Malcolm J. Atherton

Activation of C–F and C–H bonds by polyalkylcyclopentadienylrhodium complexes: crystal structure of [(η5-C5Me4Et)RhCl{(C6F5)2PCH2CH2P(C6F5)2}]+·BF4−

Abstract The reaction between [( η 5 -C 5 Me 4 Et)RhCl( μ -Cl)] 2 and the diphosphine, (C 6 F 5 ) 2 PCH 2 CH 2 P(C 6 F 5 ) 2 (dfppe), proceeded via the activation of two C–F and two C–H bonds and the formation of two C–C bonds to give a mixture of isomers of a salt with formulation `[( η 5 -C 5 Me 4 Et)RhCl{(C 6 F 5 ) 2 PCH 2 CH 2 P(C 6 F 5 ) 2 }-2HF] + ·Cl − ( 3a ). Treatment of [( η 5 -C 5 Me 4 Et)RhCl( μ -Cl)] 2 with NH 4 BF 4 followed by dfppe yielded [( η 5 -C 5 Me 4 Et)RhCl{(C 6 F 5 ) 2 PCH 2 CH 2 P(C 6 F 5 ) 2 }] + ·BF 4 − ( 4b ) which, on thermolysis in ethanol underwent C–F and C–H bond activation to yield the tetrafluoroborate salt of 3a ( 3b ). The structure of 4b was determined by a single crystal X-ray diffraction study. The salt 4b crystallizes in the triclinic space group P 1 with a =15.743 (4), b =16.429 (2), c =16.970 (3) A, α =79.41 (2), β =84.34 (2), γ =82.01 (2)° and Z =4. Refinement gave final R 1 and wR 2 [ I >2 σ ( I )] values of 0.0955 and 0.2200 respectively for 7254 observed reflections. When the reaction between [( η 5 -C 5 Me 4 Et)RhCl( μ -Cl)] 2 and dfppe was carried out in ethanol, a mixture of 3b , 4b and the singly C–F bond activated complex `[( η 5 -C 5 Me 4 Et)RhCl{(C 6 F 5 ) 2 PCH 2 CH 2 P(C 6 F 5 ) 2 }–HF] + ·BF 4 − ( 5b ) were obtained after addition of NH 4 BF 4 . The monophosphines P(C 6 F 5 ) 3 and PPh(C 6 F 5 ) 2 failed to react with [( η 5 -C 5 Me 5 )RhCl( μ -Cl)] 2 and the reaction between [( η 5 -C 5 Me 5 )RhCl( μ -Cl)] 2 and PPh 2 (C 6 F 5 ) did not lead to C–F bond activation but yielded ( η 5 -C 5 Me 5 )RhCl 2 {PPh 2 (C 6 F 5 )} ( 6 ).

Intermediates and anion effects in the activation of carbon–fluorine bonds by η5-pentamethylcyclopentadienylrhodium halide complexes; crystal structure of [{η5-C5Me3[CH2C6F4P(C6F5)CH2]2-1,3}RhBr]+·Br−

The reaction between [(η 5 -C 5 Me 5 )RhBr(μ-Br)] 2 and the diphosphine, (C 6 F 5 ) 2 PCH 2 CH 2 P(C 6 F 5 ) 2 (dfppe), in benzene proceeded via the intermediate cation [(η 5 -C 5 Me 5 )RhBr(dfppe)] + , which underwent Cue5f8F and Cue5f8H bond activation and Cue5f8C bond formation to give sequentially [{η 5 -C 5 Me 4 CH 2 C 6 F 4 P(C 6 F 5 )CH 2 CH 2 P(C 6 F 5 ) 2 }RhBr] + and then [{η 5 -C 5 Me 3 [CH 2 C 6 F 4 P(C 6 F 5 )CH 2 ] 2 -1,3}RhBr] + , as evidenced by mass spectrometry and NMR spectroscopy. The bromide salt of the final product ( 4c ) has been structurally characterized by X-ray diffraction. Compound 4c crystallizes in the triclinic space group P with a =10.616(1), b =13.904(2), c =14.911(1) A, α =66.86(1), β =86.38(1), γ =84.72(1)° and Z =2. Refinement gave final R 1 and wR 2 [ I =2 σ ( I )] values of 0.0581 and 0.1641, respectively, for 6837 unique reflections. In contrast to the BF 4 − salt, the Cl − and BPh 4 − salts of cation [(η 5 -C 5 Me 5 )RhCl(dfppe)] + undergo reaction upon thermolysis in benzene to give the cation [{η 5 -C 5 Me 3 [CH 2 C 6 F 4 P(C 6 F 5 )CH 2 ] 2 -1,3}RhCl] + .

Remarkable regioselectivity in the reaction between [(η5-C5Me4H)RhCl(μ-Cl)]2 and (C6F5)2PCH2CH2P(C6F5)2: synthesis of a chiral-at-metal rhodium complex cation via carbon–fluorine and –hydrogen bond activation and carbon–carbon bond formation

Abstract The reaction between [(η5-C5Me4H)RhCl(μ-Cl)]2 and (C6F5)2PCH2CH2P(C6F5)2 proceeds in refluxing benzene via activation of two C–F and C–H bonds and formation of two C–C bonds to yield the chiral cation [{η5-C5HMe2-2,4-[CH2C6F4P(C6F5)CH2]2-1,3}RhCl]+, with >90% selectivity.

Intermediates and action effects in the activation of carbon-fluorine bonds by eta(5)-pentamethylcyclopentadienylrhodium halide complexes; crystal structure of [{eta(5)-C5Me3[CH2C6F4P(C6F5)CH2](2)-1,3}RhBr](+)center dot Br-

The reaction between [(η 5 -C 5 Me 5 )RhBr(μ-Br)] 2 and the diphosphine, (C 6 F 5 ) 2 PCH 2 CH 2 P(C 6 F 5 ) 2 (dfppe), in benzene proceeded via the intermediate cation [(η 5 -C 5 Me 5 )RhBr(dfppe)] + , which underwent Cue5f8F and Cue5f8H bond activation and Cue5f8C bond formation to give sequentially [{η 5 -C 5 Me 4 CH 2 C 6 F 4 P(C 6 F 5 )CH 2 CH 2 P(C 6 F 5 ) 2 }RhBr] + and then [{η 5 -C 5 Me 3 [CH 2 C 6 F 4 P(C 6 F 5 )CH 2 ] 2 -1,3}RhBr] + , as evidenced by mass spectrometry and NMR spectroscopy. The bromide salt of the final product ( 4c ) has been structurally characterized by X-ray diffraction. Compound 4c crystallizes in the triclinic space group P with a =10.616(1), b =13.904(2), c =14.911(1) A, α =66.86(1), β =86.38(1), γ =84.72(1)° and Z =2. Refinement gave final R 1 and wR 2 [ I =2 σ ( I )] values of 0.0581 and 0.1641, respectively, for 6837 unique reflections. In contrast to the BF 4 − salt, the Cl − and BPh 4 − salts of cation [(η 5 -C 5 Me 5 )RhCl(dfppe)] + undergo reaction upon thermolysis in benzene to give the cation [{η 5 -C 5 Me 3 [CH 2 C 6 F 4 P(C 6 F 5 )CH 2 ] 2 -1,3}RhCl] + .

Tris(pentafluorophenyl)phosphine complexes of iridium: Molecular structure of trans-IrBr(CO){P(C6F5)3}2

Abstract The first tris(pentafluorophenyl)phosphine complexes of iridium, IrX(CO){P(C6F5)3}2 (X ue5fb Cl, Br), formed by the reaction between IrX3 and P(C6F5)3 in 2-methoxyethanol, are described and the crystal structure of trans-IrBr(CO){P(C6F5)3}2 is reported.

Synthesis and structure of η5-pentamethylcyclopentadienyldichloro-iridiumtris(2,6-difuluorophenyl)phosphite

Abstract The new fluorine containing ligand, tris(2,6-difluorophenyl)phosphite, prepared from the reaction between 2,6-difluorophenol and phosphorus trichloride, reacts with η5-pentamethylcyclopentadienyldichloroiridium dimer to give the title compound in high yield. The molecular structure of this compound has been determined by single crystal X-ray crystallography.

Tris(2,6-difluorophenyl)phosphite complexes of platinum group metals: Structure of trans-PtCl2(PEt3){P(O-2,6-C6H3F2)3}

Abstract The reactions between the fluorine-containing ligand tris(2,6-difluorophenyl)phosphite and the transition metals species [{η6-1,4-CH3C6H4CH(CH3)2}RuCl2]2, [Cp∗RhCl2]2, [RhCl(CO)2]2, [PtCl2(PEt3)]2 and PtCl2 yield the complexes }η6-1,4-CH3C6H4CH(CH3)2}RuCl2{P(O-2,6-C6H3F2)3}, Cp∗RhCl2{P(O-2,6-C6H3F2)3}, trans-RhCl((CO){P(O-2,6-C6H3F2)3}2, trans-PtCl2(PEt3){PO-2,6-C6H3F2)2} and trans-PtCl2{P(O-2,6-C6H3F2)3}2, respectively. The molecular structure of trans-PtCl2(PEt3){P(O-2,6-C6H3F2)3} has been determined by single-crystal X-ray crystallography.

Chapter 1 – Following fluorine in nuclear fuel manufacture at BNFL

Publisher Summary nThe requirements of uranium processing dictated that the (BNFL) needed access to the fluorine technology to establish the base for an indigenous nuclear fuel cycle. The decision to use the Springfields for uranium metal manufacture was made early in 1946 by Hinton, and the Springfields became the first production plant to be established in March 1946. Process research and development continued throughout the operating lifetime of the first uranium plant. To meet the unprecedented demand for metal fuel, the construction of a complex of new facilities began at Springfields in May 1955, known collectively as “The Second Uranium Plant;” they became operational in 1958. The expansion of world markets in the early 1970s prompted by the growth of civil nuclear power programs offered an opportunity for the BNFL to develop a business based on the toll conversion of uranium ore concentrate (UOC) to uranium hexafluoride. The existing dissolution, purification, and denitration technologies of the second uranium plant clearly could be upgraded and expanded to accommodate the new business; by contrast, increasing the scale of the fluidized-bed reactors used for reduction of UO3 and hydrofluorination of UO2 was economically unacceptable. Following a technological review, the rotary kiln technology was chosen as the basis for plant expansion. The first fluorine generator operated at the Springfields site was a medium temperature ICI 1 kA cell. The ICI 4.4 kA cell design formed the basis for the first cell room installation for the commercial-scale manufacture of UF6.

Cis-dichloro(triethylphosphine-P) [tris(2,6-difluorophenyl)phosphite-P]platinum(II)

In cis-[PtCl 2 (C 18 H 9 F 6 O 3 P)(C 6 H 15 P)], the Pt-P and Pt-Cl distances are comparable to those of the triphenylphosphite analogue, while the P-Pt-P angle is ca 5° larger.

Preliminary communicationSynthesis and crystal structure of dioxobis(μ-pentafluorophenylimido)di-(η-methylcyclopentadienyl)dimolybdenum

Abstract The reaction between C 6 F 5 NO 2 and [(η-MeC 5 H 4 )Mo(CO) 3 ] 2 yields the dioxobisimido complex, [(η-MeC 5 H 4 )MoO (η-NC 6 F 5 )] 2 ( 1 ). The X-ray crystal structure of compound 1 shows a cis arrangement of the methylcyclopentadienyl ligands and a puckered metallacyclic core.