaction of W(CO)5(cyclohexane) with a series of ligands L of the form cyclo-C4HnO (n = 4, 6, 8). Second-order rate constants for the formation of W(CO)5(L) are obtained over the temperature range 20-60 °C, and from these temperature-dependent rate constants, activation parameters for the ligand substitution reaction are obtained. We find that for L = furan, ΔH‡ = 7.1 ± 0.7 kcal mol-1 and ΔS‡ = -7.1 ± 5.1 eu; for L = 2,3-dihydrofuran, ΔH‡ = 5.9 ± 0.5 kcal mol-1 and ΔS‡ = -8.9 ± 7.3 eu; and for L = 2,5-dihydrofuran, ΔH‡ = 3.8 ± 0.2 kcal mol-1 and ΔS‡ = -14.0 ± 3.5 e.u. We find that as L becomes less strongly electron-donating, as determined by the trans C-O stretching force constant of W(CO)5L, ΔH‡rises and ΔS‡ becomes less negative. The correlation of the activation enthalpy with the properties of the products and the low activation enthalpies relative to the (CO)5W-cyclohexane bond dissociation energy are consistent with an associative interchange (Ia) mechanism for the ligand exchange.

اللغة الأصليةالإنجليزيّة
الصفحات (من إلى)10587-10593
عدد الصفحات7
دوريةJournal of Physical Chemistry A
مستوى الصوت104
رقم الإصدار45
المعرِّفات الرقمية للأشياء
حالة النشرنُشِر - 16 نوفمبر 2000
منشور خارجيًانعم

بصمة

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