In:
European Journal of Mass Spectrometry, SAGE Publications, Vol. 25, No. 1 ( 2019-02), p. 58-72
Abstract:
Electrospray ionization was used to generate species such as [ZnNO 3 (CH 3 OH) 2 ] + from Zn(NO 3 ) 2 •XH 2 O dissolved in a mixture of CH 3 OH and H 2 O. Collision-induced dissociation of [ZnNO 3 (CH 3 OH) 2 ] + causes elimination of CH 3 OH to form [ZnNO 3 (CH 3 OH)] + . Subsequent collision-induced dissociation of [ZnNO 3 (CH 3 OH)] + causes elimination of 47 mass units (u), consistent with ejection of HNO 2 . The neutral loss shifts to 48 u for collision-induced dissociation of [ZnNO 3 (CD 3 OH)] + , demonstrating the ejection of HNO 2 involves intra-complex transfer of H from the methyl group methanol ligand. Subsequent collision-induced dissociation causes the elimination of 30 u (32 u for the complex with CD 3 OH), suggesting the elimination of formaldehyde (CH 2 = O). The product ion is [ZnOH] + . Collision-induced dissociation of a precursor complex created using CH 3 - 18 OH shows the isotope label is retained in CH 2 = O. Density functional theory calculations suggested that the “rearranged” product, ZnOH with bound HNO 2 and formaldehyde is significantly lower in energy than ZnNO 3 with bound methanol. We therefore used infrared multiple-photon photodissociation spectroscopy to determine the structures of both [ZnNO 3 (CH 3 OH) 2 ] + and [ZnNO 3 (CH 3 OH)] + . The infrared spectra clearly show that both ions contain intact nitrate and methanol ligands, which suggests that rearrangement occurs during collision-induced dissociation of [ZnNO 3 (CH 3 OH)] + . Based on the density functional theory calculations, we propose that transfer of H, from the methyl group of the CH 3 OH ligand to nitrate, occurs in concert with the formation of a Zn–C bond. After dissociation to release HNO 2 , the product rearranges with the insertion of the remaining O atom into the Zn–C bond. Subsequent C–O bond cleavage, with H transfer, produces an ion–molecule complex composed of [ZnOH] + and O = CH 2 .
Type of Medium:
Online Resource
ISSN:
1469-0667
,
1751-6838
DOI:
10.1177/1469066718809881
Language:
English
Publisher:
SAGE Publications
Publication Date:
2019
detail.hit.zdb_id:
2021540-X
detail.hit.zdb_id:
2021340-2
SSG:
11
SSG:
12
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