In:
Chemistry – An Asian Journal, Wiley, Vol. 5, No. 5 ( 2010-05-03), p. 1192-1201
Abstract:
Theoretical studies on the binuclear (cycloheptatrienyl)molybdenum carbonyl complexes [(C 7 H 7 ) 2 Mo 2 (CO) n ] ( n =6, 5, 4, 3, 2, 1, 0) indicate structures with fully bonded heptahapto η 7 ‐C 7 H 7 rings and four or fewer carbonyl groups to be energetically competitive. This is in striking contrast to the corresponding chromium derivatives. The lowest energy of such a structure for [(η 7 ‐C 7 H 7 ) 2 Mo 2 (CO) 4 ] is a singlet unbridged structure with a formal MoMo single bond with a length of approximately 3.2 Å. A higher‐energy pentahapto structure [(η 5 ‐C 7 H 7 ) 2 Mo 2 (CO) 4 ] is also predicted with a formal Mo≡Mo triple bond with a length of approximately 2.56 Å. Low‐energy structures are predicted for [(C 7 H 7 ) 2 Mo 2 (CO) 3 ] with two heptahapto η 7 ‐C 7 H 7 rings, either one or two bridging carbonyl groups, and formal MoMo double bonds with a length of approximately 2.8 Å. However, the global minimum for [(C 7 H 7 ) 2 Mo 2 (CO) 3 ] is a [(η 7 ‐C 7 H 7 )(η 5 ‐C 7 H 7 )Mo 2 (CO) 3 ] structure with a formal Mo≡Mo triple bond with a length of approximately 2.53 Å. The lowest‐energy structures for [(C 7 H 7 ) 2 Mo 2 (CO) 2 ] and [(C 7 H 7 ) 2 Mo 2 (CO)] have heptahapto η 7 ‐C 7 H 7 rings and predicted metal–metal bond lengths of approximately 2.54 and 2.31 Å, respectively, consistent with the formal triple and quadruple bonds, respectively, needed to give both metal atoms the favored 18‐electron configuration. The lowest‐energy structures for the carbonyl‐richer systems [(C 7 H 7 ) 2 Mo 2 (CO) n ] ( n =6, 5) contain one trihapto η 3 ‐C 7 H 7 ring and one pentahapto η 5 ‐C 7 H 7 ring.
Type of Medium:
Online Resource
ISSN:
1861-4728
,
1861-471X
DOI:
10.1002/asia.200900363
Language:
English
Publisher:
Wiley
Publication Date:
2010
detail.hit.zdb_id:
2233006-9
