Bridging 1,2-Bis(diphenylphosphino)methane Ligands Facilitate the Formation of Binuclear Complexes with Both Two-Coordinate and Three-Coordinate Gold(I) Ions.

Five new crystalline gold(I) complexes β-Au(μ-dppm)Br·2CHCl (), [Au(μ- dppm)Br]Br·2CHCl (), [Au(μ-dppm)Br](PF) (), [Au(μ-dppm)Cl](BPh)·3CHCl () and [Au(μ-dppm)]Cl(AsF)·2CHCl () (where dppm is bis(diphenylphosphino)methane) have been prepared and structurally characterized by single crystal X-ray diffraction. Colorless β-Au(μ-dppm)Br·2CHCl () has centrosymmetric structure with two three-coordinate gold(I) ions held in close proximity by the dppm ligands. Crystals of [Au(μ- dppm)Br]Br·2CHCl (), [Au(μ-dppm)Br](PF) (), and [Au(μ-dppm)Cl](BPh)·3CHCl () have a cation with an unusual arrangement that binds a two-coordinate gold(I) ion to a three-coordinate gold(I) ion through an aurophilic interaction.

Molecular Flexibility in Solvated Crystals of the Dimer, Au(μ-1,2-bis(diphenylphosphino)ethane)I, with Three-Coordinate Gold(I).

We report the ability to trap the dimer Au(μ-dppe)I (dppe is 1,2-bis(diphenylphosphino)ethane) with different separations between the three-coordinate gold ions in crystalline solvates. All of these solvates ((Au(μ-dppe)I·4(CHCl) (), Au(μ-dppe)I·2(CHCl) (), the polymorphs α-Au(μ-dppe)I·2(HC(O)NMe) () and β-Au(μ-dppe)I·2(HC(O)NMe) (), and Au(μ-dppe)I·4(CHCl) ()) along with polymeric {Au(μ-dppe)I}·(CHCl) ()) originated from the same reaction, only the solvent system used for crystallization differed. In the different solvates of Au(μ-dppe)I, the Au···Au separation varied from 3.

Covalently linked thieno[2,3-]thiophene-fullerene dimers: synthesis and physical characterization.

Thienothiophene (TT) has received great attention in the fields of electronics and optoelectronics. Here we report a synthesis and characterization of fullerene-donor-fullerene triads linked to thieno[2,3-]thiophene as a donor. The photophysical and electrochemical properties of the new dumbbells were investigated using UV-vis spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and square wave voltammetry.

Open-cage fullerenes as ligands for metals.

The remarkable structures of open-cage fullerenes with functionalization on the outer surface and an accessible inner void make them interesting ligands for reactions with metal complexes. The behaviors of open-cage fullerenes in reactions with various metal complexes are examined and compared to the corresponding reactions with intact fullerenes. The structural results from X-ray diffraction are emphasized.

Structure and Luminescence Studies of Salts of the Helical Dication, [Au(μ-bis(diphenylphosphine)ethane)] and Comparison with Salts of [Au(μ-bis(diphenylphosphine)propane)].

Six salts ([Au(μ-dppe)](BF)·CHCl, [Au(μ-dppe)](BF)·1,2-ClCH, [Au(μ-dppe)](PF)·CHCl, [Au(μ-dppe)](PF), [Au(μ-dppe)](SbF), and [Au(μ-dppe)](OTf)·2CHCl), (dppe is bis(diphenylphosphine)ethane) containing the dication, [Au(μ-dppe)], have been prepared and structurally characterized by single-crystal X-ray crystallography. Unlike the three-coordinate dppe-bridged dimers, AuX(μ-dppe) (X = Br, I), which show considerable variation in the distance between the gold(I) ions over the range 3.0995(10) to 3.

Reactions of Thianthrene and 10-Phenylphenothiazine with the Lewis Acids─Titanium Tetrachloride, Titanium Tetrabromide, Tin(IV) Tetrachloride, or Antimony(V) Pentachloride: The Competition between Coordination and Oxidation.

The oxidation of thianthrene and 10-phenylphenothiazine into cation radicals has been examined using redox-active Lewis acids. The reaction of titanium(IV) tetrachloride with thianthrene in toluene produces a solution with an EPR spectrum indicative of oxidation of thianthrene to a cation radical, but the molecular compound () (μ-thianthrene)Ti(μ-Cl)Cl crystallized exclusively. Red crystalline () (μ-thianthrene)Ti(μ-Br)Br formed similarly from titanium(IV) tetrabromide.

Self-Assembled Encapsulation of CuX (X = Br, Cl) in a Gold Phosphine Box-like Cavity with Metallophilic Au-Cu Interactions.

Synthetic routes to the crystallization of two new box-like complexes, [Au(Triphos)(CuBr)](OTf)·(CHCl)·(CHOH)·(HO) () and [Au(Triphos) (CuCl)](PF)·(CHCl) () (triphos = bis(2-diphenylphosphinoethyl)phenylphosphine), have been developed. The two centrosymmetric cationic complexes have been structurally characterized through single-crystal X-ray diffraction and shown to contain a CuX (X = Br or Cl) unit suspended between two Au(I) centers without the involvement of bridging ligands. These colorless crystals display green luminescence (λ = 527 nm) for () and teal luminescence (λ = 464 nm) for ().

Metal-mediated rearrangement of 1,2-diphenylhydrazine to -semidine upon reaction with dichlorotris(triphenylphosphine)ruthenium(II).

Reaction between RuCl(PPh) and 1,2-diphenylhydrazine resulted in rearrangement and coordination of -semidine. The product, RuCl(PPh)(κ-NH-1,2-CH-NHPh), was characterized spectroscopically and the molecular structure was conclusively determined using X-ray crystallography. Computational chemistry was employed to probe the energetics surrounding the rearrangement reaction and product.

Direct Crystallization of Diamine Radical Cations: Carbon-Nitrogen Bond Formation from the Reaction of Triphenylamine with TiCl , TiBr , or SnCl versus Carbon-Carbon Bond Formation with SbCl.

Direct synthesis of diamine radical cations in crystalline form proceeding through oxidation of triphenylamine followed by the formation of a new C-N bond is reported. Although the oxidative coupling of triphenylamine is well studied, diamine products are rarely captured in their radical cation state. The neutral diamine most frequently obtained from this reaction pathway is N,N,N',N'-tetraphenylbenzidine.

Introduction of a (PhP)Pt group into the rim of an open-cage fullerene by breaking a carbon-carbon bond.

Treatment of an open-cage fullerene, designated as MMK-9, with (PhP)Pt in toluene solution at room temperature allows a (PPh)Pt unit to be incorporated into the rim of the cage so that it becomes an integral part of the carbon cage skeleton. The structure of the adduct has been determined by single crystal X-ray diffraction and reveals that the platinum atom has planar PtCP coordination, rather than the usual η-bonding to an intact C-C double bond of the fullerene.

Synthesis and Electrochemistry of Novel Dumbbell-Shaped Bis-pyrazolino[60]fullerene Derivatives Formed Using Microwave Radiation.

The design of covalently linked [60]fullerene dimers has gained increased attention, as the linked electron donors or acceptors are in close proximity to the surface of the C, providing a valuable approach to novel molecular electronic devices. Herein, new compounds involving C dumbbells covalently connected by the π-conjugated system from azobenzene and diaryl ether linkers were synthesized following the bifunctional cycloaddition reactions to C using microwave radiation. The structural identity of the fullerene dimers has been determined using spectroscopic techniques including Fourier transform infrared (FT-IR), matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF), and NMR spectroscopy, and the photophysical and the electrochemical properties for the new dumbbells have been examined using UV-vis spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and square wave voltammetry.

Seeing luminescence appear as crystals crumble. Isolation and subsequent self-association of individual [(CHNC)Au] ions in crystals.

Non-luminescent, isostructural crystals of [(CHNC)Au](EF)·CH (E = As, Sb) lose benzene upon standing in air to produce green luminescent (E = As) or blue luminescent (E = Sb) powders. Previous studies have shown that the two-coordinate cation, [(CHNC)Au], self-associates to form luminescent crystals that contain linear or nearly linear chains of cations and display unusual polymorphic, vapochromic, and/or thermochromic properties. Here, we report the formation of non-luminescent crystalline salts in which individual [(CHNC)Au] ions are isolated from one another.

A non-luminescent polymorph of [(cyclohexyl isocyanide)Au]PF that becomes luminescent upon grinding or exposure to dichloromethane vapor.

The discovery of a third, non-luminescent crystalline polymorph of [(C6H11NC)2Au]PF6 is reported. Remarkably, crystals of this polymorph are sensitive to mechanical pressure or to exposure to dichloromethane vapor. In both cases, the conversion produces the yellow, green luminescent polymorph of [(C6H11NC)2Au]PF6 and not the colorless, blue luminescent polymorph.

Fullerene nanostructures: how the oblong shape of C forms a cocrystal with an enormous asymmetric unit and related cocrystals.

Cocrystallization of NiII(OEP) (where OEP is the dianion of octaethylporphyrin) with C70 in p-xylene produces black plates of 12NiII(OEP)·12C70·18p-xylene (1). Single crystal X-ray diffraction at 90 K reveals that the crystal contains 42 individual, well-ordered molecules in the asymmetric unit with distinctive interactions between each NiII(OEP)/C70 pair and each pair of neighboring C70 molecules. Warming the crystal to 186 K produces a phase change so that only four NiII(OEP)/C70 sites and six p-xylene molecules are present.

Role of Anions and Mixtures of Anions on the Thermochromism, Vapochromism, and Polymorph Formation of Luminescent Crystals of a Single Cation, [(CHNC)Au].

Noncoordinating anions, which generally play a subordinate role in coordination chemistry, alter the structure, the luminescence, as well as the thermochromic and vapochromic behaviors of salts of the two-coordinate cation, [(CHNC)Au]. Thus whereas the yellow polymorphs of [(CHNC)Au](PF) and [(CHNC)Au](AsF) contain single chains of cations and are vapochromic, yellow [(CHNC)Au](SbF) does not form the same polymorph and is not vapochromic but contains two distinct chains of cations connected through aurophilic interactions. Mixed crystals such as [(CHNC)Au](PF)(AsF) have been prepared by adding diethyl ether to a dichloromethane solution containing equimolar amounts of [(CHNC)Au](PF) and [(CHNC)Au](AsF).

Unsymmetrical Coordination of Bipyridine in Three-Coordinate Gold(I) Complexes.

The unsymmetrical coordination of gold(I) by 2,2'-bipyridine (bipy) in some planar, three-coordinate cations has been examined by crystallographic and computational studies. The salts [(PhP)Au(bipy)]XF (X = P, As, Sb) form an isomorphic series in which the differences in Au-N distances range from 0.241(2) to 0.

Isolation and Crystallographic Characterization of Two, Nonisolated Pentagon Endohedral Fullerenes: Ho N@C (22010)-C and Tb N@C (22010)-C.

Purified samples of Ho N@C (22010)-C and Tb N@C (22010)-C have been isolated by two distinct processes from the rich array of fullerenes and endohedral fullerenes present in carbon soot from graphite rods doped with Ho O or Tb O . Crystallographic analysis of the endohedral fullerenes as cocrystals with Ni(OEP) (in which OEP is the dianion of octaethylporphyrin) shows that both molecules contain the chiral C (22010)-C cage. This cage does not obey the isolated pentagon rule (IPR) but has two sites where two pentagons share a common C-C bond.

Cleavage of Carbon Disulfide by n-Propyldiphenylphosphine and Nickel(II) Bromide.

Carbon disulfide is cleaved by n-propyldiphenylphosphine and nickel(II) bromide in a one-step process, to form two unprecedented complexes: orange, [Ni(S C (P PrPh ) )Br(P PrPh )]Br⋅CS (1) and purple [Ni{η -SC(P PrPh ) }Br(P PrPh )]Br⋅0.5CS (2). Orange (1) contains a dithiolene-related ligand that results from carbon-carbon bond formation, while purple (2) contains a remarkable ligand in which two n-propyldiphenylphosphine molecules have added to a carbon atom of a CS unit that is coordinated to nickel.

The Preparation of Luminescent, Mechanochromic Molecular Containers from Non-Emissive Components: The Box Cations, [Au (Triphos) Br] and [Au (Triphos) Br ].

Two new molecular boxes, the mono-bromo box [Au (Triphos) Br](SbF ) ⋅6(CH Cl ), 4 mB, and the dibromo box, [Au (Triphos) Br ⋅H O](SbF ) ⋅4(CH Cl ), 5 dB, have been prepared in crystalline form. Although constructed from non-luminescent components, both are strongly luminescent. Like its chloro counterpart, the mono-bromo box [Au (Triphos) Br](SbF ) ⋅6(CH Cl ), 4 mB, is mechanochromic.

Single-Crystal X-ray Diffraction Studies of Solvated Crystals of C Reveal the Intermolecular Interactions between the Component Molecules.

The solid-state structures of seven solvates of C (C·4tetrachloroethylene, C·2tetrachloroethylene, C·3benzene, C· n-pentane, C·diethyl ether, C·chlorobenzene, and C·benzene·dichloromethane) were determined by single-crystal X-ray diffraction at low temperature. At 90 K, the fullerene and solvate components are generally well-ordered and do not show the orientational disorder that plagues similar structures determined at room temperature. Interactions between the solvate molecules and the fullerene and between adjacent C molecules were examined and analyzed.

Vapoluminescent Behavior and the Single-Crystal-to-Single-Crystal Transformations of Chloroform Solvates of [Au (μ-1,2-bis(diphenylarsino)ethane) ](AsF ).

The mono- and di-chloroform solvates of [Au (μ-1,2-bis(diphenylarsino)ethane) ](AsF ) undergo single-crystal-to-single-crystal transformations that result in gain (over 12 hours) or slow loss (over five years) of only one chloroform molecule. The change in solvation results in changes in the structure and luminescence of the digold cation. The cation consists of a pair of slightly bent As-Au-As units that are connected through the two bridging dpae ligands and by aurophilic interactions with Au⋅⋅⋅Au contacts of 3.

Identifying a Needle in a Haystack: Isolation and Structural Characterization of Er C as the Carbide Er C @D (85)-C.

A method has been developed for isolating a pure sample of Er C from the myriad of fullerenes and endohedral fullerenes that are formed in the electric arc process. Crystallographic analysis of Er C in a cocrystal formed with Ni(OEP) reveals that the molecule is the carbide Er C @D (85)-C . Crystals of Er C @D (85)-C ⋅Ni(octaethylporphyrin)⋅2 C H are isostructural with those of Sm @D (85)-C ⋅Ni(octaethylporphyrin)⋅2 (chlorobenzene).