TY - JOUR
T1 - Pentadienyl-Metal-Phosphine Chemistry. 15.1 Synthesis, Structure, and Reactivity of (η5-Pentadienyl)(η3-pentadlenyl)Fe(PR3) Complexes
AU - Bleeke, John R.
AU - Hays, Mary K.
AU - Wittenbrink, Robert J.
PY - 1988/6
Y1 - 1988/6
N2 - Reaction of FeCl2(PMe3)2 with 2 equiv of potassium pentadienide (K+pd~) produces (η3-pd)2Fe(PMe3)2(1). Upon refluxing in diethyl ether, 1 slowly loses PMe3 and is converted to (η5-pd)(η3-pd)Fe(PMe3) (2). The PEt3 and P-n-Pr3 analogues of 2, (η5-pd)(η3-pd)Fe(PEt3) (3) and (η5-pd)(η3-pd)Fe(P-n-Pr3) (4), are obtained directly upon reaction of the appropriate FeCl2(PR3)2 reagent with 2 equiv of K+pd-. 3 crystallizes in the triclinic space group PI with a = 9.762 (6) Å, b = 10.136 (5) Å, c = 9.271 (5) Å, α = 97.95 (2)°, β = 111.56 (4)°, γ= 92.26 (4)°, V = 840.8 (7) A3, and Z = 2. The η5-pentadienyl ligand in 2 is U-shaped, while the η3-pd ligand is bonded in a W-shaped syn geometry. The η-pentadienyl ligand assumes an exo rotational orientation with respect to the η5-pd ligand. Compounds 3 and 4 react with excess PMe3 in refluxing diethyl ether to produce 1. When 3 and 4 are refluxed in diethyl ether in the absence of PMe3, the pentadienyl ligands couple stereoselectively to produce (η8-trans, trans-1,3,7,9-decatetraene)Fe(PEt3) (5) and (η8-trans,trans-l,3,7,9-decatetraene)Fe(P-n-Pr3) (6), respectively. 5 crystallizes in the monoclinic space group P21/n with a = 7.434 (4) Å, b = 27.536 (3) Å, c = 7.662 (1) Å, β = 93.112 (3)°, V = 1566 (1) Å3, and Z = 4. The two butadiene moieties of the decatetraene ligand are bonded to the Fe center in a cisoid fashion and are eclipsed. Compound 3 is converted to (η5-pd)Fe(PMe3)3+X-(7a, X-= BF4-; 7b, X- = PF6-) and (η5-pd)Fe[(Me2PCH2)3CMe]+X~(8a, X = BF4~; 8b, X-= PF6-) upon treatment with HX-OEt2 or Ag+X-, followed by addition of the appropriate phosphine reagent. 7a crystallizes in the monoclinic space group P21/c with a = 9.697 (2) Å, b = 12.923 (4) Å, c = 16.834 (4) Å, β = 90.48 (2)°, V = 2109.6 (9) Å3, and Z = 4. The coordination geometry of 7a is pseudooctahedral; one phosphorus atom resides under the open “mouth” and the other two reside in sites under the “edges” of the pd ligand. 7 and 8 undergo dynamic processes in solution, involving rotation of the pd ligand with respect to the FeP3 framework. Treatment of 3 with HX-OEt2 or Ag+X, followed by addition of P(OMe)3, produces (η6-pd)Fe[P-(OMe)3]2(PEt3)+X-(9a, X-= BF4-; 9b, X~= PF6-). In solution, 9 exists as an equilibrium mixture of two isomers—a symmetrical isomer in which the PEt3 ligand resides under the “mouth” of the pd ligand and an unsymmetrical isomer in which PEt3 resides under a pd “edge”. These isomers interconvert via pentadienyl ligand rotation.
AB - Reaction of FeCl2(PMe3)2 with 2 equiv of potassium pentadienide (K+pd~) produces (η3-pd)2Fe(PMe3)2(1). Upon refluxing in diethyl ether, 1 slowly loses PMe3 and is converted to (η5-pd)(η3-pd)Fe(PMe3) (2). The PEt3 and P-n-Pr3 analogues of 2, (η5-pd)(η3-pd)Fe(PEt3) (3) and (η5-pd)(η3-pd)Fe(P-n-Pr3) (4), are obtained directly upon reaction of the appropriate FeCl2(PR3)2 reagent with 2 equiv of K+pd-. 3 crystallizes in the triclinic space group PI with a = 9.762 (6) Å, b = 10.136 (5) Å, c = 9.271 (5) Å, α = 97.95 (2)°, β = 111.56 (4)°, γ= 92.26 (4)°, V = 840.8 (7) A3, and Z = 2. The η5-pentadienyl ligand in 2 is U-shaped, while the η3-pd ligand is bonded in a W-shaped syn geometry. The η-pentadienyl ligand assumes an exo rotational orientation with respect to the η5-pd ligand. Compounds 3 and 4 react with excess PMe3 in refluxing diethyl ether to produce 1. When 3 and 4 are refluxed in diethyl ether in the absence of PMe3, the pentadienyl ligands couple stereoselectively to produce (η8-trans, trans-1,3,7,9-decatetraene)Fe(PEt3) (5) and (η8-trans,trans-l,3,7,9-decatetraene)Fe(P-n-Pr3) (6), respectively. 5 crystallizes in the monoclinic space group P21/n with a = 7.434 (4) Å, b = 27.536 (3) Å, c = 7.662 (1) Å, β = 93.112 (3)°, V = 1566 (1) Å3, and Z = 4. The two butadiene moieties of the decatetraene ligand are bonded to the Fe center in a cisoid fashion and are eclipsed. Compound 3 is converted to (η5-pd)Fe(PMe3)3+X-(7a, X-= BF4-; 7b, X- = PF6-) and (η5-pd)Fe[(Me2PCH2)3CMe]+X~(8a, X = BF4~; 8b, X-= PF6-) upon treatment with HX-OEt2 or Ag+X-, followed by addition of the appropriate phosphine reagent. 7a crystallizes in the monoclinic space group P21/c with a = 9.697 (2) Å, b = 12.923 (4) Å, c = 16.834 (4) Å, β = 90.48 (2)°, V = 2109.6 (9) Å3, and Z = 4. The coordination geometry of 7a is pseudooctahedral; one phosphorus atom resides under the open “mouth” and the other two reside in sites under the “edges” of the pd ligand. 7 and 8 undergo dynamic processes in solution, involving rotation of the pd ligand with respect to the FeP3 framework. Treatment of 3 with HX-OEt2 or Ag+X, followed by addition of P(OMe)3, produces (η6-pd)Fe[P-(OMe)3]2(PEt3)+X-(9a, X-= BF4-; 9b, X~= PF6-). In solution, 9 exists as an equilibrium mixture of two isomers—a symmetrical isomer in which the PEt3 ligand resides under the “mouth” of the pd ligand and an unsymmetrical isomer in which PEt3 resides under a pd “edge”. These isomers interconvert via pentadienyl ligand rotation.
UR - https://www.scopus.com/pages/publications/0000724159
U2 - 10.1021/om00096a030
DO - 10.1021/om00096a030
M3 - Article
AN - SCOPUS:0000724159
SN - 0276-7333
VL - 7
SP - 1417
EP - 1425
JO - Organometallics
JF - Organometallics
IS - 6
ER -