Metal functionalized POSS as fire retardants in polypropylene

This paper deals with the study of the combustion properties of dimeric and oligomeric Al-and Zn-isobutyl silsesquioxane (POSS)/polypropylene (PP) composites, in comparison with neat PP and PP/octaisobutyl POSS. The presence of Al-POSS leads to a decrease in combustion rate with respect to PP, resulting in a decrease of Heat Release Rate (-43% at 10 wt% POSS loading) as well as reduction in CO and CO2 production rates, whereas a negative effect on the above parameters is obtained with octaisobutyl POSS. Zn-POSS does not significantly affect the PP combustion behaviour. The effect of Al-POSS is most likely related to its chemical activity, which favours the formation of a moderate amount of char residue, by catalysing secondary reactions in the polymer during combustion

Lignin oxidation with an organic peroxide and subsequent aromatic ring opening

The oxidation of an organosolv lignin with tert-butylhydroperoxide, initiated by titanium grafted into the lignin structure, was investigated. Titanation of reactive groups on lignin is responsible for the cross-linking of the lignin structure. IR and MAS 13C NMR spectroscopy spectra confirmed the oxidation of the lignin structure and other pronounced structural changes. A study with guaiacol as a model compound helped to recognise that aromatic ring opening occurs under the given conditions and is catalysed by the grafted titanium. The structure of the oxidised lignin becomes less robust and therefore potentially more susceptible to be depolymerised and converted into monomeric units

Successful application of a “forgotten” phosphine in asymmetric catalysis: A 9-phosphabicyclo[3.3.1]non-9-yl ferrocene derivative as chiral ligand

The technical mixture phobane”, containing the two isomers 9-phospha-9H-bicyclo[3.3.1]-nonane (3a) and 9-phospha-9H-bicyclo[4.2.1]nonane (3b) in a ~2:1 ratio was reacted with N,N-dimethyl-(S)-l-[(R)-2-(diphenylphosphino)ferrocenyl]ethylamine (4) in acetic acid. The clean amine substitution product is the new chiral biphosphine 5. When only 2 equiv of 3 were reacted with 4, a 4:1 mixture of the two isomeric products 5a and 5b were obtained. However, the use of a 10-fold excess of 3 afforded the pure [3.3.1]-isomer 5a, 9-phospha-9-[(S)-l-{(R)-2-(diphenylphosphino)ferrocenyl}ethyl][3.3.1]bicyclononane, in 68% isolated yield. (S)-(R)-5a crystallizes in the orthorhombic space group P212121, Z = 4, α = 7.393(3) Å, b = 19.261(5) Å, and c = 19.546(8) Å. 5a was used in the asymmetric Pd-catalyzed alkylation of l,3-diphenyl-3-acetoxypropene with dimethyl malonate. Enantioselectivities up to 85% ee were obtained. The cationic Pd—allyl complexes [Pd(η3-C3H5)(5a)]O3SCF3(6) and [Pd(η3-PhCHCHCHPh)(5a)]O3SCF3 (7) were prepared and characterized by X-ray diffraction. Complex 6 crystallizes in the monoclinic space group P21, Z = 2, α = 9.162(4) Å, b = 16.069-(5) Å, c = 11.816(5) Å, and β = 96.86(3)°. Crystalline 7 was obtained as a CH2Cl2 monosolvate and belongs to the triclinic system: space group P1, Z = 1, a = 11.07(2) Å, b = 11.216(14) Å, c = 11.888(16) Å, a = 62.37(9)°, β = 65.96(11)°, and γ = 70.29(11)°. The ligand assumes very different conformations in its complexes, as compared to the free state. Multidimensional 31P, 13C, and 1H NMR studies reveal that 7 exists in solution as a mixture of four isomers. Aspects of the selective equilibria were elucidated using 31P- and 1H-exchange spectroscopy

CCDC 228465: Experimental Crystal Structure Determination

Related Article: J.I.van der Vlugt, M.Fioroni, J.Ackerstaff, R.W.J.M.Hanssen, A.M.Mills, A.L.Spek, A.Meetsma, H.C.L.Abbenhuis, D.Vogt|2003|Organometallics|22|5297|doi:10.1021/om030522y,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

CCDC 228464: Experimental Crystal Structure Determination

Related Article: J.I.van der Vlugt, M.Fioroni, J.Ackerstaff, R.W.J.M.Hanssen, A.M.Mills, A.L.Spek, A.Meetsma, H.C.L.Abbenhuis, D.Vogt|2003|Organometallics|22|5297|doi:10.1021/om030522y,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

CCDC 228463: Experimental Crystal Structure Determination

Related Article: J.I.van der Vlugt, M.Fioroni, J.Ackerstaff, R.W.J.M.Hanssen, A.M.Mills, A.L.Spek, A.Meetsma, H.C.L.Abbenhuis, D.Vogt|2003|Organometallics|22|5297|doi:10.1021/om030522y,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

CCDC 228462: Experimental Crystal Structure Determination

Related Article: J.I.van der Vlugt, M.Fioroni, J.Ackerstaff, R.W.J.M.Hanssen, A.M.Mills, A.L.Spek, A.Meetsma, H.C.L.Abbenhuis, D.Vogt|2003|Organometallics|22|5297|doi:10.1021/om030522y,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.