Formazanate Complexes of Bis-Cyclometalated Iridium

<div>In this work we describe a series of bis-cyclometalated iridium(III) formazanate complexes, expanding the coordination chemistry of the redox-active formazanate class to iridium. A total of 18 new complexes are described, varying the substituent pattern on the formazanate and the identity of the cyclometalating ligand on iridium. Eight of the new compounds are structurally characterized by single-crystal X-ray diffraction, which along with NMR spectroscopy evinces two binding modes of the formazanate. Two of the compounds are isolated in a C2-symmetric geometry where the formazanate is bound in a six-member chelate “closed” conformation, involving the 1- and 5-positions of the 1,2,4,5-tetraazapentadienyl formazanate core. In most of the examples, the major isomer that forms and is exclusively isolated involves the formazanate bound in a five-member chelate “open” form, coordinating through the 1- and 4-positions of the formazanate core and resulting in C1 point-group symmetry. All complexes are characterized by UV-vis absorption spectroscopy and cyclic voltammetry, with these features depending primarily on the substitution pattern on the formazanate, and to a lesser extent on the identity of the cyclometalating ligand and formazanate binding mode.</div>

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Darstellung und Kristallstruktur von [(NH3)5Rh(H7O4)Rh(NH3)5](S2O6)2,5 · H2O (1). Ein gemischtes Aquopentamminrhodium(III)-hydroxopentamminrhodium(III)- dithionat mit einer neuartigen μ-H7O4-Struktureinheit / Preparation and Crystal Structure of [(NH3)5Rh(H7O4)Rh(NH3)5](S2O6)2,5 · H2O (1). A Mixed Aquopentaamminerhodium(III)-hydroxopentaamminerhodium(III) Dithionate with a Novel μ-H7O4 Structural Unit

Zeitschrift für Naturforschung B ◽

10.1515/znb-1988-0210 ◽

1988 ◽

Vol 43 (2) ◽

pp. 189-195 ◽

Cited By ~ 4

Author(s):

Walter Frank ◽

Thomas Stetzer ◽

Ludwig Heck

Keyword(s):

Crystal Structure ◽

Structural Unit ◽

Small Difference ◽

Point Group ◽

Group Symmetry ◽

Monoclinic Space Group ◽

Crystal Data ◽

X Ray Diffraction ◽

Hydrogen Atoms ◽

X Ray

The title compound 1 can be obtained from an aqueous solution of aquopentaammine rhodium(III) dithionate and hydroxopentaammine rhodium(III) dithionate. The crystal structure has been determined from single crystal X-ray diffraction data and refined to R = 0.035 for 4390 unique reflections. Crystal data: monoclinic, space group P21/c, a = 1300.9(5) pm. b = 1472.3(6) pm. c = 1478.8(9) pm, β = 106.20(4)°, Z = 4.In the crystal dinuclear rhodium cations with point group symmetry 1 (C1) are found. A central μ-H3O2-bridge is formed by strong hydrogen bonding between aquo and hydroxo ligands; this bridge is additionally coordinated by two molecules of water. The entire bridging system is therefore H7O4-(H3O2- · 2 H2O). O-O distances characterizing the strength of the three hydrogen bonds within this new kind of structural unit are O(H2O-Rh 1)-O(HO-Rh2): 248 pm. O(H2O-Rh 1)-O(H2Oa): 273 pm, O(HO-Rh2)-O(H2Ob): 287 pm. The hydrogen atoms involved in these bridges have been located. The small difference in the Rh 1-O(H2O) - (205.4(3) pm) and Rh2-O(OH)- (204.3(3) pm) distances indicates that the entire H7O4-- moiety serves as a μ-bridging unit between Rh 1 and Rh 2

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Redetermination of the crystal structure of caesium tetrafluoridobromate(III) from single-crystal X-ray diffraction data

IUCrData ◽

10.1107/s2414314620001145 ◽

2020 ◽

Vol 5 (1) ◽

Author(s):

Artem V. Malin ◽

Sergei I. Ivlev ◽

Roman V. Ostvald ◽

Florian Kraus

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Diffraction Data ◽

Point Group ◽

Group Symmetry ◽

Site Symmetry ◽

X Ray Diffraction ◽

Cation Site ◽

X Ray ◽

Square Planar

Caesium tetrafluoridobromate(III), CsBrF4, was crystallized in form of small blocks by melting and recrystallization. The crystal structure of CsBrF4 was redetermined from single-crystal X-ray diffraction data. In comparison with a previous study based on powder X-ray diffraction data [Ivlev et al. (2013). Z. Anorg. Allg. Chem. 639, 2846–2850], bond lengths and angles were determined with higher precision, and all atoms were refined with anisotropic displacement parameters. It was confirmed that the structure of CsBrF4 contains two square-planar [BrF4]− anions each with point group symmetry mmm, and a caesium cation (site symmetry mm2) that is coordinated by twelve fluorine atoms, forming an anticuboctahedron. CsBrF4 is isotypic with CsAuF4.

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Group 11 Pincer Oxazoline Complexes

10.32920/ryerson.14645448 ◽

2021 ◽

Author(s):

Mahroo T. Seighalani

Keyword(s):

Point Group ◽

Diffraction Method ◽

Binding Mode ◽

Group Symmetry ◽

Pincer Complexes ◽

Pincer Ligands ◽

Henry Reaction ◽

X Ray Diffraction ◽

Pincer Ligand ◽

Nitroaldol Reaction

The synthesis and characterization of new copper pincer complexes via cyclometallation of potentially anionic pincer ligands with C1 point group symmetry is reported. All of these complexes have been characterized by single crystal X-ray diffraction method, which confirms the proposed tridentate binding mode of pincer ligand and the formation of an amido N-Cu bond. The reactivity of two of the complexes was investigated towards C-C bond formation reaction, notably the Henry reaction. One of the complexes, which was derived from the achiral pincer ligand, is shown to be a suitable catalyst for the Henry reaction under the standard conditions. The Henry or nitroaldol reaction is one of the organic reactions which affords a C-C bond. The product of this reaction is a β-nitro alcohol which is formed by addition of a nitroalkane to a carbonyl compound.

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Dinuclear Complexes of Flexidentate Pyridine-Substituted Formazanate Ligands

10.26434/chemrxiv.12077586.v1 ◽

2020 ◽

Author(s):

Ge Mu ◽

Thomas Teets

Keyword(s):

Ligand Binding ◽

Building Blocks ◽

Binding Mode ◽

Redox Properties ◽

Dinuclear Complexes ◽

Binding Modes ◽

X Ray Diffraction ◽

Frontier Orbitals ◽

X Ray ◽

Dinuclear Structure

In this work we show the utility of flexidentate pyridyl‐substituted formazanate ligands in assembling dinuclear coordinationcomplexes with iridium(III) and/or platinum(II) building blocks. The versatile binding modes of these ligands allow the preparation of several different dinuclear structures, highlighting the potential of these formazanates to serve as redoxactive supporting ligands for multimetallic complexes. The dinuclear complexes are typically prepared in a stepwise strategy, adding one metal unit at a time, with the coordination mode of the formazanate with the first metal dictating the binding mode in the final dinuclear structure. Eight of the new complexes, including both mononuclear precursors and dinuclear products, are structurally characterized by single‐crystal X‐ray diffraction, which along with NMR spectroscopy unambiguously establish ligand binding modes and symmetries of the compounds. All complexes are characterized by UVVis absorption spectroscopy and cyclic voltammetry. The frontier orbitals are localized on the formazanate ligand, and a characteristic, intense formazanate‐centered π→π* absorption band is observed in the absorption spectrum. Structureproperty relationships are established, relating the ligand binding mode to the redox properties and spectroscopic features. .<br>

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Redetermination of the crystal structure of β-zinc molybdate from single-crystal X-ray diffraction data

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s205698901501186x ◽

2015 ◽

Vol 71 (7) ◽

pp. i6-i7 ◽

Cited By ~ 1

Author(s):

Olfa Mtioui-Sghaier ◽

Rafael Mendoza-Meroño ◽

Lilia Ktari ◽

Mohamed Dammak ◽

Santiago García-Granda

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Diffraction Data ◽

Point Group ◽

Structure Type ◽

Group Symmetry ◽

X Ray Diffraction ◽

X Ray ◽

Bond Lengths ◽

Anisotropic Displacement Parameters

The crystal structure of the β-polymorph of ZnMoO4was re-determined on the basis of single-crystal X-ray diffraction data. In comparison with previous powder X-ray diffraction studies [Katikaneani & Arunachalam (2005).Eur. J. Inorg. Chem. pp. 3080–3087; Cavalcanteet al.(2013).Polyhedron,54, 13–25], all atoms were refined with anisotropic displacement parameters, leading to a higher precision with respect to bond lengths and angles. β-ZnMoO4adopts the wolframite structure type and is composed of distorted ZnO6and MoO6octahedra, both with point group symmetry 2. The distortion of the octahedra is reflected by variation of bond lengths and angles from 2.002 (3)–2.274 (4) Å, 80.63 (11)–108.8 (2)° for equatorial and 158.4 (2)– 162.81 (14)° for axial angles (ZnO6), and of 1.769 (3)–2.171 (3) Å, 73.39 (16)–104.7 (2), 150.8 (2)–164.89 (15)° (MoO6), respectively. In the crystal structure, the same type ofMO6octahedra share edges to built up zigzag chains extending parallel to [001]. The two types of chains are condensed by common vertices into a framework structure. The crystal structure can alternatively be described as derived from a distorted hexagonally closed packed arrangement of the O atoms, with Zn and Mo in half of the octahedral voids.

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Group 11 Pincer Oxazoline Complexes

10.32920/ryerson.14645448.v1 ◽

2021 ◽

Author(s):

Mahroo T. Seighalani

Keyword(s):

Point Group ◽

Diffraction Method ◽

Binding Mode ◽

Group Symmetry ◽

Pincer Complexes ◽

Pincer Ligands ◽

Henry Reaction ◽

X Ray Diffraction ◽

Pincer Ligand ◽

Nitroaldol Reaction

The synthesis and characterization of new copper pincer complexes via cyclometallation of potentially anionic pincer ligands with C1 point group symmetry is reported. All of these complexes have been characterized by single crystal X-ray diffraction method, which confirms the proposed tridentate binding mode of pincer ligand and the formation of an amido N-Cu bond. The reactivity of two of the complexes was investigated towards C-C bond formation reaction, notably the Henry reaction. One of the complexes, which was derived from the achiral pincer ligand, is shown to be a suitable catalyst for the Henry reaction under the standard conditions. The Henry or nitroaldol reaction is one of the organic reactions which affords a C-C bond. The product of this reaction is a β-nitro alcohol which is formed by addition of a nitroalkane to a carbonyl compound.

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Crystal structure of the formal 20 electron zirconocene pentafulvene complex Cp2Zr(η5,η1-adamantylidenepentafulvene):toluene:n-hexane = 1:0.125:0.125

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989017015560 ◽

2017 ◽

Vol 73 (12) ◽

pp. 1823-1826 ◽

Cited By ~ 3

Author(s):

Malte Fischer ◽

Marc Schmidtmann ◽

Rüdiger Beckhaus

Keyword(s):

Crystal Structure ◽

Binding Mode ◽

X Ray Diffraction ◽

Substitution Pattern ◽

Complex Molecules ◽

Coordination Environment ◽

X Ray ◽

Zirconocene Dichloride ◽

Solvent Molecules ◽

Distorted Tetrahedral Coordination

The crystal structure of a solvated zirconocene pentafulvene complex with a bulky adamantylidene substitution pattern, namely (η5,η1-adamantylidenepentafulvene)bis(η5-cyclopentadienyl)zirconium(IV)–toluene–n-hexane (8/1/1), [Zr(C15H18)(C5H5)2]·0.125C7H8·0.125C6H14, is reported. Reducing zirconocene dichloride with magnesium results in the formation of a low-valent zirconocene reagent that reacts readily with adamantylidenepentafulvene to give the aforementioned complex. Single crystal X-ray diffraction proves the dianion-like η5:η1binding mode of the fulvene ligand to the central ZrIVatom. The asymmetric unit contains four independent molecules of [η5:η1-adamantylidenepentafulvene]bis[(η5)-cyclopentadienyl]zirconium(IV), together with half a molecule of toluene disordered with half a molecule ofn-hexane (the solvent molecules have no direct influence on the complex). In each of the four complex molecules, the central ZrIVatom has a distorted tetrahedral coordination environment. The measured crystal consisted of two domains with a refined ratio of 0.77:0.23.

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Crystal structure of tetrawickmanite, Mn2+Sn4+(OH)6

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015001632 ◽

2015 ◽

Vol 71 (2) ◽

pp. 234-237 ◽

Cited By ~ 2

Author(s):

Barbara Lafuente ◽

Hexiong Yang ◽

Robert T. Downs

Keyword(s):

Crystal Structure ◽

Hydrogen Bonds ◽

Point Group ◽

The Other ◽

Group Symmetry ◽

Tetragonal Symmetry ◽

Point Group Symmetry ◽

Natural Sample ◽

X Ray Diffraction ◽

X Ray

The crystal structure of tetrawickmanite, ideally Mn2+Sn4+(OH)6[manganese(II) tin(IV) hexahydroxide], has been determined based on single-crystal X-ray diffraction data collected from a natural sample from Långban, Sweden. Tetrawickmanite belongs to the octahedral-framework group of hydroxide-perovskite minerals, described by the general formulaBB'(OH)6with a perovskite derivative structure. The structure differs from that of anABO3perovskite in that theAsite is empty while each O atom is bonded to an H atom. The perovskiteB-type cations split into orderedBandB′ sites, which are occupied by Mn2+and Sn4+, respectively. Tetrawickmanite exhibits tetragonal symmetry and is topologically similar to its cubic polymorph, wickmanite. The tetrawickmanite structure is characterized by a framework of alternating corner-linked [Mn2+(OH)6] and [Sn4+(OH)6] octahedra, both with point-group symmetry -1. Four of the five distinct H atoms in the structure are statistically disordered. The vacantAsite is in a cavity in the centre of a distorted cube formed by eight octahedra at the corners. However, the hydrogen-atom positions and their hydrogen bonds are not equivalent in every cavity, resulting in two distinct environments. One of the cavities contains a ring of four hydrogen bonds, similar to that found in wickmanite, while the other cavity is more distorted and forms crankshaft-type chains of hydrogen bonds, as previously proposed for tetragonal stottite, Fe2+Ge4+(OH)6.

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M+M3+2As(HAsO4)6and α- and β-M+M3+(HAsO4)2(M+M3+= RbAl or CsFe): six new compounds crystallizing in three closely related structure types

Acta Crystallographica Section C Structural Chemistry ◽

10.1107/s2053229618007064 ◽

2018 ◽

Vol 74 (6) ◽

pp. 721-727 ◽

Cited By ~ 4

Author(s):

Karolina Schwendtner ◽

Uwe Kolitsch

Keyword(s):

Single Crystal ◽

Crystal Structures ◽

General Formula ◽

Structure Type ◽

Group Symmetry ◽

Charge Balance ◽

X Ray Diffraction ◽

X Ray ◽

Stacking Order ◽

New Compounds

The crystal structures of hydrothermally synthesized (T= 493 K, 7–9 d) rubidium aluminium bis[hydrogen arsenate(V)], RbAl(HAsO4)2, caesium iron bis[hydrogen arsenate(V)], CsFe(HAsO4)2, rubidium dialuminium arsenic(V) hexakis[hydrogen arsenate(V)], RbAl2As(HAsO4)6, and caesium diiron arsenic(V) hexakis[hydrogen arsenate(V)], CsFe2As(HAsO4)6, were solved by single-crystal X-ray diffraction. The four compounds with the general formulaM+M3+(HAsO4)2adopt the RbFe(HPO4)2structure type (R\overline{3}c) and a closely related new structure type, which is characterized by a different stacking order of the building units, leading to noncentrosymmetric space-group symmetryR32. The second new structure type, with the general formulaM+M3+2As(HAsO4)6(R\overline{3}c), is also a modification of the RbFe(HPO4)2structure type, in which one third of theM3+O6octahedra are replaced by AsO6octahedra, and two thirds of the voids in the structure, which are usually filled byM+cations, remain empty to achieve charge balance.

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