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 compounds part IV: heterotetranuclear clusters

2013 ◽  
Vol 11 (12) ◽  
pp. 1902-1953 ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Clive Holloway
Keyword(s):  
Structural Characterization ◽  
Structural Parameters ◽  
Platinum Compounds ◽  
Metal Atoms ◽  
Platinum Clusters

AbstractThis review includes over two hundred heterotetranuclear platinum clusters. The clusters are of the compositions Pt3M, Pt3M2, PtM3, Pt′2MM′, PtM2M′ and PtMM′M”. There are twenty five different M atoms (transition and non-transition) as a partner(s) of platinum. The four metal atoms are found in a tetrahedral, planar-rhombohedral, butterfly, spited-triangular, cubane, eight — and oligo-membered rings and a unique structures. There is wide variety of the ligands from uni to- undecadentate, with the most common P and C donor sites. The shortest Pt-M (transition) versus Pt-M (non-transition) bond distances are 2.4833(8)Å (M=Pd) vs. 2.4365(5)Å (Ge). Several relationships between the various structural parameters were found and are discussed.

scholarly journals Crystalographic and structural characterization of heterometallic platinum compounds. Part III: heterotrinuclear compounds

2013 ◽  
Vol 11 (6) ◽  
pp. 827-900 ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš ◽  
Clive Holloway
Keyword(s):  
Structural Characterization ◽  
Structural Parameters ◽  
Bond Distance ◽  
Platinum Complexes ◽  
Review Article ◽  
Platinum Compounds ◽  
Metal Atoms ◽  
Wide Variability ◽  
Independent Molecules

AbstractThis review article includes over three hundred and sixty heterotrinuclear platinum complexes of the composition Pt2M (205 examples), PtM2 (132 examples) and PtMM (24 examples). The heterometals include the non-transition and transition metals. Three metal atoms form a wide variability of frameworks: M3 triangular, dicapped M3 triangular, V shaped M3, M3 linear, five-, six- and seven- metallocycles and unique structures of which triangular and linear are the most common. This has led to a rich chemistry of platinum not only from variability of metals, but also from their framework and stereochemistry. The shortest Pt-M (non-transition) and Pt-M (transition) bonds are 2.315(1) Å for Pt-Ga and 2.4896(9) Å for Pt-Co. The shortest Pt-Pt bond distance is 2.581(1) Å. Two complexes exist in two isomeric forms and several others contain crystallographically independent molecules. All are typical examples of distortion isomerism. Correlations between structural parameters, heterometal and ligand donor atoms are developed and discussed.

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 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.

scholarly journals Chemical and Structural Characterization of Maize Stover Fractions in Aspect of Its Possible Applications

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1527
Author(s):  
Magdalena Woźniak ◽  
Izabela Ratajczak ◽  
Dawid Wojcieszak ◽  
Agnieszka Waśkiewicz ◽  
Kinga Szentner ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Biogas Production ◽  
Structural Parameters ◽  
C:N Ratio ◽  
Crystallinity Index ◽  
Degree Of Crystallinity ◽  
Cellulose Content ◽  
X Ray Diffraction ◽  
Maize Stover

In the last decade, an increasingly common method of maize stover management is to use it for energy generation, including anaerobic digestion for biogas production. Therefore, the aim of this study was to provide a chemical and structural characterization of maize stover fractions and, based on these parameters, to evaluate the potential application of these fractions, including forbiogas production. In the study, maize stover fractions, including cobs, husks, leaves and stalks, were used. The biomass samples were characterized by infrared spectroscopy (FTIR), X-ray diffraction and analysis of elemental composition. Among all maize stover fractions, stalks showed the highest C:N ratio, degree of crystallinity and cellulose and lignin contents. The high crystallinity index of stalks (38%) is associated with their high cellulose content (44.87%). FTIR analysis showed that the spectrum of maize stalks is characterized by the highest intensity of bands at 1512 cm−1 and 1384 cm−1, which are the characteristic bands of lignin and cellulose. Obtained results indicate that the maize stover fraction has an influence on the chemical and structural parameters. Moreover, presented results indicate that stalks are characterized by the most favorable chemical parameters for biogas production.

A Methyl Group Bridging on Three Metal Atoms. Solid-State and Solution Structural Characterization of the [Re3(μ-H)3(μ3-CH3)(CO)9]-Anion

1999 ◽  
Vol 121 (10) ◽  
pp. 2307-2308 ◽  
Author(s):  
T. Beringhelli ◽  
G. D'Alfonso ◽  
M. Panigati ◽  
F. Porta ◽  
P. Mercandelli ◽  
...  
Keyword(s):  
Solid State ◽  
Structural Characterization ◽  
Methyl Group ◽  
Metal Atoms

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 Crystallographic and structural characterization of heterometallic platinum compounds. Part II. Heterobinuclear Pt compounds with Pt⋯M (M = transition or lantanide metal) > 3.0 Å

2012 ◽  
Vol 10 (6) ◽  
pp. 1709-1759 ◽  
Author(s):  
Milan Melnik ◽  
Ondrej Sprusansky ◽  
Clive Holloway
Keyword(s):  
Transition Metal ◽  
Chlorine Atom ◽  
Structural Characterization ◽  
Platinum Compounds ◽  
Factors Affecting ◽  
Bond Lengths ◽  
Trigonal Bipyramidal ◽  
Square Planar ◽  
Independent Molecules

AbstractThis review covers almost two hundred and twenty heterobinuclear platinum compounds in which Pt⋯M separation is over 3.0 Å. The M is a transition metal (Cu, Ag, Au, Ti, V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni and Pd). There is an example of a lanthanide, Yb and a actinide, U. The Pt atom has oxidation numbers 0, +2 and +4. The Pt coordination geometries include trigonal planar Pt(0); square planar Pt(II); trigonal bipyramidal, and pseudo octahedral Pt(IV), with the most frequent being square planar. The most common ligands for Pt are P and C donor atoms, as well as a chlorine atom. The Pt — Ag distance of 3.002(1) Å is the shortest found in this series. There are examples which contain two crystallographically independent molecules, which differ mostly by degree of distortion and even one unique example, which contains eight such molecules. These are examples of distortion isomerism. Factors affecting bond lengths and angles are discussed and some ambiguities in coordination polyhedral are outlined.

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