Exploring the solid state and solution structural chemistry of the utility amide potassium hexamethyldisilazide (KHMDS)

The structural chemistry of eleven donor complexes of the important Brønsted base potassium 1,1,1,3,3,3-hexamethyldisilazide (KHMDS) has been studied. Depending on the donor, each complex adopted one of four general structural motifs. Specifically, in this study the donors employed were toluene (to give polymeric 1 and dimeric 2), THF (dimeric 3), N,N,N',N'-tetramethylethylenediamine (TMEDA) (dimeric 4), (R,R)-N,N,N',N'-tetramethyl-1,2-diaminocyclohexane [(R,R)-TMCDA] (dimeric 5), 12-crown-4 (dimeric 6), N,N,N',N'-tetramethyldiaminoethyl ether (TMDAE) (tetranuclear dimeric 8 and monomeric 10), N,N,N',N',N''-pentamethyldiethylentriamine (PMDETA) (tetranuclear dimeric 7), tris[2-dimethyl(amino)ethyl]amine (Me6TREN) (tetranuclear dimeric 9) and tris{2-(2-methoxyethoxy)ethyl}amine (TMEEA) (monomeric 11). The complexes were also studied in solution by 1H and 13C NMR spectroscopy as well as DOSY NMR spectroscopy

New hybrid inorganic-organic polymers as supports for heterogeneous catalysis: a novel Pd(0) metalated cyclophosphazene-containing polymer as an efficient heterogeneous catalyst for the heck reaction

A new Pd(0) complex of a pendant cyclophosphazene-containing cross-linked polymer is found to be an effective heterogeneous catalyst for the Heck arylation reaction. The catalyst is robust and can be recycled without significant loss of activity

Synthesis of a platinum(II) bis(trimethylsilyl)amido complex: A better starting material for the cyclometalation of pincer ligands

Treatment of [(COD)PtCl2] with LiN(SiMe3)(2) gives [COD]PtClN(SiMe3)(2) in high yield. This product was fully characterized, including an X-ray structure. From a number of examples it is shown to be a very convenient starting material for the preparation of PXP platinum pincer complexes, giving excellent yields of the cyclometalated product under mild conditions

Synthesis and characterisation of PCsp3P phosphine and phosphinite iridium complexes. Cyclometallation and dehydrogenation of a cyclohexyl ring.

A cyclohexyl based pincer phosphine ligand undergoes cyclometalation with an iridium cyclooctadiene precursor to give a highly thermally stable iridium(III) complex where a C(sp3)-H bond has been oxidatively added. This iridium(III) hydride complex is reduced with potassium to give a terminal iridium(I) dinitrogen complex with no tendency to dimerization. The corresponding cyclohexyl phosphinite ligand undergoes reversible dehydrogenation to give the aromatic cyclometalated iridium(III) hydride complex together with 3 equivalents of dihydrogen

Crystal structure of mu-(cis-1,3-bis(di-tert-butylphosphinomethyl)cyclohexane-kappa(2)-P,P)-b is[chloro(1,5-cyclooctadiene)iridium(I)] - tetrahydrofuran (1:0.5), Ir2Cl2(C8H12)(2)[C8H14P2(C4H9)(4)] center dot 0.5C(4)H(8)O

C42H78Cl2Ir2O0.50P2, monoclinic, P12(1)/c1 (no. 14), a = 9.1257(1) angstrom, b = 16.8704(2) angstrom, c = 29.4032(4) angstrom, beta = 98.101(1)degrees, V = 4481.6 angstrom(3), Z = 4, R-gt(F) = 0.028, wR(ref)(F-2) = 0.063, T = 293 K

Carboxylation of pincer PCP platinum methoxide complexes under formation of metalla carbonates

The ligand 2,6-bis[(diphenylphosphino)methyl]benzene ((PCP)H) was prepared and characterised in an improved manner. With platinum it forms the complex (PCP)PtOTf which reacts with sodium methoxide to give (PCP)PtOMe as the major product together with a small amount of [(PCP)Pt](2)-mu-H. The platinum methoxide reacts with carbon dioxide to give (PCP)PtO(CO)OMe. Also the dinuclear [(PCP)Pt](2)(mu-O(CO)OMe) is formed in this reaction if (PCP)PtOTf is present. The crystal structures for [(PCP)PtOH2]OTf, PCP)PtOMe, [(PCP)Pt](2)-mu-H and [(PCP)Pt](2)(mu-O(CO)OMe) are reported. (c) 2011 Elsevier Ltd. All rights reserved

Synthesis and characterisation of PCsp3P phosphine and phosphinite platinum (II) complexes. Cyclometallation and simple coordination

New and improved preparative routes to the previously known PCP ligands cis-1,3-bis(di-isopropylphosphinito)cyclohexane and cis-1,3-bis[(di-tert-butylphosphino)methyl]cyclohexane are reported. They react with 1 equivalent of dichloro(1,5-cyclooctadiene)platinum(II) [(COD)PtCl2] to give the cis coordinated complex cis-[PtCl2{cis-1,3-bis(di-isopropylphosphinito)}cyclohexane] and the Csp3-H activated complex trans-[PtCl{cis-1,3-bis(di-tert-butylphosphino)}cyclohexane]. The new PCP ligand cis-1,3-bis(di-tert-butylphosphinito)cyclohexane was synthesised and reacts with [(COD)PtCl2] giving the di-nuclear trans-[PtCl2{cis-1,3-bis(di-tert-butylphosphinito)cyclohexane}]2, which is highly insoluble. All metal complexes were characterised with X-ray crystallography. DFT calculations indicate that the inability of the phosphinite ligands to cyclometallate is due to a kinetic barrier, possibly involving an axial–equatorial conformational change necessary for the C–H activation process

Cyclocarbophosphazene-containing tetrameric assemblies formed by the mediation of P-O-P and P-O-Cu linkages

Cyclocarbophosphazene-containing tetrameric assemblies formed by the mediation of P-O-P and P-O-Cu linkages have been isolated and characterized

A copper-metalated, hybrid inorganic-organic polymer as an oxidative nuclease

This study describes nucleolytic activity of a copper-metalated, multisite-coordinating, hybrid polymer CPPL-Cu under oxidative conditions. Rapid relaxation of supercoiled plasmid DNA was observed and mechanistic probing by chemical and enzymatic assays revealed involvement of singlet-oxygen-derived reactive species. The heterogeneous nature of the catalyst allowed a facile recycling of the artificial nuclease