PubMed Health⌕ Search

Biomedical subjects

Werner Massa

Publications and source records attributed to Werner Massa.

At least 19 recordsLinked to original sources
PubMed2006

Proton-stabilized three-dimensional anionic framework in H[Zn6O2(BO3)3].

A three-dimensional anionic framework built up from [ZnO4] tetrahedra and planar [BO3] groups, stabilized by H atoms, has been found for hydrogen zinc oxide borate, H[Zn6O2(BO3)3]. Boron and one of the borate O atoms are on 18e (2) positions. Triple units of [ZnO4] tetrahedra sharing a common oxygen vertex on a 12c (3) site and strong asymmetrical linear hydrogen bonds with the H atom [on a 12c (3) position] disordered over a twofold axis are specific structural features of this zincoborate. There is evidence that the reported Zn4O(BO3)2 [Harrison, Gier & Stuky (1993). Angew. Chem. Int. Ed. Engl. 32, 724-726] corresponds to this structure.

Journal Article↗
PubMed2005

Low-dimensional compounds containing cyano groups. XII. Bis(1,3-diaminopropane-kappa2N,N')(dicyanamido-kappaNPart XI: Potocnák, Burcák, Baran and Jäger (2005).)copper(II) perchlorate.

The title compound, [Cu(C2N3)(C3H10N2)2]ClO4, is made up of [Cu(tn)2{N(CN)2}]+ complex cations (tn is 1,3-diaminopropane) and ClO4- anions. The Cu(II) atom is coordinated by four N atoms of two equatorial tn ligands, with an average distance of 2.041 (7) A, and one nitrile N atom of the dicyanamide anion in an axial position, at a distance of 2.236 (3) A, in a manner approaching square-planar coordination geometry. The complex has C(s) symmetry, with the mirror plane lying through the central C atoms of both tn ligands and the dca ligand. The ClO4- anion might be considered as very weakly coordinated in the opposite axial position [Cu-O = 2.705 (3) A], thus completing the Cu(II) coordination to asymmetric elongated octahedral (4+1+1*). The Cu atom and the perchlorate anion both lie on mirror planes.

Journal Article↗
PubMed2004

Tetra-mu-benzoato-kappa8O:O'-bis([1-[(3,4-dimethoxyphenyl)methyl]-6,7-dimethoxyisoquinoline-kappaN]zinc(II)): the first crystal structure with papaverine as a ligand.

The title complex, [Zn(2)(C(7)H(5)O(2))(4)(C(20)H(21)NO(4))(2)], forms dimers of the paddle-wheel cage type located at crystallographic inversion centres. The two Zn atoms [Zn.Zn = 3.0533 (4) A] are connected by four syn-syn benzoate ligands. The apical positions of the square-pyramidal zinc coordination polyhedra are occupied by the N atoms of the papaverine ligand. Upon coordination, the mutual orientation of the phenyl and isoquinoline rings in papaverine is changed compared with that in the uncoordinated ligand.

Crystallography, X-Ray↗
PubMed2003

The three-dimensional coordination polymer tetraethylammonium (ethylenediamine)cadmium(II) hexacyanoferrate(III), (Et(4)N)[[Cd(en)](4)[Fe(CN)(6)](3)].

The title compound, tetraethylammonium dodeca-mu-cyano-hexacyanotetrakis(ethylenediamine)tetracadmium(II)triferrate(III), (C(8)H(20)N)[Cd(4)Fe(3)(CN)(18)(C(2)H(8)N(2))(4)], was prepared from a reaction mixture containing CdCl(2), K(3)[Fe(CN)(6)], ethylenediamine (en) and [Et(4)N]Br in a 1:1:3:1 molar ratio. The crystal structure consists of a negatively charged three-dimensional framework of [[Cd(en)](4)[Fe(CN)(6)](3]n)(n-) anions, with [Et(4)N](+) cations located in the cavities of the framework. The Cd atom is octahedrally coordinated by one disordered chelating en molecule [mean Cd-N = 2.35 (3) A] and four N-bonded bridging cyano groups [Cd-N distances are in the range 2.283 (2)-2.441 (2) A]. There are two crystallographically independent [Fe(CN)(6)](3-) anions in the structure and in each the Fe atom lies on a twofold axis. In the first [mean Fe-C = 1.941 (5) A], all the cyano groups are bridging ligands, while in the second [mean Fe-C = 1.945 (2) A], there are two terminal cyano ligands in trans positions. The Cd-N-C angles range from 128.6 (2) to 172.8 (2) degrees.

Journal Article↗
PubMed2002

Low-dimensional compounds containing cyano groups. IV. Bis(2,2'-bipyridine-kappa(2)N,N1)(dicyanamido-kappaN')copper(II) perchlorate and mu-dicyanamido-kappa(2)N1:N5-bis[bis(2,2'-bipyridine-kappa(2)N,N')copper(II)] triperchlorate ethanol hemisolvate, complexes with unusual dicyanamide coordination.

From reaction mixtures containing the same reagents, the two novel title complexes, with unusual coordination modes of the dicyanamide (dca) ligand, have been prepared. The first compound, [Cu(C(2)N(3))(C(10)H(8)N(2))(2)]ClO(4), represents a relatively rare class of compounds, with the dca ligand coordinated in a monodentate manner. Its structure is formed by the [Cu(bpy)(2)N(CN)(2)](+) complex cation (bpy is 2,2'-bipyridine) and a ClO(4)(-) anion, which does not enter the inner coordination sphere. The Cu centre is five-coordinate within a strongly distorted trigonal bipyramid to two bpy molecules and one dca ligand, which is coordinated through one nitrile N atom in the equatorial plane. The second compound, [Cu(2)(C(2)N(3))(C(10)H(8)N(2))(4)](ClO(4))(3).0.5C(2)H(6)O, contains dca coordinated in the more common bidentate manner, but instead of a chain structure, a unique binuclear complex is formed. The asymmetric unit consists of the [Cu(bpy)(2)N(CN)(2)(bpy)(2)Cu](3+) binuclear complex cation, the charge of which is neutralized by three uncoordinated perchlorate anions, and a half-molecule of ethanol. Both Cu centres in the cation are five-coordinate, adopting a slightly distorted trigonal-bipyramidal environment.

Journal Article↗
PubMed2002

Cu2(dien)2Ag5(CN)9 containing the one-dimensional polymeric cation [Cu(dien)Ag(CN)2](n+)(n) and the unusual [Ag2(CN)3]- anion (dien is diethylenetriamine).

From the 1:1 system of [Cu(dien)(2)](NO(3))(2) and K[Ag(CN)(2)] in water (dien is diethylenetriamine, C(4)H(13)N(3)), the novel compound catena-poly[bis[[mu-cyano-1:2kappa(2)C:N-diethylenetriamine-2kappa(3)N-copper(II)silver(I)]-mu-cyano-1:2'kappa(2)C:N] dicyanosilver(I) tricyanodisilver(I)], [CuAg(CN)(2)(dien)](2)[Ag(CN)(2)][Ag(2)(CN)(3)], has been isolated. The structure is formed from positively charged [-Cu(dien)-NC-Ag-CN-](n+)(n) chains and two isolated centrosymmetric [Ag(CN)(2)](-) and [Ag(2)(CN)(3)](-) anions. In the cationic chains, the Cu atoms are linked by bridging dicyanoargentate groups, and the deformed square-pyramidal coordination polyhedron of the Cu(II) cation is formed from a tridentate chelate-like bonded dien ligand and two N-bonded bridging cyano groups. One of the bridging cyano groups occupies the apical (ap) position [mean Cu-N(eq) = 2.02 (2) A, and Cu-N(ap) = 2.170 (3) A; eq is equatorial]. Short argentophilic interactions in the range 3.16-3.30 A are present in the crystal structure.

Journal Article↗