NDLI: Mechanism of proton transfer to coordinated thiolates: encapsulation of acid stabilizes precursor intermediate

Content Provider	World Health Organization (WHO)-Global Index Medicus
Author	Clegg, William Henderson, Richard A. Harrington, Ross W. Alwaaly, Ahmed Petrou, Athinoula L.
Description	Author Affiliation: Alwaaly A ( School of Chemistry, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK. richard.henderson@ncl.ac.uk.)
Abstract	Earlier kinetic studies on the protonation of the coordinated thiolate in the square-planar $[Ni(SC_{6}H_{4}R′-4)(triphos)]^{+}$ (R′ = $NO_{2},$ Cl, H, Me or MeO) by $lutH^{+}$ (lut = 2,6-dimethylpyridine) indicate a two-step mechanism involving initial formation of a (kinetically detectable) precursor intermediate, $\{[Ni(SC_{6}H_{4}R′-4)(triphos)]⋯Hlut\}^{2+}$ $(K^{R}_{1}),$ followed by an intramolecular proton transfer step $(k^{R}_{2}).$ The analogous $[Ni(SR)(triphos)]BPh_{4}$ {R = Et, $Bu^{t}$ or Cy; triphos = $PhP(CH_{2}CH_{2}PPh_{2})_{2}\}$ have been prepared and characterized by spectroscopy and X-ray crystallography. Similar to the aryl thiolate complexes, $[Ni(SR)(triphos)]^{+}$ are protonated by $lutH^{+}$ in an equilibrium reaction but the observed rate law is simpler. Analysis of the kinetic data for both $[Ni(SR)(triphos)]^{+}$ and $[Ni(SC_{6}H_{4}R′-4)(triphos)]^{+}$ shows that both react by the same mechanism, but that $K^{R}_{1}$ is largest when the thiolate is poorly basic, or the 4-R′ substituent in the aryl thiolates is electron-withdrawing. These results indicate that it is both NH⋯S hydrogen bonding and encapsulation of the bound $lutH^{+}$ (by the phenyl groups on triphos) which stabilize the precursor intermediate.
ISSN	14779226
Issue Number	26
Journal	Dalton Trans.
Volume Number	44
e-ISSN	13645447
Language	English
Publisher	Royal Society of Chemistry
Publisher Date	2015-07-14
Publisher Place	Great Britain (UK)
Access Restriction	Subscribed
Subject Keyword	Chemistry
Content Type	Text
Resource Type	Article
Subject	Inorganic Chemistry

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in