Noble‐Gas Complexes: Theoretical Investigation of Multicenter Polynuclear Species |
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Authors: | Stefano Borocci Nicoletta Bronzolino Felice Grandinetti |
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Institution: | Dipartimento di Scienze Ambientali, Università della Tuscia, L.go dell' Università, s.n.c., I‐01100 Viterbo |
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Abstract: | Ab initio calculations at the MP2 level of theory disclose the conceivable existence of neutral complexes containing four or five distinct noble gases (Ng) each bound to a distinct Be‐atom. These multicenter polynuclear Ng molecules are formally obtained by replacing the H‐atoms of CH4 and but‐2‐yne with ? NBeNg moieties, which behave as independent monovalent ‘functional groups’. Our investigated complexes include the five homotetranuclear C(NBeNg)4] complexes 1 – 5 (Ng=He? Xe), the five heterotetranuclear complexes CN4Be4(He)(Ne)(Ar)(Kr)] ( 6 ), CN4Be4(He)(Ne)(Ar)(Xe)] ( 7 ), CN4Be4(He)(Ne)(Kr)(Xe)] ( 8 ), CN4Be4(He)(Ar)(Kr)(Xe)] ( 9 ), and CN4Be4(Ne)(Ar)(Kr)(Xe)] ( 10 ), and the heteropentanuclear complex HC4N5Be5(He)(Ne)(Ar)(Kr)(Xe)] ( 11 ). We also investigated the five model complexes H3CNBeNg] (Ng=He? Xe) containing a single ? NBeNg moiety. The geometries and vibrational frequencies of all these species, invariably characterized as minimum‐energy structures, were computed at the MP2(full)/6‐31G(d,p)/SDD level of theory, and their stability with respect to the loss of the various Ng‐atoms was evaluated by single‐point calculations at the MP2(full)/6‐311G(d)/SDD level of theory. The beryllium‐Ng binding energies range from ca. 17 (Ng=He) to ca. 63 (Ng=Xe) kJ/mol, and the results of natural‐bond‐orbital (NBO) and atoms‐in‐molecules (AIM) analysis reveal that the Be? Ng interaction is essentially electrostatic for helium, neon, argon, and krypton, and has probably a small covalent contribution for xenon. |
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Keywords: | Ab initio calculations Noble‐gas complexes Beryllium complexes Bond energies Polynuclear species |
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