Reactivity of Scorpionate-Anchored Yttrium Alkyl Complex toward Organic Nitriles

Abstract

The mixed TpMe2/Cp-supported yttrium monoalkyl (TpMe2)CpYCH2Ph(THF) (1) reacted with 1 equiv of PhCN in THF at room temperature to afford the imine–enamine tautomer (TpMe2)CpY(N(H)C(Ph)CHPh)(THF) (2) and the insertion product (TpMe2)CpY(NC(CH2Ph)Ph)(THF) (3), in 61% and 12% isolated yields, respectively. 2 further reacted with PhCN in toluene at 120 °C to give the N–H bond addition product (TpMe2)CpY(N(H)C(Ph)NC(Ph)CHPh) (4). Treatment of 1 with 1 equiv of anthranilonitrile produced the dimer [(TpMe2)CpY(μ-NHC6H4CN)]2 (5). The monomer product (TpMe2)CpY(NHC6H4CN)(HMPA) (6) can be obtained through the coordination of HMPA (hexamethylphosphoric triamide). The reaction of 5 with 1 in THF at room temperature gave the cyano group insertion product [(TpMe2)CpY(THF)]2(μ-NHC6H4C(CH2Ph)N) (7). However, this reaction under the heating conditions gave an unexpected rearrangement product, (TpMe2)CpY(THF)(η2-NHC6H4C(CH2Ph)NH) (8). 5 further reacted with o-aminobenzonitrile at 120 °C to afford the nucleophilic addition/cyclization product TpMe2Y[κ3-(4-NH(C8N2H4)(2-NHC6H4)](HMPA) (9), accompanied with the elimination of the Cp ring. These results indicated that the yttrium alkyl complex exhibits high activity toward organic nitriles and reveals some unusual transformations during the insertion process. All these new complexes were characterized by elemental analysis and spectroscopic methods, and their solid-state structures were also confirmed by single-crystal X-ray diffraction analysis.

Rare‐Earth Amido and Borohydrido Complexes Supported by Tetradentate Amidinate Ligands: Synthesis, Structure, and Catalytic Activity in Polymerization of Cyclic Esters

“…The lengths of the covalent Ln(1)–N(5) bond ( 3 : 2.295(3) Å; 4 : 2.389(3)–2.408(4) Å) are comparable with those in the formerly described amido yttrium [{Me 3 SiNC(Ph)N} 2 (CH 2 ) 3 ]Y(2,6‐Pr i 2 C 6 H 3 NH)DME (2.237(4) Å), {(3,5‐Me 2 C 3 HN 2 ) 3 B}Y[κ 3 ‐(4‐NH=(C 8 N 2 H 4 )(2‐NHC 6 H 4 ))]{(Me 2 N) 3 P=O} (2.309(5) Å) and neodymium complexes [3,5‐Bu t 2 ‐2‐O‐C 6 H 2 CH=N‐C 5 H 4 N] 2 NdN(SiMe 3 ) 2 (2.385(3) Å), [{Me 3 SiNC(Ph)N} 2 (CH 2 ) 3 ]Nd(2,6‐Pr i 2 C 6 H 3 NH)DME (2.342(7) Å), [{(NC 5 H 4 )NHCH 2 (3,5‐Bu t 2 ‐C 6 H 2 ‐2‐OH)}NdN(SiMe 3 ) 2 (THF)] 2 (2.372(3) Å) . The Ln–N amidinate distances in 3 and 4 are somewhat different (κ 4 ‐NNOO‐ligand 2.378(3)–2.379(3) Å ( 3 ), 2.473(2)–2.483(2) Å ( 4 ); κ 2 ‐NN‐ligand 2.21(2)–2.45(2) Å, average 2.34(6) Å ( 3 ), 2.415(5)–2.487(4) Å, average 2.46(2) Å ( 4 )), but are comparable with the corresponding values measured in the related seven‐coordinate yttrium amidinate complexes [{1,3‐C 6 H 4 (NC(Ph)NSiMe 3 ) 2 } 3 Y(THF)Y(µ‐Cl)Li(THF) 3 ] (2.341(6), 2.455(6) Å), [Y{ o ‐CH 3 O‐C 6 H 4 NC(Ph)N(SiMe 3 )}Cl 2 (THF) 2 ] 2 (2.384(2), 2.375(2) Å), [(2,6‐Et 2 C 6 H 3 N) 2 C(4‐Me‐C 6 H 4 )] 2 Y(THF)(Cl)(µ‐Cl)Li(THF) 3 (2.402(6)–2.464(5) Å), [1,8‐C 10 H 6 {NC(Bu t )N‐2,6‐Me 2 ‐C 6 H 3 } 2 ]YCl(DME) (2.331(1)–2.369(1) Å) [{Me 3 SiNC(Ph)N} 2 (CH 2 ) 3 ]YCl(DME) (2.360(3)–2.379(3) Å) and seven‐coordinate neodymium complexes (2.385(2)–2.604(7) Å) , .…”

Reactions of Group 4 Metallocene Complexes with Mono‐ and Diphenylacetonitrile: Formation of Unusual Four‐ and Six‐Membered Metallacycles

“…[27] The coupling product of two nitriles with an yttrium complex was published very recently. [28] The difference between complex 7 and the known structures, except the yttrium complex, [28] is the substitution of the nitrogen atoms. N1 carries a hydrogen atom, whereas an organic residue is found at N2.…”

“…Compound 7 is comparable to the complexes of titanium and zirconium with guanidinate ligands, which consist of substituents at the ring carbon atom as well 27. The coupling product of two nitriles with an yttrium complex was published very recently 28…”

“…The difference between complex 7 and the known structures, except the yttrium complex,28 is the substitution of the nitrogen atoms. N1 carries a hydrogen atom, whereas an organic residue is found at N2.…”

Nitril‐Nitril‐C‐C‐Kupplungen an Gruppe‐4‐Metallocenen zu 1‐Metalla‐2,5‐diazacyclopenta‐2,4‐dienen und deren Reaktionen

“…Der Ringschluss wird meist durch eine daraus resultierende Stabilisierung oder eine Wechselwirkung mit einem Zusatzliganden begünstigt. Nach unserer Kenntnis wurden bisher nur zwei viergliedrige Ringe (D), einer für Yttrium [14] und einer für Titan, [15] durch eine N-C-Kupplung von Nitrilen erhalten.…”