Structure and dynamics of the η2-hexafluorobenzene complexes [Re(η5-C5H4R)(CO) 2(η2-C6F6)] (R = H or Me) and [Rh(η5-C5Me5)(PMe3)( η2-C6F6)]

From para‐Benziporphyrin to Rhodium(III) 21‐Carbaporphyrins: Imprinting Rh⋅⋅⋅η2‐CC, Rh⋅⋅⋅η2‐CO, and Rh⋅⋅⋅η2‐CH Coordination Motifs

“…[42] The RhÀC (21) and RhÀC (22) bond lengthsa re within the limits (2.050-2.787)o fd istances for Rh I Àh 2 -CC bonding interactions. [43,44] The Rh III Àh 2 -CC coordination prevents the libration of paraphenylene, andt he 1 HNMR spectrumo f1-Rh contains sharp para-phenylene signals (d 2 , 3 = 8.97, d 21 , 22 = 0.78 ppm;3 00 K) with no signs of conformational exchange (Figure 2a). The Rh III /para-phenylene interaction can be readily confirmed by the coordination shift;that is, the 13 CNMR chemical shift-difference (Dd = 28.1 ppm) determined betweent he C(21) resonances of 1-Rh and 1 or between C(2) and C(21) (Dd = 37.9 ppm) of 1-Rh.…”

Organometallic chemistry using partially fluorinated benzenes

“…In the context of C-H bond activation, Perutz, Clot, and co-workers have systematically studied η 2fluoroarene adducts of rhenium cyclopentadienyl complexes. In addition to experimental work, 56 the apotheosis of which included the isolation and comprehensive structural characterisation of [ReCp(CO) 2 (η 2 -HFB)], 57 trends in regioselectivity were studied computationally for a wide range of fluorobenzenes (C 6 H 6-n F n , n = 0 -5, selected binding energies shown in Chart 3). 58 A clear preference for metal coordination in the order HC=CH > HC=CF > FC=CF was established and attributed to greater πdensity at these positions, although there was no clear trend in binding strength amongst the arenes.…”

“…Calculated binding energies (kJ•mol -1 ) of the {ReCp(CO) 2 } fragment to various arenes.With the exception of π-acidic HFB, which typically distorts away from planarity on binding,57,60,61 welldefined examples of partially coordinated fluorobenzenes are rare 62,64 Bimetallic 6 and 7 that feature bridging arenes are notable examples (Chart 4).65 The solid-state structure of 6 indicates μ-η 4 :η 4coordination of the FB, which is distorted dramatically away from planarity.…”

Photochemical CCl bond activation of trichloroarenes by the rhenium complex (η5-C5Me5)Re(CO)3. X-ray structure of trans-(η5-C5Me5)Re(CO)2(2-methoxy-4,5-dichlorophenyl)chloride

“…With regard to photochemical reactions, we and others have demonstrated that cyclopentadienylrheniumtricarbonyl complexes (h 5 -C 5 R 5 )Re(CO) 3 (R 0/H and Me) serve as useful precursors to produce complexes of the type (h 5 -C 5 R 5 )Re(CO) 2 L, when they are UV-irradiated in the presence of THF [6], PR 3 [7], alkenes [8], etc. These complexes are also appropriate photochemical precursors for studying the coordination [9], CÃ/F and C Ã/H bond activation of fluorinated benzenes [10 Á/12] and C Ã/ Cl bond activation of chlorobenzenes [3,4]. As part of our continuing investigation on the C Ã/halogen bond activation by cyclopentadienyl rhenium carbonyl complexes, in this paper we wish to report the photochemical reaction of (h 5 -C 5 Me 5 )Re(CO) 3 in the presence of 2,4,5-trichloroanisole and 3,4,5-trichlorotrifluoromethyl benzene, with the aim to focus on the electronic or steric effects of the methoxy and trifluoromethyl groups on the C Ã/Cl bond activation of the trichlorobenzene ring.…”