New Soluble Polysiloxane Polymers Containing a Pendant Terdentate Aryldiamine Ligand Substituent Holding a Highly Catalytically Active Organometallic Nickel(II) Center

Abstract

A new type of grafted polysiloxane polymer is described in which a n aryldiamine substituent, [CsH3(CHzNMe2)2-2,61-, provides a pendant terdentate ligand environment for a catalytically active (0rgano)nickel center. The novel strategy employed involves initial grafting of the aryl bromide 5-amino-2-bromo-1,3-bis[(dimethylamino)methyllbenzene into the side chain of poly((2-(chlorocarbonyl)ethyl)methylsiloxane~ followed by nickel incorporation through a n oxidative addition reaction with [Nio(COD)21 (COD = cycloocta-1,5-diene). Soluble polymers with different amounts of nickel incorporation have been prepared and characterized by NMR, FT-IR, and W/vis spectroscopy as well as by differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). These polymeric materials having a n immobilized organonickel(I1) center show good catalytic activity in the Kharasch addition reaction of polyhalogenated alkanes to alkenes that is of the same order of magnitude as for the comparable model organonickel(I1) complex [Ni{ CsH2(CH2NMe2)2-2,6-N(H)C(O)-Me-4)BrI.

Thermodynamics of Pyridine Coordination in 1,4-Phenylene Bridged Bimetallic (Pd, Pt) Complexes Containing Two N,C,N‘ Motifs, 1,4-M2-[C6(CH2NR2)4-2,3,5,6]

“…Deuterated solvents, DMSO-d 6 and CDC1 3 , were purchased at CIL (Cambridge Isotope Laboratories, Inc.) 1 H NMR spectra were acquired using a Varian 400 MHz spectrometer. 13 C NMR spectra were acquired at 100 MHz. Mass spectra were acquired by Georgy Dubay at Duke University.…”

“…1 H NMR (CDC1 3 ) δ 3.85 (s, 8H, PhCH 2 3 J pt-H not observed due to very poor S/N ratio), 3.07 (s, 24H, NCH 3 3 J PtH not observed due to very poor S/N ratio). 13 C NMR and mass spectra could not be obtained due to the poor solubility of compound 10b, but the structure was confirmed from its subsequent conversion to 12c. The product was converted directly into the triflated product, 12c, without further purification.…”

Platinum Group Organometallics Based on “Pincer” Complexes: Sensors, Switches, and Catalysts

“…Direct immobilization of the pincer ligand on commercially available silica has been achieved with urea-type linkers containing protected silanol end groups. [134] Nickel insertion was achieved by oxidative addition to give homogeneous, polymer-supported catalysts. A model system, which allowed a more detailed investigation of the influence of this specific support on the catalyst, was provided by soluble siloxane polymers, on which pincer ligands were attached by using an amide linker (Figure 10, right).…”

Synthesis and Properties of para‐Substituted NCN‐Pincer Palladium and Platinum Complexes

“…[6] The NCN-and SCS-pincer complexes have been supported via a para substituent on poly(ethylene glycol), [7] poly-(Noctadecylacrylamide), [8] polysiloxanes, [9] benzene rings, [10] hyperbranched polytriallylsilanes and polyglycerols, [11] carbosilane [12,13] and Frÿchet-type [14] dendrimers and dendronised polymers, [14e] buckminsterfullerene, [15] and silica. [16] Substitution in the para position also allows the buildup of supramolecular assemblies, [17,18] the placement of an additional metal centre, [19,20] or the introduction of functional groups such as a-amino acid residues [21,22] or other auxiliaries [23] to give new materials.…”