Relative to other cyclic poly‐phosphorus species (that is,
Relative to other cyclic poly‐phosphorus species (that is,
- NSF-PAR ID:
- 10113384
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie
- Volume:
- 131
- Issue:
- 43
- ISSN:
- 0044-8249
- Page Range / eLocation ID:
- p. 15473-15477
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract cyclo ‐Pn ), the planarcyclo ‐P4group is unique in its requirement of two additional electrons to achieve aromaticity. These electrons are supplied from one or more metal centers. However, the degree of charge transfer is dependent on the nature of the metal fragment. Unique examples of dianionic mononuclear η4‐P4complexes are presented that can be viewed as the simple coordination of the [cyclo ‐P4]2−dianion to a neutral metal fragment. Treatment of the neutral, molybdenumcyclo ‐P4complexes Mo(η4‐P4)I2(CO)(CNArDipp2)2and Mo(η4‐P4)(CO)2(CNArDipp2)2with KC8produces the dianionic, three‐legged piano stool complexes, [Mo(η4‐P4)(CO)(CNArDipp2)2]2−and [Mo(η4‐P4)(CO)2(CNArDipp2)]2−, respectively. Structural, spectroscopic, and computational studies reveal a similarity to the classic η6‐benzene complex (η6‐C6H6)Mo(CO)3regarding the metal‐center valence state and electronic population of the planar‐cyclic ligand π system. -
more » « less
Abstract A new class of conjugated macrocycle, the cyclo[4]thiophene[4]furan hexyl ester (C4TE4FE), is reported. This cycle consists of alternating α‐linked thiophene‐3‐ester and furan‐3‐ester repeat units, and was prepared in a single step using Suzuki–Miyaura cross‐coupling of a 2‐(thiophen‐2‐yl)furan monomer. The ester side groups help promote a
syn conformation of the heterocycles, which enables formation of the macrocycle. Cyclic voltammetry studies revealed that C4TE4FE could undergo multiple oxidations, so treatment with SbCl5resulted in formation of the [C4TE4FE]2+dication. Computational work, paired with1H NMR spectroscopy of the dication, revealed that the cycle becomes globally aromatic upon 2e−oxidation, as the annulene pathway along the outer ring becomes Hückel aromatic. The change in ring current for the cycle upon oxidation was clear from1H NMR spectroscopy, as the protons of the thiophene and furan rings shifted downfield by nearly 6 ppm. This work highlights the potential of sequence control in furan‐based macrocycles to tune electronic properties. -
more » « less
Abstract Antiaromaticity, as introduced in 1965, usually refers to monocyclic systems with 4
n π electrons. This concept was extended to all‐metal molecules after the observation of Li3Al4−in the gas phase. However, the solid‐phase counterparts have not been documented to date. Herein, we describe a series of all‐metal antiaromatic anions, [Ln(η 4‐Sb4)3]3−(Ln=La, Y, Ho, Er, Lu), which were isolated as the K([2.2.2]crypt) salts and identified by single‐crystal X‐ray diffraction. Based on the results obtained from the chemical bonding analysis, multicenter indices, and the electron‐counting rule, we conclude that the core [Ln(η 4‐Sb4)3]3−fragment of the crystal has three locally π‐antiaromatic Sb4fragments. This complex represents the first locally π‐antiaromatic all‐metal system in the solid state, which is stabilized by interactions of the three π‐antiaromatic units with the central metal atom. -
more » « less
Abstract Metalation of the polynucleating ligandF,tbsLH6(1,3,5‐C6H9(NC6H3−4‐F−2‐NSiMe2tBu)3) with two equivalents of Zn(N(SiMe3)2)2affords the dinuclear product (F,tbsLH2)Zn2(
1 ), which can be further deprotonated to yield (F,tbsL)Zn2Li2(OEt2)4(2 ). Transmetalation of2 with NiCl2(py)2yields the heterometallic, trinuclear cluster (F,tbsL)Zn2Ni(py) (3 ). Reduction of3 with KC8affords [KC222][(F,tbsL)Zn2Ni] (4 ) which features a monovalent Ni centre. Addition of 1‐adamantyl azide to4 generates the bridging μ3‐nitrenoid adduct [K(THF)3][(F,tbsL)Zn2Ni(μ3‐NAd)] (5 ). EPR spectroscopy reveals that the anionic cluster possesses a doublet ground state (S =). Cyclic voltammetry of 5 reveals two fully reversible redox events. The dianionic nitrenoid [K2(THF)9][(F,tbsL)Zn2Ni(μ3‐NAd)] (6 ) was isolated and characterized while the neutral redox isomer was observed to undergo both intra‐ and intermolecular H‐atom abstraction processes. Ni K‐edge XAS studies suggest a divalent oxidation state for the Ni centres in both the monoanionic and dianionic [Zn2Ni] nitrenoid complexes. However, DFT analysis suggests Ni‐borne oxidation for5 . -
more » « less
Abstract Metalation of the polynucleating ligandF,tbsLH6(1,3,5‐C6H9(NC6H3−4‐F−2‐NSiMe2tBu)3) with two equivalents of Zn(N(SiMe3)2)2affords the dinuclear product (F,tbsLH2)Zn2(
1 ), which can be further deprotonated to yield (F,tbsL)Zn2Li2(OEt2)4(2 ). Transmetalation of2 with NiCl2(py)2yields the heterometallic, trinuclear cluster (F,tbsL)Zn2Ni(py) (3 ). Reduction of3 with KC8affords [KC222][(F,tbsL)Zn2Ni] (4 ) which features a monovalent Ni centre. Addition of 1‐adamantyl azide to4 generates the bridging μ3‐nitrenoid adduct [K(THF)3][(F,tbsL)Zn2Ni(μ3‐NAd)] (5 ). EPR spectroscopy reveals that the anionic cluster possesses a doublet ground state (S =). Cyclic voltammetry of 5 reveals two fully reversible redox events. The dianionic nitrenoid [K2(THF)9][(F,tbsL)Zn2Ni(μ3‐NAd)] (6 ) was isolated and characterized while the neutral redox isomer was observed to undergo both intra‐ and intermolecular H‐atom abstraction processes. Ni K‐edge XAS studies suggest a divalent oxidation state for the Ni centres in both the monoanionic and dianionic [Zn2Ni] nitrenoid complexes. However, DFT analysis suggests Ni‐borne oxidation for5 .
