Synthesis and Crystal Structures of Monomeric Diamidonickel(II) Complexes

Abstract

The thermally stable nickel(II) diamides [NiL2] [L = −N(SiMe3)(8‐C9H6N) (1), −N(SitBuMe2)(8‐C9H6N) (2)] have been synthesized from the reaction of NiCl2 with the appropriate lithium amide. X‐ray crystallography revealed that the amido ligands bind in a chelating manner, forming a distorted tetrahedral environment around the nickel center. Complexes 1 and 2 have magnetic moments of 3.05 and 2.74 μB, respectively, which indicate a d8 electronic configuration with two unpaired electrons.

Low-Valent Chemistry of Cobalt Amide. Synthesis and Structural Characterization of Cobalt(II) Amido, Aryloxide, and Thiolate Compounds

“…The amido nitrogen centers [N(1) and N(3)] exhibit a nearly trigonal planar geometry [sum of bond angles: 359.02° (av)], which is consistent with sp 2 -hybridized nitrogen atoms. The observed Si−N bond distances in 1 [1.725(4)−1.735(3) Å] are similar to the Si−N distances found in other silylamido complexes. ,,,− Moreover, delocalization of the lone-pair electrons onto the pyridyl ring is evidenced by the short C pyridyl −N amido bond distances of 1.359(5)−1.362(5) Å in 1 . They are close to the observed C aromatic −N amido distances in other metal arylamido complexes, in which delocalization of electron density onto the aromatic substituents have been suggested. 3l,m,,, Apparently, ligand L behaves as a weak π -acceptor in complex 1 , and this may account for the stability of the complex.…”

“…We reasoned that bulkiness of substituents on the amido nitrogen does impose an important influence on the structure of the corresponding amido metal complexes. Accordingly, two sterically more encumbered N -functionalized amido ligands [N(R)(2-C 5 H 3 N-6-Me)] - (R = Si t BuMe 2 , Si t BuPh 2 ) have been developed in our laboratory. ,22a With these sterically more demanding ligands, a number of main-group and transition metal amido complexes with quite different structures have been prepared and structurally characterized. , Herein we report the synthesis and crystal structure of a novel binuclear cobalt(II) amide [(CoL 2 ) 2 ·(TMEDA)] ( 1 ) [L = N(Si t BuMe 2 )(2-C 5 H 3 N-6-Me); TMEDA = Me 2 NCH 2 CH 2 NMe 2 ] in which the TMEDA ligand binds two cobalt ions in an unusual N , N ‘ -bridging coordination mode. Subsequent reactions of 1 with the bulky phenol Ar Me OH (Ar Me = 2,6- t Bu 2 -4-MeC 6 H 2 ) and thiophenol ArSH (Ar = 2,4,6- t Bu 3 C 6 H 2 ) gave the neutral mononuclear cobalt(II) bis(aryloxide) [Co(OAr Me ) 2 (TMEDA)] ( 2 ) and dithiolate [Co(SAr) 2 (TMEDA)] ( 3 ), respectively.…”

Cobalt(ii) amido complexes derived from a monodentate arylamido ligand featuring a highly electron-withdrawing C6F5 substituent

“…17,23 We are interested in the chemistry of metal amides, especially the synthesis and reaction chemistry of amido complexes of divalent 3d metals and lanthanide metals. [29][30][31][32][33] Earlier, we have reported on the chemistry of a few Fe(II) and Co(II) complexes supported by the monodentate N-silylated and N-alkylated arylamido system [N(R)(C 6 H 3 R′ 2 -2,6)] − (R = SiMe 3 , CH 2 Bu t ; R′ = Me, Pr i ). 32 It was noted that minor modifications in the steric and electronic properties of the R and R′ substituents in this system can change the metal-ligand stoichiometry of the corresponding metal amides.…”

Divalent europium and ytterbium complexes supported by a bulky 2-pyridyl amido ligand: synthesis, structure and reactivity studies

“…We are interested in the coordination chemistry and reactivity of metal complexes supported by anionic nitrogen-based ligands, such as amides 19,21,22 and amidinates. 23 Earlier, we have studied the coordination behaviour of 2-pyridyl amides with transition-metal 19a,b and trivalent lanthanide ions.…”