Chiral [16]-ane P4N2 macrocycles: stereoselective synthesis and unexpected intermolecular exchange of endocyclic fragments.

Chiral 1,9-diaza-3,7,11,15-tetraphosphacyclohexadecanes were stereoselectively synthesized as pure RPSPSPRP isomers via a one-pot Mannich-type condensation reaction of 1,3-bis(arylphosphino)propane, formaldehyde and optically active, as well as racemic, primary amines. An unprecedented intermolecular exchange of endocyclic amino fragments of 1,9-diaza-3,7,11,15-tetraphosphacyclohexadecanes was observed. The lability of the P-CH2-N fragment in macrocyclic aminomethylphosphines is the reason of the stereoisomerization, formation of products with medium-sized cycles as well as the exchange of endocyclic amino fragments. The mechanism of these transformations involving the formation of a methylenephosphonium intermediate and further intra- and intermolecular nucleophilic substitution is discussed.

Unique anisotropic optical properties of a highly stable metal-organic framework based on trinuclear iron(iii) secondary building units linked by tetracarboxylic linkers with an anthracene core.

A highly stable metal-organic framework, [{Fe3(ACTBA)2}X·6DEF]n (1; X = monoanion), based on trinuclear iron(iii) secondary building units connected by tetracarboxylates with an anthracene core, 2,6,9,10-tetrakis(p-carboxylatophenyl)anthracene (ACTBA), is reported. Depending on the direction of light polarisation, crystals of 1 exhibit anisotropic optical properties with birefringence Δn = 0.3 (λ = 590 nm).

Reduction of hydroxy-functionalised carbaboranyl carboxylic acids and ketones by organolithium reagents.

While the reaction of carbaboranyl carboxylic acids and ketones with organolithium reagents generally leads to cleavage of the exo-polyhedral C-C bond, introduction of a hydroxyl group at the second carbon atom of the cluster enables the reduction of the carbonyl compounds to tertiary alcohols. The proposed mechanism involving the formation of dimeric contact ion pairs was supported by X-ray crystallography and theoretical calculations.

Tuning the coordination properties of phenothiazine by regioselective introduction of diphenylphosphanyl groups.

The palladium and platinum complexes of the newly synthesized 1-(diphenylphosphino)-10-methyl-10H-phenothiazine (1) and the previously reported 3-(diphenylphosphino)-10-alkyl-10H-phenothiazine [alkyl = Me (2), Et (3)] and 4-(diphenylphosphino)-10-ethyl-10H-phenothiazine (4) were prepared. Density functional calculations were carried out to explain the electronic properties of compounds 1, 3 and 4. Compounds 1, 3 and 4 can interact with DNA, as was observed in agarose gel electrophoresis experiments. In addition, the cytotoxicity of the platinum complexes of ligands 2 and 4 towards breast, colorectal and hepatocarcinoma cell lines was studied.

Hydrogen-bonded pillars of alternating chiral complex cations and anions: 1. Synthesis, characterization, X-ray structure and thermal stability of catena-{[Co(H(2)oxado)(3)][Cr(C(2)O(4))(3)].5H(2)O} and of its precursor (H(3)oxado)[Co(H(2)oxado)(3)](SO(4))(2).2H(2)O.

Compound (H(3)oxado)[Co(H(2)oxado)(3)](SO(4))(2).2H(2)O () (H(3)oxado(+) = oxamide dioximemonoximium) reacted metathetically with Ba(6)(H(2)O)(17)[Cr(C(2)O(4))(3)](4).7H(2)O in water to give the one-dimensional complex salt {[Co(H(2)oxado)(3)][Cr(C(2)O(4))(3)].5H(2)O}(infinity) () (H(2)oxado = oxamide dioxime). Compounds and were characterized by elemental analysis, FTIR, UV-Vis and by single crystal X-ray structure determination. The structure of consists of infinite pillars of alternating chiral complex cations and anions linked together along [100] by electrostatic and longitudinal O-HO interactions, with an average intrachain CoCr separation of 4.94 A. Equatorial N-HO bridges cross-link neighboring pillars (which are of opposite chirality) and consolidate a three-dimensional lattice framework which delineates elliptic nanochannels parallel to the a axis, encapsulating highly disordered water molecules. The thermal stability of both compounds was assessed by TGA, and the effective magnetic moment of , checked at room temperature, revealed considerable spin-orbit coupling.

P,N-Containing cyclophanes with large helical hydrophobic cavities: prospective precursors for the design of a molecular reactor.

The highly effective self-assembly process between 2,4,6-tris(isopropyl)phenylphosphine or mesitylphosphine, formaldehyde and 1,4-bis(alpha-(4'-aminophenyl)isopropyl)benzene results in the formation of a novel type of heterocyclophane which is able to encapsulate organic molecules as well as being a potential ligand for transition metals inside the intramolecular cavity. Compounds of this type can be regarded as potential precursors for a new kind of molecular reactors.

Bis(phosphanylamino)benzene ligands: a zinc(II) complex and an unusual nickel(I) complex with a Dewar-benzene-type Ni2P2N2 backbone.

ZnPr(2) reacts with 1,2-(NHPPh(2))(2)C(6)H(4) (1) to give the bis-amido complex [Zn(THF){1-N(PPh(2))-2-N(mu-PPh(2))C(6)H(4)-kappa(3)N,N',P}](2) (3), while monolithiated 1 (prepared in situ from 1 and LiBu(n)) reacts with NiCl(2) with formation of the unusual nickel(I) complex [Ni{1-NH(PPh(2))-2-N(micro-PPh(2))C(6)H(4)-kappa(2)N,P}](2) (4), which has a Ni-Ni bond. Complexes 3 and 4 were structurally characterised. Furthermore, the structure of the sterically demanding bis-aminophosphine 1,2-(NHPMes(2))(2)C(6)H(4) (2, Mes = 2,4,6-Me(3)C(6)H(2)) is compared with that of the corresponding phenyl-substituted derivative 1,2-(NHPPh(2))(2)C(6)H(4) (1). B3LYP/LANL2DZ molecular orbital calculations on 4 indicate that a two-electron reduction should convert the Dewar-benzene-like six-membered Ni(2)N(2)P(2) ring 4 in to a benzene-like structure, a structure which is observed for the isoelectronic Zn(II) complex 3.