Palladium Phosphino-Iminolate Complexes as Metalloligands for Coinage Metals:  A Versatile, Ambivalent Behavior

Abstract

Reactivity studies with the bis-chelated Pd(II) phosphino-iminolate complex [Pd(dmba)(κ2-P,O-PPh2NC(O)Me)] (2) (dmba = orthometalated dimethylbenzylamine) have shown that it readily reacts as a metalloligand with electrophilic complexes of the coinage metals, selectively via the nitrogen atom of the P,O chelate. After examining its reaction with AgOTf (OTf = SO3CF3), which afforded the first 1-D coordination polymer containing Ag−Pd bonds, [{Ag(2)}OTf] n (3·OTf), we have examined and compared its reactions with H+, Au(PPh3)+, [AuCl(THT)], [Au(THT)]BF4, and [Cu(NCMe)4]BF4. Depending on the nature of the electrophilic metal reagent used, the interaction between the iminolate N atom of 2 and the electrophile can be formally described as a dative bond involving its lone pair, which would formally place the positive charge of the complex more on the coinage metal, or as a more covalent interaction resulting in an increased carbon−oxygen bond order and thus in the pos/baitive charge being more localized on the Pd(II) center. In the former case, the metalloligand formally behaves as a two-electron, L-type donor, whereas in the latter, as a one-electron, X-type donor ligand. This ambivalent behavior explains the formation of the heterobimetallic complexes (6) and ([Au(PPh3)(2)]OTf) or (7·BF4), respectively. Double substitution of the d10 metal center by 2 afforded the Pd/Au/Pd and Pd/Cu/Pd heterotrinuclear complexes (8·BF4) and (9·BF4), respectively. The complexes 2, 5·OTf, 6, 7·BF4, 8·BF4·2CH2Cl2, and 9·BF4 have been structurally characterized by X-ray diffraction.

Synthesis and characterization of Co and Ni complexes stabilized by keto- and acetamide-derived P,O-type phosphine ligands

“…Previous work has shown that transition metal complexes containing a phosphino-enolate or iminolate function react with electrophilic metal centres at the C enolate or N iminolate atoms, respectively, leading to heterometallic complexes and unique coordination polymers. 3,20, 21 The complexes reported in this work, therefore represent interesting candidates to extend such studies.…”

“…3 The replacement of the PCH 2 group of such ketophosphines with an isoelectronic PNH group in amide-derived ligands, or of the PCH functionality of phosphinoenolates with a PN group in iminolate phosphines, can bring about very interesting electronic and geometric effects in their respective metal complexes. 3,17- 21 Here, we report the synthesis and characterization of Co(III) and Ni(II) complexes containing the neutral b-ketophosphine ligands (i-Pr) 2 PCH 2 C(O)Ph (HL 1 ) and Ph 2 PCH 2 C(O)Ph (HL 2 ) 22 or the acetamide-derived phosphine ligand (i-Pr) 2 PNHC(O)Me (HL 3 ), prepared similarly to Ph 2 PNHC(O)Me (HL 4 ), 18 or the deprotonated form of these ligands.…”

Crystal packing and theoretical analysis of halogen- and hydrogen-bonded hydrazones from pharmaceuticals. Evidence of type I and II halogen bonds in extended chains of dichloromethane

“…Except for its X-ray structures obtained in pure form under high pressure (Podsiadlo et al, 2005) and very low temperature (Kawaguchi et al, 1973), the Cambridge Structural Database contains fewer than ten complexes comprising type II ClÁ Á ÁCl halogen bonds between CH 2 Cl 2 molecules. Hereafter are provided the CSD reference codes of structures containing type II contacts between CH 2 Cl 2 molecules, considering the following crystallographic parameters C-Cl1Á Á ÁCl2 and Cl1Á Á ÁCl2-C angles in the ranges 150-180 and 70-110 , respectively, and Cl1Á Á ÁCl2 distances in the range 2.5-3.6 Å : FAHGON (Kubota et al, 2016), HIQDUI (Kenny et al, 2013), REGTED (Pasynskii et al, 2005), YIHKAD (Nishimura et al, 2013), OZIJUE (Raducan et al, 2011), PAQTAD (Oberbeckmann-Winter et al, 2005), TIYQOJ (Wang et al, 2013). In these structures, the halogen bonds are present as part of a more elaborate network between CH 2 Cl 2 molecules, forming two-dimensional sheets or one-dimensional propagating ribbons.…”

Phosphino‐Aminothiazoline Platinum(II) and Platinum(II)/Gold(I) Complexes: Structural, Chemical and Vapoluminescent Properties

“…www.chemeurj.org in the heterodimetallic product. This procedure has been used previously, [11] for example, with…”