Preparation of Cr2(CO)8(NO)2 and X-ray crystal structures of Cr2(CO)8(NO)2 and Cr2(CO)9NO−. Stereochemical comparisons to Cr2(CO)102−

1991 ◽  
Vol 69 (12) ◽  
pp. 2136-2141 ◽  
Author(s):  
A. P. Masters ◽  
M. Parvez ◽  
T. S. Sorensen

Cr2(CO)8(NO)2 (1) has been prepared and characterized, and the crystal structure determined, along with that of the related salt Cr2(CO)9NO− monoanion (2) as the CH2Cl2-solvated PPN+ salt (where PPN+ denotes the (PPh3)2N+ monocation). Both 1 and 2 possess a metal–metal bonded structure analogous to that of Mn2(CO)10 and the electronically equivalent Cr2(CO)102− dianion. Although Cr2(CO)8(NO)2 (1) is slowly formed in poor yield from Cr(CO)4NO− and Cr(CO)4NOBr, it can be prepared in an almost quantitative yield by the one-electron oxidation of the monoanion with trityl hexafluorophosphate. The slowness of the former reaction makes Cr(CO)4NO− useful as a two-electron reductant of organohalide bonds. Triclinic crystals of 1 incorporate two distinct molecules in die [Formula: see text] space group, although the geometries of each are almost identical. Triclinic crystals of monoanion (2) also belong to the [Formula: see text] space group. The Cr—Cr bond length is 3.00–3.02 Å in 1 and 2.995 Å in 2, compared to 2.904 Å for the central Mn—Mn bond in Mn2(CO)10. Key words: chromium nitrosyl, chromium carbonyl, X-ray crystal structure, metalate anion, metal–metal dimer.

1980 ◽  
Vol 35 (5) ◽  
pp. 522-525 ◽  
Author(s):  
Gisela Beindorf ◽  
Joachim Strähle ◽  
Wolfgang Liebelt ◽  
Kurt Dehnicke

The complexes AsPh4[Cl4V = N-Cl] and AsPh4[VOCl4] are prepared by the reaction of AsPh4Cl with Cl3VNCl and VOCl3, respectively. The IR spectra indicate C4v symmetry for the complex anions with multiple VN and VO bonds and a linear arrangement for the VNCl-group. AsPh4[VOCl4] crystallizes in the tetragonal space group P4/n with two formula units in the unit cell. The crystal structure was solved by X-ray diffraction methods (R = 0,062, 1096 observed, independent reflexions). The structure consists of AsPh4+ cations and [VOCl4]- anions with symmetry C4v. The extremely short VO bond length corresponds with a VO triple; its steric requirements cause the relatively large bond angle OVCl of 103.4°.


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.


1979 ◽  
Vol 34 (8) ◽  
pp. 1057-1058 ◽  
Author(s):  
Axel Czybulka ◽  
Günter Steinberg ◽  
Hans-Uwe Schuster

In the systems Li-M-X = (M = Y, Gd; X = Si, Ge) the compounds LiYSi, LiYGe and LiGdGe were prepared. Their crystal structures were determined by X-ray investigations. They crystallize hexagonally (space group P 6̄2m), and a C22-(Fe2P-type) lattice was found


1984 ◽  
Vol 39 (1) ◽  
pp. 107-110 ◽  
Author(s):  
W. Hiller ◽  
J. Strähle ◽  
H. Prinz ◽  
K. Dehnicke

The X-ray structure of PPh3Me[NbOCl4(CH3CN)] at 210 K was solved (space group P1̄, two formula units per unit cell, a = 1173.5(5), b = 1130.1(4), c = 946.8(3) pm, α = 97.70(4), β = 93.57(3), γ = 78.62(3)°, 3688 inde­pendent reflexions, R = 0.025). The material consists of cations [P(C6H5)3CH3]⊕ and anions [NbOCl4(CH3CN)]⊖. The nitrogen atom of the acetonitrile solvate molecule is coordinated to the niobium centre in the trans-position to the oxo ligand; the NbO bond length of 169 pm corresponds to a double bond.


2001 ◽  
Vol 65 (4) ◽  
pp. 523-531 ◽  
Author(s):  
A. Kyono ◽  
M. Kimata

AbstractThe crystal structure of hydrothermally synthesized Rb-feldspar (monoclinic, space group C2/m, a= 8.839(2)Å, b= 13.035(2)Å, c= 7.175(2)Å, β = 116.11(1)8, V= 742.3(3)Å3, Z= 4) has been refined to a final R of 0.0574 for 692 independent X-ray reflections. Microprobe analyses of the Rb-feldspar suggest deviation from stoichiometry, with excess Si and Al, resulting in a unit formula of Rb0.811□0.127Al1.059Si3.003O8. Infrared (IR) spectra indicate the structural occupancy of large H2O content, which implies that the □Si4O8 substitution favours the structural incorporation of the H2O molecule at the M-site. The mean T–O distances are 1.632 Å for T1 and 1.645 Å for T2, revealing highly disordered (Al,Si) distribution with Al/Si = 0.245/0.755 (T1 site) and 0.255/0.745 (T2 site).There are two geochemical implications from this refinement: (1) identification of both rubicline triclinic with (Al,Si) ordered distribution and synthetic monoclinic RbAlSi3O8 with (Al,Si) disordered distribution implies that Rb cannot be one of factors disrupting the (Al,Si) ordered and disordered distributions in feldspars; and (2) natural and synthetic feldspars capable of accommodating the large cations tend to incorporate □Si4O8, excess Al and H2O components in their crystal structures.


1988 ◽  
Vol 41 (2) ◽  
pp. 269 ◽  
Author(s):  
SF Colmanet ◽  
MF Mackay

After reaction of benzene-1,2-dithiol (bdtH2) with ammonium [99Tc] pertechnetate in aqueous alcohol, extraction of the reaction mixture with chloroform yielded wine-red crystals of the title compound, C24H16S8Tc2.CHCl3. The crystal structure of the binuclear complex has been determined by X-ray diffraction. Crystals are triclinic and belong to the space group Pī with a 8.534(1), b 8.842(2), c 11.192(3)Ǻ, α 107.02(2), β 98.13(1), γ 100.60(2)° with Z 1. Refinement on 1524 data measured with Cu Kα radiation converged at R 0.082. The complex has exact Ci point symmetry and pseudo-C2 symmetry. Each technetium atom is coordinated to a trigonal -prismatic array of six sulfur ligand atoms. These arrays are fused through a quadrilateral face defined by the four bridging sulfur atoms of two benzene-1,2- dithiolato ligands to give a Tc2S8 core of D2h pseudo-symmetry. As a Tc - Tc bond [bond length 2.591(3)Ǻ] passes through the mid point of the quadrilateral face, this novel geometry can be described in terms of capped trigonal prisms. The chloroform is disordered.


Author(s):  
Hidetomo Hongu ◽  
Akira Yoshiasa ◽  
Massimo Nespolo ◽  
Tsubasa Tobase ◽  
Makoto Tokuda ◽  
...  

Petzite, Ag3AuTe2, crystallizes in the space group I4132, which is a Sohncke type of space group where chiral crystal structures can occur. The structure refinement of petzite reported long ago [Frueh (1959). Am. Mineral. 44, 693–701] did not provide any information about the absolute structure. A new single-crystal X-ray diffraction refinement has now been performed on a sample from Lake View Mine, Golden Mile, Kalgoorlie, Australia, which has resulted in a reliable absolute structure [a Flack parameter of 0.05 (3)], although this corresponds to the opposite enantiomorph reported previously. The minimum Te–Te distance is 3.767 (3) Å, slightly shorter than the van der Waals bonding distance, which suggests a weak interaction between the two chalcogens. XANES spectra near the Au and Te L III edges suggest that the chemical-bonding character of Au in petzite is more metallic than in other gold minerals.


1978 ◽  
Vol 33 (6) ◽  
pp. 610-613 ◽  
Author(s):  
Siegfried Pohl

Abstract The crystal structure of the title compound was determined from single crystal X-ray data. The compound crystallises in the orthorhombic space group Pnma. In contrast to the solution where fluctuating P-Te bonds have been established by NMR analyses the crystals contain isolated molecules with fixed P-Te bonds (bond length: 235.4 pm). The four-membered phosphorus nitrogen ring exhibits significant deviations from planarity. The P-N bond lengths were found to be 168.3 and 175.0 pm, respectively


1992 ◽  
Vol 47 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Dietmar K. Kennepohl ◽  
Sally Brooker ◽  
George M. Sheldrick ◽  
Herbert W. Roesky

A series of manganese(II) am ides (1-4), derived from 2,6-diisopropylaniline (H2NAr; where Ar = 2,6-Pri2C6H3) and its N-silylated derivative H(SiMe3)NAr, has been prepared and characterized. The crystal structure of Mn[N(SiMe3)Ar]2[THF] (2) reveals a monomeric species with a planar three-coordinate Mn(II) center. Crystal data for 2: trigonal (hexagonal axes), a = 30.119(2) Å, c = 10.589(1) Å, V = 8319(1) Å3, T = 153 K, space group P31 (No. 144), Z = 9 (R/Rw = 0.053/0.050). In contrast, Mn3[N(H)Ar]4[N (SiMe3)2]2 · C7H8 (4) is shown to be a novel trinuclear compound held together by nitrogen-bridges. The two terminal Mn(II) atoms have a distorted trigonal planar arrangement of nitrogen donors whereas the central Mn(II) is surrounded by a distorted tetrahedral array of nitrogen donors. Crystal data for 4: orthorhombic, a = 21.301(5) Å, b = 17.021(6) Å, c = 20.519(7) Å, V = 7439(4) Å3, T = 153 K, space group Pbcn (No. 60), Z = 4 (R/Rw = 0.050/0.070).


1999 ◽  
Vol 54 (2) ◽  
pp. 288-290 ◽  
Author(s):  
Wolfgang Czado ◽  
Susanne Rabe ◽  
Ulrich Müller

(PPh4)2[As2Cl8] · CH3CN was obtained from PPh4Cl and S2Cl2 with As or As4S4 or AsCl3 in acetonitrile. PPh4Cl, S2Cl2 and Sb2S3 yielded (PPh4)[Sb2Cl8] CH3CN. PPh4Br and AsBr3 gave (PPh4)2[Sb2Br8]-CH3CN. AsCl2OPh (from AsCl3 and NaOPh) reacted with Ph4Br in acetonitrile in the presence of Na2Se, selenium, and HCl, affording (PPh4)2[As2Br4,2Cl3,8] · CH3CN. According to their X-ray crystal structure determinations, all products are isotypic (space group C2/c, Z=4). The centrosymmetric anions consist of two ψ octahedra sharing an edge. In the [As2Br4,2Cl3,8]2- ion the bridging positions are taken solely by bromine atoms, whereas Br and Cl atoms occupy the other halogen positions randomly.


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