34753-62-3Relevant academic research and scientific papers
New bidentate trans-chelating N-heterocyclic carbene ligands for palladium
Blakemore, James D.,Chalkley, Matthew J.,Farnaby, Joy H.,Guard, Louise M.,Hazari, Nilay,Incarvito, Christopher D.,Luzik, Eddie D.,Suh, Hee Won
, p. 1818 - 1829 (2011/06/24)
A family of imidazolium salts of the type [BnN(CH2CH 2CH2RIm)2]A·2[Cl] (Bn = CH2Ph; RIm = 1-methylimidazole (1a), 1-tert-butylimidazole (1b), 1-benzylimidazole (1c), 1-methylbenzimidazole (1d)), which contain a tertiary amine linking two imidazolium groups, has been synthesized. These imidazolium salts can be deprotonated with Ag2O to generate the Ag carbene complexes [{BnN(CH2CH2CH2 RIm)2}Ag].[AgCl2] (RIm = 1-methylimidazole (2a), 1-tert-butylimidazole (2b), 1-benzylimidazole (2c), 1-methylbenzimidazole (2d)). In the solid state 2d exists as an unusual tetramer, which consists of an [Ag2Cl4]2- core bridging two Ag(NHC) cations. Subsequent reaction of the Ag complexes with PdCl2(MeCN)2 generates Pd species of the type {BnN(CH 2CH2CH2RIm)2}PdCl 2 (RIm = 1-methylimidazole (3a), 1-tert-butylimidazole (3b), 1-benzylimidazole (3c), 1-methylbenzimidazole (3d)), which is a rare example of a family of Pd complexes that contain a bidentate trans-chelating N-heterocyclic carbene ligand. Compounds 3a and 3c were crystallographically characterized by X-ray crystallography and contain unusual 12-membered metallacycles. DFT calculations suggest that the preference for trans binding of the ligand is related to conformational effects of the linker. Compound 3b reacts with excess MeI to form {BnN(CH2CH2CH 2tBuIm)2}PdI2 (5b), a reaction in which we believe a Pd(IV) intermediate is generated. Compound 5b was crystallographically characterized. Compounds 3a-d are all active catalysts for the Heck reaction, and 3a can also catalyze the Suzuki reaction.
New linked macrocyclic systems derived from selectively protected S2N2 macrocycles
Groth, Andrew M.,Lindoy, Leonard F.,Meehan, George V.
, p. 1553 - 1558 (2007/10/03)
Novel application of a protecting group strategy has enabled a simple and efficient synthesis of the new tri-linked S2N2 macrocycles 12, 15, 17 and 20. This strategy involves the introduction of complementary protecting groups (R1 and R2) into the precursor macrocycle 4, which can then be manipulated to provide a synthetically versatile set of mono-N-protected S2N2 macrocyclic building blocks 5, 7 and 8.
First unequivocal synthesis of 1 or 8-N-monosubstituted 1,4,8,12-tetraazacyclopentadecane
Granier, Colin,Guilard, Roger
, p. 1197 - 1208 (2007/10/02)
A novel method derived from Kaden's modification of the Richman and Atkins's cyclization using tosylated synthons allows the unequivocal synthesis of 1 and 8-monofunctionalized 1,4,8,12-tetraazacyclo-pentadecane. Both syntheses are described.
Metal Chelates of Medical Interest, III. - 99mTc Complexes with Tetradentate Dicatechol Ligands
Hahn, Ekkehardt F.,Rupprecht, Stefan
, p. 487 - 491 (2007/10/02)
The dicatechol ligand bisamine hydrochloride, DIPACE (6), reduces the 99m- ion to lower valent 99mTc and subsequently forms a complex with the reduced 99mTc.The structure of benzylbisamine (4) is determined by X-ray crystallography.
