A Monometallic Bis(cyaphido) Complex.

The first example of a bis(cyaphido) complex, trans-[Ru(dppe)(C≡P)], is described, unequivocally demonstrating the synthetic accessibility and stability of complexes that feature more than one cyaphido ligand. Synthesis is achieved from the precedent cation [Ru(dppe)(C≡P)] via sequential coordination and desilylation of the phosphaalkyne MeSiC≡P. The heteroleptic analogue trans-[Ru(dppe)(C≡N)(C≡P)] is also prepared from the same cation and NaCN; both cyaphido complexes are structurally characterized, enabling the first direct comparison of cyaphide with cyanide, its isoelectronic and isolobal counterpart.

Geoff Cloke at 65: a pioneer in organometallic chemistry.

Professor Geoff Cloke FRS celebrates his 65th birthday in 2018. In a career spanning four decades, his research endeavours have accounted for some of the most innovative synthetic chemistry of the modern era, with his many publications describing truly exceptional compounds and experimental methods that portray a unique chemical imagination. In addition to his scientific accomplishments, Cloke can be particularly proud of his successful mentoring, a level of dedication that propelled many students and post-docs on to become research leaders in their own right.

Equilibration of vibrationally excited OH in atomic and diatomic bath gases.

In this work, a computational model of state-to-state energy flow in gas ensembles is used to investigate collisional relaxation of excited OH, present as a minor species in various bath gases. Rovibrational quantum state populations are computed for each component species in ensembles consisting of 8000 molecules undergoing cycles of binary collisions. Results are presented as quantum state populations and as (approximate) modal temperatures for each species after each collision cycle.

Quantum state-resolved energy redistribution in gas ensembles containing highly excited N2.

A computational model is used to quantify the evolution of quantum state populations as highly vibrationally excited (14)N(2) ((14)N(2)∗) equilibrates in various bath gases. Multicollision energy disposal follows general principles established in related single collision processes. Thus when state-to-state routes permit, maximum amounts of energy are deposited into partner species by direct vibration-to-vibration (V-V) exchange.

Synthesis of a C-linked hyaluronic acid disaccharide mimetic.

The synthesis of a C-disaccharide that is designed as a mimetic for the repeating unit disaccharide of hyaluronic acid is described. The target compound was obtained via the SmI2-promoted coupling reaction of the sulfone, 2-acetamido-4,6-O-benzylidene-3-O-tert-butyldimethylsilyl-1,2-dideoxy-1-pyridinylsulfonyl-beta-D-glucopyranose (6), and the aldehyde, p-methoxyphenyl 2,3-di-O-benzyl-4-deoxy-4-C-formyl-6-O-p-methoxybenzyl-beta-D-glucopyranoside (14).

On the solid state structure of 4-iodobenzoic acid.

The solid-state structure of 4-iodobenzoic acid has been confirmed by variable temperature X-ray diffraction, variable temperature solid-state NMR and differential scanning calorimetry. 4-iodobenzoic acid crystallizes in the space group P2(1)/n, and dimerizes in the solid state about a center of inversion. Using extensive X-ray crystallographic data collections, the placement of the carboxylate H atoms from the residual electron density in difference Fourier maps was determined.

Electron and nuclear positions in the short hydrogen bond in urotropine-N-oxide.formic acid.

The crystal structure of urotropine-N-oxide.formic acid, as determined from multiple temperature single-crystal X-ray diffraction experiments in the range 123-295 K and from neutron diffraction at 123 K, is reported. There is a strong hydrogen bonding interaction between the OH of formic acid and the N-oxide of urotropine, with the oxygen-oxygen distance ranging from 2.

Magnetic behaviour of layered Ag(II) fluorides.

Fluoride phases that contain the spin-1/2 4d9 Ag(II) ion have recently been predicted to have interesting or unusual magnetochemistry, owing to their structural similarity to the 3d9 Cu(II) cuprates and the covalence associated with this unusual oxidation state of silver. Here we present a comprehensive study of structure and magnetism in the layered Ag(II) fluoride Cs2AgF4, using magnetic susceptometry, inelastic neutron scattering techniques and both X-ray and neutron powder diffraction. We find that this material is well described as a two-dimensional ferromagnet, in sharp contrast to the high-T(C) cuprates and a previous report in the literature.

An NMR and molecular modeling study of carbosilane-based dendrimers functionalized with phenolic groups or titanium complexes at the periphery.

Dendrimers are modified polymers whose architecture is defined by the presence of a central atom or core with multiple branches. These molecules lend themselves to a variety of architectures and uses, including drug delivery and catalysis. The study of the molecular conformations and shapes of dendritic molecules is necessary but not yet routine.

Homoleptic cobalt and copper phenolate A2[M(OAr)4] compounds: the effect of phenoxide fluorination.

Two series of homoleptic phenolate complexes with fluorinated aryloxide ligands A2[M(OAr)4] with M=Co2+ or Cu2+, OAr-=(OC6F5)- (OArF) or [3,5-OC6H3(CF3)2]- (OAr'), A+=K (18-crown-6)+, Tl+, Ph4P+, Et3HN+, or Me4N+ have been synthesized. Two related complexes with nonfluorinated phenoxide ligands have been synthesized and studied in comparison to the fluorinated aryloxides demonstrating the dramatic structural changes effected by modification of OPh to OAr(F). The compounds [K(18-crown-6)]2[Cu(OArF)4], 1a; [K(18-crown-6)]2[Cu(OAr')4], 1b; [Tl2Cu(OArF)4], 2a; [Tl2Cu(OAr')4], 2b; (Ph4P)2[Cu(OArF)4], 3; (nBu4N)2[Cu(OArF)4], 4; (HEt3N)2[Cu(OArF)4], 5; [K(18-crown-6)]2[Cu2(mu2-OC6H5)2(OC6H5)4], 6; [K(18-crown-6)]2[Co(OArF)4], 7a; [(18-crown-6)]2[Co(OAr')4], 7b; [Tl2Co(OArF)4], 8a; [Tl2Co(OAr')4], 8b; (Me4N)2[Co(OArF)4], 9; [Cp2Co]2[Co(OAr')4], 10; and [(18-crown-6)])[Co2(mu2-OC6H5)2(OC6H5)4], 11, have been characterized with UV-vis and multinuclear NMR spectroscopy and solution magnetic moment studies.

A pair of epimeric 13-hydroxy-2,3,6,7-tetramethoxy-8b,11,12,12a,13,13a-hexahydro-9H-9a-azacyclopenta[b]triphenylene-10-ones.

The structures of two compounds which are intermediates in the synthesis of phenanthroindolizidine alkaloids have been determined. (8bS,13aS,14R,14aR)-8b,9,11,12,13,13a,14,14a-Octahydro-14-hydroxy-2,3,6,7-tetramethoxydibenzo[f,h]pyrrolo[1,2-b]isoquinolin-11-one acetone solvate, C24H27NO6.C3H6O, (II), crystallizes in a chiral space group with one solvent molecule (acetone) present in the asymmetric unit.

Tetrakis(tetrahydrofuran-kappaO)lithium mer-tris(carbazolyl-kappaN)-trans-dichloro(tetrahydrofuran-kappaO)zirconate.

In the title compound, [Li(C(4)H(8)O)(4)][ZrCl(2)(C(12)H(8)N)(3)(C(4)H(8)O)], the environment of the Zr atom is pseudo-octahedral, with the three carbazolyl ligands in a mer configuration. The counter-ion of the zirconium complex is composed of an Li atom surrounded by four tetrahydrofuran (THF) molecules. The THF molecule attached to the Zr atom is disordered over two sites, as are two of the THF molecules in the lithium moiety.

Trans-dichloro-cis-bis(3,6-dimethylcarbazolyl)-cis-bis(tetrahydrofuran)zirconium(IV) benzene sesquisolvate.

In the title compound, [ZrCl(2)(C(14)H(12)N)(2)(C(4)H(8)O)(2)].1.5C(6)H(6), the Zr atom is pseudo-octahedral, with two Cl atoms in trans positions and two tetrahydrofuran molecules in cis positions.

(Tetrahydrofuran)potassium mer-trans-tris(carbazolyl)dichloro(tetrahydrofuran)zirconate.

In the title compound, [K(C(4)H(8)O)][ZrCl(2)(C(12)H(8)N)(3)(C(4)H(8)O)], the Zr atom is pseudo-octahedral, with two Cl ligands in trans positions. There is extensive interaction between the potassium cation and two of the aromatic carbazolyl ligands in eta(6) [C.K = 3.

Molecular structures of two metal tetrakis(tetrahydroborates), Zr(BH4)(4) and U(BH4)(4): equilibrium conformations and barriers to internal rotation of the triply bridging BH4 groups.

The molecular structures of Zr[(mu-H)(3)BH](4) and U[(mu-H)(3)BH](4) have been investigated by density functional theory (DFT) calculations and gas electron diffraction (GED). The triply bridged bonding mode of the tetrahydroborate groups in the former is confirmed, but both DFT calculations and GED structure refinements indicate that the BH(4) groups are rotated some 12 degrees away from the orientation in which the three bridging B-H bonds are staggered with respect to the opposing ZrB(3) fragment. As a result the symmetry of the equilibrium conformation is reduced from T(d) to T.