A density functional theoretical (DFT) study is presented, implicating a1O2oxidation process to reach a dihydrobenzofuran from the reaction of the natural homoallylic alcohol, glycocitrine. Our results predict an interconversion between glycocitrine and an
Organofunctionalized tetranuclear clusters [(MIICl)2(VIVO)2{((HOCH2CH2)(H)N(CH2CH2O))(HN(CH2CH2O)2)}2] (
- Award ID(s):
- 1834750
- PAR ID:
- 10491744
- Publisher / Repository:
- John Wiley & Sons, Ltd
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 29
- Issue:
- 59
- ISSN:
- 0947-6539
- Page Range / eLocation ID:
- e202301389
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract iso ‐hydroperoxide intermediate [R(H)O+– O−] that provides a key path in the chemistry which then follows. Formations of allylic hydroperoxides are unlikely from a1O2‘ene’ reaction. Instead, the dihydrobenzofuran arises by1O2oxidation facilitated by a 16° curvature of the glycocitrine ring imposed by a pyramidalN ‐methyl group. This curvature facilitates the formation of theiso ‐hydroperoxide, which is analogous to theiso species CH2I+– I−and CHI2+– I−formed by UV photolysis of CH2I2and CHI3. Theiso ‐hydroperoxide is also structurally reminiscent of carbonyl oxides (R2C=O+– O−) formed in the reaction of carbenes and oxygen. Our DFT results point to intermolecular process, in which theiso ‐hydroperoxide's fate relates to O‐transfer and H2O dehydration reactions for new insight into the biosynthesis of dihydrobenzofuran natural products. -
Abstract Coordination complexes of general formula
trans ‐[MX2(R2ECH2CH2ER2)2] (MII=Ti, V, Cr, Mn; E=N or P; R=alkyl or aryl) are a cornerstone of coordination and organometallic chemistry. We investigate the electronic properties of two such complexes,trans ‐[VCl2(tmeda)2] andtrans ‐[VCl2(dmpe)2], which thus representtrans ‐[MX2(R2ECH2CH2ER2)2] where M=V, X=Cl, R=Me and E=N (tmeda) and P (dmpe). These VIIcomplexes haveS =3/2 ground states, as expected for octahedral d3. Their tetragonal distortion leads to zero‐field splitting (zfs) that is modest in magnitude (D ≈0.3 cm−1) relative to analogousS =1 TiIIand CrIIcomplexes. This parameter was determined from conventional EPR spectroscopy, but more effectively from high‐frequency and ‐field EPR (HFEPR) that determined the sign ofD as negative for the diamine complex, but positive for the diphosphine, which information had not been known for anytrans ‐[VX2(R2ECH2CH2ER2)2] systems. The ligand‐field parameters oftrans ‐[VCl2(tmeda)2] andtrans ‐[VCl2(dmpe)2] are obtained using both classical theory andab initio quantum chemical theory. The results shed light not only on the electronic structure of VIIin this environment, but also on differences between N and P donor ligands, a key comparison in coordination chemistry. -
Abstract Three new polynuclear clusters with the formulae [Mn10O4(OH)(OMe){(py)2C(O)2}2{(py)2C(OMe)(O)}4(MeCO2)6](ClO4)2(
1 ), Na[Mn12O2(OH)3(OMe){(py)2C(O)2}6{(py)2C(OH)(O)}2(MeCO2)2(H2O)10](ClO4)8(2 ) and [Mn12O4(OH)2{(py)2C(O)2}6{(py)2C(OMe)(O)}(MeCO2)3(NO3)3(H2O)(DMF)2](NO3)2(3 ) were prepared from the combination of di‐2‐pyridyl ketone, (py)2CO, with the aliphatic diols (1,3‐propanediol (pdH2) or 1,4‐butanediol (1,4‐bdH2)) in Mn carboxylate chemistry. The reported compounds do not include the aliphatic diols employed in this reaction scheme; however, their use is essential for the formation of1 –3 . The crystal structures of1 –3 are based on multilayer cores which, to our knowledge, are reported for the first time in Mn cluster chemistry. Direct current (dc ) magnetic susceptibility studies showed the presence of dominant antiferromagnetic exchange interactions within1 –3 . Alternating current (ac ) magnetic susceptibility studies revealed the presence of out‐of‐phase signals below 3.0 K for2 and3 indicating the slow relaxation of the magnetization vector, characteristic of single‐molecule magnets; theUeff value of2 was found to be 23 K and the preexponential factorτ0 ~7.6×10−9 s. -
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Abstract A novel transition metal chalcohalide [Cr7S8(en)8Cl2]Cl3 ⋅ 2H2O, with [Cr7S8]5+dicubane cationic clusters, has been synthesized by a low temperature solvothermal method, using dimethyl sulfoxide (DMSO) and ethylenediamine (
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