ABSTRACT
This project work present the alkylating reaction of [Pt2(μ-S)2(PPh3)4] with boronic
acid alkylating agents.The reactivity of the metalloligand [Pt2(μ-S)2(PPh3)4] with the
boron-functionalized alkylating agents BrCH2(C6H4)B(OR)2 (R = H or C(CH3)2) was
investigated by electrospray ionization mass spectrometry (ESI-MS) in real time using
the pressurized sample infusion (PSI). The macroscopic reaction of [Pt2(μ-S)2(PPh3)4]
with one mole equivalent of alkylating agents BrCH2(C6H4)B{OC(CH3)2}2and
BrCH2(C6H4)B(OH)2 gave the dinuclear monocationic μ-sulfide thiolate complexes
[Pt2(μ-S){μ-SCH2(C6H4)B{OC(CH3)2}2}(PPh3)4]+ and [Pt2(μ-S){μ-S+CH2
(C6H4)B(OH)(O–)}(PPh3)4]. The products were isolated as the [PF6]– salts and
zwitterion respectively, and fully characterized by ESI-MS, IR, 1H and 31P NMR
spectroscopy and single crystal X-ray structure determinations. The alkylation
reaction of BrCH2(C6H4)B{OC(CH3)2}2 with [Pt2(μ-S)2(PPh3)4 + H]+was determined
via kinetic analysis by PSI-ESI-MS to be second order consistent with the expected
SN2 mechanism for an alkylation reaction. The PSI-ESI-MS microscale synthesis
showed that[Pt2(μ-S)2(PPh3)4]disappeared rapidly with consequent formation of
onlymonoalkylated cationic product, [Pt2(μ-S){μ-
SCH2(C6H4)B{OC(CH3)2}2}(PPh3)4]+. This was indicated by the immediate
appearance of the monoalkylated product peak at m/z 1720.6.The reaction came to
completion within 6 minutes after injection and no trace of any other product or
dialkylated species. The desk top synthesis observed after further stirring for six hours
also show the formation of no other product. The reaction ofBrCH2(C6H4)B(OH)2,
with({[Pt2(μ-S)2(PPh3)4] + H}+)within same time interval yielded three monocationic
species that were detected by ESI-MS and assignable to the three alkylated products:
[Pt2(μ-S){μ-SCH2C6H5)(PPh3)4]+, m/z 1593.4 from the loss of B(OH)2 moiety; a
hemiketal-like species [Pt2(μ-S){μ-SCH2(C6H4)B(OH)(OCH3)}(PPh3)4]+, m/z 1651.5
and [Pt2(μ-S){μ-SCH2(C6H4)OH}(PPh3)4]+, m/z 1609.5. The laboratory scale
synthesis indicated the same products.The masses were identified by comparing the
experimental isotope patterns with calculated ones. No peak was observed in the
mass spectrum that was attributable to the formation of the expected product [Pt2(μ-
S){μ-SCH2(C6H4)B(OH)2}(PPh3)4]+. The structural determination by X-ray
diffraction showed that the compound formed was a zwitter ion (neutral complex)
[Pt2(μ-S){μ-S+CH2(C6H4)B(OH)(O-)}(PPh3)4]. [Pt2(μ-S){μ-S+CH2(C6H4)B(OH)(O-
)}(PPh3)4] is a neutral species and not detectable in ESI-MS. 1H NMR spectra showed
a complicated set of resonances in the aromatic region due to the terminal
triphenylphosphine ligands and were broadly assigned as such. However, SCH2
hydrogen atoms were easily identified as broad peaks at δ 3.59 ppm and 3.60 ppm for
[Pt2(μ-S){μ-SCH2(C6H4)B{OC(CH3)2}2}(PPh3)4]+PF6 and [Pt2(μ-S){μ-
S+CH2(C6H4)B(OH)(O-)}(PPh3)4], respectively. The monoalkylated products shows
IR and 31P{1H} NMR spectra expected of the complexes. The OH vibration (3336 cm-
1) in 2.1 shifted to 3435 cm-1 in 2.1a. The absorption bands of the B-O bond in 2.2
(1355 cm-1) and 2.1 (1350 cm-1) shifted to 1360 cm-1 and 1367 cm-1 in 2.2a·(PF6) and
2.1a respectively. The 31P{1H} NMR spectra showed nearly superimposed central
resonances and clearly separated satellite peaks due to 195Pt coupling. The 1J(PtP)
coupling constants showed the differences due to the trans influences of the
substituted and the unsubstituted sulfide centers. The trans influence of the
unsubstituted sulfide is greater than the thiolate (substituted) species demonstrated by
the coupling constants at (2628 and 3291 Hz) for 2.2a·(PF6) and (2632 and 3272 Hz)
2.1a,respectively.
ETHEL, O (2021). Alkylation Of [Pt2(Μ-S)2(Pph3)4] With Boronic Acid Derivatives By Pressurized Sample Infusion Electrospray Ionization Mass Spectrometry (Psiesi- Ms) Technique. Afribary. Retrieved from https://track.afribary.com/works/alkylation-of-pt2-m-s-2-pph3-4-with-boronic-acid-derivatives-by-pressurized-sample-infusion-electrospray-ionization-mass-spectrometry-psiesi-ms-technique
ETHEL, OFFIE "Alkylation Of [Pt2(Μ-S)2(Pph3)4] With Boronic Acid Derivatives By Pressurized Sample Infusion Electrospray Ionization Mass Spectrometry (Psiesi- Ms) Technique" Afribary. Afribary, 14 May. 2021, https://track.afribary.com/works/alkylation-of-pt2-m-s-2-pph3-4-with-boronic-acid-derivatives-by-pressurized-sample-infusion-electrospray-ionization-mass-spectrometry-psiesi-ms-technique. Accessed 05 Nov. 2024.
ETHEL, OFFIE . "Alkylation Of [Pt2(Μ-S)2(Pph3)4] With Boronic Acid Derivatives By Pressurized Sample Infusion Electrospray Ionization Mass Spectrometry (Psiesi- Ms) Technique". Afribary, Afribary, 14 May. 2021. Web. 05 Nov. 2024. < https://track.afribary.com/works/alkylation-of-pt2-m-s-2-pph3-4-with-boronic-acid-derivatives-by-pressurized-sample-infusion-electrospray-ionization-mass-spectrometry-psiesi-ms-technique >.
ETHEL, OFFIE . "Alkylation Of [Pt2(Μ-S)2(Pph3)4] With Boronic Acid Derivatives By Pressurized Sample Infusion Electrospray Ionization Mass Spectrometry (Psiesi- Ms) Technique" Afribary (2021). Accessed November 05, 2024. https://track.afribary.com/works/alkylation-of-pt2-m-s-2-pph3-4-with-boronic-acid-derivatives-by-pressurized-sample-infusion-electrospray-ionization-mass-spectrometry-psiesi-ms-technique