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.

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.

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).

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 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.

Distortion isomers of cis-PtP2X2 and cis-PtP2XY derivatives – structural aspects

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Milan Melník ◽  
Peter Mikuš
Keyword(s):  
Crystal Packing ◽  
Structural Parameters ◽  
Coordination Complexes ◽  
Mean Value ◽  
Covalent Radius ◽  
Mean Values ◽  
Trans Influence ◽  
Coordination Spheres ◽  
The Mean ◽  
Structural Aspects

AbstractIn this review, the structural parameters of distortion isomers of cis-monomeric Pt(II) coordination complexes with inner coordination spheres: Pt(PL)2X2 (X = OL, NL, SL, Br, I); Pt(PL)2(η2-X2L) (X = O2L, N2L, S2L, OSL, NSL, NSeL); Pt(η2-P2L)X2 (X = Br, I); Pt(η2-P2L)(η2-X2L) (X = O2L, OSL, NSL); Pt(η2-P2L)(NL)(Cl) and Pt(PL)(η2-P,SiL)(H) are analyzed. None of the distortion isomers with cis-configuration has a trans-partner. The distortion isomers differ mostly by the degree of distortion in the Pt-L and L-Pt-L angles. Some of the isomers also differ by crystal packing. The total mean values of Pt-P (monodentate) and Pt-P (bidentate) bond distances are 2.279 Å and 2.244 Å, respectively. The mean value of Pt-P (monodentate) (trans to H¯) of 2.320 Å is the highest one because of higher trans-influence of H¯ over PP3. The total mean values of Pt-X (trans to P) elongate quite well with the covalent radius of the X in the sequence: 1.57 Å (X = H) < 2.062 Å (O2L) < 2.095 Å (OL) < 2.108 Å (NL) < 2.154 Å (N2L) < 2.329 Å (Cl) < 2.342 Å (S2L) < 2.347 Å (SL) < 2.480 Å (Br) < 2.616 Å (I).

scholarly journals Combining Metal-Metal Cooperativity, Metal-Ligand Cooperativity and Chemical Non-Innocence in Diiron Carbonyl Complexes

2021 ◽  
Author(s):  
Cody Bernard Beek ◽  
Nicolaas P. van Leest ◽  
Martin Lutz ◽  
Robertus J. M. Klein Gebbink ◽  
Bas de Bruin ◽  
...  
Keyword(s):  
Bond Activation ◽  
Binding Mode ◽  
Carbonyl Complexes ◽  
Bimetallic Systems ◽  
Metal Atoms ◽  
Metal Metal ◽  
Close Proximity ◽  
Catalytic Reactivity ◽  
Unstable Intermediate ◽  
Metal Ligand

Several metalloenzymes, including [FeFe]-hydrogenase, employ cofactors wherein multiple metal atoms work together with surrounding ligands that mediate heterolytic and concerted proton-electron transfer (CPET) bond activation steps. Herein, we report a new dinucleating PNNP expanded pincer ligand, which can bind two low-valent iron atoms in close proximity to enable metal-metal cooperativity (MMC). In addition, reversible partial dearomatization of the ligand’s naphthyridine core enables both heterolytic metal-ligand cooperativity (MLC) and chemical non-innocence through CPET steps. Thermochemical and computational studies show how a change in ligand binding mode can lower the bond dissociation free energy of ligand C(sp3)–H bonds by ~25 kcal mol-1. H-atom abstraction enabled trapping of an unstable intermediate, which undergoes facile loss of two carbonyl ligands to form an unusual paramagnetic (S = 1/2) complex containing a mixed-valent iron(0)-iron(I) core bound within a partially dearomatized PNNP ligand. Finally, cyclic voltammetry experiments showed that these diiron complexes show catalytic activity for the electrochemical hydrogen evolution reaction. This work presents the first example of a ligand system that enables MMC, heterolytic MLC and chemical non-innocence, thereby providing important insights and opportunities for the development of bimetallic systems that exploit these features to enable new (catalytic) reactivity.

Stereochemistry of heterobinuclear Pt-M complexes

2017 ◽  
Vol 37 (3-4) ◽  
pp. 131-146 ◽  
Author(s):  
Milan Melnik ◽  
Peter Mikus
Keyword(s):  
Structural Parameters ◽  
The Other ◽  
Oxidation States ◽  
Central Metal ◽  
Metal Atoms ◽  
Square Planar ◽  
Coordination Spheres

AbstractIn this review, the structural parameters of almost 30 isomers of heterobinuclear Pt-M (M=Sn, Tl, Cu, Ag, Ti, W, Cr, Fe, Co, Ni, Mn, Pd, or Rh) complexes are summarized and analyzed. There are three types of isomers: distortion (by far the prevailing type), polymerization, and mixed isomers. On the basis of Pt-M distance, there are two groups of complexes: one in which the Pt-M bond distances are <3.0 Å (M=Sn, Tl, W, Cr, Mn, Ni, or Pd) and the other one in which the Pt-M separations are >3.0 Å (M=Cu, Ag, Ti, W, Fe, Co, or Rh). Platinum atoms exist in two oxidation states: +2 and +4. The former by far prevails with a square-planar arrangement with varying degrees of distortion. The Pt(IV) atoms are six-coordinated. The inner coordination spheres about M atoms range from two-coordinated (AgNCl) to sandwiched (FeC10). There is wide variety of donor atoms (ligands) (H, OL, NL, CL, BL, Cl, SL, PL, Br, or I) that build up the respective inner coordination spheres about central metal atoms.

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