Nickel(0) Complexes of Acyclic Polyunsaturated Aza Ligands

Abstract

The acyclic 4,9-bis(4-tolylsulfonyl)-4,9-diazadodeca-1,11dien-6-yne (1) and 4,9-bis(4-tolylsulfonyl)-4,9-diazatrideca-1,(E)-6-dien-11-yne (2), which differ in the sequence of the two ene and one yne functions in the chain, have been reacted with 1 and 2 equiv of Ni(cod) 2 . The reaction with 1 equiv of Ni(cod) 2 affords the mononuclear trigonalplanar nickel(0) complexes 3 and 5. These react with a further 1 equiv of Ni(cod) 2 by addition of a Ni(cod) entity to give the dinuclear derivatives 4 and 6. While 3 forms a mixture of isomers C 2 -3 and C s -3 in solution, C 2 -3 is exclusively present in the crystal, where it is packed in parallel columns. Complex 6 crystallizes as a spherulite. Complexes 3−6 have been characterized by NMR and single-crystal X-ray structure analysis, and a detailed conformational analysis is given.

Synthesis and Structures of 9-Oxabispidine Analogues of Cisplatin, Carboplatin, and Oxaliplatin

“…The two PhSO 2 substituents at N1 and N2 formally occupy equatorial (exo) positions in the six-membered oxa rings, which leaves the electron pairs in axial (endo) positions, pointing toward one another. Because the orientation of the phenyl substituents is antiperiplanar to the N lone pairs, as is typical for this structural entity,20 the molecules assume a W-shaped conformation of which the three top tips are given by the central O1 bridge and p-CH of the flanking phenyl rings, whereas the two bottom tips can be represented by S1O2O3 and S2O3O4.Around the center and origin (viz. corners) of the unit cell, each two nonsymmetric molecules form an inversion-related racemic pair by mutual alignment of the W top tips [the intermolecular O1•••O1* distance is 3.423(2) Å].…”

Bis{μ-cis-1,3-bis[(di-tert-butylphosphanyl)oxy]cyclohexane-κ2P:P′}bis[carbonylnickel(0)] including an unknown solvent molecule

“…For 16-atom macrocyclic dimers of Pd II and Pt II with cis-1,3-bis-(di-alkylphosphinito)cyclohexane ligands, see: Sjö vall et al (2001) and Olsson et al (2007), respectively. For other examples of Ni 0 atoms adopting a close to trigonalplanar geometry, see: Rosenthal et al (1990); Maciejewski et al (2004); Brun et al (2013). For an example of a carbon monoxide-induced reductive elimination from a PNP pincersupported Ni II hydride complex to form a tetrahedral Ni 0 dicarbonyl species (PNP = [N(2-PR 2 -C 6 H 3 ) 2 ] À ), see: Liang et al (2012).…”

Ni(3,5-CF3stb)2(Et2O): A “Super-Naked” Nickel Complex

“…Indeed, together with Ni­(COD) 2 and Ni­( t -CDT), Ni­( 4‑ t Bu stb) 3 can undergo ligand-displacement in favor of other olefin ligands. This ability has rendered them valuable sources for generating other Ni(0)­(olefin) complexes through complete, ,− or partial displacement of the ligand backbone (Figure A). − Despite their great lability, the exchange of ligands in olefin-nickel complexes with arenes still remains elusive. Even in reported tris -(stilbene)­Ni­(0), only coordination of THF is allowed, leaving arenes unreacted. , While L-Ni(0)-arene complexes are known and well-studied, their formation commonly requires the use of ancillary donating ligands (L) such as phosphines, ,,− NHCs, − or NHSis − ( N -heterocyclic silylenes).…”