Tetragonal Pyramidal Coordination Research Articles

Bis(triphenylphosphine)iminium Nitrito(phthalocyaninato)zincate Hydrate

b(PNP)[Zn(ONO)Pc2−].H2O [Pc2− = (C32H16N8)2−] has been prepared from zinc phthalocyanine and bis(triphenylphosphine)iminium nitrite [(PNP)NO2] in acetone. The Zn atom has a tetragonal pyramidal coordination geometry with the Zn atom displaced out of the center (Ct) of the four inner N atoms (Niso) of the non-planar Pc ligand toward the nitrite ligand [Zn—Ct = 0.469 (3) Å]. The nitrite ion is monodentate O-coordinated [Zn—O = 2.059 (3) Å]. The average Zn—Niso distance is 2.032 Å. Pairs of weakly overlapping anions are present. The cation adopts a bent conformation [b(PNP): P1—N(K) = 1.576 (2); P2—N(K) = 1.582 (2) Å; P1—N(K)—P2 = 141.12 (13)°].

Tin(II) Oxyhydroxide by X-ray Powder Diffraction

The structure of tin(II) oxyhydroxide, Sn6O4(OH)4, has been refined by Rietveld analysis of X-ray powder diffraction data. Atomic parameters based on the isostructural lead analogue were used in the starting model. The structure was refined in the tetragonal space group P\overline{4}21c with a = 7.9268 (4) and c = 9.1025 (5) A. The title compound forms clusters of Sn6O4(OH)4 with the Sn atoms in distorted tetragonal pyramidal coordination geometries. Each Sn atom is coordinated to two bridging oxide O and two bridging hydroxy O atoms. The JCPDS file number for Sn6O4(OH)4 is 46-1486.

First Structure of a Mixed Organosodium/Lithium Alkoxide Compound: Model for a Superbase

LiO interactions dominate the structure of 1, a molecule that contains the MC and LiO functionalities suspected to play a role in superbases involving RLi and R′OM (M = Na, K, Rb, Cs). Compound 1 forms a tmeda-coordinated tetramer with a central Li4O4 cube, and its O atoms have tetragonal-pyramidal coordination. This structure offers a possible explanation of the activation of organolithium compounds by alkali metal alkoxides.

Untersuchungen zur Anionendefektverteilung in Sr2MnO4-y/ Investigation on the Distribution of Anion Vacancies in Sr2MnO4-y

At high temperatures Sr2MnO4-y crystallizes in the K2NiF4 structure with anion defects. X -ray structure determination in space group I 4/m m m (No. 139) with a = 380.58(3), c = 1253.19(11) pm reveals the composition Sr2MnO3.84±0.05 for a single crystal prepared under argon at 1510 °C. The oxygen deficiency is restricted to the basal oxygen atoms in the perovskite layer. The X -ray experiment shows a statistical distribution of the defects. They lead to a distorted tetragonal pyramidal coordination of the Mn3+ ions.

Crystal and molecular structure of the tetracyanato-bis(phenanthroline)copper(II) complex

At room temperature, the [Cu2(NCO)4(phen)2] complex possessed monoclinic symmetry, P21/n, with the unit cell parameters a = 0.7757(3) nm, b = 1.3563(5) nm, c = 1.1555(4) nm, β = 96.92(2)°, Z = 2. The central atom is involved in tetragonal pyramidal coordination comprising the CuN4Cu’ chromophor. The nitrogen atoms of the cyanate and phenanthroline ligands are in a square planar arrangement, from which the central copper atom is displaced in the axial direction. Through the Cu-Cu bond (0.320 nm), the [Cu(NCO)2(phen)] formula units are linked into centrosymmetric units, which in the crystal structure lie in parallel layers. The occurrence of the Cu-Cu bond can account for the fact that only one molecule of the heterocyclic ligand can be coordinated.

π-Olefin-Iridium-Komplexe, XV [1] Kationische Bis(2.3-dimethylbutadien)iridium-L-Verbindungen mit verschiedenen Donorliganden L/π-Olefin Iridium Complexes, XV [1] Cationic Bis(2.3-dimethylbutadiene)iridium-L Compounds with Various Donor Ligands L

Abstract (dmb)2IrCH3 (dmb = 2.3-dimethylbuta-1.3-diene) reacts with Ph3CBF4 in CH2Cl2 to form the cation [(dmb)2Ir]+ which crystallizes as the adduct [(dmb)2Ir(OCMe2)]BF4 from acetone solution. The labile acetone ligand is easily displaced by pyridine, cyclohexylisonitrile, phosphane and arsane donor molecules. X-ray diffraction analysis of [(dmb)2Ir(AsPh3)]BF4 reveals tetragonal pyramidal coordination at the iridium atom with the arsane ligand in axial position and with isolated BF4 anions. Spectroscopic data of the new [(dmb)2IrL]BF4 compounds are discussed and related with metal-ligand bond interactions.

Metal complexes of the deprotonated form of N, N′-bis(2′-pyridinecarboxamide 1′-oxide)-1,2-ethane, (enpco), a dinegative N 2O 2 quadridentate pyridine N-oxide ligand. X-ray crystal structure of [Cu(enpco-2H)] 2·8H 2O

The magnetic properties and infrared and electronic spectra of nickel(II) and copper(II) complexes with deprotonated enpco are discussed. An X-ray structure analysis shows that the complex [Cu(enpco-2H)] 2·8H 2O is triclinic, P 1 , with a = 6.988(2), b = 11.748(2), c = 12.289(2) Å, α = 63.06(2), β = 81.17(1), γ = 73.02(2)° and Z = 2. The ligand (enpco-2H) 2− coordinates as a distorted square-planar N 2O 2 donor via the deprotonated amide nitrogens and the N-oxide oxygens. An N-oxide oxygen from each (enpco-2H) 2− ligand also coordinates to the copper in an adjacent Cu(enpco-2H) entity, the resulting CuO bond length being 2.916(2) Å. This produces a centrosymmetric dimeric structure with tetragonal pyramidal coordination to each copper. The bridging CuO interaction is compared with that in a series of Cu(salen) complexes (H 2salen is the Schiff base of salicylaldehyde and ethylenediamine).

The crystal and molecular structure of thiocyanatocopper(II) complexes with 3-methylpyridine and 3,4-dimethylpyridine

Crystals of the complexes [Cu(3,4-diMepy)3(NCS)2] (I) and [Cu(3-Mepy)3(NCS)2] (II) (Me = methyl, py = pyridine) possess the monoclinic symmetry, Pc, with the unit cell parameters of I and II: a = 0.9825(7) and 0.9027(7) nm, b = 0.9740(7) and 0.9021(7) nm, c = 1.4130(60) and 1.4958(50) nm, β = 108.8(4)° and 114.08(4)°, Z = 2 in both cases, d0 = 1.32.103 and 1.37.103 kg m-3, and dc = 1.30.103 and 1.37.103 kg m-3, respectively. The central atom in the complexes exhibits tetragonal pyramidal coordination. The thiocyanate ligands are coordinated by the nitrogen atoms in the equatorial as well as axial positions of the coordination polyhedron. The three heterocyclic ligands are bonded in the equatorial plane. The arrangement of the ligands and the interatomic distances are the same in the two complexes. The crystals were prepared by reacting an ammoniacal solution of CuSO4 with an ethanolic solution of the heterocyclic ligand L and an aqueous solution of NH4NCS so that the c(Cu):c(NH3):c(L):c(NCS) ratio was 2:8:5:4.

Intramolecular Dynamics of Five‐coordinate iron Carbonyl Complexes with olefinic ligands as studied by variable‐pressure 1H‐NMR spectroscopy

AbstractVariable‐pressure 1H‐NMR Spectroscopy has been used to study the fluxionality of some five‐coordinated Fe complexes in solution. For [Fe(CO)2 1,3‐cyclooctadiene (PPh3)], the CO site exchange is known (by analogy with [Fe(CO)3(1,3‐cyclooctadiene)]) to be a non‐dissociative process, and an activation volume of ca. 0 cm3.mol−1 was indeed obtained. However, for [Fe(CO2){2,3‐η:O‐σ‐(7,7‐dimethoxybicyclo[2.2.1]hept‐2‐ene)}(PPh3)], the activation volume of +5 cm3 mol−1 suggests that an unprecedented dissociation process is responsible for the CO site exchange. The molecular structure of [Fe(CO)2(1,3‐cyclooctadiene)(PPh3)] was ascertained by single‐crystal X‐ray diffractometry. The crystals are triclinic, space group P1, a = 9.606(3), b = 16.795(2), c = 7.743(8) Å, α = 97.83(4), β = 109.63(4), γ = 83.37(2)°. The structure determination has shown that the complex possesses a tetragonal pyramidal coordination, with the endocyclic CC bond and PPh3 occupying basal sites.

An asymmetric triply-bridged Mov complex with bridging azido-ligand. The structures of [Mo2O2(µ-N3){S(CH2)3S}3]–and its precursor [MoO{S(CH2)3S}2]–

The complex [MoO(SCH2CH2CH2S)2]– reacts with HN3 in methanol to give [Mo2O2(µ-N3)(SCH2CH2S)3]–;X-ray crystallography shows the former anion to have tetragonal pyramidal co-ordination about Mo with an apical oxo-group and the latter to be an asymmetric dinuclear complex with a triple bridge comprising two dithiolate sulphurs and a bent azide group linking two distinct pseudo-octahedral molybdenums.

Synthesis and catalytic activity of alkoxyoxovanadium(IV) diketonates, crystal and molecular structure of bis-[methoxyoxovanadium(IV) acetylacetonate

Methoxyoxovanadium(IV) acetylacetonate crystalizes in the monoclinic system, space group P2 1/n, with a = 10.50(1), b = 11.10(1), c = 7.67(1) Å, and β = 107.63(3)°. The complex consists of dimeric [VO(OCH 3)acac] 2 units with molecular and crystallographic Ci symmetry, in which the vanadium atoms are in the tetragonal pyramidal coordination geometry. The VO length is 1.587(3) Å and all other VO lengths are in the range 1.953(3)–1.968(3) Å. The V ▪V separation (3.104 Å) compares well with metal-metal separations in binuclear complexes of atoms of comparable dimensions. The synthesis and the catalytic activity in ethylene-propylen co-polymerization of three other diketonates are reported.

Alkoxohalogenotellurate(IV): Darstellung und Struktur von Tetraphenylphosphonium-trichloro(dioxo-ethylen-O.O')tellurat(rV) / Alkoxohalogenotellurates(IV): Preparation and Structure of Tetraphenylphosphonium Trichloro(dioxo-ethylene-O,O')tellurate(IV)

Abstract The deprotonated glycolate dianion (OCH2CH2O)2- is shown to react as a bidentate chelating ligand towards chalcogen(IV) halides. With TeCl4, the anion TeCl3(O2C2H4)- is formed. According to a single crystal X-ray analysis of the tetraphenylphosphonium salt (P21/c, a = 7.501, b = 26.328, c = 13.582 A, β= 104.55°, Z = 4) Te is in a tetragonal pyramidal (ψ octahedral) coordination with the alcoholate ligands in the apical (Te-O 1.919 Å) and in one of the equatorial positions (Te O 1.973 Å), the Te-Cl bond lengths being between 2.495 and 2.590 Å. The trans bond lengthening effect of the equatorial alcoholate ligand (i.e. the polarizing effect towards the lone pair) is unusually low. Vibrational spectra are reported.

Reversible addition of protic molecules to co-ordinated di-2-pyridyl ketone in palladium(II), platinum(II), and gold(III) complexes. X-Ray crystal structures of dichloro(dihydroxy-di-2-pyridylmethane)palladium(II) and dichloro(dihydroxy-di-2-pyridylmethane)gold(III) chloride

Palladium(II), platinum(II), and gold(III) species react with di-2-pyridyl ketone (dpk) to give complexes in which one or two ligand molecules in the original keto- or in a newly formed diolic form are co-ordinated to the metal cation, namely: [PdCl2(dpk·HX)][X = OH (1), OMe (2), or OEt (3)]; [PdCl2(dpk)], (4); [Pd(dpk·H2O)2][ClO4]2, (5); [PtCl2(dpk)], (6); [AuCl2(dpk·H2O)]Cl, (7); and [Au(dpk·H2O)2][ClO4]3, (8). In solution, all species undergo either addition or release of the protic molecules depending upon the HX concentration; the rates of reversible hydrolysis and the stability of the hydrated species increase going from PtII to PdII to AuIII thus paralleling both the electron-withdrawing properties of the metal cations and their ability to fill the apical position of a tetragonal-pyramidal co-ordination shell. The crystal and molecular structures of (1) and (7) have been determined by X-ray diffraction: (1) crystallizes in the tetragonal space group P41 with Z= 4, a= 10.597(8), and c= 11.468(9)A; (7) crystallizes in the monoclinic space group P21/c with Z= 4, a= 10.398(10), b= 7.249(8), c= 18.406(12)A, and β= 91.6(8)°. The structures were solved by Patterson and Fourier methods and refined by full-matrix least squares to R= 0.018 and 0.063 for (1) and (7) respectively. Neutral [PdCl2(dpk·H2O)] and cationic [AuCl2(dpk·H2O)]+ are present in the crystals of (1) and (7) respectively; the co-ordination geometry of the metal atom is square planar in both cases and involves two Cl and two N atoms, the dpk·H2O molecule acting as a chelating N-donor ligand. The ligand conformation is very similar in both complexes, the six-membered chelate being in a boat form with a dihedral angle between the pyridyl rings of 114.54 and 116.63° respectively; this allows a very favourable co-ordination angle of 87.1(2) and 86.4(6)°, and a short contact between the oxygen atom of a hydroxyl group and the metal cation of 2.824(6) and 2.77(1)A for (1) and (7) respectively.

Crystal structure and spectroscopic properties of mercury(II) halide complexes. Part 3. The di-n-butyl sulphoxide–mercury(II) chloride (1/1) adduct

The structure of the title compound was solved from diffractometer data by the heavy-atom method and refined by least-squares techniques to R 0.109 for 1 134 observed reflections. Crystals are monoclinic, space group P21/c, with unit-cell dimensions: a= 20.710(10), b= 8.113(3), c= 8.090(4)Å, β= 94.74(5)°, and Z= 4. A distorted tetragonal-pyramidal co-ordination around the mercury atom involves the di-n-butyl sulphoxide molecule at the apex via the oxygen atom at 2.59 Å, two close chlorine atoms at 2.35 and 2.33 Å, and two chlorine atoms from neighbouring molecules at 3.13 and 3.16 Å at the base. The structural parameters of the title compound and of similar adducts have been correlated with their vibrational frequencies.

Crystal structure and magnetic properties of copper formate anhydrate [α-Cu(HCOO) 2

The crystal structure of anhydrous copper formate [α-Cu(HCOO) 2] has been refined from neutron powder data by the profile analysis technique at three different temperatures. Hydrogen atoms were located and refined with anisotropic temperature factors. The copper ion has a Jahn-Teller distorted tetragonal pyramidal coordination. Magnetic measurements showed a paramagnetic behaviour in the temperature region 10–300 K. The positive Curie temperature of θ c = 9.8(3) suggests, however, a ferromagnetic ordering at low temperatures.

Effects of temperature and pressure on the molecular and electronic structure of N,N′-ethylenebis(salicylideneiminato)nitrosyliron, Fe(NO)(salen)

The crystal and molecular structures of the two magnetically distinct forms of Fe(NO)(salen), C 16H 14N 3O 3Fe, have been determined by single crystal X-ray diffraction at 23 °C and at −175 °C. The complex crystallizes in the orthorhombic space group Pna2 1 with 4 molecules per unit cell. The unit cell dimensions are a = 26.377(2), b = 8.598(5) and c = 6.951(5) Å at 23 °C and a = 26.18(2), b = 8.52(1) and c = 6.783(6) Å at −175 °C. Full-matrix least-squares refinement of the 23 °C structure based on the 840 reflections with F 2 o ⩾ 3σ(F 2 o) gave a conventional R-factor of 0.038. The structure consists of discrete Fe(NO)(salen) molecules with tetragonal pyramidal coordination about the iron atom. The disordered nitrosyl group occupies the axial coordination site in a bent geometry (average FeNO angle 147°). Full-matrix least-squares refinement of the −175°C structure based on the 406 reflections with F 2 o ⩾ 2σ(F 2 o) gave a conventional R-factor of 0.087. This form of Fe(NO)(salen) also exhibits tetragonal pyramidal coordination geometry with a bent disordered nitrosyl group in the apical position. Marginally significant structural changes are observed: 1) the FeNO angle is 127°; 2) the Fe atom is 0.1 Å closer to the mean coordination plane of the salen ligand are more nearly coplanar. These structural changes are consistent with a spin state of Fe(NO)(salen) from S = 3 2 to S = 1 2 upon cooling. The significant differences in th conformations of the salen ligand at the two temperatures are attributed to crystal packing. The infrared spectra of Fe(NO)(salen) at room temperature for various pressures ranging from ambient pressure up to 37 kbar are reported. The spectra suggest that Fe(NO)(salen) is converted to the S = 1 2 state at high pressure.

Polymorphism in Schiff base complexes of copper(II): the crystal and molecular structure of a second brown form of bis(N-methyl-2-hydroxy-1-naphthaldiminato)copper(II)

A third polymorph of the title compound has been grown by careful choice of solvent and an X-ray analysis has allowed comparison with the structure of the two forms already known. The space group is P21c, a = 10.525, b = 14.740, c = 12.605 Å, β = 104.8°. The molecule is dimeric with a tetragonal pyramidal coordination arrangement about copper atoms. The three isomers so far investigated thus show 4-, 5- and 6-fold stereochemistry. Details of bond lengths and angles are compared within the isomers.

Conformational influences in copper co-ordination compounds. Part I. The conformation of the ethylene bridge in aquo-NN′-ethylenebis-(acetylacetoneiminato)copper(II)

A three-dimensional X-ray analysis of aquo-NN′-ethylenebis(acetylacetoneiminato)copper(II) has confirmed an eclipsed conformation for the carbon atoms of the ethylene bridge which are displaced, by 0·11 and 0·14 A, to the same side of the plane through the four donor-atoms of the chelating group. It is suggested that this is a result of the bending of the molecule consequent upon the adoption of a tetragonal pyramidal co-ordination geometry. Hydrogen atoms were located and the hydrogen-bonding scheme is revealed in some detail. Bifurcation occurs in the accepted sense, but in addition it is suggested that double interaction by a negative dipole, rather than a positive one, also takes place.

The colour isomerism and structure of copper co-ordination compounds. Part XVII. The crystal structure of the pyridine solvate of bis-(N-phenylsalicylaldiminato)copper(II)

A three-dimensional X-ray structural analysis of the pyridine solvate of bis-(N-phenylsalicylaldiminato)copper(II) has revealed a tetragonal pyramidal co-ordination arrangement in which the pyridine molecule occupies the apical position. Bond lengths are almost identical with corresponding values determined for the unsolvated complex but there are small differences in bond angles due to the additional co-ordination.

Direct Determination of the Crystal Structure of Cornetite, Cu3PO4(OH)3, by the Monte Carlo Method

The crystal structure of the peacock-blue mineral cornetite, Cu3PO4(OH)3, orthorhombic, with a0=10.845, b0=14.045, c0=7.081 Å, space group Pbca, has been determined. The phase problem has been solved by the direct determination of the heavy atom positions through the application of the Monte Carlo and optimal shift methods. Subsequent three-dimensional Fourier synthesis revealed all the light atom positions. The atomic parameters have been refined, using three-dimensional data, by the method of full-matrix least squares. Two of the three independent copper atoms have essentially fivefold tetragonal pyramidal coordination, the coordination plane being curved in a boat shape towards the fifth ligand. The third copper atom has a highly distorted tetragonal bipyramidal coordination. Cornetite contains two sets of dimeric cupric complex ions. The first set [Cu2(OH)4O2] is formed by two different copper coordination planes sharing an edge, and the second [Cu2(OH)4O4] by two tetragonal pyramids, related by a center of symmetry, sharing a pyramidal edge. The [Cu2(OH)4O2] dimers are stacked upon each other along the c axis in a zigzag fashion, so that each dimer has two (OH) groups common with two other dimers above and below it. The dimeric chains thus formed are held together in a three-dimensional network, through isolated [Cu2(OH)4O4] dimers, PO4 groups, and O–H···O bonds.