Polyhedral palladaborane chemistry: isolation and structural characterization of ten-vertex [(PMe2Ph)2PdB9H12(PMe2Ph)] and eleven-vertex [(PMe2Ph)2PdB10H12]

Ten-vertex [6,6-(PMe₂Ph)₂-arachno-6-PdB₉H₁₂-9-(PMe₂Ph)] 1a and eleven-vertex [7,7-(PMe₂Ph)₂-nido-7-PdB₁₀H₁₂] 2a have been isolated as occasional by-products from an extension to palladaborane chemistry of the one-pot route for the preparation of the nine-vertex platinaborane [(PMe₂Ph)₂PtB₈H₁₂] 3b from [PtCl₂(PMe₂Ph)₂] and B₁₀H₁₄, but using [PdCl₂(PMe₂Ph)₂] instead of [PtCl₂(PMe₂Ph)₂] to generate [4,4-(PMe₂Ph)₂-arachno-4-PdB₈H₁₂] 3a in yields of upto 75%. The two by-products 1a and 2a are each characterized by single-crystal X-ray diffraction analysis. Space group and cell parameters are as follows: for 1a, triclinic, , a = 10.1139(2) Å, b = 10.3955(2) Å, c = 31.5086(7) Å, = 94.4720(12)°, = 91.6420(10)°, and = 105.3790(11)°; for 2a, monoclinic, P2₁/n, a = 14.6059(3) Å, b = 10.9988(2) Å, c = 15.1516(3) Å, and = 93.0000(14)°. Whereas 1a and 1b are isomorphous, Compounds 2a and 2b are not, and show significant differences in intramolecular conformation.     

Synthesis, spectroscopy, and X-ray structures of fac-(CO)3(dppe)MnSC(S)H, fac-(CO)3(dppe)ReSC(S)H, fac-(CO)3(dppp)ReSC(S)H, and fac-(CO)3(dppb)ReSC(S)H

The monodentate dithioformato complexes, fac-(CO)₃(dppe)MnSC(S)H (1), fac- (CO)₃(dppe)ReSC(S)H (2), fac-(CO)₃(dppp)ReSC(S)H (3), and fac-(CO)₃ (dppb)ReSC(S)H (4), where dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane, were synthesized from the treatment of the corresponding hydrides, fac-(CO)₃ (P-P)MSC(S)H with CS₂. Compounds 1–4 crystallize in the monoclinic crystal system: for 1, space group = P2₁/c, a = 15.3139(3) Å, b = 9.7297(4) Å, c = 19.0991(6) Å, = 105.928(1), V = 2736.5 ų, Z = 4; for 2, space group = P2₁/c, a = 15.6395(8) Å, b = 9.8182(5) Å, c = 19.4153(11) Å, = 106.741(1), V = 2854.9(3) ų, Z = 4; for 3, space group = P2₁/n, a = 11.3570(10) Å, b = 19.465(2) Å, c = 15.5702(14) Å, = 104.776(2), V = 3328.3(5) ų, Z = 4; and for 4, space group = C2/c, a = 32.078(2) Å, b = 10.4741(6) Å, c = 19.0608(9) Å, = 94.315(2), V = 6386.1(6) ų, Z = 8.     

Synthesis and structural characterization of fac-BrMn(CO)3{PH(C6H5)2}2

In attempts to find appropriated methods for preparation of unstable sulfinyl and sulfonylphosphane complexes we have synthesized the diphenylphosphine complexes of Mn(I), BrMn(CO)₄PHPh₂, (1) and BrMn(CO)₃(PHPh₂)₂ (2). Both should undergo electrophilic substitution in the presence of an adequated base. Parallel to the reactions of stabilization of phosphanes we have studied by means of x-ray analysis the structure of fac-BrMn(CO)₃(PHPh₂)₂ (2). The compound crystallizes in the triclinic space group P, a = 9.840(2), b = 11.207(2), c = 13.083(3) Å, = 72.00(3), = 69.59(3), = 81.41(3)°, U = 1284.7(4) ų, and Z = 2. In this complex the manganese atom shows an octahedral coordination geometry, with three carbonyl ligands in a fac arrangement, and one bromide and two diphenylphosphine ligands cis to each other.     

Crystal structure of 4-methyl-2-phenylbenzo[de]cyclobut[i] isoquinoline-3,5(2H)-dione

4-Methyl-2-phenylbenzo[de]cyclobut[i]isoquinoline-3,5(2H)-dione, C₂₁H₁₅NO₂, resulted from the photochemical reaction of N-methyl-1,8-naphthalenedicarboximide with phenylacetylene, has been characterized by ¹H NMR, IR, and MS spectra and established by single-crystal X-ray crystallography. The crystal structure belongs to the monoclinic space group P2₁/n with cell parameters a = 12.530(2) Å, b = 9.324(2) Å, c = 13.296(2) Å, = 96.85(1), V = 1542.3(4) ų, and Z = 4.     

X-ray diffraction structure of (5S)-3,4-dichloro-5-menthoxy-2(5H)-furanone

The structure of (5S)-3,4-dichloro-5-menthoxy-2(5H)-furanone is reported. The title compound crystallizes in the monoclinic space group P2₁: a = 6.650(2) Å, b = 8.038(3) Å, c = 14.858(8) Å, = 97.01(3), V = 788.3(6) ų, Z = 2, R = 0.0718, R _w = 0.0795 for 735 observed reflections with I > 3 (I), and the absolute configuration at C-5 of the furanone ring is shown to be (S).     

Regiospecific ligand addition to the donor–acceptor compound Ru2(CO)6(bpcd): syntheses and X-ray diffraction structures of Ru2(CO)5L(bpcd) and Ru2(CO)5L[μ-C=C(PPh2)C(O)CH2C}(O)](μ2-PPh2) (where L = PMe3 and tBuNC)

Thermal and Me₃NO-assisted activation of the donor–acceptor complex Ru₂(CO)₆(bpcd) (1) [where bpcd = 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione] with PMe₃ or ^tBuNC affords the mono-substituted complexes Ru₂(CO)₅L(bpcd), as a result of regiospecific ligand attack at the diphosphine-substituted ruthenium center. Solution NMR measurements (¹H and ³¹P) reveal that the PMe₃ derivative exists as a noninterconverting mixture of axial (3a) and equatorial (3e) isomers, with the only the equatorial isomer being observed for Ru₂(CO)₅(^tBuNC)(bpcd) (5). Near-UV irradiation of 1 in the presence of added ligand yields Ru₂(CO)₅L(bpcd), in addition to the known ₂-phosphido complex Ru²(CO)⁶ [-C=C(PPh₂)C(O)CH₂C(O)](₂-PPh₂) (2) and the corresponding phosphido-substituted complexes Ru²(CO)_5L[-{C =C(PPh₂)C(O)CH₂C}(O)]₂-PPh₂)[4 (L = PMe₃); 6 (L = ^tBuNC)]. As with compounds 3a, 3e, and 5, both 4 and 6 exhibit ligand attachment at the diphosphine-substituted ruthenium center. The molecular structures of 3e, 4, 5, and 6 were determined by X-ray crystallography. 3e, as the 1/2 C₆H₆ solvate, crystallizes in the monoclinic space group C2/c: a = 40.573(3) Å, b = 10.2663(9) Å, c = 18.347(1) Å, = 95.371(6)°, V = 7609(1) ų and Z = 8; 4, crystallizes in the monoclinic space group P2₁/n: a = 10.8241(8) Å, b = 18.074(1) Å, c = 19.194(1) Å, = 96.968(6)°, V = 3727.3(5) ų, and Z = 4; 5, as the 1/2CH₂Cl₂ solvate, crystallizes in the monoclinic space group C2/c: a = 40.955(3) Å, b = 9.7230(6) Å, c = 20.542(1) Å, = 106.596(5)°, V = 7839.2(9) ų, and Z = 8; 6, as the 1/2C₅H₁₂ solvate, crystallizes in the monoclinic space group P2₁/c: a = 21.773(2) Å, b = 10.907(3) Å, c = 18.744(4) Å, = 114.68(1)°, V = 4045(1) ų, and Z = 4. The site occupied by the PMe₃ and ^tBuNC ligands in these compounds is discussed relative to the steric size/electronic properties of the ancillary ligand and its interaction with the bpcd ligand.     

Molecular structure of [CpFe(CO)2]3In

The molecular structure of [CpFe(CO)₂]₃In (Cp=⁵-C₅H₅) has been determined and contains a planar, three-coordinate indium center bound to three CpFe(CO)₂ moieties by unsupported In–Fe bonds. The orientation of the CpFe(CO)₂ units relative to the Fe₃In plane precludes -type interaction between iron and indium, while comparison with the isostructural gallium analog suggests the orientation of the CpFe(CO)₂ units is controlled by the size of the central atom and the inter-ligand steric repulsion. Crystal data: monoclinic, monoclinic, C2/c, a = 26.911(5), b = 10.838(2), c = 16.474(3)Å, = 111.63(3)°, V = 4465(2)ų and, Z = 8.     

Crystal and molecular structure of (η5-C5H5)Ta(η2-C2H4)Cl2(PMe2Ph)2, a sterically crowded molecule which exhibits a distorted η5-coordination mode of the cyclopentadienyl ligand

The X-ray structure determination of (⁵-C₅H₅)Ta(²-C₂H₄)Cl₂(PMe₂Ph)₂ has revealed that the compound crystallizes in the orthorhombic space groupFdd2 witha=21.098(9),b=29.848(9),c=7.694(3) Å, andD _c=1.70g cm^–3 forZ=8. Least-squares refinement based on 893 independent observed reflections resulted in a finalR value of 0.026. The molecule resides on a crystallographic two-fold axis, with disordered ethylene and cyclopentadienyl groups. The Ta-Cl and Ta-P separations are 2.473(4) and 2.649(3) Å, respectively. Since the two carbon atoms of the ethylene molecule are indistinguishable from two of the cyclopentadienyl carbon atoms, the Ta-C bond lengths are 2.37(1) and 2.39(2) Å for the ethylene and for two of the cyclopentadienyl carbon atoms. The other three Ta-C(cyclopentadienyl) distances are much longer: 2.54(3), 2.54(3), and 2.62(3) Å. In order to achieve 18e ^– at the tantalum atom, the cyclopentadienyl ligand must be viewed in an ⁵-bonding mode. The variation of the Ta-C lengths is thus considered to be steric in origin. The carbon atoms of the C⁵H ₅ ^– group are planar to 0.03 Å.     

X-ray diffraction structure of the pentamethylcyclopentadienylruthenium complex Cp*Ru(NO)(ox)

The reaction between the pentamethylcyclopentadienyl complex Cp^*Ru(NO)Cl₂ and oxalic acid in methanolic KOH affords the corresponding oxalate compound Cp^*Ru(NO)(ox) in moderate yield. The title complex has been isolated and characterized in solution by IR and NMR (¹H and¹³C) spectroscopy, and the solid-state structure has been established by X-ray diffraction analysis, which confirmed the presence of the chelating oxalate ligand in Cp^*Ru(NO)(ox). Cp^*Ru(NO)(ox) crystallizes in the triclinic space group ,a=7.0875(9) Å,b=8.589(2) Å,c=12.784(4) Å, =73.58(2)°, =88.93(2)°, =66.86(2)°,V=682.7(8) ų,Z=2,d _calc=1.724 g·cm^–3; R=0.053, R_w=0.071 for 1561 observed reflections withI>3(I).     

Hydrogen bonding in labdane diterpenoids, labda-7,12(E),14-triene-17-oic acid and labda-12(Z),14,17-triene-18-oic acid

Two labdane diterpenoids, labda-7,12(E),14-triene-17-oic acid (1) and labda-12(Z),14,17-triene-18-oic acid (2), C₂₀H₃₀O₂, have been isolated from Croton oblongifolius. Both 1 and 2 crystallized in the monoclinic system, space group C2, with cell dimensions of a = 21.912(1) Å, b = 7.4002(4) Å, c = 11.5079(7) Å, = 101.999(1)^o and a = 21.308(2) Å, b = 11.9067(9) Å, c = 7.5606(6) Å, = 100.763(1)^o, respectively. Compound 1, a rare example of carboxylic group bound to a cyclohexene ring, forms an infinite intermolecular hydrogen-bonded polymer [O1 O2(–x + 1/2, y + 1/2, –z + 2) 2.697(2) Å], whereas molecules of compound 2 are linked to form an asymmetric hydrogen-bonded dimer [O1 O2(–x, y, –z) 2.657(3) Å].     

Reaction of bis(dimethoxyphosphino)dimethylhydrazine (dmpdmh) with PhCCo3(CO)9: synthesis and X-ray characterization of the dmpdmh-bridged polymorphs of PhCCo3(CO)7[(MeO)2PN(Me)N(Me)P(OMe)2]

The tricobalt cluster PhCCo₃(CO)₉ reacts with the bis(phosphanyl)hydrazine ligand bis(dimethoxyphosphino)dimethylhydrazine (dmpdmh) to give the monosubstituted cluster [PhCCo₃(CO)₈]₂(dmpdmh) and the disubstituted cluster PhCCo₃(CO)₇(dmpdmh) as the major products. This latter cluster contains a bridging dmpdmh ligand. Both IR and NMR spectroscopies (³¹P and ¹H) have been employed in the solution characterization of these two clusters. The solid-state structure of PhCCo₃(CO)₇(dmpdmh) was unequivocally established by X-ray diffraction analysis, which has revealed the presence of two different polymorphs for this particular cluster. The first polymorph crystallizes in the monoclinic space group P2₁/n, a = 9.7127(7) Å, b = 17.025(2) Å,c = 16.894(1) Å, = 96.245(5)°, V = 2777.0(4) ų, Z = 4, and d _calc = 1.689 g/cm³; while the second polymorph crystallizes in the orthorhombic space group Pbca, a = 16.925(2) Å, b = 16.208(2) Å, c = 20.541(3) Å, V = 5635(1) ų, Z = 8, and d _calc = 1.665 g/cm³.     

Stereochemistry of racemic hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) thiocyanate,C16H32N4Ni(SCN)2 · H2O

The diamagnetictrans-diene thiocyanate salt of the macrocyclic hexamethyl-1,4,8,11-tetraazacyclotetradecadienenickel(II) complex crystallizes in the triclinic system with unit cell dimensions:a = 7·334(4),b = 8·808(6),c = 21·04(2) Å; = 63·7(0·9), = 103·8(1·4), = 110·2(1·3) °; space groupP¯1;Z = 2. The positions of all 62 atoms of the formula unit C₁₆H₃₂N₄Ni(SCN)₂.H₂O have been determined and refined by least-squares methods toR= 0·071 for 3536 X-ray diffractometric reflections. The optical activity of the two amine groups yields a racemic isomer. The only local symmetry element of the macrocyclic complex is the twofold rotation axis with the N-H bonds oriented on the same side of the approximate ligand plane. Both the C(CH₃)₂ and the imine groups are in atrans-configuration in the ring. The space group ensures that the crystal is a racemate, containing equal numbers of both enantiomers. One of the (SCN)^– groups is at a distance Ni-S 3·28 Å, the other one is 4·65 Å. No rotational disorder of the CH₃ groups has been observed. The three C-H bonds of the CH₃ groups are in approximately antiprismatic orientations with respect to the three -bonds in the case of bonding to a C(sp³) atom. The average of the C(sp³)-C(sp²) bond lengths is 1·53 Å, and the mean value for the C(sp³)-C(sp²) bonds is 1·50 Å, with 3 = 0·03 to 0·04 Å. The distances N(sp²)-C(sp³) 1·47 Å and 1·48 Å are significantly longer than the bond lengths N(sp²)=C(sp²) of 1·28 and 1·30 Å.     

Intramolecular hydrogen bonding and tautomerism in 1-[N-(4-bromophenyl)]aminomethylidene-2(1H) naphthalenone

1-[N-(4-bromophenyl)]aminomethylidene-2(1H)naphthalenone (C₁₇H₁₂NOBr) (1) was synthesized and its crystal structure was determined. Compound (1) is monoclinic, space group P2₁/n with a = 4.808(1) Å, b = 20.617(1) Å, c = 13.750(1) Å, = 93.004(1)°, V = 1361.11(3) ų, Z = 4, D_c = 1.592 g·cm^–3, (Mo K) = 3.014 mm^–1, R = 0.051 for 1013 reflections [I > 2(I)]. There is a strong intramolecular hydrogen bond of distance 2.544(2) Å between the hydroxyl oxygen atom and imine nitrogen atom, the hydrogen atom essentially being bonded to the nitrogen atom. The title molecule is not planar. X-ray crystal structure determination reveals the existence of the keto (or predominantly keto) tautomer in (1). Spectra of compound (1) were observed by IR and NMR, and UV–visible spectra of (1) were studied in different solvents and acidic media.     

The crystal and molecular structure of bis(melamine)silver(I) perchlorate, Ag(C3H6N6)2ClO4

The crystal structure of the title compound, Ag(mela)₂ClO₄ (mela = melamine), has been investigated by X-ray diffraction techniques, the crystals are triclinic, space group P1¯, with a = 5.236(2), b = 7.5385(9) c = 19.063(3) Å, = 99.91(1), = 90.53(2), = 108.32(2)° and Z = 2. The Ag atom has a coordination geometry with two strong bonds (2.162(2) and 2.179(4) Å) to the nitrogen of the melamines and two weak bonds (2.776(4) and 2.785(4) Å) to oxygen atoms of the ClO^– ₄anions. The N—Ag—N vector is markedly nonlinear (angle at Ag 167.7(2)°).     

Structure of tetrahydro-2-naphthyl-4H-1,3,6,2-dioxazaboracine

Intramolecular B-N coordination occurs in tetrahydro-2-naphthyl-4H-1,3,6,2-dioxazaboracine, 2: (R = 2-naphthyl; R = H) both in the solid state and in CDCl₃ solution. Compound 2: (R = 2-naphthyl; R = H) crystallizes in the orthorhombic space group P2₁2₁2₁ (Z = 4), with a = 9.266(6), b = 11.034(8), c = 12.0635(10) Å. Molecules are linked, in the solid state, into spiral chains. As only one of the two oxygen atoms present in each molecule is involved in H-bonding, the boron and nitrogen centres are chiral. The intramolecular B-N bond length is 1.671(4) Å; other geometric parameters are B-O bond lengths of 1.448(4) and 1.464(4) Å, a B-C bond length of 1.598(4) Å, and bond angles at B between 100.6(3) and 115.4(3)°. The ¹¹B value for 2 (R = 2-naphthyl, R = H) at 25°C in CDCl₃ solution is 10.7 ppm.     

Structure of 2-{2-[3-methyl-3-(2,4,6-trimethylphenyl) cyclobutyl]-2-oxoethyl}isoindole-1,3-dione

2-{2-[3-Methyl-3-(2,4,6-trimethylphenyl)cyclobutyl]-2-oxoethyl}isoindole-1,3-dione (C₂₄ H₂₅NO₃) was synthesized, and its crystal structure was determined by X-ray crystallographic techniques. The compound crystallizes in the triclinic space group P-1, with unit cell parameters: a = 14.109(9) Å, b = 14.130(8) Å, c = 12.152(6) Å, = 105.62(5)°, = 113.75(4)°, = 98.78(5)°, V = 2039.8(19) ų, D _c= 1.223 g/cm³, and Z = 4. The crystal structure has two crystallographically independent molecules, I and II. These molecules are held together by weak intermolecular C—H···O interactions, forming a continuous chain. The dihedral angles between the N-substituted phthalimide moiety and cyclobutane ring in molecules I and II are 60.37(14) and 68.18(18)°, respectively.     

Molecular and crystal structure of Cp2Mo(mto), mto=monothiooxalate

Compoundl, Cp₂Mo(mto) is obtained by the reaction of Cp₂MoCl₂ with methanol solutions of potassium dithiooxalate in air. Red platelike crystals of Cp₂Mo(mto) were grown by the slow diffusion of pentane into a CH₂Cl₂ solution ofl and have been studied by X-ray crystallography: space group, P2₁/n,a=7.578(1),b=10.551(2),c=14.090(3) Å, =94.38(2)°,V=1123.1(4) ų,Z=4. The mto ligand chelates to the Mo atom through one oxygen atom and the sulfur atom. The two Cp rings form dihedral angles of 24° with the least-squares plane of the mto ligand. The Mo–O and Mo–S bond distances are 2.193(5) and 2.449(2) Å, respectively.     

Formation and crystal structure of 1-methyl-2-phenylindolizine-3-acetonitrile

1-Methyl-2-phenylindolizine-3-acetonitrile was unexpectedly obtained in the reaction of 1-methyl-2-phenylindolizine-3-thioaldehyde with cyanide ions. Its structure was determined by IR, ¹H NMR, MS, elemental analyses, and X-ray crystallography. Colorless regular prism shaped crystals of C₁₇H₁₄N₂ crystallize in the space group C2/c with cell dimensions a = 12.956(3) Å, b =10.516(2) Å, c = 20.429(4) Å, and = 90°, = 104.98(3)°, = 90°, V =2688.7(9) ų, D _calc =1.217 Mg/m³, and Z = 8.     

Crystal structure oftrans-tetrachlorobis[2-(2-1H-imidazolyl)-1H-imidazolium]cadmium(II), [Cd(H3biim)2Cl4]

The reaction between cadmium(II) chloride and 2,2'-bi-1H-imidazole (H₂biim) in an acidic solution affords [Cd(H₃biim)₂Cl₄] (H₃biim=2-(2-1H-imidazolyl)-1H-imidazolium) in 63% yield. The compound crystallizes in the triclinic space groupP1, wherea=8.072(2),b=8.100(2),c=8.593(2) Å, =75.89(2), =62.94(2), =63.29(1)°,V=446.4(2) ų, andZ=1. The central Cd atom exhibits an octahedral geometry composed of a Cl₄N₂ core. The Cd-N bond distance is 2.392(2) Å. Cd–Cl distances are 2.5919(9) and 2.671(1) Å.     

Structural characterization of the edge double-bridged triruthenium cluster complex Ru3(μ-Cl)2(CO)8(PPh3)2

The title compound is Ru₃(-Cl)₂(CO)₈(PPh₃)2. Crystal data: formula C₄₄H₃₀O₈Cl2P2Ru₃;f _w =1122.9; monoclinic,P2₁; cell parameters (at 293 K)a=10.971(2) Å,b=17.066(2) Å,c=11.833(2) Å,=92.91(1)°,V=2213 ų,Z=2, _calcd=1.68, _meas=1.68. Final discrepancy indices areR(F)=0.030,R _W (F)=0.036. The structure consists of an open trinuclear unit involving two metal-metal bonds [Ru(1)-Ru(2)=2.845(1) Å, Ru(2)-Ru(3)=2.860(1) Å]. The open edge of the metal framework [Ru(1)Ru(3)=3.254(1) Å] is supported by two symmetric bridging chloride ligands [Cl(1)-Ru(1)=2.461(2) Å; Cl(1)-Ru(3)=2.464(2) Å; Cl(2)-Ru(1)=2.470(2) Å; Cl(2)-Ru(3)=2.472(2) Å]. Both phosphorus ligands are cis to the Cl atoms and trans to the unique ruthenium atom Ru(2). Geometric features of the edge dibridged complex are discussed.