Complexes with New Chelate Anionic Ligands Formed by Nucleophilic Addition in Copper(II) Coordination Sphere. III. The Crystal Structures of (2,2'-Bipyridine-N,N')(cyanato-N)[methyl(2-cyano-2-imidoxy Ethaneimidate-N,N')]copper(II) and (2,2'-Bipyridine-N,N')(2-cyano-2-imidoxy Ethaneimidate-N,N')copper(II)

1999 ◽  
Vol 64 (4) ◽  
pp. 600-612 ◽  
Author(s):  
Michal Dunaj-Jurčo ◽  
Ivan Potočňák ◽  
Dušan Mikloš ◽  
Robert Klement

Crystal structures of Cu(II) compounds with new chelate anionic ligands are presented. The formulae of these compounds are [Cu(bipy)(mcoe)(NCO)] (1) and [Cu(bipy)(coe)] (2), where bipy is 2,2'-bipyridine, mcoe and coe are the anionic chelate ligands methyl(2-cyano-2-imidoxy ethaneimidate), [(ON)(NC)C-C(NH)(OCH3)]1- (3), and 2-cyano-2-imidoxy ethaneimidate, [(ON)(NC)C-C(NH)(O)]2- (4), respectively, formed by nucleophilic addition of methanol and hydroxide ion to the coordinatively activated β-carbon of the nitroso-dicyanomethanide. Formation of the hydroxide ion from water in the reaction mixture can be explained by protonation of the C(CN)3- anion. The coordination polyhedra in 1 and 2 are quite different. The coordination polyhedron around the Cu(II) ion in 1 is a distorted trigonal bipyramid and in 2 a distorted square. The Cu(II) ion in 1 is coordinated by four N atoms from two bidentate ligands and one N atom from the NCO- group. The crystal structure consists of discrete molecules with {CuN5} chromophore. On the other hand, the Cu(II) ion in 2 is coordinated by four N atoms from two bidentate ligands in square coordination and the molecules are linked by weaker contacts between copper and oxygen atoms (Cu-O1i = 2.503(3), Cu-O2ii = 2.801(3) Å; i = -x, -y, -z + 1; ii = -x + 1, -y, -z + 1) to infinite chains parallel with c. Thus the coordination polyhedron is completed to an elongated tetragonal bipyramid with the {CuN4O*O*} chromophore. The angle O1i-Cu-O2ii is 167.9(1)° and the crystal structure cannot be considered as molecular but consisting of chains running in one direction. Inspection of the bond distances in mcoe and coe indicates strongly delocalized π-bonding systems. This is also supported by the fact that the anions are almost planar with bond angles close to 120°. The calculated Wiberg (bond-order) indices show that due to conjugation, the bonds within the metallocycle in mcoe and coe exhibit partially multiple character.

1995 ◽  
Vol 48 (12) ◽  
pp. 1933 ◽  
Author(s):  
CT Abrahams ◽  
GB Deacon ◽  
CM Forsyth ◽  
WC Patalinghug ◽  
BW Skelton ◽  
...  

With the facile displacement being utilized of thf from Yb(pin)2(thf)4 (pin = 2-phenylindol-1-yl, thf = tetrahydrofuran) in toluene solution, the complexes Yb(pin)2(dme)2 (dme = 1,2- dimethoxyethane), Yb(pin)2 (tmen)(tmen = N,N,N′,N′-tetramethylethane-1,2-diamine) and Yb(pin)2(diglyme)(thf) (diglyme = bis(2-methoxyethyl) ether) have been prepared from the respective ligands and Yb(pin)2(thf)4. Yb(pin)2 (diglyme) (thf) [monoclinic, space group P 21 /c, a 15.35(1), b 16.179(5), c 14.45(2) Ǻ, β 107.51(8)°, Z 4, R 0.044 for 2956 (I > 3σ(I)) 'observed' reflections] has a monomeric six-coordinate structure with transoid nitrogen donor atoms, N-Yb-N 143.6(4)° and an irregular coordination polyhedron described as either a distorted trigonal prism or a monocapped square pyramid. Attempted crystallization of Yb(pin)2 (thf) by partial desolvation of Yb(pin)2(thf)4 in hot toluene, containing a trace of dme, gave a mixture of red Yb(pin)2(thf) and orange [Yb(pin)2(dme)]2. The latter was independently synthesized by partial desolvation of Yb(pin)2(dme)2 in toluene. An X-ray crystal structure showed [Yb(pin)2(dme)]2 [monoclinic, space group P 21/c, a 11 .614(2), b 15.945(7), c 15.327(4) Ǻ, β 110.19(2)°, Z 2 dimers, R 0.070 for 2314 (I ≥ 3σ(I)) 'observed' reflections] to be a dimer with two bridging pin ligands, coordinated through nitrogen only. There is an approximately square pyramidal five-coordinate ytterbium environment with an apical dme oxygen, and with two bridging nitrogens, a terminal nitrogen, and a dme oxygen in the basal plane.


1982 ◽  
Vol 37 (12) ◽  
pp. 1499-1503 ◽  
Author(s):  
Heinrich Nöth

Mg(BH4)2 • 3 THF was prepared from MgHo and B2H6 in tetrahydrofuran. It crystallizes monoclinically, space group C2/c, Z = 4. The crystal structure reveals that the molecule contains a seven-coordinate Mg center. Its BH4 groups form double hydrogen bridges to magnesium. The geometry at Mg corresponds to a slightly distorted trigonal bipyramid for the O 3 B 2 (Mg)-coordination polyhedron, with two THF molecules in apical and one in equatorial position. A two-fold crystallographic axis passes through Mg and the equatorial oxygen atom thus posing C2 symmetry on the molecule


1989 ◽  
Vol 44 (3) ◽  
pp. 249-256 ◽  
Author(s):  
Brigitte Eisenmann ◽  
Roland Zagler

Abstract The crystal structures of Na3SbSe4, K3SbSe4 and [Ba(en)4]2[Ba(en)3](SbSe4)2 contain isolated tetrahedral anions SbSe43-, which are the first examples of selenoantimonates(V). Na3SbSe4 (space group 143m , a = 750.1(2) pm, Z = 2) is an isotype of the (NH4)3SbS4-structure type; K3SbSe4 (space group R3c, a = 1137.5(4) pm, c = 1359.6(4) pm, Z = 6) forms a slightly distorted variant. In the crystal structure of [Ba(en)4]2[Ba(en)3](SbSe4)2 (space group P21, a = 965.8(4) pm, b = 1764.8(8) pm, c = 1463.2(6) pm, β = 90.8(1)°, Z = 2) the cations are in six- and eight-fold coordinations by the bidentate ligands.


Author(s):  
Mamadou Ndiaye ◽  
Abdoulaye Samb ◽  
Libasse Diop ◽  
Thierry Maris

In the structure of the title salt, {(C5H14N3)[CdCl3]}n, the CdIIatom of the complex anion is five-coordinated by one terminal and four bridging Cl atoms. The corresponding coordination polyhedron is a distorted trigonal bipyramid, with Cd—Cl distances in the range 2.4829 (4)–2.6402 (4) Å. The bipyramids are condensed into a polyanionic zigzag chain extending parallel to [101]. The tetramethylguanidinium cations are situated between the polyanionic chains and are linked to them through N—H...Cl hydrogen bonds, forming a layered network parallel to (010).


2019 ◽  
Vol 57 (5) ◽  
pp. 571-581
Author(s):  
Emil Makovicky

Abstract Crystal structures of the three polymorphs of Cu5(PO4)2(OH)4, namely pseudomalachite, ludjibaite, and reichenbachite, can be described as being composed of rods perpendicular to their crystal-chemical layering. Two different sorts of rods can be defined. Type 1 rods share rows of Cu coordination polyhedra, forming a series of slabs. Slab boundaries and slab interiors represent alternating geometric OD layers of two kinds, with layer symmetries close to P21/m and , which make up two different stacking schemes of geometric OD layers in the structures of ludjibaite and pseudomalachite. Such OD layers, however, are not developed in reichenbachite. Type 2 rods are defined as having columns of PO4 tetrahedra in the corners of the rods. In the Type 2 slabs composed of these rods, geometric Pg OD layers of glide-arrayed tetrahedra alternate with more complex OD layers; in ludjibaite this system of layers is oriented diagonally with respect to the Type 1 OD layer system. Two different OD stackings of Type 2 OD layers form the ludjibaite and reichenbachite structures but not that of pseudomalachite. Thus, ludjibaite might form disordered intergrowths with either of the other two members of the triplet but reichenbachite and pseudomalachite should not form oriented intergrowths. Current knowledge concerning formation of the three polymorphs is considered.


2012 ◽  
Vol 68 (6) ◽  
pp. m745-m745
Author(s):  
Susanne Wöhlert ◽  
Mario Wriedt ◽  
Inke Jess ◽  
Christian Näther

In the crystal structure of the title compound, [Ni(C2N3)2(C5H5N)4], the NiII cations are coordinated by four pyridine ligands and two dicyanamide anions into discrete complexes. The shortest Ni...Ni separation is 8.1068 (10) Å. The structure is pseudo-centrosymmetric and can also be refined in the space group C2/c in which both anionic ligands are strongly disordered and the refinement leads to significantly poorer reliability factors.


2021 ◽  
Vol 236 (1-2) ◽  
pp. 11-21
Author(s):  
Evgeny V. Nazarchuk ◽  
Oleg I. Siidra ◽  
Dmitry O. Charkin ◽  
Stepan N. Kalmykov ◽  
Elena L. Kotova

Abstract Three new rubidium polychromates, Rb2[(UO2)(Cr2O7)(NO3)2] (1), γ-Rb2Cr3O10 (2) and δ-Rb2Cr3O10 (3) were prepared by combination of hydrothermal treatment at 220 °C and evaporation of aqueous solutions under ambient conditions. Compound 1 is monoclinic, P 2 1 / c $P{2}_{1}/c$ , a = 13.6542(19), b = 19.698(3), c = 11.6984(17) Å, β = 114.326(2)°, V = 2867.0(7) Å3, R 1 = 0.040; 2 is hexagonal, P 6 3 / m $P{6}_{3}/m$ , a = 11.991(2), c = 12.828(3) Å, γ = 120°, V = 1597.3(5) Å3, R 1 = 0.031; 3 is monoclinic, P 2 1 / n $P{2}_{1}/n$ , a = 7.446(3), b = 18.194(6), c = 7.848(3) Å, β = 99.953(9)°, V = 1047.3(7) Å3, R 1 = 0.037. In the crystal structure of 1, UO8 bipyramids and NO3 groups share edges to form [(UO2)(NO3)2] species which share common corners with dichromate Cr2O7 groups producing novel type of uranyl dichromate chains [(UO2)(Cr2O7)(NO3)2]2−. In the structures of new Rb2Cr3O10 polymorphs, CrO4 tetrahedra share vertices to form Cr3O10 2− species. The trichromate groups are aligned along the 63 screw axis forming channels running in the ab plane in the structure of 2. The Rb cations reside between the channels and in their centers completing the structure. The trichromate anions are linked by the Rb+ cations into a 3D framework in the structure of 3. Effect of solution acidity on the crystallization of polychromates in uranyl-bearing systems is discussed.


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 807
Author(s):  
Ilya V. Kornyakov ◽  
Sergey V. Krivovichev

Single crystals of two novel shchurovskyite-related compounds, K2Cu[Cu3O]2(PO4)4 (1) and K2.35Cu0.825[Cu3O]2(PO4)4 (2), were synthesized by crystallization from gaseous phase and structurally characterized using single-crystal X-ray diffraction analysis. The crystal structures of both compounds are based upon similar Cu-based layers, formed by rods of the [O2Cu6] dimers of oxocentered (OCu4) tetrahedra. The topologies of the layers show both similarities and differences from the shchurovskyite-type layers. The layers are connected in different fashions via additional Cu atoms located in the interlayer, in contrast to shchurovskyite, where the layers are linked by Ca2+ cations. The structures of the shchurovskyite family are characterized using information-based structural complexity measures, which demonstrate that the crystal structure of 1 is the simplest one, whereas that of 2 is the most complex in the family.


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