ReviewInverse coordination. Organic nitrogen heterocycles as coordination centers. A survey of molecular topologies and systematization. Part 1. Five-membered and smaller rings

Haiduc, Ionel

doi:10.1080/00958972.2019.1641702

Cited by 21 publications

(15 citation statements)

References 205 publications

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“…The term inverse coordination chemistry (ICC) was coined by Haiduc to describe an emerging research area in the field of coordination chemistry, where the bridging ligand plays the role of coordination center surrounded by transition metal ions which can be further coordinated to other co-ligands acting as additional bridging or terminal donors [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. ICC provides new concepts for the structural description and future perspectives in the design and synthesis of inverse polynuclear complexes (IPCs) and inverse coordination polymers (ICPs) with tailor-made nuclearity and dimensionality ( n D, n = 1−3) or topology [ 1 ].…”

Section: Introductionmentioning

confidence: 99%

Ferro- and Antiferromagnetic Interactions in Oxalato-Centered Inverse Hexanuclear and Chain Copper(II) Complexes with Pyrazole Derivatives

et al. 2021

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Two novel copper(II) complexes of formulas {[Cu(4-Hmpz)4][Cu(4-Hmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(ClO4)2]}n (1) and {[Cu(3,4,5-Htmpz)4]2[Cu(3,4,5-Htmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(H2O)(ClO4)]2[Cu2(3,4,5-Htmpz)4(µ-ox-κ2O1,O2:κ2O2′,O1′)]}(ClO4)4·6H2O (2) have been obtained by using 4-methyl-1H-pyrazole (4-Hmpz) and 3,4,5-trimethyl-1H-pyrazole (3,4,5-Htmpz) as terminal ligands and oxalate (ox) as the polyatomic inverse coordination center. The crystal structure of 1 consists of perchlorate counteranions and cationic copper(II) chains with alternating bis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) and tetrakis(pyrazole)copper(II) fragments. The crystal structure of 2 is made up of perchlorate counteranions and cationic centrosymmetric hexanuclear complexes where an inner tetrakis(pyrazole)(µ-κ2O1,O2:κ2O2′,O1′-oxalato)dicopper(II) entity and two outer mononuclear tetrakis(pyrazole)copper(II) units are linked through two mononuclear aquabis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) units. The magnetic properties of 1 and 2 were investigated in the temperature range 2.0–300 K. Very weak intrachain antiferromagnetic interactions between the copper(II) ions through the µ3-ox-κ2O1,O2:κO2′:κO1′ center occur in 1 [J = −0.42(1) cm−1, the spin Hamiltonian being defined as H = −J∑S1,i · S2,i+1], whereas very weak intramolecular ferromagnetic [J = +0.28(2) cm−1] and strong antiferromagnetic [J’ = −348(2) cm−1] couplings coexist in 2 which are mediated by the µ3-ox-κ2O1,O2:κO2′:κO1′ and µ-ox-κ2O1,O2:κ2O2′,O1′ centers, respectively. The variation in the nature and magnitude of the magnetic coupling for this pair of oxalato-centered inverse copper(II) complexes is discussed in the light of their different structural features, and a comparison with related oxalato-centered inverse copper(II)-pyrazole systems from the literature is carried out.

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Section: Introductionmentioning

confidence: 99%

Ferro- and Antiferromagnetic Interactions in Oxalato-Centered Inverse Hexanuclear and Chain Copper(II) Complexes with Pyrazole Derivatives

et al. 2021

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“…[20,21] Later, the significant research to utilize cyclic S 2 N 2 compounds as ligands to transition metal complexes have been largely developed by Dehnicke, Muller and others (Scheme 2). [22][23][24] A majority of the cyclic sulfur-nitrogen complexes structurally studied to date shows that the nitrogen atoms act as donors to the transition metal fragments. [22][23][24] In the majority of the S 2 N 2 complexes, S 2 N 2 ring acts as a η 2 -bridging ligand between two metal fragments.…”

Section: Introductionmentioning

confidence: 99%

“…[22][23][24] A majority of the cyclic sulfur-nitrogen complexes structurally studied to date shows that the nitrogen atoms act as donors to the transition metal fragments. [22][23][24] In the majority of the S 2 N 2 complexes, S 2 N 2 ring acts as a η 2 -bridging ligand between two metal fragments. Nevertheless, sulfur coordinated transition metal complexes are also known, such as Ag(S 4 N 4 H 4 ) 2 and (S 4 N 4 H 4 )M(CO) 5 (M = Cr and W) (Scheme 1b).…”

Section: Introductionmentioning

confidence: 99%

“…Also note that, to the best of our knowledge, all the experimentally reported S 2 N 2 transition metal complexes that are known so far contains one or more halogen ligands in the S 2 N 2 σ-plane (Scheme 2). [22][23][24] Therefore, herein we aim to provide insight into the σ-and π-reactivity of S 2 N 2 as a ligand and the role of halogens in the S 2 N 2 transition metal complexes. Our results might help in expanding the ligand knowledge-base for the use of inorganic aromatic compounds in coordination chemistry.…”

Section: Introductionmentioning

confidence: 99%

“…The major difference in the η 2 -coordination vs η 1 -coordination is observed in the higher dissociation energy of 2Mo (52.3 kcal/mol) as compared to 1Mo (6.1 kcal/mol), corroborating with the experimental isolation of a higher number of bi-metallic complexes (Scheme 2). [22][23][24] This nature of ligand is quite similar to heterocycles such as pyrazine in organometallic chemistry. [75] However interestingly, S 2 N 2 can also acts as a σ-acceptor due to the presence of electro-positive S-atom, which can lead to additional stability to the transition metal complexes of S 2 N 2 with appropriate donor ligands at the metal center.…”

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confidence: 99%

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Cyclic Aromatic 6π-Electron S2N2 ‒ A Ligand with Tunable σ- and π- Donor-Acceptor Property

Sadik

2020

Preprint

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The usage of inorganic aromatic N-donor based ligands, whose electronic properties can be easily and extensively tuned, are still underdeveloped. One such system is cyclic compounds of sulfur-nitrogen, which is known to form η1 and η2-complexes with mono-and bi-metallic transition metal fragments. We have undertaken an extensive theoretical investigation of the bonding nature between S2N2 ligand and 14 valence electron (VE) metal fragments in the mono and bi-metallic S2N2[Mo(NO)Cl4] and S2N2[Mo2(NO)2(Cl)8]2. Our results indicate that S2N2 ligand in S2N2[Mo(NO)Cl4] is a σ-donor and π-acceptor. The EDA-NOCV analysis indicates that the interaction between S2N2 and metal fragments has a higher electrostatic character than a covalent character. The nature of S2N2 as a ligand is similar in the bi-metallic complex S2N2[Mo2(NO)2(Cl)8]2 as well. On the contrary, the σ-lone pair on N-atom in S2N2 is donated to the electron-deficient 12 valence electron [Mo(NO)Cl4]+ fragment in S2N2[Mo(NO)Cl4]+ and the electrons from the S2N2 π-MO are donated to the vacant d-orbitals of the metal fragment. Similar bonding nature is also observed in the bi-metallic S2N2[Mo2(NO)2(Cl)8]2+ complex. Besides, all these complexes show donation of lone pair on Cl attached to transition metal fragment to the S-N σ*-MO, which is majorly located on the S-atom. Here, the S-atom in S2N2 can be considered as a σ-hole, which is involved in the chalcogen bond formation by accepting an electron pair from Cl-atom. Hence, our theoretical calculations suggest that the S2N2 is a versatile ligand which can be tuned as σ-donor, σ-acceptor, π-donor and π-acceptor.

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Dinuclear Nickel(II) and Copper(II) Complexes of 8‐Quinoline‐1H‐pyrazole‐3‐carboxamide: Crystal Structure, Magnetic Properties, and DFT Calculations

et al. 2021

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Homoleptic dinuclear complexes [M2(qpyzc)2] (M=Cu (1) or Ni (2) were obtained from the readily synthesised trischelate pyrazole‐based qpyzc ligand (H2qpyzc=8‐quinoline‐1H‐pyrazole‐3‐carboxamide). Their crystal and molecular structures, magnetic properties, and UV‐vis spectra were reported alongside with DFT and TD‐DFT calculations. Trigonality index τ’4 values of 0.25 and 0.21 for the Cu and Ni centres, respectively reveal a marked distortion from square planar geometry. The two metal coordination planes within a complex are tilted towards each other with 40.2(1)° for Cu(II) and 34.5(2)° for Ni(II). The central six‐membered M2N4 metallocycle is almost planar and the two anionic pyrazolate rings are tilted towards each other by 37.4(1)° (1) and 38.5(2)° (2), respectively. Regardless of this peculiar bonding situation magnetic measurements on 1 are in line with medium‐sized antiferromagnetic coupling with a coupling constant of J=−100 cm−1, an isotropic g value of 2.11 and an S=0 ground state. Complex 2 seems to be diamagnetic. DFT calculations gave an excellent agreement between calculated and experimental metrics of the complexes and supported the prevalence of the singlet ground state for 1. TD‐DFT calculated UV‐vis absorption spectra agree well with observed absorptions and the red colour of both compounds.

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ReviewInverse coordination. Organic nitrogen heterocycles as coordination centers. A survey of molecular topologies and systematization. Part 1. Five-membered and smaller rings

Cited by 21 publications

References 205 publications

Ferro- and Antiferromagnetic Interactions in Oxalato-Centered Inverse Hexanuclear and Chain Copper(II) Complexes with Pyrazole Derivatives

Ferro- and Antiferromagnetic Interactions in Oxalato-Centered Inverse Hexanuclear and Chain Copper(II) Complexes with Pyrazole Derivatives

Cyclic Aromatic 6π-Electron S2N2 ‒ A Ligand with Tunable σ- and π- Donor-Acceptor Property

Dinuclear Nickel(II) and Copper(II) Complexes of 8‐Quinoline‐1H‐pyrazole‐3‐carboxamide: Crystal Structure, Magnetic Properties, and DFT Calculations

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