Ethylene ligand structures of Os(CO)4(C2H4) and Os2(CO)8(C2H4) determined by 1H NMR in liquid crystal solvents

被引:3
作者
Bender, BR
Hembre, RT
Norton, JR
Burnell, EE
机构
[1] Colorado State Univ, Dept Chem, Ft Collins, CO 80523 USA
[2] Univ British Columbia, Dept Chem, Vancouver, BC V6T 1Z1, Canada
关键词
D O I
10.1021/ic971637v
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
The ethylene complexes Os-2(CO)(8)(mu-eta(1),eta(1)-C2H4) (1) and Os(CO)(4)(eta-C2H4) (2) have been studied by H-1 NMR in liquid crystal (nematic phase) solvents. For 1 or 2, three dipolar couplings were observed and assigned to intramolecular geminal, cis, and trans H-1-H-1 dipolar couplings. The H-1 NMR spectrum of Os(CO)(4)((CH2CH2)-C-13)(2-C-13) has also been analyzed and two additional C-13-H-1 dipolar couplinps have allowed determination of the absolute bond angles and relative bond lengths of the ethylene portion of 2 C-13. The observed dipolar couplings for 2-C-13 have been corrected for harmonic vibrations. A comparison of the ethylene geometry of 2 with that of other transition metal ethylene complexes and with free ethylene shows that the (C-2-H-4)Os unit of 2 is best described as a metallacyclopropane. Deuterium substitution is used to demonstrate liquid crystal NMR as a stereochemical probe. The H-1 NMR spectrum of Os-2(CO)(8)(mu-eta(1),eta(1)-(CH2CH2)-C-13) (1-C-13) has also been analyzed in a nematic phase solvent. The dimetallacyclobutane ring of 1-C-13 is best described as two rapidly interconverting ring-puckered conformers of C-2-symmetry. The liquid crystal NMR derived structural parameters for 1-C-13 are compared with those previously determined by neutron diffraction. The solution and solid-state structures are very similar. The ethylene complexes 1 and 2 are proposed as structural and spectroscopic models for ethylene chemisorbed on metal surfaces.
引用
收藏
页码:1720 / 1728
页数:9
相关论文
共 69 条
[51]   NEUTRON-DIFFRACTION STUDY OF STRUCTURE OF ZEISES SALT, KPTCL3(C2H4).H2O [J].
LOVE, RA ;
KOETZLE, TF ;
WILLIAMS, GJB ;
ANDREWS, LC ;
BAU, R .
INORGANIC CHEMISTRY, 1975, 14 (11) :2653-2657
[53]   NUCLEAR MAGNETIC-RESONANCE STUDY OF A PLATINUM-ETHYLENE COMPLEX IN A LIQUID-CRYSTAL SOLVENT [J].
MCMILLIN, DR ;
DRAGO, RS .
INORGANIC CHEMISTRY, 1974, 13 (03) :546-549
[54]   SYNTHESIS AND STRUCTURE OF DIOSMACYCLOALKANES - REVERSIBLE ADDITION OF ETHYLENE TO A METHYLENE-BRIDGED DIMER [J].
MOTYL, KM ;
NORTON, JR ;
SCHAUER, CK ;
ANDERSON, OP .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1982, 104 (25) :7325-7327
[55]   STRUCTURE AND CONFORMATION OF 4,4'-DICHLOROBIPHENYL DETERMINED BY NMR OF ORIENTED MOLECULES IN NEMATIC SOLVENTS [J].
NIEDERBERGER, W ;
DIEHL, P ;
LUNAZZI, L .
MOLECULAR PHYSICS, 1973, 26 (03) :571-576
[56]   R-S-STRUCTURE OF ETHYLENE SULFIDE [J].
OKIYE, K ;
HIROSE, C ;
LISTER, DG ;
SHERIDAN, J .
CHEMICAL PHYSICS LETTERS, 1974, 24 (01) :111-113
[57]   Molecular dynamics simulation of biphenyl dissolved in a liquid crystalline solvent: A test of theoretical methods of deriving rotational potentials from partially averaged nuclear spin dipolar couplings [J].
Palke, WE ;
Catalano, D ;
Celebre, G ;
Emsley, JW .
JOURNAL OF CHEMICAL PHYSICS, 1996, 105 (16) :7026-7033
[58]   THEORETICAL-STUDIES OF ORGANOMETALLIC PROCESSES - SCIENTIFIC VISUALIZATION [J].
RAPPE, AK ;
CASTONGUAY, LA .
PURE AND APPLIED CHEMISTRY, 1991, 63 (06) :867-872
[59]  
Rendell JCT, 1997, MOL PHYS, V90, P541, DOI 10.1080/00268979709482636
[60]   HIGH-RESOLUTION NUCLEAR MAGNETIC RESONANCE SPECTRA OF ORIENTATED MOLECULES [J].
SAUPE, A ;
ENGLERT, G .
PHYSICAL REVIEW LETTERS, 1963, 11 (10) :462-&