Structural aspects of heterotetranuclear platinum clusters-distortion isomers

2018 ◽  
Vol 38 (2) ◽  
pp. 77-86 ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš
Keyword(s):  
Membered Ring ◽  
Metal Atoms ◽  
Platinum Clusters ◽  
Independent Molecules ◽  
Structural Aspects

AbstractThis review includes 16 examples of distortion isomers of heterotetranuclear platinum clusters. The clusters are of the compositions: Pt3Sn, Pt2M2 (M=Au, Ag, W, Mo), and PtM3 (M=Os, Ru, Re). The four metal atoms are found in a distorted tetrahedral core (most common), planar-rhombohedral, spiked-triangular, and eight-membered ring skeleton. There are three pairs (Pt2W2, Pt2Au2, and Pt2Ag2) of clusters and all remainder clusters contain two crystallographically independent molecules within the same crystal. All are classical examples of distortion isomerism. Their structures are analyzed and discussed.

Structural aspects of heterooligonuclear platinum clusters – distortion isomers

2019 ◽  
Vol 39 (1) ◽  
pp. 1-12
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Mária Bodnár Mikulová
Keyword(s):  
Metal Bond ◽  
Metal Atoms ◽  
Metal Metal ◽  
Platinum Clusters ◽  
Coordination Spheres ◽  
Independent Molecules ◽  
Structural Aspects

AbstractThis review covers 15 clusters of the compositions Pt3Re2, Pt2Os3, Pt3AgAu, Pt3Ir3, Pt2M4 (M=Ag or Pd), PtM5 [M=Ru (×2) or Os], Pt3Os4, Pt6Au2, Pt2Ru6, Pt3Ru6, Pt2Ru8, and PtAu9. Each of the cluster contains two crystallographically independent molecules that differ mostly by degree of distortion and are classical examples of distortion isomerism. Their structures are very complex. The inner coordination spheres about the metal atoms (Pt and M) are very complex as well. The clusters are rich in metal-metal bond distances with the shortest being 2.573 Å (Pt-Au), 2.615 (Pt-Pt), and 2.673 Å (Ru-Ru).

Distortion isomers of PtM, Pt2M, PtM2 and PtMM′ (M = non-transition metals) derivatives-structural aspects

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš
Keyword(s):  
Transition Metals ◽  
Structural Parameters ◽  
Bond Angles ◽  
Bond Lengths ◽  
Metal Atoms ◽  
Independent Molecules ◽  
Structural Aspects

Abstract An analysis of the structural parameters of PtM, Pt2M, PtM2 and PtMM′ (M = non-transition metals) derivatives shows that each complex contains two crystallographically independent molecules within the same crystal. The respective molecules differ by the degrees of distortion and exemplify the distortion isomerism. These are discussed in terms of the coordination with the platinum and the M atoms and the correlations are drawn among the metal atoms, donor atoms, bond lengths and bond angles. A wide variety of non-transition metals (Sn, Ga, In, Tl, Zn, Cd, Hg, Sb) exist, among which the most prevalent is Sn.

scholarly journals Crystallographic and structural characterization of heterometallic platinum clusters Part VIII. Heteronona- and heterodecanuclear clusters

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Clive E. Holloway
Keyword(s):  
Structural Characterization ◽  
Structural Parameters ◽  
Platinum Atom ◽  
Metal Bond ◽  
Metal Atoms ◽  
Metal Metal ◽  
Platinum Clusters ◽  
Metal Composition ◽  
Independent Molecules

AbstractThis review classifies and analyses fifty heteronona- and heterodecanuclear Pt clusters of metal composition: Pt4Ru5, Pt3Ru6, Pt20sr PtRh8, PtAu8; Pt6M4, Pt5M5, Pt4M6, Pt3M2, Pt2M8, PtM9, Pt3Ru6M and PtAu8M. There are nine different heterometals: M = Ru, Au, Ag, Cu, Hg, Os, Rh, Ir and Fe, of which Ru and Au are the most frequent. The clusters crystallize mostly into two crystal classes, monoclinic (74%) and triclinic (18%), and their structures are complex. Three triangular layers of nine metal atoms arranged in the form of a face-shared bioctahedron are common in the series of heterononanuclear clusters. In the series of heterodecanuclear clusters distorted skeletal icosahedrons, where a central platinum atom is surrounded by nine metal atoms, and face (edge) shared (fused) bioctahedral cluster of the metal atoms are the most common. The most frequent ligands are CO and PPh3. The shortest metal-metal bond distances are: 2.540(4) Å (Pt-Fe), 2.580(2) Å (Ru-Ru), 2.584 Å (Pt-Pt) and 2.629(4) Å (Cu-Au). Several relationships between the structural parameters were found and are discussed. Some clusters contain two crystallographically independent molecules within the same crystal and are examples of distortion isomerism.

Structural aspects of heterotrinuclear Pt2M, PtM2, and PtMM′ complexes – distortion isomers

2018 ◽  
Vol 38 (4) ◽  
pp. 151-162 ◽  
Author(s):  
Milan Melnik ◽  
Peter Mikus ◽  
Andrea Forgacsova ◽  
Maria Bodnar Mikulova
Keyword(s):  
Structural Parameters ◽  
Bond Angles ◽  
Metal Atoms ◽  
Metal Metal ◽  
Coordination Spheres ◽  
Independent Molecules ◽  
Structural Aspects ◽  
Metal Ligand ◽  
Ligand Bond

AbstractIn this review, the structural parameters of 18 heterotrinuclear Pt2M (M=Hg, Zn, Cd, Au, Mn, Ag, Pd), PtM2 (M=Al, Ga, Sb, In, Mo, Fe), PtFeMn, PtHgMn, and PtFeOs types are summarized and analyzed. The Pt atoms are four-, five-, and even six-coordinated, among which the four-coordinated ones are the most common. The M atoms are found to be two- (Hg), three- (Hg), four- (Hg, Sb, In, Ag, Au), and six- (Ga, In, Al, Mo, Mn, Fe, Pd) coordinated and even sandwiched (FeC10). There is a wide variety of donor atoms (ligands) (O+NL, N+CL, NL, CO, CN, CL, Cl, SL, PL, I), which build up the respective inner coordination spheres about the metal atoms. The 17 complexes contain two crystallographically independent molecules within the same crystal, and 1 complex contains four such molecules. In each complex, the respective molecules are differing mostly by the degree of distortion in metal-metal and metal-ligand bond distances and ligand-metal-ligand bond angles, and are examples of distortion isomerism.

scholarly journals Crystallographic and structural characterization of heterometallic platinum compounds Part VII. Heterohepta- and heterooctanuclear clusters

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Milan Melnik ◽  
Peter Mikuš ◽  
Clive E. Holloway
Keyword(s):  
Structural Characterization ◽  
Structural Parameters ◽  
Bond Distance ◽  
Point Of View ◽  
Platinum Compounds ◽  
Metal Atoms ◽  
Platinum Clusters ◽  
Structural Point

AbstractThis review classifies and analyzes over fifty heterohepta- and heterooctanuclear platinum clusters. There are eight types of metal combinations in heteroheptanuclear: Pt6M, Pt5M2, Pt4M3, Pt3M4, Pt2M5, PtM6, Pt3Hg2Ru2 and Pt2Os3Fe2. The seven metal atoms are in a wide variety of arrangements, with the most common being one in which the central M atom (mostly M(I)) is sandwiched by two M3 triangles. Another arrangement often found is an octahedron of M6 atoms asymmetrically capped by an M atom. The shortest Pt-M bond distances (non-transition and transition) are 2.326(1) Å (M = Ga) and 2.537(6) Å (M = Fe). The shortest Pt-Pt bond distance is 2.576(2) Å.In heterooctanuclear platinum clusters there are eight types of metal combinations: Pt6M2, Pt4M4, Pt3Ru5, Pt2M6, PtM7, Pt2W4Ni2, PtAu6Hg and PtAu5Hg2. From a structural point of view, the clusters are complex with bicapped octahedrons of eight metal atoms prevailing. The shortest Pt-M bond distances (non-transition and transition) are 2.651(3) Å (M = Hg) and 2.624(1) Å (M = Os). The shortest Pt-Pt bond distance is 2.622(1) Å. These values are somewhat longer than those in the heteroheptanuclear clusters. Several relationships between the structural parameters were found, and are discussed and compared with the smaller heterometallic platinum clusters

scholarly journals Crystallographic and structural characterization of heterometallic platinum complexes Part VI. Heterohexanuclear complexes

2014 ◽  
Vol 12 (11) ◽  
pp. 1101-1126 ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Clive Holloway
Keyword(s):  
Metal Ion ◽  
Structural Parameters ◽  
Bond Distance ◽  
Transition Element ◽  
Platinum Complexes ◽  
Hard Metals ◽  
Wide Range ◽  
Platinum Clusters ◽  
Soft Metal ◽  
Independent Molecules

AbstractThis review classifies and analyzes heterohexanuclear platinum clusters into seven types of metal combinations:Pt5M, Pt4M2, Pt3M3, Pt2M4, PtM5, Pt2M3M′, and Pt2M2M2′. The crystals of these clusters generally belong to six crystal classes: monoclinic, triclinic, orthorhombic, tetragonal, trigonal and cubic. Among the wide range of stereochemistry adopted by these clusters, octahedral and capped square-pyramidal are the most common. Although platinum is classified as a soft metal atom, it bonds to a variety of soft, borderline and hard metals. Nineteen different heterometal ions are involved in hexanuclear platinum clusters. The shortest Pt-M bond distance in the case of M being a non-transition element is 2.395(4) Å for germanium and for M being a transition metal ion it is 2.402(2) Å for Cobalt. The shortest Pt-Pt bond distance observed in these clusters is 2.532 Å. Several relationships between the structural parameters are identified and discussed. Some clusters exist in two isomeric forms and some show crystallographically independent molecules within the same crystal. Such isomers and independent molecules are examples of distortion isomerism.

scholarly journals (1R,4R,6S,7R)-5,5-Dibromo-1,4,8,8-tetramethyltricyclo[5.4.1.04,6]dodecan-12-one

2014 ◽  
Vol 70 (5) ◽  
pp. o526-o526 ◽  
Author(s):  
Mohamed Zaki ◽  
Ahmed Benharref ◽  
Jean-Claude Daran ◽  
Moha Berraho
Keyword(s):  
Title Compound ◽  
Chair Conformation ◽  
Membered Ring ◽  
The Other ◽  
Boat Conformation ◽  
Asymmetric Unit ◽  
Cedrus Atlantica ◽  
Compound C ◽  
Independent Molecules

The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene), which was isolated from Atlas cedar (Cedrus atlantica). The asymmetric unit contains two independent molecules with similar conformations. Each molecule is built up from two fused seven-membered rings and an additional three-membered ring. In both molecules, one of the seven-membered rings has a chair conformation, whereas the other displays a screw-boat conformation.

scholarly journals Crystal structure of 3-(3-oxo-2,3,4,4a,5,6-hexahydrobenzo[h]cinnolin-2-yl)propionic acid

2014 ◽  
Vol 70 (10) ◽  
pp. o1088-o1089
Author(s):  
Fiorella Meneghetti ◽  
Daniela Masciocchi ◽  
Arianna Gelain ◽  
Stefania Villa
Keyword(s):  
Chair Conformation ◽  
Membered Ring ◽  
Side Chain ◽  
Boat Conformation ◽  
Asymmetric Unit ◽  
Torsion Angles ◽  
Compound C ◽  
Centroid Distance ◽  
Independent Molecules ◽  
Twisted Boat

The asymmetric unit of the title compound, C15H16N2O3, contains two independent molecules, which present a different conformation of the carboxylic acid side chain [C—C—C—OH torsion angles = 65.3 (7) and −170.1 (5)°]. In both molecules, the dihydropyridazinone ring adopts a geometry intermediate between a twisted-boat and a half-chair conformation, while the central six-membered ring is almost in a half-boat conformation. In the crystal, molecules are linked by O—H...Ok(k = ketone) hydrogen bonds, generating [01-1] chains. Aromatic π–π stacking contacts between the benzene and the dihydropyridazinone rings [centroid–centroid distance [3.879 (9) Å] are also observed.

scholarly journals Crystallographic and structural characterization of heterometallic platinum complexes Part V. Heteropentanuclear complexes

2014 ◽  
Vol 12 (3) ◽  
pp. 283-306 ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Clive Holloway
Keyword(s):  
Structural Characterization ◽  
Structural Parameters ◽  
Bond Distance ◽  
Platinum Complexes ◽  
Trigonal Bipyramidal ◽  
Metal Atoms ◽  
Independent Molecules

AbstractThis review classifies and analyzes over eighty heteropentanuclear Pt complexes. There are eight types of metal combinations: Pt4M, Pt3M2, Pt2M3, PtM4, Pt3MM′, Pt2M2M′, PtM2M′2 and PtM3M′. The five metal atoms are in a wide variety of arrangements: trigonal-bipyramidal (most common), square-pyramidal, spike-triangular, butterfly, cubane, linear and one unique. Platinum bonds to a variety of triad partner metal atoms, soft, through borderline to hard. The shortest Pt-M bond distances for non-transition and transition M are 2.406(4) Å (M = Ge) and 2.30(1) Å (M = Co). The shortest Pt-Pt bond distance is 2.580(1) Å. Several relationships between the structural parameters were found and are discussed. Several complexes exist in two isomeric forms and others contain two crystallographically independent molecules. Both the isomers as well as independent molecules are examples of distortion isomerism.

scholarly journals 2-[(3S,3aS,5R,8S,8aS)-3,8-Dimethylhexahydro-1H,4H-3a,8a-epoxyazulen-5-yl]propan-2-ol

2014 ◽  
Vol 70 (7) ◽  
pp. o776-o777 ◽  
Author(s):  
Stacey Burrett ◽  
Dennis K. Taylor ◽  
Edward R. T. Tiekink
Keyword(s):  
Crystal Packing ◽  
Minor Component ◽  
Membered Ring ◽  
Asymmetric Unit ◽  
Torsion Angles ◽  
Oh Groups ◽  
Compound C ◽  
Independent Molecules ◽  
A Chain ◽  
Independent Chain

Four independent molecules (A–D) comprise the asymmetric unit of the title compound, C15H26O2, which differ only in the relative orientations of the terminal –C(Me)2OH groups [e.g.the range of Cmethylene—Cmethine—Cquaternary—Ohydroxytorsion angles is 52.7 (7)–57.1 (6)°, where the Cmethyleneatom is bound to an epoxide C atom]. The five-membered rings adopt envelope conformations, with the methylene C atom adjacent to the methine C atom being the flap atom in each case. In each molecule, the conformation of the seven-membered ring is a half-chair, with the Cmethylene—Cmethinebond, flanked by methylene C atoms, being the back of the chair. Supramolecular helical chains along thebaxis are found in the crystal packing, sustained by hydroxy–epoxide O—H...O hydrogen bonding. Molecules ofAself-associate into a chain as do those ofD. A third independent chain comprisingBandCmolecules is also formed. The studied crystal is a pseudo-merohedral twin (minor componentca21%).

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