X-ray crystal structures ofcis-bis(diphenylphosphinamide)tetracarbonylmolybdenum(0) andtrans-bis(N-methyl diphenylphosphinamide)tetracarbonylmolybdenum(0)

The X-ray crystal structures ofcis-Mo(CO)₄(Ph₂PNH₂)₂,I, andtrans-Mo(CO)₄(Ph₂PNHMe)₂,II, are presented. ComplexI crystallizes in the monoclinic space groupP2₁/c(a=13.433(1),b=12.2719(8),c=17.318(2)Å;=109.79(1)°;V=2686.1(8)ų;Z=4). ComplexII crystallizes in the triclinic space groupP¯1 (a=6.9986(8),b=10.328(1),c=11.241(2)Å,=107.58(1)°,=91.76(1)°, =101.28(1)°,V=756.1(4)ų,Z=1). The molybdenum coordination geometry in each complex is a slightly distorted octahedron. The molybdenum-carbon bond lengths for the carbonyls trans to phosphorus in complexI are shorter than those the carbonyls trans to other carbonyls. The average molybdenum-phosphorus distance inI (2.525(5)Å) is similar to those in other diphenylphosphinamide complexes and longer than the molybdenum-phosphorus distance inII in 2.4585(7)Å). The distance between two nitrogen atoms incis Mo(CO)₄(Ph₂PNH₂)₂ (3.74(3)Å) is significantly larger than the sum of their van der Waals radii (3.10 Å) indicating that the two nitrogens are not hydrogen bonded.     

Neutron diffraction and vibrational spectroscopic study of single crystals of KH(D)(CHCl2COO)2

The hydrogen atoms in the short (2.498 Å) hydrogen bonds of potassium hydrogen bis-dichloroacetate are placed asymmetrically with respect to the oxygen atoms. The geometric mass effect (R 0.02 Å) is well within the range observed with this type of hydrogen bond. The thermal ellipsoids of the bridging protons are slightly elongated, the longer axis being at 40 ° with respect to the O(2)-O(4) direction. This coincides with the direction of the transition dipole moment of thev _a OH vibration. The two infrared components of this vibration are rather different, one (A_u) being very broad and intense and the other (B_u) only moderately broad. Thev _a OH/v _a OD ratio is small (1.05).     

Crystal structures of 4,11-pregnadiene-3,20-dione and 21-methyl-20-oxa-4-pregnene-3,20-dione

The structures of the title compounds were solved by direct methods and refined by anisotropic full-matrix least-squares methods. 4,11-Pregnadiene-3,20-dione, C₂₁H₂₈O₂(1) crystallizes in the monoclinic space groupP2₁ (Z=2). The unit cell parametersa, b, c (Å), and (°) were: 12.319(2), 7.700(2), 9.717(2), 109.41(2). TheA- andC-rings exhibit intermediate sofa-halfchair conformations. TheB-ring has a chair conformation and theD-ring assumes an intermediate envelope-half-chair conformation. The progesterone side chain has a typical conformation; the C16–C17–C20–O20 torsion angle is –15.1(4)°. 21-Methyl-20-oxa-4-pregnene-3,20-dione, C₂₁H₃₀O₃ (2) crystallizes in the orthorhombic space groupP2₁2₁2₁ (Z=4). The unit cell parametersa, b, c (Å) were: 12.926(2), 19.447(4), 7.313(1). The progesterone side chain has an unusual conformation; the C16–C17–C20–O20 torsion angle is 174.6(4)°. TheA-ring has a 1, 2-half-chair conformation, ringsB andC exhibit chair conformations and ringD is in a 13,14-half-chair conformation.     

Studies of systemic acylanilide fungicides. Part IV. Crystal structure and molecular conformation ofN-(2-methoxyacetyl)-N-(2,6-xylyl)-α-amino-γ-butyrolactone

The crystal structure of the title compound (C₁₅H₁₉NO₄, MW 277.3 amu) was determined by three-dimensional X-ray analysis from diffractometer data. Crystal data are: monoclinic,P2₁/n,a=9.600(3) Å,b=11.964(6) Å,c=12.802(4) Å,=101.25(3)°,V=1442.1(16) ų,Z=4;D _x =1.277 Mg m^–3;(MoK)=0.10 mm^–1. FinalR=0.055 for 1686 observed reflections having 2 (MoK)<50° andI>2.5 (I). The compound is isostructural withN-(2-methoxyacetyl)-N-(2,6-xylyl)-3-amino-1,3-oxazolidin-2-one. The dimethylphenyl ring is almost perpendicular to the amidic plane of the molecule (dihedral angle 81.9°); the butyrolactone ring is in the typical envelope conformation.     

Synthesis and crystal structure of two vanadium(V) hydroxylamido complexes with amino acid ligands

Two vanadium(V) hydroxylamido complexes with amino acid ligands including Alanine, [VO(NH₂O)₂(Ala)]·2H₂O, and Threonine, VO(NH₂O)₂(Thr), were synthesized and characterized by elemental analyses, IR spectrum, and single crystal X-ray diffraction. The two complexes are seven-coordinated with four nitrogen atoms and three oxygen atoms in pentagonal bipyramidal geometry. The different hydrogen bonds (N–H···O, O–H···O) observed in the two complexes result in the two-dimensional network structure. [VO(NH₂O)₂(Ala)]·2H₂O belongs to monoclinic: space group P2(1)/c, with a = 21.874(13) Å, b = 8.874(5) Å, c = 15.865(9) Å, = 100.423(8)°, V = 3029(3) ų, Z = 12, D _c = 1.678 g/cm³, (MoK) = 1.002 mm^–1, F (000) = 1584, and final R ₁ = 0.0375, wR ₂ = 0.0886 for observed reflections 1189 (IT > I> 2(I)). VO(NH₂O)₂(Thr) is rhombohedral: space group R-3, with a = 21.460(16) Å, b = 21.460(16) Å, c = 11.184(12) Å, = 120°, V = 4461(7) ų, Z = 18, D _c = 1.669 g/cm³, (MoK) = 1.012 mm^–1, F(000) = 2304, and final R ₁ = 0.0356, wR ₂ = 0.0924 for observed reflections 1306 (I > 2(I)).     

Crystal structures of five policyclic compounds related to the natural product forskolin

(3(Z),4,6a,9a,9b)-(±)-3a,4,6a,7,8,9,9a,9b-octahydro-4,7,7, 9b-tetramethyl-3a-[3-(methoxymethyloxy)-3-methyl-1-butenyl]-5H-naphto[1,8-de]-1,3-dioxin-6-one (I), C₂₂H₃₆O₅,M _r=378.51, monoclinic,P2₁/n,a=6.330(1),b=14.576(2),c=22.837(2)Å,=93.04(1)°,V=2104.1(2)ų,Z=4,D _c=1.19 Mg/m³, (MoK)=0.71069Å,=0.8 cm^–1,F(000)=832,T=298 K,R=0.054 for 1971 observed reflections; (7a,10a,10b,12)-(±)-7a,9, 10,10a,10b,11,12,12a-octahydro-2,2,10,10,10b,12a-hexamethyl-2H,8H-1-benzopyrano[4a,5,6,-de][1,3,2]-benzodioxin-11-one (II), C₂₀H₂₉O₄,M _r=334.5, triclinic,P-1,a=10.595(2),b=12.152(1),c=8.073(1)Å,=106.53(1),=105.65(1), =66.29(1)°,V=897.9(2)ų,Z=2,D _c=1.24 Mg/m³, (MoK)=0.71069Å,=0.8 cm^–1,F(000)=362,T=298 K,R=0.046 for 2848 observed reflections; (7a,10a,10b,12, 12a)-(±)-7a,9,10,10a,10b,11,12,12a-octahydro-2,2,10,10,10b,12a-hexamethyl-2H,8H-1-benzopyrano[4a,5,6-de][1,3,2]-benzodioxin-11, 12-diol (III), C₂₀H₃₂O₅ (two molecules in the asymmetric unit),M _r=352.2, triclinic,P-1,a=12.948(3),b=13.615(3),c=12.197(4)Å,=101.16(2),=111.88(2), =69.48(2)°,V=1863.8(9)ų,Z=2,D _C=1.26 Mg/m³,(MoK)=0.71069 Å,=0.8 cm^–1,F(000)=768,T=298 K,R=0.060 for 4570 observed reflections; 4-acetoxy-4-[[(4a,5,8a)-(±)-hexahydro-4a,6,6-trimethyl-4H-1,3-benzodioxin-4-one]-5-yl]butan-2-one (IV), C₁₇H₂₆O₆,M _r=326.4, monoclinic,P2₁/c,a=10.495(2),b=12.050(2),c=14.216(2)Å,=108.51(1)°,V=1704.8(5)ų,Z=4,D _c=1.27 Mg/m³,(MoK)=0.71069 Å,=0.9 cm^–1,F(000)=704,T=298 K,R=0.049 for2455 observed reflections; (3a,4,5,6,6a,9a,9b)-(±)-4,5-epoxy-decahydro-3, 3a-dihydroxy-2-ethoxy-4,7,7,9b-tetramethyl-naphto-[1,8-bc]-pyran-6-ol-acetate (V), C₂₀H₃₂O₇,M _r=383.5, monoclinic,C2/c,a=10.353(2),b=17.975(3),c=21.188(3)Å,=91.29(1)°,V=3942(1)ų,Z=8,D _c=1.29 Mg/m³,(MoK)=0.71069 Å,=0.8 cm^–1,F(000)=1664,T=298 K,R=0.051 for 2120 observed reflections. We report here the complete structures of four decalin derivatives (compoundsI, II, III, V) and one related compound (compoundIV) synthetized in order to find an efficient synthetic approach for the natural productforskolin.     

Crystal and molecular structure of methylene bis(piperidine-dithiocarbamate), C13H22N2S4

Reaction of anhydrous sodium piperidine dithiocarbamate with methylene chloride yields methylene bis(piperidine dithiocarbamate). The crystals, C₁₃H₂₂N₂S₄ (M=334.57), are monoclinic with space group ,a=6.421(3),b=29.321(7),c=9.022(4)Å,=109.05(3)°,V=1605.6 ų,Z=4,D _c =1.384 g cm^–3,F(000)=712,T=295°K (Mo-K)=0.71069 Å,=5.62 cm^–1 andR=0.032 for 1734 reflections. The molecular structure shows that the methylenic group is bonded to two planar moieties at distances of 1.782(3) and 1.803(3)Å with an S-CH₂-S angle of 114.7(2)°. The configuration about each N atom is planar rather than pyramidal. The two C-N bond lengths adjacent to the C=S bonds are both very short 1.330(4) and 1.336(4) Å indicating the influence of the C=S bond on C-N bond lengths. The six-membered piperidine ring has a classical chair conformation with average C-C distance of 1.511 (5)Å.     

Crystal and molecular structure of tris-(O-isopropylxanthato)-chromium(III)

The title compound has been synthesized by the reaction of CrCl₃6H₂O with K{S₂COCH(CH₃)₂} in a 13 molar ratio in an aqueous medium. It has been characterized by elemental analysis and IR spectral studies. Crystals of Cr{S₂COCH(CH₃)₂}₃ are monoclinic, space group P2₁/n witha=10.002(2),b=10.973(1),c=18.961(6) Å,=91.78(2)°,V=2079.9 ų,Z=4,D _calc=1.46 g cm^–3, monochromatic radiation (Mo-K), =0.71069 Å,=11.2 cm^–1,F(0 0 0)=948,T=295K, finalR=0.0320 for 2641 reflections. The environment of the chromium atom is based on an octahedral geometry having six sulfur donor atoms from three symmetrically chelated ligands with average distances: Cr-S=2.396(9) Å, C-S=1.690(3) Å and C-O=1.315(3) Å. The bond distance between oxygen atom and the carbon atom of the isopropyl group (O-C_av=1.478(4) Å) suggests that the form –S ₂ ^(–) C=O⁽⁺⁾CH(CH₃)₂ contributes significantly to the structure of the isopropyl group.     

Crystal structures of bis-11-aminoundecanoic chlorocuprate and bis-11-aminoundecanoic-Cu(II) sulfate trihydrate

Bis-11-aminoundecanoic chlorocuprate: (I),M _r =609.5, triclinic,P¯1 (No. 2),a=7.237(1),b=7.536(1),c=27.605(2) Å, =97.98(8),=92.45(8), =90.02(8)°,V _c =1492 ų,Z=2,D _x =1.357 g cm^–3,D _m =1.35(1) g cm^–3 (flotation), =43.85 cm^–1, CuK radiation=1.5418 Å,F(000)=642,T=23 °C,R=0.065 for 4121 observed reflections. Bis-11-aminoun-decanoic sulfate Cu(II) trihydrate: (II),M _r =616.4, triclinic,P¯1,a=7.745(2),b=9.553(4),c=20.343(5) Å, =80.91(3),=79.28(2), =87.58(3)°,V _c =1460 ų,Z=2,D _x =1.40(1) g cm^–3,D _m =1.38(2) g cm^–3 (flotation),=8.16 cm^–1, MoK radiation=0.71069 Å,F(000)=658,T=23°C,R=0.064 for 3384 observed reflections. In (I) the two copper ions are in special positions 0, 0, 0 and 1/2, 1/2, 0 octahedrally coordinated to Cl^–. The CuCl ₂ ^2– ions make square planes with the short bonds of mean values 2.289 and 2.295 Å. The carbonyls are hydrogen bonded, and the conformation of the amino acid chains ist for whole chain except at C(11) of chainA and N of chainB where it isg. In (II) Cu²⁺ shows a very distorted octahedral coordination with a mean value of 1.959 Å for the short bonds Cu-O and 2.512 Å for the long bonds. TheB amino acid chain presents a similar conformation change at C(11) as in theA chain of complex (I).     

Structure of 2-(2′-bromo-5′-nitrostyryl)benzothiazole

The title compound C₁₅H₉BrN₂O₂S (brnsb) is monoclinic, witha=7.730(2),b=26.847(5),c=7.773(2) Å,=117.48(1)°,V=1431(1) ų,Z=4,D _x=1.677,(MoK)=29.9 cm^–1,F(000)=720,T=298K in space groupP2₁/c. The structure was solved by heavy atom and Fourier methods and refined toR=0.034 for 1776 unique observed reflections. The molecule is nearly planar, with a dihedral angle of only 3.8(1.1)° between the benzothiazole and phenyl rings. The C-S-C angle in the thiazole ring is 89.0°, while the C-N-C angle in that ring is 111.5(3)°.     

Synthesis,spectroscopic studies,and crystal structure of theophyllinium tetrabromopalladate(II)

The theophyllinium tetrabromopalladate(II), [Thph]₂PdBr₄, has been synthesized and its molecular structure has been determined by single crystal X-ray diffraction. The salt crystallizes in the monoclinic space group C2 with two formula units in a cell of dimensionsa=11.074(1),b=8.545(2),c=11.804(2) Å;=95.22(1)°,V=1112.3(4) ų,D _c=2.353 mg m^–3,D _exp=2.352 mg m^–3,M _w=788.4, (MoK)=84.5 cm^–1,F(000)=752. The structure has been refined by full-matrix least-squares techniques to a final value of theR factor of 0.058 based on 907 independent intensities. The compound consists of theophyllinium cations protonated at N(9). The [PdBr₄]^2– anion is planar, with distances Pd-Br(1)=2.441(12) and Pd-Br(2)=2.412(6) Å, and Br(1)-Pd-Br(2) and Br(1)-Pd-Br(3) angles of 90.34(14)° and 89.66(14)°, respectively. The¹H-NMR spectrum of [Thph]₂PdBr₄ in DMSO-d₆ (300 MHz) is consistent with the observed solid-state structure, and its thermal behavior shows two steps: (i) a dehalogenation process about 327°C and (ii) a rapid pyrolitic decomposition in the 340–575°C temperature range giving PdO as final product.     

Synthesis and molecular structure of {[Se(CH3)3][(CH3)AlCl3]}n: A novel two-dimensional layered organoaluminum-selenium polymer

The crystalline product {[Se(CH₃)₃][(CH₃)AlCl₃]}_n was prepared from reaction of SeCl₄ with A1(CH₃)₃ in heptane. The organo-main group polymer crystallizes in the monoclinic space group P2₁/c with unit cell parametersa=11.218(3) Å,b=11.119(3) Å,c=9.915(2) Å,=107.82(2)°,V=1177.4(5) ų, andD ^calcd=1.54 g cm^–3 forZ=4. Least-squares refinement based on 1195 observed reflections I>3(I) in the range 3.50°<2<45.0° led to a finalR factor of 0.036 (R ^w=0.047). The asymmetric unit contains one selenonium ion, Se(CH₃) ₃ ⁺ , and one organoaluminum anionic species, (CH₃)AlCl ₃ ^– . Secondary interactions (SeCl) serve to link the ions along two dimensions to form infinite layers. Thus, {[Se(CH₃)₃] [(CH₃)A1C1₃]}_n may be regarded as a layered organoaluminum-selenium polymer. The mean Se-C bond distance is 1.921(5) Å while the mean C-Se-C bond angle is 99.1(4)°. The independent Al-C bond distance is 1.927(8) Å while the mean Al-Cl bond distance is 2.166(7) Å.     

The molecular structure of the diacetic acid adduct of guanidinium tetrabromochromate(II)

The diacetic acid adduct of guanidinium tetrabromochromate(II) crystallizes in the monoclinic crystal system:a=8.778,b=9.125,c=12.195 Å,=89.84°, space groupP2₁/n,Z=2. The structure was determined using the heavy atom method followed by Fourier methods and refined by full-matrix least-squares toR=0.061 for 2221 observed reflections. The structure contains discrete [CrBr₄(HO₂CCH₃)₂]^2– anions separated by [C(NH₂)₃]⁺ cations. The chromium(II) atom is six-coordinate withtrans pairs of Cr-Br bonds of unequal length (2.84 and 2.63 Å), and two acetic acid molecules completing the coordination.     

Structure of 11α-hydroxy-progesterone,C21H30O3

The structure of the title compound, C₂₁H₃₀O₃, was determined by X-rays.M _r =330.5, orthorhombic,P2₁2₁2₁,a=8.4451(9),b=10.7074(8),c=20.1525(40) Å,V=1822(8) ų,Z=4,D _x =1.205 mg m^–3. CuK radiation (1.54184 Å),(CuK)=5.85 cm^–1,F(000)=720. FinalR=0.054R _w =0.049 for 1774 unique reflections. The structure was solved usingMultan. TheA ring adopts an intermediate sofa-half-chair conformation and is bent toward the face of the steroid skeleton. RingsB andC have typical chair conformations, and theD ring has a slightly distorted half-chair conformation. The progesterone side chain has a typical conformation, and the C16-C17-C20-O20 torsion angle is –17.9°. An intermolecular hydrogen bond is formed between the hydroxyl group and the progesterone side chain.     

Crystal structure of bis-[dihydrido(3,5-dimethyl-1-pyrazolyl) (3,5-diphenyl-1-pyrazolyl)borate]zinc(II), [Zn{H2B(3,5-Me2Pz)(3,5-Ph2Pz)}2]

Crystals of the title compound are monoclinic,a=13.796(1),b=16.727(1),c=16.1937(8) Å,=102.063(5)°,V=3654.3(4) ų, space groupP2₁/c,Z=4. The crystal structure was solved by Patterson and Fourier methods and refined toR=0.033 for 3883 unique reflections withF _o>3(F _o). The metal atom is tetrahedrically coordinated to two bidentate ligands with Zn-N distances and N-Zn-N angles in the range 1.982(2)–2.019(2) Å and 100.3(1)–119.5(1)°. The boat conformations of both BN₄Zn chelate rings are unusually asymmetric (quasi-sofa), with the B atoms at 0.71 Å from the N₄ mean plane, while the Zn atoms are at only 0.07 Å. ZnB distances (3.784 and 3.794 Å) andv(B-H) stretching frequencies (2497 and 2400 cm^–1) rule out agostic bonds. Overall the molecule displays approximate C₂ symmetry. The temperature-dependent NMR spectra show no fluxional behavior in solution.Paper presented at the XV Congress of the International Union of Crystallography, Bordeaux, France, 19–28 July 1990 (abstract PS-06.03.01).     

X-ray crystal structure of the 1∶2 triethyleneglycol dimethyl ether (triglyme): Dichloropicric acid adduct

The anhydrous 12 triglyme:Dichloropicric acid adduct is triclinic, space group ; at 24°Ca=8.703(5),b=10.381(4), c=10.404(3) Å, =114.42(3), =99.69(5), =106.40(6)°,D _x=1.656 g cm^–3, V = 776(2)ų,Z=1. Bond lengths and angles are normal except that one C–C–O–C torsion angle in the triglyme is approximately 90° rather than the expected 60 or 180°. Each phenolic OH group hydrogen bonds with a terminal OCH₃ of the polyether. The O...O distance, 2.557(3) Å, is in fair agreement with the 2.52 Å estimated from the single observed IRv (OH) stretch at 1714 cm^–1.     

Crystal and molecular structure of aqua(2,2′-bipyridine)bis(betaine)copper(II) perchlorate monohydrate

A new monomeric copper(II) complex with 2,2-bipyridine (bpy) and betaine (bet), [Cu(byy)(bet)₂(H₂O)](ClO₄)₂ · H₂O, has been prepared and characterized by X-ray crystallography. The complex crystallizes in the triclinic space groupP-1 witha=8.859(2),b=11.191(2),c=14.850(3) Å, =91.41(1), =97.19(1), =91.97(1)°,V=1459.2(7) ų, andZ=2. The structure comprises discrete cations [Cu(bpy)(bet)₂(H₂O)]²⁺ in which the metal atom is coordinated in a distorted square-pyramidal environment by two oxygen atoms from a pair of monodentate carboxylato ligands [Cu–O=1.950(2) Å] and two nitrogen atoms of a bidentate bpy ligand [Cu–N=1.997(3)–2.005(3) Å] on the basal plane, and one aqua [Cu–O=2.267(3) Å] ligand at the apical position.     

Structure of the larvicideN-(2-chlorobenzoyl)-N′-[4-(2-chloro-3,3,3-trifluoroprop-1-enyl)phenyl]urea,C17H11Cl2F3O2N2

Mw=403,2 amu,P2₁/c,a 18.944(8) Å,b=8.540(4) Å,c=10.794(7) Å,=98.11(4)°,V=1729(2) ų,Z=4,D _x=1.548 g·cm^–3, (MoK)=4.26 cm^–1; m.p. 202–204°C. FinalR=0.083 for 1632 independent observed reflections having 2 (Mo K)<50° andI>2 (I). The molecule has an extended overall nonplanar conformation with onecis and twotrans-C(O)-NH- units and intramolecular hydrogen bridges. The relatively highR factor is on account of conformational disorder of the trifluoromethyl and chloro substituents of the 2-chloro-3,3,3-trifluoropropenyl moiety.     

Isomerism in some 1-oxa-3,5-dithians and the X-ray structure determination of 2,6-bis(trichloromethyl)-4-dichloromethylene-1-oxa-3,5-dithian

2,6-bis (trichloromethyl)-4-dichloromethylene-1-oxa-3,5-dithian is triclinic,P¯1,a=10.125(3),b=10.294(3),c=14.631(10) Å,=92.84(5),=96.51(5), =96.18(2)°,V=1503 ų,Z=4. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least squares to a finalR value of 0.035 using 3961 reflections. The conformation of the molecules is twist-boat, one molecule being almost symmetrically twisted about the O-C(Cl₂) direction. The range of endocyclic O-C-S angles is 111.8(3) to 115.1(3)° and data are given which support the possibility of there being a correlation between the endocyclic O-C(X)-S angle, the C-O-C(X)-C(Cl₃) torsion angle, and the C-S-C(X)-C(Cl₃) torsion angle. The -CCl₃ groups are in pseudoequatorial positions. Average bond lengths (Å) for the two molecules are C-O 1.405, C(sp ³)-S 1.822, C(sp ²)-S 1.759, C-C_eq 1.529 and average endocyclic angles (°) are O 117.3, C (sp ³) 113.5, S 97.4, C(sp ²) 119.3, the esds on the individual bond lengths and angles being in the ranges of 0.003–0.004 Å and 0.2–0.4° respectively.     

Crystal and molecular structures of trans-bis(acetonitrile)bis(bipyridine)ruthenium(II) perchlorate and trans-diamminebis(bipyridine)ruthenium(II) perchlorate

The structures of trans-[(MeCN)₂(bpy)₂Ru](ClO₄)₂(I) andtrans-[(NH₃)₂(bpy)₂Ru](ClO₄)₂(II) have been determined by single crystal X-ray diffraction methods. (I) forms monoclinic crystals in the space groupP2₁/c witha=8.399(2),b=10.406(2),c=15.590(3) Å,=93.78(2)° andZ=2 atT=293 K. The final refinement gaveR=0.040 for 2448 reflections withF _o ² >3(F _o ² ). (II) crystallizes in the triclinic space groupP¯1 witha=1.702(1),b=8.439(2),c=10.525(2) Å,=107.56(2),=104.63(1), =100.89(2)° andZ=1 atT=293 K. Refinement using 1878 reflections withF _o ² >3(F _o ² ) produced a finalR value of 0.036. Both of these structures have the ruthenium atom located on a crystallographic inversion center. The bipyridine ligands in both structures are in the bowed conformation as a means of circumventing the steric problems associated with the trans arrangement of the bipyridine ligands. The Ru-N(monodentate) distance is longer for the ammonia complex (2.106(3) Å) than for the acetonitrile complex (2.008(4) Å); there are no significant differences in the distances and angles of the two Ru(bpy)₂ frameworks.