Remarkable similarity of molecular packing in crystals of racemic and enantiopure 2-phenylpropionamide: Z' = 4 structures, molecular disorder, and the formation of a partial solid solution.

Substituted acetamides (many of which are chiral) are known to be pharmacologically active. 2-Phenylpropionamide (2PPA) is one of the simplest chiral α-substituted acetamides and thus is of interest as a model compound in the growth and design of pharmaceutical crystals. In this study, the crystal structures of racemic and enantiopure forms of 2PPA were determined for the first time using single crystal X-ray diffraction at 100 K.

Hypercoordinated eka-tin materials with dangling aryl-methoxy and -methylthio ligands exhibiting intramolecular secondary bonding and aryl bond stabilization in reactions with organotin chlorides.

The syntheses of [2-(CHECH)CH]PbPhCl, ( = 0, E = O (4), E = S (5); = 1, E = O (6), E = S (7); = 2, E = O (8), are described. NMR and single crystal data illustrate significant Pb⋯E interactions increasing as n progresses from 0 to 2. The Pb⋯E interactions stabilize the Pb-aryl bonding to the extent that the reactions of 4 and 5 with MeSnCl result in interchange of a Ph group and Cl to produce 6 and 7, respectively, together with MePhSnCl.

Redox Potential Tuning of Dimolybdenum Systems through Systematic Substitution by Guanidinate Ligands.

We report the synthesis and characterization of a series of dimolybdenum paddlewheel complexes of the type Mo(DAniF)(hpp) ( = 1-3), where DAniF is the anion of ,'-di--anisyl-formamidine and hpp is the anion of 1,3,4,6,7,8-hexahydro-2-pyrimido[1,2-]pyrimidine. The effect on the electronic structure of these tetragonal paddlewheel dimolybdenum compounds was studied upon systematic substitution of formamidinate ligands by the more basic guanidinates. Mo-Mo distances in the paddlewheel structures decreased upon guanidinate ligand substitution, and were found to be 2.

Titanium-Mediated Catalytic Hydrogenation of Monocyclic and Polycyclic Arenes.

Two electron-reduction of the Ti guanidinate complex (Im N)( guan)TiCl gives (η -Im N)( guan)Ti (1 ) and (Im N)( guan)Ti(η -C H ) (1 ) ( guan=[(tBuC=N)C(NXylyl) ] , Xylyl=2,5-dimethylphenyl) in the absence or presence of benzene, respectively. These complexes have been found to hydrogenate monocyclic and polycyclic arenes under relatively mild conditions (150 psi, 80 °C)-the first example of catalytic, homogeneous arene hydrogenation with TON >1 by a Group IV system.

Crystal structure at 100 K of bis-[1,2-bis-(di-phenyl-phosphan-yl)ethane]-nickel(II) bis-(tri-fluoro-methane-sulfonate): a possible negative thermal expansion mol-ecular material.

In the title salt, [Ni(CHP)](CFSO) or [Ni(dppe)]·(OTf) [dppe = 1,2-bis-(di-phenyl-phosphan-yl)ethane and OTf = tri-fluoro-methane-sulfonate], the Ni atom (site symmetry ) has a square-planar geometry with the bidentate ligands chelating the metal. As a result of the steric hindrance of the phenyl rings, the counter-ions are blocked from the metal coordination sphere. The dynamic disorder of the anion existing at 296 K is reduced at 100 K and based on these two temperatures, negative thermal expansion behaviour is observed.

A Terminal Iron(IV) Nitride Supported by a Super Bulky Guanidinate Ligand and Examination of Its Electronic Structure and Reactivity.

Utilizing the bulky guanidinate ligand [L] (L = (Ar*N)C(R), Ar* = 2,6-bis(diphenylmethyl)-4-tert-butylphenyl, R = NCBu) for kinetic stabilization, the synthesis of a rare terminal Fe(IV) nitride complex is reported. UV irradiation of a pyridine solution of the Fe(II) azide [L]FeN(py) (3-py) at 0 °C cleanly generates the Fe(IV) nitride [L]FeN(py) (1). The N NMR spectrum of the 1 (50% Fe≡N) isotopomer shows a resonance at 1016 ppm (vs externally referenced CHNO at 380 ppm), comparable to that known for other terminal iron nitrides.

Unusual C -Symmetric trans-1-(Bis-pyrrolidine)-tetra-malonate Hexa-Adducts of C : The Unexpected Regio- and Stereocontrol Mediated by Malonate-Pyrrolidine Interaction.

A totally unanticipated regio- and stereoisomerically pure C -symmetric trans-1-(bis-pyrrolidine)-tetra-malonate hexa-adduct of C was obtained via a topologically controlled method, followed by a 1,3-dipolar cycloaddition reaction. The structures of the products were elucidated by H and C NMR and by X-ray crystallography. The unexpected regio- and stereoselectivity observed, supported by theoretical calculations, was found to be a consequence of malonate-pyrrolidine interactions.

C(sp )-H Oxidative Addition and Transfer Hydrogenation Chemistry of a Titanium(II) Synthon: Mimicry of Late-Metal Type Reactivity.

Two-electron reduction of the Ti compound ( guan)(Im N)Ti(OTf) (3) gives the arene-masked complex ( guan)(η -Im N)Ti (1) in excellent yield. Upon standing in solution, 1 converts to a Ti metallacycle (4) through dehydrogenation of a pendant isopropyl group. Spectroscopic evidence shows this transformation initially proceeds via the oxidative addition of a C(sp )-H bond and can be reversed upon exposure of 4 to H .

Synthesis and characterization of a trans-1 hexakis-fullerene linker that forms crystalline polymers with silver salts.

A new flexible hexakis-fullerene adduct with two bis(pyridin-4-ylmethyl)malonate groups located at trans-1 positions was synthesized. Via reaction with Ag(PF6) under two different conditions, two new 1D coordination polymers were obtained; under a nitrogen atmosphere, the silver ions are connected by argentophilic interactions but under an ambient atmosphere, the silver ions exhibit no interaction between them but coordination to the (H2PO4)(-) ions.

Donor Properties of a New Class of Guanidinate Ligands Possessing Ketimine Backbones: A Comparative Study Using Iron.

Addition of 1 equiv of LiN═C(t)Bu2 or LiN═Ad (Ad = 2-adamantyl) to the aryl carbodiimide C(NDipp)2 (Dipp = 2,6-diisopropylphenyl) readily generates the lithium ketimine-guanidinates Li(THF)2[(X)C(NDipp)2] (X = N═C(t)Bu2 (1-(t)Bu), N═Ad (1-Ad)) in excellent yields. These new ligands can be readily metalated with iron to give the N,N'-bidentate chelates [{(X)C(NDipp)2}FeBr]2 (X = N═C(t)Bu2 (5-(t)Bu), N═Ad (5-Ad)), in which the ketimines behave as noncoordinating backbone substituents. In an effort to understand the potential electronic contributions of the ketimine group to the ligand architecture, a thorough structural and electronic study was conducted comparing the features and properties of 5-(t)Bu and 5-Ad to their guanidinate and amidinate analogues [{(X)C(NDipp)2}FeBr]2 (X = (i)Pr2N (6), (t)Bu (7)).

Synthesis of a "super bulky" guanidinate possessing an expandable coordination pocket.

Friedel-Crafts alkylation of 4-tert-butylaniline with 2 equiv of benzhydrol affords bulky 2,6-bis(diphenylmethyl)-4-tert-butylaniline (Ar*NH2) in good yield, which can be readily synthesized on a tens of grams scale. The reaction of 6 equiv of Ar*NH2 with triphosgene generates the symmetric urea (Ar*NH)2CO, which, upon dehydration with a P2O5/Al2O3 slurry in pyridine, produces the sterically encumbered carbodiimide (Ar*N)2C as an air-stable white solid. The treatment of (Ar*N)2C with LiN═C(t)Bu2 in tetrahydrofuran cleanly gives the monomeric lithium guanidinate Li[(Ar)*ketguan], free of coordinating solvent, in 85% yield.

Synthesis and characterization of electron donor-acceptor platinum(II) complexes composed of N,N-diphenylpyridineamine and triphenylamine ligands.

The synthesis and electronic properties of a series of platinum(II) complexes composed of electron-donor and electron-acceptor components as potential photovoltaic materials is reported. The complexes are composed of triphenylamines (TPA) and pyridine-derivatized TPAs as the electron-donating components, and alkynyl derivatives of 2,1,3-benzothiadiazole and cyclopentadithiophenone as the electron acceptors. The complexes containing the pyridine-derivatized ligands were prepared to examine the effect that direct coordination of a heteroatom-modified TPA may have on the electronic properties of donor-acceptor (D-A) complexes.

Synthesis, characterization, and evaluation of cis-diphenyl pyridineamine platinum(II) complexes as potential anti-breast cancer agents.

Although cisplatin is considered as an effective anti-cancer agent, it has shown limitations and may produce toxicity in patients. Therefore, we synthesized two cis-dichlorideplatinum(II) compounds (13 and 14) composed of meta- and para-N,N-diphenyl pyridineamine ligands through a reaction of the amine precursors and PtCl2 with respective yields of 16 and 47 %. We hypothesized that compounds 13 and 14, with lipophilic ligands, should transport efficiently in cancer cells and demonstrate more effectiveness than cisplatin.

Design, synthesis, and X-ray crystal structure of a fullerene-linked metal-organic framework.

Given the unique structural and electronic properties of C60 , metal-organic frameworks (MOFs) containing C60 linkers are expected to exhibit interesting characteristics. A new hexakisfullerene derivative possessing two pairs of phenyl pyridine groups attached to two methano-carbon atoms located at the trans-1 positions was designed and synthesized. The four pyridyl nitrogen atoms define a perfectly planar rectangle.

A tripodal ligand constructed from mesoionic carbene donors.

A tripodal ligand constructed solely from mesoionic carbene donors is reported. The donor strength of this ligand is lower than most imidazol-2-ylidene-based tris(carbene)borate ligands, as measured by IR spectroscopy of {NiNO}(10) and {Mn(CO)3}(+) derivatives. The attenuated donor strength is proposed to be due to the collective electron-withdrawing effect of the ligand's aryl substituents.

Unexpected isomerism in cis-2 bis(pyrrolidino)[60]fullerene diastereomers.

Similar yet different: A one-step regio- and diastereoselective synthesis of three new bis(pyrrolidine)[60]fullerenes, one cis-1 and two unprecedented cis-2 diastereoisomers, is reported. The compounds are easily purified using simple chromatographic techniques, and were fully characterized by spectroscopic techniques and X-ray crystallography. A mechanism for the isomeric conversion observed is proposed.

8-Alkoxy- and 8-aryloxy-BODIPYs: straightforward fluorescent tagging of alcohols and phenols.

We demonstrate herein that both alcohols and phenols can be tagged with a BODIPY (borondipyrromethene) moiety to yield highly fluorescent products. Thus, 8-(methylthio)-BODIPY (1) undergoes an S(N)Ar-type reaction with a host of alcohols and phenols in the presence of a base and a Cu(I) additive. The BODIPY dyes bearing alkoxy or nonfunctionalized phenoxy moieties are characterized by a highly efficient fluorescence emission, regardless of the media, in the blue-green part of the visible region.

High yield synthesis of a new fullerene linker and its use in the formation of a linear coordination polymer by silver complexation.

A new hexakis-fullerene adduct with two 4,5-diazafluorene groups strategically located at trans-1 positions to allow linear polymerization was selectively synthesized in very high yield. By reaction with Ag(triflate), a one dimensional metal-organic coordination polymer was obtained.

Intramolecular chalcogen-tin interactions in [(o-MeEC6H4)CH2]2SnPh(2-n)Cl(n) (E = S, O, CH2; n = 0, 1, 2) and intermolecular chlorine-tin interactions in the meta- and para-methoxy isomers.

Organotin(IV) compounds of the type [(o-MeEC(6)H(4))CH(2)](2)SnPh(2-n)Cl(n) were synthesized, E = O, n = 0 (1), n = 1 (2), and n = 2 (3); E = S, n = 0 (4), n = 1 (5), and n = 2 (6); and E = CH(2), n = 0 (7), n = 1 (8), and n = 2 (9). The dichloro compounds 3 and 6 have been investigated by single-crystal X-ray diffraction and exhibit bicapped tetrahedral geometry at the tin atom as a consequence of significant intramolecular Sn..

Theoretical study of the experimental coordination behavior of N-(2-aminophenyl)-D-glycero-D-gulo-heptonamide to Hg(II) ion.

The reactivity of N-(2-aminophenyl)-d-glycero-d-gulo-heptonamide (adgha), with the group 12 cations, Zn(II), Cd(II), and Hg(II), was studied in DMSO-d(6) solution. The studied system showed a selective coordination to Hg(II), and the products formed were characterized by (1)H and (13)C NMR in DMSO-d(6) solution and fast atom bombardment (FAB(+)) mass spectra. The expected coordination compounds, [Hg(adgha)](NO(3))(2) and [Hg(adgha)(2)](NO(3))(2), were observed as unstable intermediates that decompose to bis-[2-(d-glycero-d-gulo-hexahydroxyhexyl)-benzimidazole-κN]mercury(II) dinitrate, [Hg(ghbz)(2)](NO(3))(2).

Crystal structure and NMR spectroscopy of aldonamides derived from D-glycero-D-gulo-heptono-1,4-lactone.

We report the preparation of 12 aldonamides derived from D-glycero-D-gulo-heptono-1,4-lactone, their NMR characterization and study (13C, 1H, 15N NMR) in Me2SO-d6 solution. The evaluation of the coupling constants 3JH,H has shown that the sugar chain conformation in solution is all-trans for the studied amides. Because some amides crystallized, we discussed the crystal packing and found motifs.