In:
Zeitschrift für Naturforschung B, Walter de Gruyter GmbH, Vol. 43, No. 11 ( 1988-11-1), p. 1427-1438
Abstract:
Diolefincobalt(O) complexes Co(L 2 )(PMe 3 ) 2 {L 2 -[CH 2 = CHSi(OMe) 2 ] 2 O (1), [CH 2 =CHSi(OEt) 2 ] 2 O (2), (CH 2 =CHCH 2 ) 2 SiMe 2 (3), [(CH 2 =CHCH 2 ) 2 N] 2 CH 2 (4)} have been synthesized from Co(C 5 H 8 )(PMe 3 ) 3 and diolefins at ambient temperatures. Reactions with allyl ethers or with allyltin or allylphosphorus compounds involve transfer of allyl groups to the cobalt, while allylamine simply replaces cyclopentene (C 5 H 8 ) to give Co(CH 2 =CHCH 2 NH 2 )(PMe 3 ) 3 (5). Cationic cobalt(I) complexes containing olefin ligands as in 1-4 could not be obtained under conditions where norbornadiene readily gave [Co(C 7 H 8 )(PMe 3 ) 3 ]BF 4 (6). Paramagnetic 4 shows a magnetic moment μ eff = 2.0 μв (between 3.6 and 293 K), corresponding to one unpaired electron per cobalt atom. Compound 4 crystallizes in the space group P2 1 /c with Z = 4, a = 14.986(4), b = 17.223(5), c = 15.436(3) Å,β = 117.98(2)°, V = 3518.4 Å 3 . Each cobalt atom is η 4 -coordinated to a diolefin involving the smaller of two possible chelating rings. The Co-C distances range only from 2.029(6) to 2.058(6) Å for the olefin ligands, whereas Co-P bond lengths at each cobalt differ significantly: Co1-P1 2.188(2), Co1-P2 2.248(2); Co2-P3 2.185(2), Co2-P4 2.258(2) Å. This feature of two significantly different Co-L bond lengths is hitherto seen in all structurally characterized (bisolefin)CoL 2 complexes (L = PMe 3 , CH 3 CN) and can be rationalized by molecular orbital calculations (Extended Hückel) on the 17 electron model system (PH 3 ) 2 Co(C 2 H 4 ) 2 .
Type of Medium:
Online Resource
ISSN:
1865-7117
,
0932-0776
DOI:
10.1515/znb-1988-1107
Language:
English
Publisher:
Walter de Gruyter GmbH
Publication Date:
1988
detail.hit.zdb_id:
2078109-X
detail.hit.zdb_id:
124635-5
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