Syntheses and crystal structures for the first two examples of the four-membered PNSiS heterocycle

Capturing HBCy2: Using N,O‐Chelated Complexes of Rhodium(I) and Iridium(I) for Chemoselective Hydroboration

“…Treatment of a solution of 3 or 4 in C 6 D 6 with HBCy 2 (1 equiv) resulted in the clean formation of the four‐coordinate complexes [M{κ 2 ‐ N , H ‐Xyl(N)P(OHBCy 2 )(OEt) 2 }(η 4 ‐cod)] (M=Rh ( 7 ) or Ir ( 8 )), which feature six‐membered chelating LX amidoborane moieties formed from hemilabile ring‐opening of a [M]−O bond (Scheme ). Complexes 7 and 8 are rare examples of six‐membered genuine metallaheterocycles, consisting of six unique atoms (M, H, B, O, P, and N, where M=Rh or Ir) oriented in a near‐coplanar fashion. Evidence for a significant [M]⋅⋅⋅H−B bonding interaction comes from a combination of solution‐ and solid‐state techniques.…”

“…Having established as imple protocol for access to such LX-chelated [10] metal complexes,w en ext focused our attention on the capture of dicyclohexylborane (HBCy 2 )b y complexes 3-6.T reatment of as olution of 3 or 4 in C 6 D 6 with HBCy 2 (1 equiv) resulted in the clean formation of the four-coordinate complexes [M{k 2 -N,H-Xyl(N)P(OHBCy 2 )-(OEt) 2 }(h 4 -cod)] (M = Rh (7)o rI r( 8)), which feature sixmembered chelating LX amidoborane moieties formed from hemilabile ring-opening of a[ M]ÀOb ond (Scheme 2). Complexes 7 and 8 are rare examples of six-membered genuine metallaheterocycles, [12] consisting of six unique atoms (M, H, B, O, P, and N, where M = Rh or Ir) oriented in an earcoplanar fashion. Evidence for asignificant [M]···H À Bbonding interaction comes from ac ombination of solution-and solid-state techniques.Inthe solution state,complexes 7 and 8 show characteristic 1 HNMR resonances,i na ccordance with their proposed structure.Strikingly,broad upfield resonances, which sharpen on 11 Bd ecoupling,a td = À8.70 ppm (dd, 1 J Rh,H = 23.8 Hz, 3 J P, H = 9.5 Hz) for 7 and d = À4.89 ppm (d, 3 J P, H = 7.7 Hz) for 8,corroborate interaction of the metal with the B À He ntity.…”

Toward anti-Markovnikov 1-Alkyne O-Phosphoramidation: Exploiting Metal–Ligand Cooperativity in a 1,3-N,O-Chelated Cp*Ir(III) Complex

“…X-ray quality crystals of [ 3 ]­[BAr F 4 ] and [ 5 ]­[BAr F 4 ] could be reliably obtained from a saturated hexanes solution at −35 °C ([ 3 ]­[BAr F 4 ]; Figure ) and confirm (1) ( E )-vinyl stereochemistry and, more importantly, (2) regioselective O -phosphoramidation. As inferred from NMR spectroscopic data, the structures feature a genuine five-membered irida­(III)­cycle comprised of a near planar Ir–N–P–O–C core. Given that crystals of [ 2 ]­[BAr F 4 ] were unattainable, the structure of [ 3 ]­[BAr F 4 ] will be discussed as a representative example; the Ir(1)–N(1) contact [2.050(8) Å] is similar to that observed in [ 1 ]­[BAr F 4 ] [1.989(3) Å], while Ir(1)–C(1) and C(1)–C(2) bond lengths of 1.999(2) and 1.378(2) Å are in good agreement [1.9886(18) and 1.334(3) Å] to those reported for a related Ir­(III) phenylvinyl complex, formed through 1-alkyne dimerization .…”

Reactivity of an Unsaturated Iridium(III) Phosphoramidate Complex, [Cp*Ir{κ2-N,O}][BArF4]

“…The crystal structure of [ 9 ]­[BAr F 4 ] (Figure ), obtained at −35 °C from hexanes-layered CH 2 Cl 2 , shows a noncrystallographically imposed C s -symmetric Ir­(III) complex bonded to both the phosphoramidate N atom and a Si atom of the activated H 2 SiPh 2 unit. For this genuine heterocycle (a ring system containing only one atom of each element), the Ir(1)–Si(1) (2.343(1) Å) and Si(1)–O(1) (1.758(2) Å) bond lengths are consistent with those found in related Ir-SiPh 2 OR complexes, while an augmented O(1)–P(1)–N(1) angle of 108.0(1)° is consistent with ring expansion. − Scheme illustrates a possible reaction manifold for the formation of this complex. We suggest that the first step involves Si–H oxidative addition to provide a κ 1 - N Ir­(III) hydride.…”