The Contrasting Character of Early and Late Transition Metal Fluorides as Hydrogen Bond Acceptors

The association constants and enthalpies for the binding of hydrogen bond donors to group 10 transition metal complexes featuring a single fluoride ligand (trans-[Ni(F)(2-C5NF4)(PR3)2], R = Et 1a, Cy 1b, trans-[Pd(F)(4-C5NF4)(PCy3)2] 2, trans-[Pt(F){2-C5NF2H(CF3)}(PCy3)2] 3 and of group 4 difluorides (Cp2MF2, M = Ti 4a, Zr 5a, Hf 6a; Cp2MF2, M = Ti 4b, Zr 5b, Hf 6b) are reported. These measurements allow placement of these fluoride ligands on the scales of organic H-bond acceptor strength. The H-bond acceptor capability β (Hunter scale) for the group 10 metal fluorides is far greater (1a 12.1, 1b 9.7, 2 11.6, 3 11.0) than that for group 4 metal fluorides (4a 5.8, 5a 4.7, 6a 4.7, 4b 6.9, 5b 5.6, 6b 5.4), demonstrating that the group 10 fluorides are comparable to the strongest organic H-bond acceptors, such as Me3NO, whereas group 4 fluorides fall in the same range as N-bases aniline through pyridine. Additionally, the measurement of the binding enthalpy of 4-fluorophenol to 1a in carbon tetrachloride (?23.5 ± 0.3 kJ mol-1) interlocks our study with Laurence's scale of H-bond basicity of organic molecules. The much greater polarity of group 10 metal fluorides than that of the group 4 metal fluorides is consistent with the importance of p?-d? bonding in the latter. The polarity of the group 10 metal fluorides indicates their potential as building blocks for hydrogen-bonded assemblies. The synthesis of trans-[Ni(F){2-C5NF3(NH2)}(PEt3)2], which exhibits an extended chain structure assembled by hydrogen bonds between the amine and metal-fluoride groups, confirms this hypothesis

Vanadium (β-(Dimethylamino)ethyl)cyclopentadienyl Complexes with Diphenylacetylene Ligands

Reduction of the V(III) (β-(dimethylamino)ethyl)cyclopentadienyl dichloride complex [η5:η1-C5H4(CH2)2NMe2]VCl2(PMe3) with 1 equiv of Na/Hg yielded the V(II) dimer {[η5:η1-C5H4(CH2)2NMe2]V(µ-Cl)}2 (2). This compound reacted with diphenylacetylene in THF to give the V(II) alkyne adduct [η5:η1-C5H4(CH2)2NMe2]VCl(η2-PhC≡CPh). Further reduction of 2 with Mg in the presence of diphenylacetylene resulted in oxidative coupling of two diphenylacetylene groups to yield the diamagnetic, formally V(V), bent metallacyclopentatriene complex [η5:η1-C5H4(CH2)2NMe2]V(C4Ph4).

Intermolecular hydrogen bonding in isostructural pincer complexes [OH-(t-BuPOCOPt-Bu)MCl] (M = Pd and Pt)

In the crystal structure of the isostructural title compounds, namely {2,6-bis[(di-tert-butylphosphanyl)oxy]-4-hydroxyphenyl}chloridopalladium(II), [Pd(C22H39O3P2)Cl], 1, and {2,6-bis[(di-tert-butylphosphanyl)oxy]-4-hydroxyphenyl}chloridoplatinum(II), [Pt(C22H39O3P2)Cl], 2, the metal centres are coordinated in a distorted square-planar fashion by the POCOP pincer fragment and the chloride ligand. Both complexes form strong hydrogen-bonded chain structures through an interaction of the OH group in the 4-position of the aromatic POCOP backbone with the halide ligand

Crystal structure of 1-hydroxy-2,2,6,6-tetramethylpiperidin-1-ium trifluoromethanesulfonate

In the cation of the title salt, C9H20NO+·CF3O3S-, the six-membered heterocyclic ring displays a chair conformation. In the crystal, centrosymmetric pairs of cations and anions are linked by N-H...O and O-H...O hydrogen bonds to form rings with a R44(14) graph-set motif

Crystal structure of bis(pentamethylcyclopentadienyl)(1-tert- butylisocyanido)-2-trimethylsilyl-3-[(trimethylsilyl)ethynyl]-hafnacyclopropene, (C10H15)2(C5H9N) Hf(C10H18Si2)

C35H57HfNSi2, monoclinic, P121/c1 (no. 14), a = 10.7410(3) Å, b = 16.2302(5) Å, c = 21.6945(7) Å, β = 104.512(2)°, V = 3661.3 Å3, Z = 4, R gt(F) = 0.049, wRref(F2) = 0.138, T = 200 K. © 2014 Oldenbourg Wissenschaftsverlag, München

Crystal structure of 1,1,2,2-tetramethyl-1,2-bis(2,3,4,5-tetramethylcyclopenta-2,4-dien-1-yl)disilane

The mol­ecular structure of the title compound, C22H38Si2, features a trans arrangement of the cyclo­penta­dienyl rings to avoid steric strain [C-Si-Si-C torsion angle = -179.0 (5)°]. The Si-Si bond length is 2.3444 (4) Å. The most notable inter­molecular inter­actions in the mol­ecular packing are C-H...[pi] contacts that lead to the formation of wave-like supra­molecular chains along the b axis

Crystal structure of μ-oxo-bis(σ- 1,2-bis(trimethylsilyl) vinylhafnocene) benzene solvate, [C2H{Si(CH3) 3}2Hf(C5H5)2] 2O ·C6H6

C42H64Hf2OSi4, monoclinic, P121/c1 (no. 14), a = 11.442(1) Å = 9.7998(6) Å, c = 19.827(2) Å, β = 95.229(7)°, V = 2213.9 Å, Z = 2, R gt(F) = 0.017, wRref(F2)=0.037, T=200K. © by Oldenbourg Wissenschaftsverlag,

Crystal structure of 1, 1-bis(pentamethylcyclopentadienyl)-4, 5-bis(trimethyIsilyl)-1-hafnafuran-3-one, Hf(C10H15) 2(Me3SiC2SiMe3CO2)

C29H48HfO2Si2, orthorhombic, Pnma (no. 62), a = 16.8546(4) Å= 14.4139(6) Å= 12.1421(3) Å, V= 2949.8 Å3, Z = 4, Rgt(F) = 0.020, WR ref(F2) = 0.041, T= 200 K. © by Oldenbourg Wissenschaftsverlag

Crystal structures of two ansa-titanocene tri-fluoro-methane-sulfonate complexes bearing the Me2Si(C5Me4)2 ligand

The crystal structures of two ansa-titanocene tri-fluoro-methane-sulfonate complexes bearing the Me2Si(C5Me4)2 ligand are reported, namely [di-methylbis-(η5-tetra-methyl-cyclo-penta-dien-yl)silane](tri-fluoro-methane-sulfonato-κ2O,O')titanium(III) toluene monosolvate, [Ti(CF3O3S)(C20H30Si)]·C7H8, 1, and chlorido-[di-methyl-bis-(η5-tetra-methyl-cyclo-penta-dien-yl)silane](tri-fluoro-methane-sulfonato-κO)titanium(IV), [Ti(CF3O3S)(C20H30Si)Cl], 2. Both complexes display a bent metallocene unit, the metal atom being coordinated in a distorted tetra-hedral geometry, with the tri-fluoro-methane-sulfonate anion acting as a bidentate or monodentate ligand in 1 and 2, respectively. In 1, weak π-π stacking inter-actions involving the toluene solvent mol-ecules [centroid-to-centroid distance = 3.9491 (11) Å] are observed

Crystal structure of rac-[1, 2-ethylene-bis(η5-4, 5, 6, 7-tetrahydroindenyl)]1-hafna-4, 5-bis(trimethylsilyl)furan-3-one- tris(pentafluorophenyl)borane, (C20H24)Hf(Me 3SiC2SiMe3CO2)B(C6F 5)3

C47H42BF15HfO2Si2, monoclinic, P121/n1 (no. 14), a = 15.7496(4) Å = 20.4074(5) Å= 16.3115(5) Å, β = 96.313(2)°, V= 5210.9 Å3, Z = 4, Rgt(F) = 0.027, WRref(F 2) = 0.049, T= 200 K. © by Oldenbourg Wissenschaftsverlag