Impact of Coordination Geometry, Bite Angle, and Trans Influence on Metal–Ligand Covalency in Phenyl-Substituted Phosphine Complexes of Ni and Pd

2015 ◽  
Vol 54 (12) ◽  
pp. 5646-5659 ◽  
Author(s):  
Courtney M. Donahue ◽  
Samuel P. McCollom ◽  
Chelsie M. Forrest ◽  
Anastasia V. Blake ◽  
Brian J. Bellott ◽  
...  
Keyword(s):  
Coordination Geometry ◽  
Phosphine Complexes ◽  
Bite Angle ◽  
Trans Influence ◽  
Metal Ligand

Correction to Impact of Coordination Geometry, Bite Angle, and Trans Influence on Metal–Ligand Covalency in Phenyl-Substituted Phosphine Complexes of Ni and Pd

2015 ◽  
Vol 54 (17) ◽  
pp. 8857-8857 ◽  
Author(s):  
Courtney M. Donahue ◽  
Samuel P. McCollom ◽  
Chelsie M. Forrest ◽  
Anastasia V. Blake ◽  
Brian J. Bellott ◽  
...  
Keyword(s):  
Coordination Geometry ◽  
Phosphine Complexes ◽  
Bite Angle ◽  
Trans Influence ◽  
Metal Ligand

scholarly journals Estimation of Bite Angle Effect on the Electronic Structure of Cobalt-Phosphine Complexes: A QTAIM Study

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Tamara Papp ◽  
László Kollár ◽  
Tamás Kégl
Keyword(s):  
Electronic Structure ◽  
Simple Model ◽  
Dft Calculations ◽  
Model Compound ◽  
Carbonyl Ligand ◽  
Reaction Conditions ◽  
Phosphine Complexes ◽  
Bite Angle ◽  
Angle Effect ◽  
Donor Character

The influence of bite angle in bisphosphine complexes has been modeled by DFT calculations employing the simple model compound HCo(CO)(PP) (PP = Xantphos or two monophosphine ligands). The increase of the bite angle increases the strength of the H–Co bond, whereas the C–O bond in the carbonyl ligand is weakened revealing an increase also in the donor character. The model compound cis-[HCo(CO)(PPh3)2] shows a flexibility both in terms of energy, and in terms of electronic structure upon the change of the P-Co-P angle, which can be a sign of the flexibility of PPh3 ligands in real reaction conditions.

Metal Organic Complexes for Optical Power Limiting

1994 ◽  
Vol 374 ◽  
Author(s):  
Chris M. Lawson ◽  
Tianyi Zhai ◽  
David C. Gale ◽  
Gary M. Gray
Keyword(s):  
Optical Power ◽  
Four Wave Mixing ◽  
Phosphine Ligands ◽  
Coordination Geometry ◽  
Wave Mixing ◽  
Phosphine Complexes ◽  
Organic Complexes ◽  
Metal Organic ◽  
Optical Power Limiting ◽  
532 Nm

AbstractNonlinear optical properties of transition metal-phosphine complexes have been measured at 532 nm by degenerate four-wave mixing. Large second-order molecular hyperpolarizabilities, γ, have been found for complexes containing two phosphine ligands. The measured γ values are closely related to the type and coordination geometry of the phosphine ligands, and the γ values vary as the fifth power of the number of substituents with π-electrons structure.

Structural studies of steric effects in phosphine complexes. Part VII. Synthesis, crystal and molecular structure of the chloroperchloratotri(o-tolyl)phosphinemercury(II) dimer

1979 ◽  
Vol 57 (17) ◽  
pp. 2217-2222 ◽  
Author(s):  
Elmer C. Alyea ◽  
Shelton Dias ◽  
George Ferguson ◽  
Masood Khan
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Cone Angle ◽  
Mercury Atom ◽  
Intramolecular Interactions ◽  
Coordination Geometry ◽  
Structural Studies ◽  
Orthorhombic Space Group ◽  
Phosphine Complexes ◽  
Trigonal Bipyramidal

The synthesis and crystal and molecular structure of the chloroperchloratotri(o-tolyl)phosphinemercury(II) dimer are reported. The compound [HgP(o-tolyl)3ClClO4]2 belongs to the orthorhombic space group Pbca [Formula: see text] with a = 12.218(2), b = 13.814(2), c = 26.074(3) Å, and Z = 4. The structure was refined to a final R of 0.046 for 2584 reflections measured by diffractometer. The crystal structure consists of discrete centrosymmetric dimeric molecules of [HgP(o-tolyl)3ClClO4]2 separated by normal van der Waals distances. The unique mercury atom forms two strong bonds (Hg—P 2.395(3), Hg—Cl(1) 2.332(4) Å) which deviate from linearity (P—Hg—Cl 164.1(1)°) and two weak bonds (Hg—O(1) 2.73(2) to the perchlorato group, Hg—Cl(1 *) 3.109(4) Å linking the mercury atoms about centers of symmetry). The four-fold coordination geometry about each mercury can be described as trigonal bipyramidal with the phosphorus and Cl(1) axial, and one equatorial site unoccupied. Intramolecular interactions are discussed with the assistance of cone angle calculations and a ligand profile for P(o-tolyl)3 (θ = 198°). Vibrational and 31P nmr spectra data are also presented for [HgP(o-tolyl)3ClClO4]2.

scholarly journals The inverse-trans-influence in tetravalent lanthanide and actinide bis(carbene) complexes

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Matthew Gregson ◽  
Erli Lu ◽  
David P. Mills ◽  
Floriana Tuna ◽  
Eric J. L. McInnes ◽  
...  
Keyword(s):  
Oxidation State ◽  
Theoretical Data ◽  
High Oxidation State ◽  
Carbene Complexes ◽  
Trans Influence ◽  
High Oxidation ◽  
High Valent ◽  
Tetravalent Cerium ◽  
Limited Scope ◽  
Metal Ligand

Abstract Across the periodic table the trans-influence operates, whereby tightly bonded ligands selectively lengthen mutually trans metal–ligand bonds. Conversely, in high oxidation state actinide complexes the inverse-trans-influence operates, where normally cis strongly donating ligands instead reside trans and actually reinforce each other. However, because the inverse-trans-influence is restricted to high-valent actinyls and a few uranium(V/VI) complexes, it has had limited scope in an area with few unifying rules. Here we report tetravalent cerium, uranium and thorium bis(carbene) complexes with trans C=M=C cores where experimental and theoretical data suggest the presence of an inverse-trans-influence. Studies of hypothetical praseodymium(IV) and terbium(IV) analogues suggest the inverse-trans-influence may extend to these ions but it also diminishes significantly as the 4f orbitals are populated. This work suggests that the inverse-trans-influence may occur beyond high oxidation state 5f metals and hence could encompass mid-range oxidation state actinides and lanthanides. Thus, the inverse-trans-influence might be a more general f-block principle.

Vier- und fünffach koordinierte Organometall-Phosphankomplexe von Aluminium, Gallium, Indium und Thallium / Four- and Five-Coordinate Organometal Phosphine Complexes of Aluminum, Gallium, Indium, and Thallium

1993 ◽  
Vol 48 (11) ◽  
pp. 1544-1554 ◽  
Author(s):  
Gerhard Müller ◽  
Joachim Lachmann
Keyword(s):  
Solid State ◽  
Diethyl Ether ◽  
Coordination Geometry ◽  
Chelating Ligands ◽  
Metal Centers ◽  
Aluminum Complex ◽  
Nonrigid Molecules ◽  
The Third ◽  
Phosphine Complexes ◽  
Trigonal Bipyramidal

The organometal phosphine complexes ML3 (L = [o-(Ph2PCH2)C6H4]-; M = Al3+, Ga3+, In3a+) are obtained from MC13 and the lithiated ligand in diethyl ether. Tl[o-(Ph2PCH2)C6H4]3 is prepared from T1C1 by a disproportionation reaction. M1 species could not be detected with L as ligand. Al[o-(Ph2PCH2)C6H4]3 is the first triorganoaluminum bis(phosphine) adduct where C3P2 pentacoordination at aluminum has been definitely proven for both the solution (δ(27Al) =131 ppm, w1/2 = 12 kHz) and the solid state (d(Al–P) = 2.676(3)/2.782(2) A). The trigonal-bipyramidal coordination geometry (C3P2) at Al is achieved by two of the anionic phosphines acting as chelating ligands, spanning equatorial (C atoms) and axial sites (P atoms), while the third phosphine is only carbon-bonded. Like AlL3, the heavier congeners ML3 (M = Ga, In, Tl) are stereochemically nonrigid molecules in solution. Surprisingly, in the solid state only InL3 resembles the aluminum complex (C3P2 penta-coordination) while GaL3 and T1L3 contain four-coordinate metal centers (C3P). This may be rationalized by the noticeably less polar Ga–P bonds as compared to Al–P and In–P bonds, while in T1L3 the span of the ligand is not sufficient to allow for chelating coordination at a five- (or six-)coordinate Tl center.

scholarly journals Synthesis, Properties, and Coordination Chemistry of t-Bu-Xantphos Ligands

2021 ◽  
Author(s):  
◽  
Melanie Ruth Maria Nelson
Keyword(s):  
Crystal Structure ◽  
Coordination Chemistry ◽  
Pincer Complexes ◽  
Diphosphine Ligands ◽  
Late Transition Metals ◽  
Tert Butyl ◽  
Bite Angle ◽  
Trans Influence ◽  
Synthesis Properties ◽  
Chloride Ligand

<p>This thesis provides an account of research into a group of diphosphine ligands with a rigid xanthene backbone and tert -butyl substituents on the phosphorus atoms. The three ligands have different groups in the bridgehead position of the backbone (CMe₂, SiMe₂, or S) which change the natural (calculated) bite-angle of the ligand. The coordination chemistry of these t -Bu-xantphos ligands with late-transition metals has been investigated with a focus on metal complexes that may form in catalytic reactions.  The three t -Bu-xantphos ligands were synthesised by lithiation of the backbone using sec -butyllithium/TMEDA and treatment with PtBu₂Cl. The natural biteangles of the Ph-xantphos (111.89–114.18°) and t -Bu-xantphos (126.80–127.56°) ligands were calculated using DFT. The bite-angle of the t -Bu-xantphos ligands is larger due to the increased steric bulk of the tert -butyl substituents. The electronic properties of the t -Bu-xantphos ligandswere also investigated by synthesis of their phosphine selenides. The values of ¹J PSe (689.1–698.5Hz) indicate that the t -Bu-xantphos ligands have a higher basicity than Ph-xantphos between PPh₂Me and PMe₃.  The silver complexes, [Ag(t -Bu-xantphos)Cl] and [Ag(t -Bu-xantphos)]BF₄ were synthesised with the t -Bu-xantphos ligands. In contrast to systems with phenyl phosphines, all species were monomeric. [Rh(t -Bu-xantphos)Cl] complexes were synthesised, which reacted with H₂, forming [Rh(t -Bu-xantphos-ĸP,O,P ’)Cl(H)₂] complexes, and with CO, forming [Rh(t -Bu-xantphos)(CO)₂Cl] complexes. The [Rh(t -Bu-xantphos)Cl] species are air-sensitive readily forming [Rh(t -Bu-xantphos)Cl(ƞ²-O₂)] complexes. The crystal structure of [Rh(t -Bu-xantphos)Cl(ƞ²-O₂)], contained 15% of the dioxygen sites replaced with an oxo ligand. This is the first crystallographic evidence of a rhodium(III) oxo complex, and only the third rhodium oxo species reported.  The coordination chemistry of the ligands with platinum(0) and palladium(0) showed some differences. [Pt(t -Bu-xantphos)(C₂H₄)] complexes were synthesised for all three ligands. However, reaction with [Pt(nb)₃] produced a mixture of [Pt(t -Bu-xantphos)] and [Pt(t -Bu-xantphos)(nb)] for t -Bu-sixantphos and t -Buthixantphos. Although few examples of isolable [Pt(PP)] complexes with diphosphines have been reported [Pt(t -Bu-thixantphos)] was isolated by removal of the norbornene. t -Bu-Xantphos formed small amounts of [Pt(t -Bu-xantphos)] initially, which progressed to [Pt(t -Bu-xantphos)H]X. The analogous reactions with [Pd(nb)₃] gave [Pd(t -Bu-xantphos)] and [Pd(t -Bu-xantphos)(nb)] complexes in all cases. [Pt(t -Bu-thixantphos)(C₂H₄)] and [M(t -Bu-thixantphos)] (M = Pd, Pt) react with oxygen forming [Pt(t -Bu-thixantphos)(ƞ²-O₂)], which reacts with CO to give [Pt(t -Bu-thixantphos-H-ĸ-C,P,P ’)OH] through a series of intermediates.  [M(t -Bu-xantphos)Cl₂] (M = Pd, Pt) complexes were synthesised, showing exclusive trans coordination of the diphosphine ligands. The X-ray crystal structure of [Pt(t -Bu-thixantphos)Cl₂] has a bite-angle of 151.722(15)°. This is the first [PtCl₂(PP)] complex with a bite-angle between 114 and 171°. In polar solvents a chloride ligand dissociates from the [Pt(t -Bu-xantphos)Cl₂] complexes producing [Pt(t -Bu-xantphos-ĸP,O,P ’)Cl]⁺. The analogous [Pd(t -Bu-xantphos-ĸP,O,P ’)Cl]⁺ complexes were formed by reaction of the dichlorides complexes with NH₄PF₆. The [Pt(t -Bu-xantphos-ĸP,O,P ’)Me]⁺ pincer complexes were the only product from reaction with [Pt(C₆H₁₀)ClMe], with the stronger trans influence of the methyl ligand promoting loss of the chloride. The formation of the pincer complexes was further explored using DFT.  The values of J PtC for the methyl carbons in the [Pt(t -Bu-xantphos-ĸP,O,P ’)Me]⁺ complexes, and J RhH for the hydride trans to the oxygen atom in the [Rh(t -Buxantphos-ĸP,O,P ’)Cl(H)₂] complexes were largest for t -Bu-sixantphos, then t -Buthixantphos, then t -Bu-xantphos. The trans influence of the t -Bu-xantphos oxygen donor follows the trend t -Bu-sixantphos < t -Bu-thixantphos < t -Bu-xantphos.</p>

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