Nota sullo status della gallina prataiola (Tetrax tetrax) nella Zona di Protezione Speciale Piana di Semestene, Bonorva, Macomer e Bortigali (Sardegna), 2007-2009

The little bustard Tetrax tetrax is a bird of agro-pastoral landscapes rapidly disappearing from most of Western Europe due to agricultural intensification. In Italy, the species is virtually extinct from the mainland but still occurs in Sardinia, where four Special Protection Areas (SPAs) have been designated in 2007 to protect the bustard and related habitat. In this note, we document a steep decline (between 50 and 87,5%) of the species during the last decade in one of those four SPAs, Plains of Semestene, Bonorva, Macomer and Bortigali. However, during summer 2009, a group of 17 individuals was found within the SPA, confirming that the species, although at low numbers (5-15 displaying males), still breeds successfully in the area. Potential limiting factors are also discussed. We urge to undertake conservation measures based on solid scientific evidence if the local population is to be saved from probable extinction in the near future.

Structural and spectral perspectives of a novel thiosemicarbazone synthesized from di-2-pyridyl ketone and 4-phenyl-3-thiosemicarbazide

A new thiosemicarbazone, HL is synthesized from di-2-pyridyl ketone and 4-phenyl-3-thiosemicarbazide and structurally and spectrochemically characterized. H-1 NMR, C-13 NMR, COSY, HMQC and IR spectra of the compound are studied and the proton magnetic resonance spectrum reveals some unprecedented observations. The thione form is predominant in the solid state, as supported by the crystal structure and IR data, while a thiol-thione equilibrium is proposed in the solution state by NMR studies. The compound crystallizes into a monoclinic lattice with space group C2/c and the ZE conformation is exhibited by the thiosemicarbazone. Intra- and intermolecular hydrogen-bonding interactions give rise to a two-dimensional packing in the crystal lattice. (c) 2005 Elsevier B.V. All rights reserved.

Studies in nonlinear optical materials: structure of di-2-menthyl 2-(N,N'-dimethyl-2-imidazolidinylidene)malonate monohydrate

C28H48N2Oa.H2 O, Mr=494.7, orthorhombic,P2~2~2~, a = 7.634 (2), b = 11.370 (2), c=34. 167 (4) A, V = 2966 (2) A 3, Z = 4, D m = 1.095,D x -- 1. 108 g cm -3, Mo Kct, 2 -- 0.7107 ,/k, ~ =0.43 cm -~, F(000) = 1088.0, T= 293 K, R = 0.061 for 1578 significant reflections. The second-harmonicgeneration (SHG) efficiency of this compound is negligible (1/100th of the urea standard). The observed low second-order nonlinear response has been attributed to the unfavourable packing of the molecules in the crystal lattice.

b-Turn conformations in crystal structures of model peptides containing a,a-di-n-propylglycine (Dpg) and a,a-di-n-butyl-glycine (Dbg).

The crystal state conformations of three peptides containing the a,a-dialkylated residues, a,adi n-propylglycine (Dpg) and a,@-di-n-butylglycine (Dbg), have been established by x-ray diffraction. Boc-Ala-Dpg-Ala-OMe ( I ) and Boc-Ala-Dbg-Ala-OMe (III) adopt distorted type II @-turn conformations with Ala ( I ) and Dpg/Dbg (2) as the corner residues. In both peptides the conformational angles at the Dxg residue (I: 4 = 66.23 J/ = 19.3'; III: 4 = 66S0, J. = 21 .la)deviate appreciablyfrom ideal values for the i + 2 residue in a type II @-turn. In both peptides the observed(N. 0) distances between the Boc CO andAla(3) NHgroups are far too long (I:3.44 k; III: 3.63 k) for an intramolecular 4 + 1 hydrogen bond. Boc-Ala-Dpg-Ala-NHMe (II)crystallizes with two independent molecules in the asymmetric unit. Both molecules IIA and IIB adopt consecutive @-turn (type III-III in IIA and type III-I in IIB) or incipient 3,,,-helical structures, stabilized by two intramolecular 4 --t I hydrogen bonds. In all four molecules the bond angle N-C"-C' ( T ) at the Dxg residues are 2 1109 The observation of conformational angles in the helical region of 4,J/ space at these residues is consistent with theoretical predictions

Structure of a monochloro bridged polymeric copper(II)-di-2-pyridylamine complex: [Cu(dipyam)Cl(NO3)].0.5H2O

Di-2-pyridylaminechloronitratocopper(II) hemihydrate, [CuCl(NO3)(C10H9N3)].0.5H2O, M(r) = 341.21, monoclinic, P2(1)/a, a = 7.382 (1), b = 21.494 (4), c = 8.032 (1) angstrom, beta = 94.26 (1)-degrees, V = 1270.9 angstrom 3, Z = 4, D(m) = 1.78, D(x) = 1.782 g cm-3, lambda(Mo K-alpha) = 0.7107 angstrom, mu(Mo K-alpha) = 19.47 cm-1, F(000) = 688. The structure was solved by the heavy-atom method and refined to a final R value of 0.034 for 2736 reflections collected at 294 K. The structure consists of polymeric [Cu(dipyam)Cl(NO3)] units bridged by a chloride ion.

The crystal and molecular structure of putrescine - di-glutamic acid complexes

The polyamines spermine, spermidine, putrescine, cadaverine, etc. have been implicated in a variety of cellular functions. However, details of their mode of interaction with other ubiquitous biomolecules is not known. We have solved a few structures of polyamine-amino acid complexes to understand the nature and mode of their interactions. Here we report the structure of a complex of putrescine with DL-glutamic acid. Comparison of the structure with the structure of putrescine-L-glutamic acid complex reveals the high degree of similarity in the mode of interaction in the two complexes. Despite the presence of a centre of symmetry in the present case, the arrangement of molecules is strikingly similar to the L-glutamic acid complex.

Di- and tri-metallic complexes containing two bridging cyclodiphosphazane ligands: the crystal structure of [MO2(CO)8{µ-cis-[PhNP(OC6H4Me-p)]2}2]

The reactions of the mononuclear cyclodiphosphazane complexes, cis-[Mo(CO)(4){cis-[PhNP(OR)](2)}(2)] with [Mo(CO)(4)(nbd)] (nbd = norbornadiene). [Mo(CO)(4)(NHC5H10)(2)] or [MCl(2)(cod)] (cod = cycloocta-1,5-diene) afforded the homobimetallic complexes; [Mo-2(CO)(8){mu-cis-[PhNP(OR)](2)}(2)] (R = C(5)H(4)Me-p 5 or CH2CF3 6) or the heterobimetallic complexes. [Mo-2(CO)(8){mu-cis-[PhNP(OE)](2)}(2)MCl(2)] (R = C(6)H(4)Me-p; M = Pd 7 or Pt 8). In all the above complexes, the two metal moieties are bridged by two cyclodiphosphazane ligands. The reactions of the mononuclear complexes, cis-[M(CO)(4)(A){cis-[PhNP(OC(6)H(4)Me-p)](2)}] with (M'Cl-2(cod)] afforded the trinuclear complexes, cis-[M'Cl-2[M(CO)(4)(A){cis-[PhNP(OC(6)H(4)Me-p)](2)}](2)] (M' = Pd, M = Mo, A = P(OMe)(3) 10; M' = Pt, M = Mo. A = P(OMe)(3) 11; M' = Pd. M = W. A = NHC5H10 12; M' = Pt, M = W. A = NHC5H10 13). The structure of the complex 5 has been determined by single-crystal X-ray crystallography.

N-3-benzoyl-2 ',3 '-di-O-benzoyluridine

The structure of N-3-benzoyl-2',3'-di-O-benzoyluridine, C30H24N2O9, has two molecules in the asymmetric unit. The uracil bases of both the molecules are in the anti conformation with respect to the ribose moiety and the furanosyl rings adopt a C3'-endo conformation. The orientation about the C4'-C5' bond is gauche-gauche. The two crystallographically independent molecules are linked through several C-H ... O hydrogen bonds. The nucleoside molecules pack as columns along the a axis and these columns repeat along the c axis.