Ligand Steric Effects Research Articles

Crystal structures of trans-[Ru(dppe) 2(CO)(Cl)](BF 4)·2(toluene) and trans-[Ru(dppm) 2(CO)(Cl)](BF 4)·CH 2Cl 2: a study of the steric and electronic ligand effects of trans-positioned diphosphine ligands

Single-crystal X-ray diffraction studies were carried out on the complexes trans-[Ru(dppe) 2(CO)(Cl)](BF 4) ·2(toluene) ( 1) (where dppe = 1,2-bis(diphenylphosphino)ethane) and trans-[Ru(dppm) 2(CO)(Cl)](BF 4) ·CH 2Cl 2 ( 2) (where dppm = bis(diphenylphosphino)methane). Complex 1 crystallizes in the orthorhombic space group P2 12 12 with a = 14.366(3), b = 17.075(3), c = 12.433(2) A ̊ , V = 3049.8(10) A ̊ 3 and Z = 2 . The structure was refined to R = 3.02% for 3233 reflections above 6σ ( R = 4.46% for all 3991 point-group independent data); the Ru-cation lies on a site of C 2 symmetry, leading to disorder of the Cl and CO ligands. Complex 2 crystallizes in the orthorhombic space group Pna2 1, with a = 22.425(7), b = 11.515(4), c = 19.511(10) A ̊ , V = 5038(3) A ̊ 3 and Z = 4 . The structure was refined to R = 4.43% for 4770 reflections above 6σ ( R = 7.09% for all 6631 point-group independent data). The crystal structure data suggest increased intramolecular interligand interactions with the trans-bis(dppe) complexes relative to the trans-bis(dppm) complexes. In order to furth assess the steric ligand effects of dppm and dppe on the redox chemistry of ruthenium complexes, the electrochemical data for complexes 1 and 2 as well as for trans-Ru(dppe) 2(Cl) 2 and trans-Ru(dppm) 2(Cl) 2 were analyzed. The E pa value for the oxidation of complex 1 was more positive than the E pa value for the oxidation of complex 2; similarly, the E 1 2 value for the oxidation of trans-Ru(dppe) 2(Cl) 2 was more positive than the E 1 2 value for the oxidation of trans-Ru(dppm) 2(Cl) 2. The increase in the redox potentials for the oxidation of the dope complexes may be due to the enhanced intramolecular interligand interactions of the dppe ligands, which is in agreement with the crystal structure data.

Steric ligand effects of six bidentate bipyridyl ligands

The synthesis and characterization of a series of [Ru(H 2 O)(N-N)(spy)] 2+ complexes (where N-N=2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 4,7-dimethyl-1,10-phenanthroline (4,7-Me 2 phen), 2,9-dimethyl-1,10-phenanthroline (2,9-Me 2 phen), 2,2'-biguinoline (big), and 6,6'-dichloro-2,2'-bipyridine (6,6'-Cl 2 bpy), and trpy=2,2':6',2''-terpyridine) are described. The rate constants for ligand substitution of the agua ligand for acetonisilc were determined

A molecular mechanics model of ligand effects. 3. A new measure of ligand steric effects

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA molecular mechanics model of ligand effects. 3. A new measure of ligand steric effectsTheodore L. BrownCite this: Inorg. Chem. 1992, 31, 7, 1286–1294Publication Date (Print):April 1, 1992Publication History Published online1 May 2002Published inissue 1 April 1992https://doi.org/10.1021/ic00033a029RIGHTS & PERMISSIONSArticle Views453Altmetric-Citations110LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Formation and reactivity of (tetraarylporphyrinato)rhodium(II) monocarbonyls: bent RhIICO complexes that react like acyl radicals

Reactions for a series of rhodium(II) porphyrins with CO are used in illustrating the use of ligand steric effects in both promoting and inhibiting CO coupling to form α-diketone complexes ((por)RhC(O)C(O)Rh(por))

A thermometric titration study of the interaction of Co 2+ with metallochromic indicators

A thermometric titrimetry study of the interaction in aqueous solution of Co 2+ with xylenol orange, eriochrome black T and catechol violet at a specified pH, has revealed in each case a linear reaction heat/[Co 2+] relationship, thereby suggesting the potential of metallochromic indicators for the determination of macro trace levels of cobalt in water. The relevant complexation enthalpies are rationalized in terms of a combination of ligand steric effect, cobalt-ligand bond energies and chelate effect.

The structure and redox properties of some planar [M IIN 4] compounds. Part V. The nickel(II) and palladium(II) compounds of dianionic ligands derived from diketones and 2-pyridylhydrazine

The quadridentate hydrazonato ligands, prepared by condensing two equivalents of a 2-pyridylhydrazine with an α-diketone, form two series of neutral compounds with nickel(II) and palladium(II). Monomeric species, of previously described type, are characteristic four-co-planar [M(N 4)] compounds, although the hydrazone ligands give them unusual electronic spectra. In addition, dimeric (and probably also polymeric) compounds are formed by the ligands derived from α-diketones. In the dimers, two metal atoms share two of the quadridentate ligands in an unusual arrangement, which is defined by the ligand steric effects. These also are four-co-planar [M(N 4)], diamagnetic species, but with a significant metalmetal bond. Details of a preparative study of the systems and related hydrazonato compounds of α-diketones are presented, together with the physiochemical data defining their structures, and the electronic spectra which are characteristic of the different types of compound obtained. A polarographic and cyclic voltammetric study extends the earlier work on one of the monomers, showing at lest four electrode reactions: two oxidation processes, and two reduction processes. The dimeric compounds also undergo a series of one-electron oxidations and reductions.

Ligand steric effects on the photophysics of bis- and tris(2,2'-bipyridine) complexes of rhodium(III)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLigand steric effects on the photophysics of bis- and tris(2,2'-bipyridine) complexes of rhodium(III)M. Nishizawa, T. M. Suzuki, S. Sprouse, R. J. Watts, and P. C. FordCite this: Inorg. Chem. 1984, 23, 13, 1837–1841Publication Date (Print):June 1, 1984Publication History Published online1 May 2002Published inissue 1 June 1984https://doi.org/10.1021/ic00181a012RIGHTS & PERMISSIONSArticle Views249Altmetric-Citations49LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (666 KB) Get e-Alerts Get e-Alerts

ChemInform Abstract: LEWIS‐BASE ADDUCTS OF GROUP 1B METAL(I) COMPOUNDS. PART 1. SYNTHESIS AND STRUCTURE OF CUILN COMPLEXES (L = NITROGEN BASE, N ≤ 1.5)

AbstractAbhängig vom gegenwärtigen N‐Liganden und dessen Konzentration bildet Cul beim Umkristallisieren aus Aceton Komplexe mit den unterschiedlichen Strukturen (I)‐(V).

Steric effects of ligands in silver(I) isocyanide complexes. Structure of Ag(2,4,6-t-Bu 3C 6H 2NC) 2(PF 6) containing a bidentate PF 6 ligand

Reaction of AgPF 6 with RNC in a 1:2 molar ratio gave Ag(RNC) 2(PF 6) 1 ( R = 2,4,6-t-Bu 3C 6H 2 (a), 2,4-t-Bu 2-6-Me-C 6H 2 (b), 2,6-Me 2C 6H 3 (c), or t-Bu(d)). Reactions of (1b-d) with the corresponding isocyanide yielded Ag(RNC) 3(PF 6) (2b-d), but the reaction of 1a with 2,4,6-t-Bu 3C 6H 2NC led to a recovery of the starting materials. The crystal structural analysis of 1a showed it to have a distorted tetrahedral configuration, in which a PF 6 ligand behaved as a bidentate ligand. The complex 1 exists as a 1:1 electrolyte in solution by a conductivity measurement [1].

Lewis-base adducts of Group 1B metal(I) compounds. Part 1. Synthesis and structure of CuIL n complexes (L = nitrogen base, n? 1.5)

Crystallization of copper(I) iodide from triethylamine–acetone yields a white crystalline solid of novel stoicheiometry [Cu4I4(NEt3)3]; its structure determination by single-crystal X-ray diffraction shows trigonal symmetry [space group P3, a= 19.46(2), c= 7.119(7)A, and Z= 3] and polymeric strings of Cu4I4‘cubane’ units, oriented with one body diagonal of each unit along c and linked to the next unit generated by the unit c translation by a copper–iodine interunit bond [2.930A(mean)]. There are three independent such polymeric strings in the unit cell. R was 0.074 for 2 942 ‘observed’ reflections. The structures of the 1 : 1 complexes of copper(I) iodide with 2-methylpyridine, (2Me-py)(2), 2,2,6,6-tetramethylpiperidine, (tmpip)(3), and acridine, (4), have also been determined. Each crystallizes in a structural form determined by the steric properties of the ligand. Crystals of (2) are tetragonal, space group I4cm, with a= 20.10(2) and c= 15.94(1)A; R= 0.055 for 782 independent observed reflections. The structure is a ‘cubane’-type tetramer, [Cu4I4(2Me-py)4], with Z= 8. Crystals of (3) are orthorhombic, space group Cmca, with a= 12.43(2), b= 9.964(7), and c= 19.30(3)A; R= 0.071 for 278 independent observed reflections. The structure is a di-µ-iodo-bridged dimer [Cu2I2(tmpip)2], with four molecules in the unit cell. Crystals of (4) are triclinic, space group P, with a= 14.381(4), b= 9.888(3), c= 4.117(1)A, α= 83.96(2), β= 81.57(2), and γ= 86.03(2)°; R= 0.078 for 2 649 observed reflections. The structure is a ‘split stair’ polymer, (–CuL–I–)∞. The structures of (3) and (4) are unsymmetrical as a consequence of ligand steric effects. The synthesis and structure determination at 295 K of [Cu4I4(2Me-py)6] are also reported. Crystals are triclinic, space group P, with a= 12.856(8), b= 9.736(7), c= 9.472(7), A, α= 105.38(5), β= 98.68(5), γ= 104.90(5)°, and Z= 1; 4 010 observed reflections were refined to a residual of 0.034. The molecule is centrosymmetric and based on the ‘step’ structure well known for Cu4I4L4 species; however, the copper atoms at the periphery of the chair are co-ordinated by a pair of ligands, giving rise to the first known examples of 1 : 1 : 1.5 Cu : halide : base stoicheiometry observed in nitrogen-base systems, and the first example of this stoicheiometry based on the ‘step’ array.

ChemInform Abstract: PHOSPHORUS‐31 NMR SPECTRA OF COBALOXIMES: INFLUENCE OF ELECTRONIC AND STERIC EFFECTS OF AXIAL LIGANDS

Chemischer InformationsdienstVolume 11, Issue 35 Physical Organic Chemistry ChemInform Abstract: PHOSPHORUS-31 NMR SPECTRA OF COBALOXIMES: INFLUENCE OF ELECTRONIC AND STERIC EFFECTS OF AXIAL LIGANDS J. A. KARGOL, J. A. KARGOLSearch for more papers by this authorR. W. CRECELY, R. W. CRECELYSearch for more papers by this authorJ. L. BURMEISTER, J. L. BURMEISTERSearch for more papers by this authorP. J. TOSCANO, P. J. TOSCANOSearch for more papers by this authorL. G. MARZILLI, L. G. MARZILLISearch for more papers by this author J. A. KARGOL, J. A. KARGOLSearch for more papers by this authorR. W. CRECELY, R. W. CRECELYSearch for more papers by this authorJ. L. BURMEISTER, J. L. BURMEISTERSearch for more papers by this authorP. J. TOSCANO, P. J. TOSCANOSearch for more papers by this authorL. G. MARZILLI, L. G. MARZILLISearch for more papers by this author First published: September 2, 1980 https://doi.org/10.1002/chin.198035048AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume11, Issue35September 2, 1980 RelatedInformation

Rhodium phosphine complexes as homogeneous catalysts. 7. Effect of phosphine structure on catalytic activity in acetone hydrogenation

The activity of catalysts for acetone hydrogenation formed in situ from [Rh(norbornadiene)Cl]2 and phosphines or phosphinic acid esters is determined by the electronic and steric effects of the ligand. The electronic parameter used was the infrared νco value of Rh(PR3)2(CO)Cl complexes containing the same P(III)-ligands. Catalytic activity increases with decreasing νco (i.e., increasing basicity of the ligand) and reaches its highest level with PEt3. Phosphines with larger, or branched, alkyl groups show still lower νco values but yield catalysts of lower, or even zero, activity because of the steric effects of the bulky ligands.

Sterically crowded platinum(II) phosphine cations

Cationic platinum(II) hydrides [HPtL 2L′] + (L = phosphines) have been prepared and the ligand steric effects studied; the crystal and molecular structure of trans-[PtH(PCy 3) 2PPh 3] PF 6 is described.

4-substituted quinoline N-oxide complexes of copper(II) acetate

A series of 4-substituted quinoline N-oxides (4ZQNO) and isoquinoline N-oxide (IQNO) have been found to react with copper(II) acetate to form the dimeric complexes [Cu(CH 3(COO) 2·4ZQNO] 2·nH 2O where Z is CH 3O, CH 3, H and Cl. The complexes were characterized by elemental analyses, electronic and infrared spectra and magnetic measurements. These data are all consistent with the δ-bonding model. The contributions of ligand steric effects and α- and π-bonding strengths to the magnitude of the copper-copper interaction are discussed. The isoquinoline N-oxide complex dehydrates over a period of time, resulting in crystal degradation to a powder. This is accompanied by a structural reorganization wherein the acetate groups probably change from bridging to monodentate. This results in a change in the magnetic moment from μ = 1.34 B.M. to μ = 2.00 B.M. with time.