Synthesis and structure of Rh(I) tris(pyrazolyl)borate complexes of the type TpPh,MeRhL1L2

Tris(pyrazolyl)methanesulfonate (Tpms) − A Versatile Alternative to Tris(pyrazolyl)borate in Rhodium(I) Chemistry

“…1 H NMR studies on 5a show that two pyrazole groups become equivalent at 203 K, displaying a 2:1 intensity ratio, which is consistent with a C s ‐symmetric complex or a fast exchange of only two pyrazole groups. Similar effects have been observed for the corresponding Tp′ compounds Tp*Rh(CO)PPh 3 17 ( 5e ), Tp Ph,Me Rh(CO)PPh 3 8b ( 5f ), and Tp*Rh(CO)PMe 3 18 ( 5g ). The exchange mechanisms for 5f and 5g were suggested to proceed via trigonal‐bipyramidal intermediates.…”

“…The exchange mechanisms for 5f and 5g were suggested to proceed via trigonal‐bipyramidal intermediates. The Δ G ≠ values estimated from the coalescence temperatures were 76.5 kJ/mol for the bulky 5f 8b and 63 kJ/mol for the less bulky 5g 18. As 5a is even less sterically hindered, it is consistent that its Δ G ≠ value is considerably smaller (46±2 kJ/mol).…”

“…Table 1 shows a comparison between 2a and Tp′Rh(CO) 2 compounds. The complexes Tp*Rh(CO) 2 ,6 Tp Ph,Me Rh(CO) 2 8b ( 2d ), and TpRh(CO) 2 8c ( 2e ) show bands that are shifted towards lower energies compared to those of 2a . Thus, the Tp′ ligands are evidently better donors.…”

Structure, Electrochemistry and Hydroformylation Catalytic Activity of the Bis(pyrazolylborato)rhodium(I) Complexes [RhBp(CO)P] [P = P(NC4H4)3, PPh3, PCy3, P(C6H4OMe‐4)3]

“…Complex 2 was obtained earlier by reaction of [RhCl(CO) 2 ] 2 with KBp 15,16. We adapted the other method of synthesis of [RhBp(CO)P] complexes, reported recently for [RhTp Ph,Me (CO) 2 ] and [RhTp Ph,Me (CO)(PPh 3 )], based on the replacement of an acac − ligand by a bis(pyrazolylborate) 17. The reactions were performed with isolated [Rh(acac)(CO)P] complexes, at room temperature, and were complete in ca.…”

The substitution chemistry of the tris(3,5-dimethylpyrazolyl)methanerhodium complex [Rh(CO)2{HC(pz′)3}]+

“…4 (The analogue [Rh(CO) 2 L] {L = hydrotris(3-trifluoromethyl-5methylpyrazolyl)borate} does adopt 7 the κ 3 form in the solid state, though the sterically crowded compound [Rh(CO) 2 L] {L = hydrotris(3-phenyl-5-methylpyrazolyl)borate} has a κ 2 structure. 8 )…”