trans-Carbonyl-chloridobis[diphen-yl(4-vinyl-phen-yl)phosphane-κP]rhodium(I).

In the title compound, trans-[RhCl(C(20)H(17)P)(2)(CO)], the Rh(I) atom is situated on a center of symmetry, resulting in a statistical 1:1 disorder of the chloride [Rh-Cl = 2.383 (2) Å] and carbonyl [Rh-C = 1.752 (7) Å] ligands. The distorted trans square-planar environment is completed by two P atoms [Rh-P = 2.3251 (4) Å] from two diphen-yl(4-vinyl-phen-yl)phosphane ligands. The vinyl group is disordered over two sets of sites in a 0.668 (10):0.332 (10) ratio. The crystal packing exhibits weak C-H⋯Cl and C-H⋯O hydrogen bonds and π-π inter-actions between the phenyl rings of neighbouring mol-ecules, with a centroid-centroid distance of 3.682 (2) Å.

trans-Dichloridobis[diphen-yl(thio-phen-2-yl)phosphane-κP]palladium(II).

The title compound, trans-[PdCl(2)(C(16)H(13)PS)(2)], forms a monomeric complex with a trans-square-planar geometry. The Pd-P bond lengths are 2.3387 (11) Å, as the Pd atom lies on an inversion point, while the Pd-Cl bond lengths are 2.2950 (12) Å.

cis-Dichloridobis[tris-(4-chloro-phen-yl)phosphane-κP]platinum(II) acetonitrile monosolvate.

The title compound, [PtCl(2)(C(18)H(12)Cl(3)P)(2)]·C(2)H(3)N, packs as monomeric units with a square-planar geometry around the Pt(II) atom. The two tris-(4-chloro-phen-yl)phosphane ligands are coordinated in a cis orientation, with P-Pt-P and Cl-Pt-Cl angles of 99.36 (2) and 88.02 (2)°, respectively. In the crystal, C-H⋯N inter-actions are observed between the phenyl rings and the acetonitrile solvent mol-ecules.

trans-Dichloridobis(4,8-dimethyl-2-phenyl-2-phosphabicyclo[3.3.1]nonane-κP)platinum(II).

The crystal structure of the title compound, trans-[PtCl(2)(C(16)H(23)P)(2)], has been determined at 100 K. The Pt atom is located on a twofold axis and adopts a distorted square-planar coordination geometry. The structure is only the second example of a coordination complex containing a derivative of the 4,8-dimethyl-2-phosphabicyclo[3.3.1]nonane (Lim) phosphine ligand family. The ligand contains four chiral C atoms, with the stereochemistry at three of these fixed during synthesis, therefore resulting in two possible ligand stereoisomers. The compound crystallizes in the chiral space group P4(3)2(1)2 but is racemic, comprising an equimolar mixture of both stereoisomers disordered on a single ligand site. The effective cone angles for both isomers are the same at 146°.

trans-Dibromidobis[tris-(4-chloro-phen-yl)phosphine]palladium(II).

In the title compound, [PdBr(2)(C(18)H(12)Cl(3)P)(2)], the Pd(II) ion is situated on a centre of symmetry and is coordinated by two Br anions [Pd-Br = 2.4252 (2) Å] and two P-donor ligands [Pd-P = 2.3317 (6) Å] in a slightly distorted square-planar geometry [P-Pd-Br = 86.589 (15)°].

Dibromidobis(triphenyl-arsine)palladium(II).

In the title compound, [PdBr(2)(C(18)H(15)As)(2)], the Pd(II) ion resides on a centre of symmetry and is coordinated by two As atoms [Pd-As = 2.4184 (3) Å] and two Br anions [Pd-Br = 2.4196 (3) Å] in a slightly distorted square-planar geometry [As-Pd-Br = 90.12 (1)°]. The crystal packing exhibits weak inter-molecular C-H⋯Br inter-actions.

trans-Dibromidobis(tri-p-tolyl-arsine)palladium(II).

In the title compound, [PdBr(2)(C(21)H(21)As)(2)], the Pd(II) ion, residing on a centre of symmetry, is coordinated by two As donor atoms [Pd-As = 2.4276 (2) Å] and two Br anions [Pd-Br = 2.4194 (2) Å] in a distorted square-planar geometry [Br-Pd-As = 87.786 (7)°]. A weak intra-molecular C-H⋯Br inter-action occurs. In the crystal structure, inter-molecular C-H⋯Br inter-actions are observed.

trans-Dibromidobis[diphen-yl(p-tol-yl)phosphine]palladium(II).

In the title compound, [PdBr(2)(C(19)H(17)P)(2)], the Pd(II) ion resides on a centre of symmetry and is coordinated by two Br anions [Pd-Br = 2.4266 (2) Å] and two P-donor ligands [Pd-P = 2.3462 (5) Å] in a slightly distorted square-planar geometry [P-Pd-Br = 93.528 (12)°]. Weak inter-molecular C-H⋯Br hydrogen bonds link mol-ecules into chains extended in [10].

Structures of rhenium(I) complexes with 3-hydroxyflavone and benzhydroxamic acid as O,O'-bidentate ligands and confirmation of π-stacking by solid-state NMR spectroscopy.

The synthesis and crystal structures of two new rhenium(I) complexes obtained utilizing benzhydroxamic acid (BHAH) and 3-hydroxyflavone (2-phenylchromen-4-one, FlavH) as bidentate ligands, namely tetraethylammonium fac-(benzhydroxamato-κ2O,O')bromidotricarbonylrhenate(I), (C8H20N)[ReBr(C7H6NO2)(CO)3], 1, and fac-aquatricarbonyl(4-oxo-2-phenylchromen-3-olato-κ2O,O')rhenium(I)-3-hydroxyflavone (1/1), [Re(C15H9O3)(CO)3(H2O)]·C15H10O3, 3, are reported. Furthermore, the crystal structure of free 3-hydroxyflavone, C15H10O3, 4, was redetermined at 100 K in order to compare the packing trends and solid-state NMR spectroscopy with that of the solvate flavone molecule in 3. The compounds were characterized in solution by 1H and 13C NMR spectroscopy, and in the solid state by 13C NMR spectroscopy using the cross-polarization magic angle spinning (CP/MAS) technique. Compounds 1 and 3 both crystallize in the triclinic space group P-1 with one molecule in the asymmetric unit, while 4 crystallizes in the orthorhombic space group P212121. Molecules of 1 and 3 generate one-dimensional chains formed through intermolecular interactions. A comparison of the coordinated 3-hydroxyflavone ligand with the uncoordinated solvate molecule and free molecule 4 shows that the last two are virtually completely planar due to hydrogen-bonding interactions, as opposed to the former, which is able to rotate more freely. The differences between the solid- and solution-state 13C NMR spectra of 3 and 4 are ascribed to inter- and intramolecular interactions. The study also investigated the potential labelling of both bidentate ligands with the corresponding fac-99mTc-tricarbonyl synthon. All attempts were unsuccessful and reasons for this are provided.

Rhodium hydride formation in the presence of a bulky monophosphite ligand: a spectroscopic and solid-state investigation.

A study has been carried out on rhodium catalyst preforming when modified with the bulky tris(2,4-di-tert-butylphenyl) phosphite, P(Obtbp)(3). X-Ray crystal structure determinations of a tropolone-type precursor complex [Rh(TropBr(3))(CO){P(Obtbp)(3)}].P(Obtbp)(3).CH(3)COCH(3)(TropBr(3)= 3,5,7-tribromotropolonate) and the free P(Obtbp)(3) ligand are reported. Systematic in situ IR and NMR studies of the particular rhodium phosphite modified catalyst and its precursors have led to the identification of two distinct rhodium hydride species. A {(1)H,(31)P} HMBC NMR experiment afforded clarity on the (31)P NMR spectra observed under hydroformylation conditions. The species were identified as [HRh(CO)(3){P(Obtbp)(3)}] and [HRh(CO)(2){P(Obtbp)(3)}(2)]. Attention was also given to the rate of catalyst formation when starting from different rhodium precursors.