Zinc, Cadmium and Mercury

Mukherjee, Debabrata

doi:10.1016/b978-0-12-820206-7.00162-1

Cited by 3 publications

(2 citation statements)

References 279 publications

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“…Heteroleptic zinc hydrides can be synthetically approached by a variety of methods starting from zinc alkyl, amide, alkoxide, halide, amidoborate, or even [ZnH 2 ] ∞ as precursors. , We begin with transamination between the acidic proligand NN L H 19 and Zn(HMDS) 2 [HMDS = N(SiMe 3 ) 2 ] that gives the heteroleptic disilazide [( NN L)Zn(HMDS)] ( 1 (72%); Scheme ). The reaction seems to be an equilibrium process that was earlier unseen in similar cases. Monitoring a strictly 1:1 mixture of NN L H and Zn(HMDS) 2 in C 6 D 6 consistently shows a 95% conversion after 18 h at room temperature.…”

Section: Results and Discussionmentioning

confidence: 99%

2-Anilidomethylpyridine-Derived Three-Coordinate Zinc Hydride: The Journey Unveils Anilide Backbone’s Reactive Nature

Mandal,

Joshi,

Das

et al. 2023

Inorg. Chem.

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Low-coordinate heteroleptic zinc hydrides are catalytically important but rare and synthetically challenging. We herein report three-coordinate monomeric zinc hydride on a 2anilidomethylpyridine framework ( NN L). The synthetic success comes through systematically screening a few different routes from different precursors. During the process, the ligand's anilide backbone interestingly appears to be more reactive than Zn's terminal site to electrophilic Lewis and Brønsted acids. The proligand NN LH reacts with [Zn{N(SiMe 3 ) 2 } 2 ] and ZnEt 2 to give [( NN L)ZnA] (A = N(SiMe 3 ) 2 (1), Et(2)). Both are inert to PhSiH 3 and H 2 but react with HBpin only through the internal Zn−N anilide bond to give the borylated ligand NN LBpin (3). The reactions of 1 and 2 with Ph 3 EOH (E = C, Si) afford a series of divergent compounds like [( NN LH)Zn(OSiPh 3 ) 2 ] (4), [Zn 3 (OSiPh 3 ) 4 Et 2 ] (5), and [EtZn(OCPh 3 )] (6). But in all cases, it is invariably the Zn−N anilide bond protonated by the −OH with equal or higher preference than the terminal Zn−N or Zn−C bonds. A DFT analysis rationalizes the origin of such a reactivity pattern. Realizing that an acidfree route might be the key, reacting [( NN L)Li] with ZnBr 2 gives [( NN L)Zn(μ-Br)] 2 (7), which on successively treating with KOSiPh 3 and PhSiH 3 gives the desired [( NN L)ZnH] (8) as a three-coordinate monomer with a terminal Zn−H bond. Estimating the ligand steric in 8 shows the openness in Zn's coordination sphere, a desired criterion for efficient catalysis. This and a positive influence of the pyridyl sidearm is reflected in 8's superior activity in hydroborating PhC(O)Me by HBpin in comparison to Jones' two-coordinate anilido zinc hydride.

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Section: Results and Discussionmentioning

confidence: 99%

2-Anilidomethylpyridine-Derived Three-Coordinate Zinc Hydride: The Journey Unveils Anilide Backbone’s Reactive Nature

Mandal,

Joshi,

Das

et al. 2023

Inorg. Chem.

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“…[5a,6] Zinc as a virtually main group metal proves to be an attractive choice in catalysis. [7] Zinc chemistries of both the ligand types are well established [8] including some landmark compounds like the Zn (I) -Zn (I) dimer [Cp* 2 Zn 2 ] [9] and ZnH 2 dimers [(NHC)ZnH(μ-H)] 2 . [10] NHCÀ Zn catalysts can reduce carbonyls, nitriles, imines, alkenes and alkynes, and CO 2 , but mostly by hydrosilylation and rarely by hydroboration.…”

Section: Introductionmentioning

confidence: 99%

A N‐Heterocyclic Carbene‐Supported Zinc Catalyst for the 1,2‐Regioselective Hydroboration of N‐Heteroarenes

Mondal

Singh

Baguli

et al. 2023

Chemistry A European J

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A fluorenyl-tethered N-heterocyclic carbene LH (LH = [(Flu)HÀ (CH 2 ) 2 À NHC Dipp ]) and its monoanionic version L À are explored in complexation with zinc towards the hydroboration of N-heteroarenes, carbonyl, ester, amide, and nitrile under ambient condition. The N-heteroarenes exhibit high 1,2-regioselectivity which is justified by computational analyses. The relative hydroboration rates of differently p-substituted (electron donating vs. withdrawing) pyridines are also addressed. The monodentate LH offers a better catalytic activity than the chelating L À for steric reasons despite both giving three-coordinate zinc complexes. The mechanism involves a ZnÀ H species at the heart of these catalytic processes which is trapped by Ph 2 CO. Computational studies suggest that the barrier to form the hydride complex is comparable to the barrier required for the following hydride transfer to pyridine.

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Industrial emissions of mercury in Finland between 1967 and 1987

Mukherjee

1991

Water, Air, and Soil Pollution

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Zinc, Cadmium and Mercury

Cited by 3 publications

References 279 publications

2-Anilidomethylpyridine-Derived Three-Coordinate Zinc Hydride: The Journey Unveils Anilide Backbone’s Reactive Nature

2-Anilidomethylpyridine-Derived Three-Coordinate Zinc Hydride: The Journey Unveils Anilide Backbone’s Reactive Nature

A N‐Heterocyclic Carbene‐Supported Zinc Catalyst for the 1,2‐Regioselective Hydroboration of N‐Heteroarenes

Industrial emissions of mercury in Finland between 1967 and 1987

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