کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10558336 | 968974 | 2005 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Vibrational frequencies of the homoleptic cobalt carbonyls: Co4(CO)12 and Co6(CO)16
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
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![عکس صفحه اول مقاله: Vibrational frequencies of the homoleptic cobalt carbonyls: Co4(CO)12 and Co6(CO)16 Vibrational frequencies of the homoleptic cobalt carbonyls: Co4(CO)12 and Co6(CO)16](/preview/png/10558336.png)
چکیده انگلیسی
The homoleptic cobalt carbonyls Co4(CO)12 and Co6(CO)16 are characterized by their equilibrium geometries, thermochemistry, and vibrational frequencies using density functional theory (DFT) methods with the B3LYP, BLYP, and BP86 functionals. The B3LYP predicted CoCo distances are 2.51 and 2.47Â Ã
for the C3v and Td structures, respectively, of Co4(CO)12. The global minimum for Co4(CO)12 has C3v symmetry with three bridging and nine terminal carbonyls. The 2.51 and 2.52Â Ã
CoCo distances suggest the single bond required for an 18-electron configuration for the metal atoms. This structure is close to an experimentally realized structure. A more symmetrical Co4(CO)12 structure with Td symmetry, analogous to that observed in the valence isoelectronic Ir4(CO)12 molecule, lies â¼28 kcal/mol higher in energy and exhibits a small imaginary vibrational frequency (â¼Â 40i). It has a slightly shorter CoCo distance of 2.47 Ã
. Both Co4(CO)12 structures satisfy the 18-electron rule. The Co6(CO)16 structure has Td symmetry and satisfies the Wade-Mingos rules for an octahedral cluster. The ν(CO) carbonyl frequencies for both Co4(CO)12 and Co6(CO)16 computed with the BP86 functional are closer to the experimental values than those computed with the B3LYP and BLYP functionals. The structure of Co6(CO)16 is not known experimentally, but the BP86 functional predicts 2.56 Ã
(CoCo), 1.77 and 2.02Â Ã
(CoC), and 1.66 and 1.20Â Ã
(CO) for the bond distances.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 61, Issue 7, May 2005, Pages 1693-1699
Journal: Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy - Volume 61, Issue 7, May 2005, Pages 1693-1699
نویسندگان
Yaoming Xie, R. Bruce King, Henry F. III,