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1.  (S)-N-[(4-{(S)-1-[2-(4-Meth­oxy­benz­amido)-2-methyl­propano­yl]pyrrolidine-2-carboxamido}-3,4,5,6-tetra­hydro-2H-pyran-4-yl)carbon­yl]proline dimethyl sulfoxide monosolvate (4-MeBz-Aib-Pro-Thp-Pro-OH) 
The asymmetric unit of the title compound, C28H38N4O8·C2H6OS, contains one tetra­peptide and one disordered dimethyl sulfoxide (DMSO) mol­ecule. The central five-membered ring (Pro2) of the peptide mol­ecule has a disordered envelope conformation [occupancy ratio 0.879 (2):0.121 (2)] with the envelope flap atom, the central C atom of the three ring methylene groups, lying on alternate sides of the mean ring plane. The terminal five-membered ring (Pro4) also adopts an envelope conformation with the C atom of the methylene group closest to the carboxylic acid function as the envelope flap, and the six-membered tetra­hydro­pyrane ring shows a chair conformation. The tetra­peptide exists in a helical conformation, stabilized by an intra­molecular hydrogen bond between the amide N—H group of the heterocyclic α-amino acid Thp and the amide O atom of the 4-meth­oxy­benzoyl group. This inter­action has a graph set motif of S(10) and serves to maintain a fairly rigid β-turn structure. In the crystal, the terminal hy­droxy group forms a hydrogen bond with the amide O atom of Thp of a neighbouring mol­ecule, and the amide N—H group at the opposite end of the mol­ecule forms a hydrogen bond with the amide O atom of Thp of another neighbouring mol­ecule. The combination of both inter­molecular inter­actions links the mol­ecules into an extended three-dimensional framework.
PMCID: PMC3588532  PMID: 23476594
2.  1-(4-Methyl­benz­yl)-2-(4-methyl­phen­yl)-1H-benzimidazole 
The title compound, C22H20N2, crystallizes with two independent mol­ecules (A and B) in the asymmetric unit. The benzimidazole units are almost planar [maximum deviations = 0.0161 (8) Å for A and 0.0276 (8) Å for B]. The dihedral angles between the benzimidazole unit and the benzene rings of the 4-methyl­benzyl and 4-methyl­phenyl groups are 76.64 (3) and 46.87 (4)°, respectively, in mol­ecule A. The corresponding values in mol­ecule B are 86.31 (2) and 39.14 (4)°. The dihedral angles between the planes of the two benzene rings are 73.73 (3) and 80.69 (4)° in mol­ecules A and B, respectively. Pairs of weak inter­molecular C—H⋯N hydrogen bonds link B mol­ecules, forming centrosymmetric dimers with R 2 2(8) ring motifs. There are no significant corresponding inter­actions involving the A mol­ecules.
PMCID: PMC3239139  PMID: 22199987
3.  (Z)-4-(2,5-Di-tert-butyl­anilino)pent-3-en-2-one 
In the crystal structure of the title ketoamine, C19H29NO, the bond lengths from the N atom through the alkene group to the ketone O atom show the presence of an extensively delocalized π-system. The dihedral angle between the plane of the phenyl ring and that of the alkene component is 63.45 (7)° due to steric hindrance exerted by the tert-butyl groups. The mol­ecule has a Z-configured alkene function, which is facilitated by an intra­molecular N—H⋯O hydrogen bond between the amine and ketone groups. The mol­ecules are linked into extended chains, which run parallel to the [010] direction, by a very weak C—H⋯O inter­action between the methyl substituent of the alkene group and the ketone O atom of a neighbouring mol­ecule.
PMCID: PMC3120447  PMID: 21754790
4.  Tetra­kis(μ2-4-amino­benzoato)di-μ3-oxido-tetra­kis[dibutyl­tin(IV)] 
The mol­ecule of the title compound, [Sn4(C4H9)8(C7H6NO2)4O2], lies about an inversion centre and is a tetra­nuclear bis­(tetra­butyl­dicarboxyl­ato­distannoxane) complex containing a planar Sn4O2 core in which two μ3-oxide O atoms connect an Sn2O2 ring to two exocyclic Sn atoms. Each Sn atom has a highly distorted octa­hedral coordination. In the mol­ecule, the carboxyl­ate groups of two amino­benzoate ligands bridge the central and exocyclic Sn atoms, while two further amino­benzoate ligands have highly asymmetric bidentate chelation to the exocyclic Sn atoms plus long O⋯Sn inter­actions with the central Sn atoms. Each Sn atom is also coordinated by two pendant n-butyl ligands, which extend roughly perpendicular to the plane of the Sn4O10 core. Only one of the four unique hydrogen-bond donor sites is involved in a classic N—H⋯O hydrogen bond, and the resulting supra­molecular hydrogen-bonded structure is an extended two-dimensional network which lies parallel to the (100) plane and consists of a checkerboard pattern of four-connected mol­ecular cores acting as nodes. The amine groups not involved in the hydrogen-bonding inter­actions have significant N—H⋯π inter­actions with neighbouring amino­benzene rings.
PMCID: PMC2855585  PMID: 20203395
5.  (E)-3-(1-Naphthyl­amino)­methyl­ene-(+)-camphor 
In the crystal structure of the title ketoamine {systematic name: (E)-1,7,7-trimethyl-3-[(1-naphthyl­amino)­methyl­idene]bicyclo­[2.2.1]heptan-2-one}, C21H23NO, there are two independent mol­ecules in the asymmetric unit. Both mol­ecules have an E configuration about the alkene function. The main conformational difference between the mol­ecules is in the orientation of the plane of the naphthyl rings with respect to the camphor fragment. The torsion angle about the enamine C—N bond is 21.3 (7)° for mol­ecule A, but −24.4 (8)° for mol­ecule B. Inter­molecular N—H⋯O hydrogen bonds between the amino and ketone groups of adjacent independent mol­ecules sustain the crystal, and the resulting extended chains, containing an alternating sequence of the two independent mol­ecules, run parallel to the [001] direction and can be described by a graph-set motif of C 2 2(12).
PMCID: PMC3050145  PMID: 21522692
6.  Synthesis and X-ray structural analysis of platinum and ethynyl-platinum corannulenes: supramolecular tectons† 
Organic & biomolecular chemistry  2009;7(23):4881-4885.
The synthesis and characterization of two direct platinum (1 and 6a/b) and three ethynyl-platinum corannulene derivatives (2, 8 and 9), bearing 2, 4, or 5 square planar platinum centers, are presented. The structure of the bowl bearing substituents remains comparable to corannulene and the dynamic behavior of the bowl inversion as assessed by VT NMR supports a persistent bowl structure in solution. These platinum-corannulenes are well-structured tectons for the future assembly of coordination Platonic polyhedra.
PMCID: PMC2805086  PMID: 19907778

Results 1-6 (6)