A stable .mu.-peroxo complex of rhodium(II) intercalated in the interlamellar spaces of montmorillonite. Solid-state aluminum-27, silicon-29 and phosphorus-31 NMR and ESR investigation (original) (raw)
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The rhodamine B intercalation of montmorillonite
Journal of Colloid and Interface Science, 2004
Using photometric methods the dissociation constants and weight fractions of rhodamine B dimer in water solutions at different concentrations were determined. The montmorillonite (SWy) samples were fully intercalated with rhodamine B (RhB) solutions at various monomer/dimer ratios. The amount of rhodamine B in fully intercalated montmorillonite (RhB-SWy) increases with increasing concentration of dye in water solutions, i.e., with increasing dimer/monomer ratio. The sum of exchangeable guest cations in RhB-SWy is approximately constant (0.900 meq g −1) for all samples, because RhB-SWy samples with prevailing dye monomer also contain higher amounts of nonexchanged alkali elements. The experimental data are supported by calculated structure models that illustrate the changes in RhB-SWy structure depending on monomeric and/or dimeric arrangement of guests. The analysis of the calculated structure models confirmed the existence of two phases with different basal spacings, d ∼ 1.8 and ∼2.3 nm, revealed by X-ray diffraction.
Synthesis and Characterization of Cationic Rhodium Peroxo Complexes
Organometallics, 2012
Figure S1. Crystallographically determined structures of [Rh(IPr)2(O2)(MeCN)2]BF4 (11BF4) (left) and of [Rh(SIMes)2(O2)(MeCN)2] CF3SO3 (12OTf) (right) displaying thermal ellipsoids drawn at the 50 % confidence level. Hydrogen atoms and counter-anion are omitted for clarity. Selected interatomic distances [Å] and angles [°] for 11BF4: Rh(1)-O(1), 1.974(2); Rh(1)-O(2), 1.980(3);
Structure of tris(thioacetyltrifluoroacetonato)rhodium(III)
Acta Crystallographica Section C Crystal Structure Communications, 1990
between the ligands coordinated to two centrosymmetrically related Mo atoms. A similar but consequently greater deviation (mean value 12 °) was found in the structure of the analogous i-propoxo complex (Chisholm et al., 1981). The Mo202 bridging system is almost square planar, the internal angles O(1)-Mo-O(I') and Mo-O(I)-Mo' being 95.3 (3) and 84-7 (3) °, respectively. The lateral distances Mo-O(1) and Mo-O(I') are equal within experimental error [2.027(5) and 2.029 (5) A]. The bond lengths Mo-CI(1) of 2-391 (2) and Mo-CI(2) of 2.393 (2)A agree with the values of 2.317 (3) and 2.360(4)A found in Mo2CI4(OPh)6 (Kamenar & Penavi6, 1977) and agree even better with those of 2-421 (2) and 2.416 (1)A in the above mentioned Mo2Cla(O-i-Pr)6. However, all these Mo-C1 bond lengths are considerably longer than molybdenum-terminal-chlorine bond lengths of 2-26 (2) A in MoCI30 (Drew & Tomkins, 1970), and of 2.24 (3)/~ in Mo2Cll0 (Sands & Zalkin, 1959). This bond lengthening may indicate the trans influence of the alkoxo ligands. The bond lengths between Mo and terminal methoxo O atoms [Mo-O(2) of 1.811 (5) and Mo-O(3) of 1.801 (5) A] are short and suggest M~ double bonds (Schr6der, 1975; Manojlovi6-Muir & Muir, 1972), indicating the existence of additional 7r bonding between the metal and alkoxo ligands (Huffman, Molloy, Marsella & Caulton, 1980). The same shortening of the MoOR bonds was found in the Mo-phenoxo (Kamenar & Penavi6, 1977) and Mo-propoxo complexes (Chisholm et al., 1981); in both structures such MoO bond lengths have a mean value of 1.81A. The Mo-Mo bond is also of interest because in the Mo complexes it varies with the metal oxidation state, the nature of the bridging ligands, as well as with the steric and electronic properties of the terminal ligands. In this structure the Mo-Mo bond length of 2.733 (1) A is of the d~-d | type and corresponds to a single bond (Cotton, 1977). It is the same as already found in the above mentioned analogous Mo(chloro)(propoxo) [2.731 (1)A] and Mo(bromo)-(propoxo) [2.739 (1) A] complexes.
Cationic complexes of rhodium(I) and their reactivity toward air
Inorganic Chemistry, 1971
The reaction of [CsH12RhC1]2 with an excess of the ligands L = P(O-i-C3H?)a, P (O C H~) Z C~H S , PocH3(C~Hs)z, P(CH~)ZCBHS, and PCH3(C6H5)1 in methanol at room temperature or under refluxing conditions gives the four-coordinate cations RhL4+ whereas the corresponding reaction involving the ligands L = P(OR)3 (R = CH3, CzHa, i-C4Ho, and n-C1Hs) and P(OCH2)a-CCH3 yields the five-coordinate species RhLa+. However, by employing a rhodium:ligand ratio of 1:4 in those reactions involving the ligands P(OR)a (R = CHI and CzHs) the four-coordinate cations Rh[P(OR)3]4+ are obtained. Further the reaction of [CsHI2RhCl]2 with excess of the ligands L = P(CH3)zCeHj and As(CH3)zc~Hj in methanol in the presence of air affords the stable oxygen-containing cations RhL40z'. The cations RhL4+, RhLb+, and RhL402+ were characterized as the tetraphenylborates, hexafluorophosphates, or perchlorates. The ionic compounds { Rh [P(OR)3]4 1 B (C&s)4 (R = CH3, C2Hs, and i-C3H7) and { R~[ P (O R)~]~} B (C B H~)~ (R = CH3, CzH5, i-CaH9, and n-C4Hg) decompose in air to form the neutral derivatives Rh[P(OR)3]tB(C6Ha)4 containing one of the phenyl rings of the B(C6Hj)l group bonded as an arene to the rhodium atom, The bonded B(C6Hb)4 group in R~[ P (O C H~)~] Z B (C~H~)~ is readily displaced by trimethyl phosphite and by the ligand (C6Hs)zPC2H4P(CsHs)z to give the products (Rh[P(OCH3)3]s] B(C6Hs)a and { Rh[(CsHj)zPCzHaP(CaHa)z]z} B (C~H~) I , respectively. The compound { Rh[P(OCH3)3]5) PF6 reacts with the dienes cycloocta-1,5-diene and bicyclo[2.2.1] hepta-2,5diene in the presence of air to give the ionic derivatives { Rh(C8H1z)[P(OCH3)3]~)PF6 and { R~(C,H~)[P(OCH~)~]~}PFB, respectively. The nmr spectra of the various compounds are discussed.
Synthesis and crystal structure of tris(2,2'-bipyridine)rhenium(2+) perrhenate
Inorganic Chemistry, 1987
Using in (2) the experimental Ag's, we can estimate the Jc,ef,, integrals from the PXij (i # j) elements. This procedure gives JxZJzqy = -0.2 (1.3) Jxz+y2,xy = 0.3 (-3) (3) Jy,,,z-9Jy = -0.1 (-0.4) expressed in cm-I. The values in parentheses in (3) refer to Dex2. Extracting the Je,d,, integrals from the diagonal elements of Dex is complicated by the fact that the experimental D tensor is traceless and the three principal values are not linearly independent. Assuming an overall C2, symmetry for the dinuclear complex, the four HOMO'S of the oxalato molecule35 span the A, + A, + B, + B, irreducible representations of the C2, point group (Figure 5). The Ixy) and lyz) orbitals on copper span a, + b,, and Ixzy z ) and Ixz) span a, + b, . JyZJzJy is expected to be antiferromagnetic (positive sign) due to antiferromagnetic exchange pathways of the type xyll(A, + B,)lbz, and a ferromagnetic value (negative sign) is anticipated for Jxr,xr,,y and J , L~~-, , z~~ through the exchange pathways xyll(A, + B , ) I (A, + Bu)llxz,x2 -y2. This leads in (2) to Dex,, < 0, Dex,,,, > 0, and Dex,, < 0.
Formation and Reactivity of (Octaethyltetraazaporphyrinato)rhodium Complexes
Inorganic Chemistry, 1994
A series of (octaethyltetraazaporphyrinato)rhodium, (OETAP)Rh, complexes including (0ETAP)Rh-I, (0ETAP)-Rh-CH3, and [(OETAP)Rh]2 were prepared for comparison with the corresponding (octaethylporphyrinat0)rhodium, (OEP)Rh, derivatives. [(OETAP)Rh]2 (1) reacts like [(OEP)Rh]2 (2) with CH31, CH3NC, (CH30)3P, and CH2=CH2 in forming (0ETAP)Rh-CHs and (0ETAP)Rh-I, (OETAP)Rh(CN)(CH3NC), (0ETAP)Rh-P(O)(OCH3)2, and (OETAP)Rh-CHzCH2-Rh(OETAP), respectively, but reactions of 1 are invariably much slower than those of 2. [(OETAP)Rh]2 fails to react with H2, CO, CHJCHO, and C H~C~H S , which participate in prominent substrate reactions for 2. Reactivity and equilibrium studies indicate that a substantially larger Rh-Rh bond dissociation enthalpy for 1 compared with 2 is primarily responsible for the slower rates and reduced scope of substrate reactions for [(OETAP)Rh]2. Dissolution of 1 in pyridine results in formation of a persistent OETAP anion radical complex of Rh(III), (OETAP'-)Rh111(py)2, which contrasts with 2 where disproportionation produces the (0EP)RhIanion and the (OEP)Rh111(py)2cation. (0ETAP)Rh-CHp (RhC33H43N~) crystallizes in the monoclinic system, space group P21/c, with a = 9.889(2) A, b = 22.660(4) A, c = 14.781(3) A, j3 = 106.85(2)O, and Z = 4.
Robertsite, Ca 2 Mn III 3 O 2 (PO 4 ) 3 ·3H 2 O
Acta Crystallographica Section E Structure Reports Online, 2012
This open-access article is distributed under the terms of the Creative Commons Attribution Licence http://creativecommons.org/licenses/by/2.0/uk/legalcode, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited. Acta Crystallographica Section E: Structure Reports Online is the IUCr's highly popular open-access structural journal. It provides a simple and easily accessible publication mechanism for the growing number of inorganic, metal-organic and organic crystal structure determinations. The electronic submission, validation, refereeing and publication facilities of the journal ensure very rapid and high-quality publication, whilst key indicators and validation reports provide measures of structural reliability. The journal publishes over 4000 structures per year. The average publication time is less than one month.
Londonite from the Urals, and New Aspects of the Crystal Chemistry of the Rhodizite-Londonite Series
The Canadian Mineralogist, 2010
Three old specimens, collected in the 19 th century and now deposited in Fersman Mineralogical Museum, Moscow, are labeled as rhodizite from the Sarapulka, Shaitanka (both cotype localities) and Alabashka granitic pegmatite fields, Central Urals, Russia. All are Cs-dominant (Cs > K) and must now be considered londonite. The crystal structure of londonite from Sarapulka was solved from single-crystal data collected at 193 K and refined to R = 0.0203. The mineral is cubic, space group P43m, a 7.3149(7) Å. Its structure is based on a microporous quasi-framework formed by clusters of four edge-sharing AlO 6 octahedra linked by BO 4 and BeO 4 tetrahedra. Both Cs + and K + are ordered in the cages of the quasi-framework. The very short Cs-K distance, 0.51(3) Å, prevents simultaneous occupancy of these positions in the same cage. The Be and K atoms are also separated by an unallowable short distance of 2.76(3) Å, and thus their contents are coupled. The solid-solution system between rhodizite (K-dominant), londonite (Cs-dominant) and the hypothetical K-and Cs-free analogue, (□,H 2 O){Al 4 [Be 4 B 12 O 28 ]}, is complicated, with numerous coupled heterovalent substitutions. Taking into consideration chemical, structural and IR data, it can be presented as: (A,□,H 2 O) 1 (Al,Li) 4 (Be,Li,Al,□) 4 (B,Be) 12 [O 28-x (OH,F) x ], where A = K, Cs and x < 1; the species-defining elements are marked in bold. The rhodizite-londonite series is structurally related to pharmacosiderite-and sodalite-type §