- Comparing the asymmetric dppf-type ligands with their semi-homologous counterparts
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Two series of asymmetric ferrocene diphosphines, namely the dppf-type ligands R2PfcPPh2 (protected as BH3 adducts; fc = ferrocene-1,1′-diyl) and their semi-homologous counterparts R2PfcCH2PPh2/s
- Vosáhlo, Petr,Císa?ová, Ivana,?těpni?ka, Petr
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- 1,1′-Bis[(alkyl/aryl)phosphino]ferrocenes: Synthesis and metal complex formation. Crystal structure of three metal complexes of Fe(η5-C5H4PPh2)2
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The ferrocenylphosphines Fe(η5-C5H4PR1R 2)(η5-C5H4PR3R 4) (R1?R4 = Ph or CMe3) are prepared by reacting ClPR1R2 with either Fe(η5-C5H4Li)2 or Fe(η5-C5H4Li)(η5-C 5H4PR3R4). The latter reagent is obtained by cleaving the ferrocenophane Fe(η5-C5H4PR3) (η5-C5H4) with R4Li. Best results are obtained when either or both R3 and R4 are Ph. A representative range of Pd(L-L)Cl2, [Rh(L-L)NBD]ClO4, and Ni(L-L)X2 complexes has been prepared. Crystal data for the known compounds (R1?R4 = Ph) (L-L)PdCl2·CH2Cl2, (L-L)NiBr2, and (L-L)Mo(CO)4·C6H6 are as follows: Pd, P21/c, a = 9.8615 A?, b = 18.2322 A? c = 19.1540 A?, β = 102.581°, Z = 4; Ni, Pn21a, a = 20.4163 A?, b = 14.7573 A?, c = 10.2015 A?, Z = 4; Mo, p1, a = 10.950 A?, b = 18.110 A?, c = 10.3433 A?, α = 101.777°, β = 93.322°, γ = 83.059°, Z = 2; Mo radiation; R = 0.029, 0.069, and 0.033 for 4324, 1870, and 6687 reflections, respectively. The Pd, Ni, and Mo atoms have cis square-planar, tetrahedral, and cis octahedral coordinations, respectively; mean Pd-P = 2.284 (6) A? Pd-Cl = 2.349 (9) A?, Ni-P = 2.290 (9) A?, Ni-Br = 2.348 (4) A?, Mo-P = 2.560 (16) A?, and Mo-C = 1.974 (5) (trans to P) and 2.038 (3) A? (cis to P). The ferrocene ligands have slightly nonparallel cyclopentadienyl rings, with approximately staggered arrangements in the Pd and Mo compounds but an approximately eclipsed conformation in the Ni complex and with significant displacements of the P atoms from the ring planes. Both the molybdenum compound and its chromium analogue are fluxional in solution to -80°C.
- Butler, Ian R.,Cullen, William R.,Kim, Tae-Jeong,Rettig, Steven J.,Trotter, James
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p. 972 - 980
(2008/10/08)
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