Copolymerization of styrene with CO catalysed by palladium‐substituted 1,10‐phenanthroline bis(methoxycarbonyl) complexes [Pd(L—L)(COOMe) ₂ ]

Abstract

SUMMARY: A new class of highly effective homogeneous palladium bis(methoxycarbonyl) complexes Pd(L1L)(COOMe) 2 , where (L1L) are substituted phenanthroline ligands, has been developed for the production of syndiotactic alternating styrene-carbon monoxide copolymers. The essential feature of this novel catalytic system is that it is formed by palladium complex, Pd(L1L)(COOMe) 2 , an acid cocatalyst, (L1L)HPF 6 , bearing a weakly coordinating counter anion, and an oxidant, such as 1,4-naphthoquinone (1,4-NQ). The palladium/acid cocatalyst molar ratio has been explored. A maximum of copolymerization activity was obtained at 1/1 molar ratio. For a series of palladium catalysts, Pd(phen)(COOMe) 2 appeared to be the most active one. The effect of substituents at the ligand in Pd(L1L)(COOMe) 2 on the copolymerization activity was studied. The tacticity of alternating copolymers obtained with different Pd(L1L)(COOMe) 2 catalysts was determined by NMR spectroscopy. The copolymers were thermally characterised by TGA and DSC.

Interaction studies between a 1,10-phenanthroline adduct of palladium(II) dithiocarbamate anti-tumor complex and calf thymus DNA. A synthesis spectral and in-vitro study

“…In addition, if such a system contains electric charge on the extended coplanar moiety, it may show additional interaction with nucleic acid (Scheme 1). Several Pd (II) complexes with phen have been reported [11][12][13][14][15][16], and some of them have revealed potential anti-tumor activity towards different cell lines which are equal to or more than the activity of cisplatin. However, there are few reports concerning DNA-binding of the 1,10-phenanthroline palladium (II) complexes of dithiocarbamates [15,16].…”

Long‐Lived Palladium Catalysts for CO/Vinyl Arene Polyketones Synthesis: A Solution to Deactivation Problems

“…Few reports have appeared on the use of substituted phenanthroline ligands and they mainly concern the commercially available, methyl‐containing phenanthrolines. For instance, we5 and others6 reported that a remarkable decrease in the activity is found with the monochelated carboxylato Pd derivatives, [Pd(RCOO) 2 (N–N)] (R = Me, CF 3 ), on going from phen to 4,7‐dimethyl‐1,10‐phenanthroline (4,7‐Me 2 ‐phen), to 3,4,7,8‐tetramethyl‐1,10‐phenanthroline (Me 4 ‐phen), to 2,9‐dimethyl‐1,10‐phenanthroline (2,9‐Me 2 ‐phen), the latter being completely inactive. The influence of the ligand is even more pronounced when the bischelated complexes, [Pd(N–N) 2 ][PF 6 ] 2 , are used (N–N = phen, 4,7‐Me 2 ‐phen, Me 4 ‐phen) 3d.…”

Polar, non-coordinating ionic liquids as solvents for the alternating copolymerization of styrene and CO catalyzed by cationic palladium catalystsElectronic supplementary information (ESI) available: experimental details. See http://www.rsc.org/suppdata/cc/b2/b203367d/

“…The productivity was higher than is typically observed with this catalyst system in methanol under similar conditions (0.6-2.2 kg CP (g Pd) 21 ). 16,20 Copolymers produced in [C 6 pyr][NTf 2 ] also had higher molecular weights (M n = 25000) than are obtained in methanol. 20,21 The polydisperities of the copolymers were narrow (1.3-2.5) suggesting a single-site catalyst.…”

“…16,20 Copolymers produced in [C 6 pyr][NTf 2 ] also had higher molecular weights (M n = 25000) than are obtained in methanol. 20,21 The polydisperities of the copolymers were narrow (1.3-2.5) suggesting a single-site catalyst. The isolated copolymers were pale yellow rather than the grey polymer produced in MeOH.…”