Inorganic Chemistry Communications (v.5, #2)

Liquid crystal phase crossover (columnar↔calamitic) in polycatenar CuII 5-(3,4-dialkoxybenzylidine)aminotropololonates by James M Elliott; John R Chipperfield; Stephen Clark; Ekkehard Sinn (99-101).
The new tetracatenars bis[5-(3,4-dialkoxybenzylidine)aminotropolonato] copper(II) are mesogenic. As the 3,4-dialkoxy chains on the phenyl rings increase in length, the phase behavior shifts from calamitic to discotic (columnar), the first case of a metallomesogen series to exhibit both calamitic and columnar phases. When n⩽12 the complexes melt to calamitic liquid crystals (specifically the smectic C phase), while for n⩾13 the liquid crystal phases are columnar (specifically the phase columnar hexagonal phase)

The reaction of a series of phenyl substituted cyclopentadienes C 5 Ph n H 6−n  (n=1–4) and iron pentacarbonyls in refluxing toluene was studied. The corresponding diiron complexes [(η 5 -C 5 Ph n H 6−n)Fe(CO)]2(μ-CO)2  (n=1–4) and phenyl substituted ferrocenes (η 5 -C 5 Ph n H 6−n)2 Fe  (n=3,4) were obtained. The reaction of tetraphenylcyclopentadiene and iron pentacarbonyl in refluxing toluene also led to the formation of π-complex (η4-C5Ph4H2)Fe(CO)3 (1), which exhibited exceptional air and thermal stabilities. The molecular structure of 1 has been determined by X-ray diffraction and an unusual rearrangement of a phenyl group was found.
Keywords: Substituted cyclopentadienyl; Iron pentacarbonyl; π-complex; Crystal structure;

Regioselective olefin arylation catalyzed by [Ir(acac)2Cl]2 with base by Takaya Matsumoto; Hajime Yoshida (105-106).
By addition of bases to remove Cl in situ, [Ir(acac)2Cl]2 was found to work as a catalyst for anti-Markovnikov arylation of olefin with benzene to produce straight-chain alkylbenzene in higher selectivity than the branched alkylbenzene the same as [Ir(acac)3]2.
Keywords: Iridium complex; Anti-Markovnikov; Regioselectivity; Homogeneous catalysis; C–H bond activation; Arylation;

The mixed-valence states of biferrocenium triiodide salts with bromoalkyl substituents, have been investigated by means of 57Fe Mössbauer spectroscopy and X-ray structural determinations.
Keywords: Mixed-valence compound; Biferrocenium; Metallocene; Electron transfer;

The complex CpCuI(PEt3) with Cp=cyclopentadienyl shows a longest-wavelength absorption at λ max=350 nm (in n-hexane) which is assigned to a Cp→PEt3 ligand-to-ligand charge transfer (LLCT) transition. An analogy to the ylide Cp–P+Propyl3 is drawn which displays the Cp to phosphonium charge transfer (CT) absorption at λ max=267 nm (in n-hexane). Solid CpCu(PEt3) exhibits an emission at λ max =525  nm which is assumed to originate from the LLCT triplet.
Keywords: Electronic spectra; Luminescence; Charge transfer; Copper complexes; Cyclopentadienyl complexes; Phosphine complexes;

Reaction of [WI2(CO)3(NCMe)2] with two equivalents of FcCH 2 PH 2  [Fc=Fe(η 5 -C 5 H 5)(η 5 -C 5 H 4)] in CH2Cl2 at room temperature gave [WI2(CO)3(FcCH2PH2)2] (1) in 94% yield which was crystallographically characterised. This is the first primary ferrocenylphosphine complex of tungsten(II) and has a distorted capped octahedral structure, with trans-phosphine ligands and a carbonyl group that caps a triangular face formed by two carbonyl and one phosphine ligand.
Keywords: Crystal structure; Seven-coordinate; Tungsten complex; Primary ferrocenylphosphine; Carbonyl; Iodo ligand;

The imidazolate-bridged binuclear zinc(II) macrocyclic complex, [Zn(cyclen)–im–Zn(cyclen)](ClO4)3 (1) and the free imidazole coordinated mononuclear nickel(II) complex, [Ni(cyclen)(imH)(ClO4)](ClO4) (2) (cyclen=1,4,7,10-tetraazacyclododecane, im=imidazolate) have been synthesized. Complexes 1 and 2 have been characterized by single crystal structural analyses. In complex 1 both zinc(II) ions are five-coordinated with a distorted square pyramidal geometry composed of four nitrogen atoms from cyclen and one nitrogen atom from the bridging imidazolate ion with N5 chromophore. Complex 2 is mononuclear nickel(II) having six-coordination with distorted octahedral geometry consisting of four nitrogen atoms from cyclen, one nitrogen atom from the imidazole molecule and one oxygen from one of the perchlorate ions to give a N5O chromophore.
Keywords: Crystal structures; Zinc complex; Nickel complex; Macrocyclic ligand complexes; Imidazolate-bridged complex;

Dichlorobis[1,3-dimethyl-2(3H)-imidazoleselone]zinc(II): a potential zinc selenide synthon by Daniel J. Williams; Kathleen M. White; Donald VanDerveer; Angus P. Wilkinson (124-126).
The synthesis and characterization of a potential ZnSe synthon is reported. Dichlorobis[1,3-dimethyl-2(3H)-imidazoleselone] is prepared with 57% yield by direct combination of ZnCl2 and the ligand in boiling acetonitrile. X-ray crystallography shows a discrete molecular structure with a tetrahedral coordination sphere around the zinc. Thermogravimetric analysis from 50 to 600 °C indicates a 67.22% weight loss which results in a 10% higher residual mass than that expected for pure ZnSe. X-ray powder diffraction on the residue from a larger scale thermolytic decomposition experiment confirmed the presence of both hexagonal and cubic ZnSe.
Keywords: Crystal structure; Selone; Zinc chloride; Zinc selenide;

Treatment of [8,8-(η2-dppm)-8-(η1-dppm)-nido-8,7-RhSB9H10] (I) with [Ru(η6-p-cym)Cl2]2 leads to the formation of a new bimetallic complex, [8,8-η2-{(μ-Cl)2Ru(η6-p-cym)Ph2PCH2PPh2}-nido-8,7-RhSB9H10], (II) containing the group [(μ-Cl)2Ru(η6-p-cym)Ph2PCH2PPh2] that coordinates in a multidentate mode to Rh.
Keywords: Boranes; Metallaboranes; Thiaboranes; Rhodium; Ruthenium;

Synthesis and structural characterisation of a new cobalt(II) pentanuclear complex with a tetranucleating pyrazole-derived ligand by Josefina Pons Picart; Francisco Javier Sanchez; Jaume Casabó; Jordi Rius; Angel Alvarez-Larena; Josep Ros (130-133).
Reaction of Co(O2CMe)2·4H2O with HL0 (3,5-bis(6-methyl-2-pyridyl)pyrazole) yielded unexpectedly a new pentanuclear compound Co5(L0)2(O2CMe)8(H2O)2. The complex has been characterised by elemental analyses, IR and single-crystal X-ray diffraction. The molecular structure is unusual and consists of a centrosymmetrical pentanuclear Co(II) complex containing two 3,5-bis(6-methyl-2-pyridyl)pyrazole ligands, eight MeCOO anions and two H2O molecules, all co-ordinates.
Keywords: Cobalt complex; Pentanuclear complex; Pyrazole complex; Crystal structure;

The complex K4Mo2Cl8 reacts with the substituted benzoic acids XC6H4CO2H (X=4-Ph2P, 2-Ph2P, 4-Ph2P(O) or 4-Ph2P(S)) to form the complexes Mo2(μ-O2CC6H4-4-PPh2)4 ( 1 ), Mo2(μ-O2CC6H4-2-PPh2)4(MeOH)2 ( 2 ), {Mo2[μ-O2CC6H4-4-P(O)Ph2]4·4EtOH} n ( 3 ) and Mo2[μ-O2CC6H4-4-P(S)Ph2]4(MeOH)2 ( 4 ). The presence of coordinated methanol molecules in 2 is confirmed by a single crystal X-ray structure determination, while the crystal structure of 3 reveals that a two-dimensional polymer is formed by the coordination of a trans pair of PO groups associated with each dimolybdenum unit to the axial sites of neighboring dimolybdenum [Mo2(μ-O2CR)4] units. The other trans pair of PO groups in 3 are hydrogen-bonded to ethanol.
Keywords: Dimolybdenum(II) complexes; Multiple metal–metal bonds; 4- and 2-Diphenylphosphinobenzoic acids; 4-Diphenylphosphinylbenzoic acid;

Synthesis and crystal structure of a novel bridged coenzyme B12 model complex by Xinyi Song; Kaian Yao; Chunying Duan; Huilan Chen (139-142).
A novel bridged organocobaloxime-bromo(O-trimethylene-CHEL)cobaloxime was synthesized by heating the Aqua(3-bromopropyl)cobaloxime at 50 °C in methanol/H2O and crystal structure was determined by X-ray diffraction analysis.
Keywords: Organocobaloxime; Coenzyme B12; Model complex; Crystal structures;

Hydrothermal reaction between cobalt(II) nitrate and 2,2-bipyridine-5,5-dicarboxylic acid in the presence of NaOAc gave a two-dimensional coordination-polymer of cobalt(II), [Co(2,2-bipyridine-5,5-dicarboxylato)(H2O)]·(H2O) (1). X-ray structure determination showed that compound 1 has a two-dimensional infinite network based on cobalt-bipyridinedicarboxylate building blocks and has a relatively small channel of 5.0×6.6 Å.
Keywords: 2,2-bipyridine-5,5-dicarboxylic acid; Two-dimensional coordination-polymer; Hydrothermal reaction;

A new route to prepare magnesium oxide whisker by Zhongqing Wei; Hua Qi; Peihua Ma; Jiqing Bao (147-149).
This paper presents a new route to prepare magnesium oxide whisker. The preparation process consists of the synthesis of a precursor called magnesium oxysulfate (MOS) whisker, followed by the heat treatment of the synthesized whisker. The precursor whisker was prepared by hydrothermal synthesis reaction between MgSO4 solution and MgO or Mg(OH)2 preferably at 130–170 °C and at 3–8 atm. MgO whisker can then be easily obtained by simply heating the MOS whisker at temperatures higher than 900 °C. These two whiskers were characterized by X-ray diffraction (XRD) and scanning electronic microscopy (SEM).
Keywords: Whisker; Magnesium oxide; Magnesium oxysulfate; Hydrothermal synthesis;

Preparation and structural characterization of mercury 21-thiaporphyrin complex: HgII(Stpp)Cl (Stpp=tetraphenyl-21-thiaporphyrin anion) by Jo-Yu Tung; Bing-Chuang Liau; Shanmugham Elango; Jyh-Horung Chen; Hsi-Ying Hsieh; Feng-Ling Liao; Sue-Lein Wang; Lian-Pin Hwang (150-155).
Treatment of tetraphenyl-21-thiaporphyrin (StppH) with Hg(OAc)2 in CH2Cl2 yields diamagnetic HgII(Stpp)Cl complex. The coordination sphere around Hg2+ in the monomeric molecule is described as a five-coordinate distorted trigonal bipyramid with the bonding to the three pyrrole nitrogens [Hg(1)–N=2.104(4), 2.626(4), 2.640(4) Å], the thiophene sulfur [Hg(1)–S=2.801(1) Å], and one axial chloride ligand [Hg(1)–Cl(1)=2.318(1) Å]. The plane of the three pyrrole nitrogen atoms [i.e., N(1), N(2), N(3)] bonded to Hg2+ is adopted as a reference plane 3N. Because of its larger size, the Hg2+ is considerably out of the 3N plane; its displacement of 1.41 Å is in the same direction as that of the apical Cl ligand. The thiophene ring is slightly folded so that the dihedral angle between the C(13)–C(14)–C(15)–C(16) and C(13)–S(1)–C(16) planes is 7.3°.
Keywords: Crystal structure; Mercury thiaporphyrin; Diamagnetic; Distorted trigonal bipyramid;

Lead immobilization by non-apatite-type calcium phosphates in aqueous solutions by Shigeru Sugiyama; Takuya Ichii; Hiromu Hayashi; Tahei Tomida (156-158).
The immobilization of lead (II) ion by β-Ca3(PO4)2, CaHPO4·2H2O and Ca(H2PO4)2·H2O was found to proceed more favorably than that by calcium hydroxyapatite (CaHAp), probably due to rather greater solubility of former three calcium phosphates than that of CaHAp. The contribution of dissolution–precipitation mechanism was suggested to the immobilization.
Keywords: Immobilization; Lead; Calcium phosphates; Calcium hydrogen phosphates;

A 2-indenyl-amido-bridged titanium complex with Cs-symmetry by Thomas Weiß; Sigurd Becke; Helga Sachse; Gerd Rheinwald; Heinrich Lang (159-162).
A novel Cs-symmetrical constrained titanium(IV) complex [η51-(2-C9H6)SiMe2N t Bu]TiCl2 (7) and the preparation thereof is described; the solid-state structure and the use of 7 as a single site catalyst in the (co)polymerisation of ethene and propene is reported.
Keywords: Crystal structure; Titanium complex; Indenyl complex;

Copper(II) complexes with novel chiral amidate ligands by Bae-Wook Lee; Kil Sik Min; Myung-Ki Doh (163-165).
Two new copper(II) complexes, {[Cu2(S-alaamp)2(ClO4)]ClO4} n (1) and [Cu(S-valamp)(H2O)(ClO4)] (2) [where S-alaamp=4(S)-1-(2-pyridyl)-3-oxo-4-amino-2-azapentane, S-valamp=4(S)-1-(2-pyridyl)-3-oxo-4-amino-4,5-dimethyl-2-azahexane] are prepared and characterized. Compound 1 exists as 1-D polymeric chain where an amide oxygen atom is linked to adjacent copper(II) ion, while 2 is a square-pyramid in the solid state. Compounds 1 and 2 are involved in offset π–π stacking interactions via the pyridine groups of the ligands, which give rise to 2-D sheets.
Keywords: Chiral amidate ligand; Stacking interaction; Cu(II) complex; Hydrogen bonding;

Inorganic–organic supramolecular compound [Fe(NCS)6][(Hbpy)(H2bpy)(bpy)] exhibits three-dimensional solid state structure constituted by hydrogen bonds N⋯H–N and S⋯H–C. [Fe(NCS)6]3− groups form tetragonal prisms with the dimensions of 10.3×10.8 Å2, the bpy units occupy these prisms. The compound in DMF solution has very strong third-order non-linear optical behavior with refractive index n 2 of −2.95×10−17   m 2   w −1 and third-order non-linear optical susceptibility χ (3) of 1.06×10−10 esu.Inorganic–organic supramolecular compound [Fe(NCS)6][(Hbpy)(H2bpy)(bpy)] exhibits three-dimensional solid state structure constituted by hydrogen bonds N⋯H–N and S⋯H–C. [Fe(NCS)6]3− groups form tetragonal prisms with the dimensions of 10.3×10.8 Å2, the bpy units occupy these prisms. The compound in DMF solution has very strong third-order non-linear optical behavior with refractive index n 2 of −2.95×10−17   m 2   w −1 and third-order non-linear optical susceptibility χ (3) of 1.06×10−10 esu.
Keywords: Supramolecular compound; Hydrogen bonds; Large dimensions; Third-order non-linear optical behavior;

GraphicThe neutral three-dimensional metal coordination polymer [Ni2(4,4-bpy)2(btc)(H2O)2] n ·2nH2O (4,4-bpy=4,4-bipyridine, btc=1,2,4,5-benzenetetracarboxylate) has been prepared from hydrothermal reaction of nickel(II) chloride with mixed ligands in basified aqueous solution. The magnetic study reveals that there exist ferromagnetic interactions between nickel(II) atoms. The TGA and XRPD analyses suggest that the crystallization and coordination water molecules play important roles in the formation and stabilization of the polymer and the title compound has potential applications.
Keywords: Hydrothermal reaction; Mixed ligands; Coordination polymer; Ferromagnetic;