Cooperative B–H bond activation: dual site borane activation by redox active κ²-N,S-chelated complexes

Abstract

Cooperative dual sites activation of boranes by redox-active 1,3-N,S-chelated ruthenium species, mer-[PR3{κ2-N,S-(L)}2Ru {κ1-S-(L)}], (mer-2a: R = Cy, mer-2b: R = Ph; L= NC7H4S2), generated from the aerial oxidation of borate...

Transition Metal Borate Complexes Containing κ0‐κ6 Denticity of Scorpionate Borate Ligands

“…Aerial oxidation of 36 a over time led to the formation of a redox-active Ru(III) species, mer-[PPh 3 {k 2 -N,S-(NC 7 H 4 S 2 )} 2 Ru {k 1 -S-(NC 7 H 4 S 2 )}], 38. [119] Complex 38 contains dual active sites and redox active hemilabile k 2 -1,3-N,S-bidentate chelate ligands. Therefore, the treatment of 38 with BH 3 .…”

“…, 28 [96] À 9.14 -[c] 5.16, 4.44 3.241 - [c] [{k 3 -C,C,O-HB(OCHMe 2 )}Nb( Mes Im) 2 (N t Bu)(CO) 2 ], 29 [96] 0.73 - [c] 4.35 3.072 - [c] [k 3 -H,H,N-BH 3 (NH)C 6 H 4 Mn(CO) 3 ], 33 [73] 13.4 À 9.81, À 9.64 4.41 2.182 1.227, 1.235 [k 3 -H,N,N-H 2 B(HN 2 CSC 6 H 4 ) 2 Mn(CO) 3 ], 34 [73] À 9.2 À 9.31 4.23 2.716 1.191 [k 3 -H,H,S-H 2 BMeCH 2 MeRuH(PCy 3 ) 2 ], 35 [118] 19.6 À 14.36, À 8.99 - [c] 2.267 1.148, 1.375 [Ru{k 3 -H,S,S-H 2 B(C 7 H 4 NS 2 ) 2 } 2 ], 37 [86] À 4.8 À 11.94 4.59 2.644, 2.631 - [c] [PPh 3 Ru{k 3 -H,S,S-(NH 2 BSBH 2 N)(S 2 C 7 H 4 ) 2 }], 39 [119] À 10.1 À 13.24 3.01 - [c] 1.302 trans-[Ru{(μ-H) 2 B(C 9 H 11 )(C 7 H 4 NS 2 )} 2 ], 40 [119] 39.4 (trans-40) À 11.42 (trans-40) - [c] 2.172 1.348, 1.333 [Cp*RuPPh 3 {k 3 -H,H,S-H 3 B(NC 7 H 4 S 2 )}], 42 [137] 8.4 À 8.40 5.9 2.216 1.170, 1.163 [{k 3 -S,H,H-(BH 2 C 9 H 11 )(NS 2 C 7 H 4 )}RuCp*], 43 [110] 19.6 À 8.06 - [c] 2.229 1.313, 1.279 trans-/cis-[Ru{(μ-H) 2 BH(C 5 H 4 NS)} 2 ], 45 [138] 34. 4 -N,N,N,C Ph -Tp Ph }Ir(Et)(η 2 -C 2 H 4 )], 46 [139] À 2.6 -[c] - [c] 3.229 - [c] [{k 5 -N,N,N,C Ph ,C Ph -Tp Ph }Ir{k 1 -N-(C 9 N 2 H 8 )], 48 [139] À 2.5 -[c] - [c] 3.238 - [c] [a] average distance; [b] average distance between boron and bridging hydrogen; [C] no data available ; [d] MÀ B interaction is absent.…”

“…Therefore, the treatment of 38 with BH 3 ⋅THF afforded ruthenium borate complex, [PPh 3 Ru{ κ 3 ‐ H , S , S ‐(NH 2 BSBH 2 N)(S 2 C 7 H 4 ) 2 }], 39 (Scheme 16). [119] The formation of this complex is believed to be from the insertion of two BH 2 moieties across the initial Ru−N bonds of κ 2 ‐ N , S ‐chelated heterocycles of 38 . The S atom in the butterfly core presumably generated from the C−S bond cleavage of pendant mercapto‐ benzothiazole ligand.…”

Synthesis and Chemistry of Dihydridoborate Group 7 Metal Complexes with Varied N,E-Chelated Ligands (E = O, NH, or S)

“…Over many decades, the coordination chemistry of borohydride and substituted borohydride units with transition metals (TMs) has been studied with great interest. , In this, the substituted borohydride units connected to various donor functional groups have been a special focus of investigation. , This produced the scorpionate ligands, which are compounds in which the nitrogen atoms of two or more pyrazolyl rings are bound to a boron atom. ,, They have been extensively studied, and their uses, particularly in homogeneous catalysis, bioinorganic chemistry, , and CH activation, are widely recognized. For instance, tri­(dimethyl-pyrazolyl)­borate–rhodium complex photochemically activates benzene and cyclohexane .…”

“…Typically in all of these complexes, borohydride acts as a spectator unit forming robust complexes. On the contrary, in the complexes having a direct metal–borohydride link, the BH 2 or BH moiety is capable of interacting with a metal via an M–H–B interaction (σ-borate or B-agostic complexes). ,, These complexes have attracted a lot of attention owing to their significance in metal catalyzed B–H activation . Correspondingly, various borane and hydridoborate complexes, including those of Weller, Sabo-Etienne, Owen, Love, Braunschweig, and others, have been isolated and structurally described.…”