Bis-cis-dioxomolybdenum(VI), 2>; Structure and Spectroscopic Studies

DOI: 10.1039/DT9840001333

Source and publish data:

Journal of the Chemical Society, Dalton Transactions p. 1333 - 1342 (1984)

Update date:2022-08-11

Topics:

Authors:

Buchanan, Iain

Garner, C. David

Clegg, William

Read Full Text PDF DownLoad Join now for total 90,000,000 free articles

Article abstract of DOI:10.1039/DT9840001333

The complex 2> crystallises in the monoclinic space group P2₁, with a=11.794(2), b=12.519(3), c=13.040(2) Angstroem, β=106.32(2) deg, and Z=4.The structure was solved from 5 502 unique observed reflections, and refinement gave a final R of 0.039; anomalous dispersion was employed to verify the absolute configuration at molybdenum and at the chiral carbon of the ligands.The two crystallographically independent molecules have opposite absolute configurations (Λ and Δ) for the ligand chelate rings about the metal; the expected cis-dioxo-stereochemistry is confirmed, with normal bond lengths .Proton, 13C, and 95Mo n.m.r. spectra are consistent with these two diastereoisomeric molecules persisting in solution, and together with c.d. data are taken to indicate that, for the (S)-ligand complex in (CD3)2SO at ca. 298 K, the Λ isomer is present in a ca. 2:1 excess over the Δ isomer, the reverse being the case for the (R)-ligand complex.The two diastereoisomers are in dynamic equilibrium and 1H n.m.r. data collected over the temperature range 297-385 K indicate that the activation parameters for the Λ-->Δ interconversion are ΔH(excit.)=44+/-6 kJ mol^-1 and ΔS(excit.)=-110+/-17 J K^-1 mol^-1.The mechanism for the inversion of configuration at molybdenum is considered to proceed by an intramolecular process, involving Mo-N bond rupture followed by rotation of the ligand atoms of the subsequent intermediate and ring closure.C.d. spectra resolve each of the u.v.-visible absorption bands centred at ca. 264 and 352 nm into two components.The i.r. active ν(Mo-O_t) stretching vibrations of cis-2> are manifest as a pair of doublets at 918/913 and 878/875 cm^-1, presumably due to the Λ and Δ isomers having slightly different ν(Mo-O_t) values.

Full text of DOI:10.1039/DT9840001333

View Article Online / Journal Homepage / Table of Contents for this issue

View Article Online

Products guided by the article

Product name:D-PENCILLAMINE METHYL ESTER HYDROCHLORIDE

Cas No:34297-27-3

R&D Labs maybe for 34297-27-3

QINGDAO NEW FLOURISH INTERNATIOANAL TRADE CO., LTD.

Contact:+86 532 80861829

Address:No. 1, Yinchuan East Road, 266061, Qingdao, China
PharmaResources(Kaiyuan)CO,.Ltd

Contact:+86-21-50720028

Address:No.3, Beihuan Road, Economic Development District, Kaiyuan City, Tieling City, Liaoning Province, China 112300
Chengdu Yunyi International Trade Co., Ltd

Contact:0411-39894967

Address:china
UNION PHARMPRO CO.,LTD

Contact:18710867521(wechat)

Address:Rm10516,Galaxy Tech Building #2,No.25 Tangyan Rd,Hi-Tech Zone,Xi'an, China
ANHUI CHEM-BRIGHT BIOENGINEERING CO.,LTD

Contact:86-561-4080321

Address:No.8 Lieshan Industrial Zone of Huaibei

Relevant to this article

Stereoselective Construction of β-Mannopyranosides by Anomeric O-Alkylation: Synthesis of the Trisaccharide Core of N-linked Glycans

Doi:10.1002/anie.201600488
(2016)
Doi:10.1016/0022-1902(60)80276-X
(1960)
N-monoalkylation of amines with alcohols by tandem photocatalytic and catalytic reactions on TiO₂ loaded with Pd nanoparticles

Doi:10.1021/cs300756f
(2013)
Doi:10.1016/S0022-328X(00)82641-8
(1971)
Stabilities of Carbonium Ions in Solution. 12. Heats of Formation of Alkyl Chlorides as an Entree to Heats of Solvation of Aliphatic Carbonium Ions

Doi:10.1021/ja00530a004
(1980)
The first direct synthesis of β-unsubstituted meso-decamethylcalix[5] pyrrole

Doi:10.3762/bjoc.5.2
(2009)

Article Doi