Solvation of iron(II) complexes of hexadentate tris-diimine Schiff base tripod ligands in alcohol?water and DMSO?water mixtures

Alousy, A.; Burgess, John; Elvidge, Diane L.

doi:10.1007/s11243-004-2233-x

Cited by 3 publications

(3 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… a Experimental ground states obtained from references − . b All compounds were optimized in water using the PCM, while [Fe(Me–Lt) 2 ] 2+ was optimized in vacuum. …”

Section: Resultsmentioning

confidence: 99%

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

2012

View full text Add to dashboard Cite

Pseudo-octahedral complexes of iron find applications as switches in molecular electronic devices, materials for data storage, and, more recently, as candidates for dye-sensitizers in dye-sensitized solar cells. Iron, as a first row transition metal, provides a weak ligand-field splitting in an octahedral environment. This results in the presence of low-lying (5)T excited states that, depending on the identity of iron ligands, can become the ground state of the complex. The small energy difference between the low-spin, (1)A, and high-spin, (5)T, states presents a challenge for accurate prediction of their ground state using density functional theory. In this work, we investigate the applicability of the B3LYP functional to the ground state determination of first row transition metal complexes, focusing mainly on Fe(II) polypyridine complexes with ligands of varying ligand field strength. It has been shown previously that B3LYP artificially favors the (5)T state as the ground state of Fe(II) complexes, and the error in the energy differences between the (1)A and (5)T states is systematic for a set of structurally related complexes. We demonstrate that structurally related complexes can be defined as pseudo-octahedral complexes that undergo similar distortion in the metal-ligand coordination environment between the high-spin and low-spin states. The systematic behavior of complexes with similar distortion can be exploited, and the ground state of an arbitrary Fe(II) complex can be determined by comparing the calculated energy differences between the singlet and quintet electronic states of a complex to the energy differences of structurally related complexes with a known, experimentally determined ground state.

show abstract

“… a Experimental ground states obtained from references − . b All compounds were optimized in water using the PCM, while [Fe(Me–Lt) 2 ] 2+ was optimized in vacuum. …”

Section: Resultsmentioning

confidence: 99%

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

2012

View full text Add to dashboard Cite

show abstract

“…6b) and distorts as is clearly indicated by increasing distortion parameters (Table S3 †). Comparison of the parameters of the LS 1-BF 4 with those of a similar methyl-substituted ST complex {Fe II [tren(6Me-py) 3 ]}(ClO 4 ) 2 , 19a and the non-substituted non-ST LS complex {Fe II [tren( py) 3 ]}(ClO 4 ) 2 , 25 points out an intermediate position for the title compound in accordance with the reduced substituent size and decreasing steric crowding between pendant pyridine moieties in the series Me (2.00) 26 > F (1.47) 27 > H (1.20) 27 (in parentheses are the van der Waals radii in Å). Despite the tripod ligand, the trigonal prismatic distortion of the coordination environment is insignificant as follows from the large continuous shape measure values corresponding to the trigonal distortion CShM(D 3h ) and the small values corresponding to the octahedral geometry CShM(O h ) (Table S3 †).…”

Section: Resultsmentioning

confidence: 99%

Spin transition and symmetry-breaking in new mononuclear Fe^II tren-complexes with up to 38 K hysteresis around room temperature

Seredyuk

Znovjyak

Valverde‐Muñoz

et al. 2022

Inorg. Chem. Front.

View full text Add to dashboard Cite

show abstract

“…Also, the issue of substitution kinetics [31] of the coordinating imine moiety (pyridyl or other) by water needs to be addressed. [32,33] To this end, studies of remote derivatives of 1 are currently in progress.…”

Section: Discussionmentioning

confidence: 99%

Effective Repression of the Fragmentation of a Hexadentate Ligand Bearing an Auto‐Immolable Pendant Arm by Iron Coordination

et al. 2008

View full text Add to dashboard Cite

International audienceA diamagnetic ferrous complex (1) (MRI silent) is presented that consists of a macrocyclic hexadentate ligand (7) bearing an auto-immolable arm, as seen in organic prodrug design. This arm constitutes a phenylogous N/O acetal “locked” by glycosylation. Enzymatic glycolysis is hypothesized to lead to a phenol intermediate (a phenylogous hemiaminal) that fragments spontaneously thereby liberating a paramagnetic ferrous complex (MRI active). This paper describes the synthesis of ligand 7 and complex 1, and their respective reaction with β-galactosidase, the target enzyme. While ligand 7 alone fragments swiftly to the pentadentate ligand dptacn (monitored by LCMS analysis) upon in vitro enzymatic conversion, the phenol resulting from glycosyl removal from complex 1 accumulates in the buffered reaction mixture without any apparent fragmentation. Two independent explanations are put forward: metal coordination leads to rigidification of the ligand skeleton with concomitant kinetic inhibition of fragmentation or to the liberation of enough extra free energy to shift the thermodynamic equilibrium towards the starting material

show abstract

Solvation of iron(II) complexes of hexadentate tris-diimine Schiff base tripod ligands in alcohol?water and DMSO?water mixtures

Cited by 3 publications

References 42 publications

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

Spin transition and symmetry-breaking in new mononuclear Fe^II tren-complexes with up to 38 K hysteresis around room temperature

Effective Repression of the Fragmentation of a Hexadentate Ligand Bearing an Auto‐Immolable Pendant Arm by Iron Coordination

Contact Info

Product

Resources

About

Solvation of iron(II) complexes of hexadentate tris-diimine Schiff base tripod ligands in alcohol?water and DMSO?water mixtures

Cited by 3 publications

References 42 publications

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

Low-Spin versus High-Spin Ground State in Pseudo-Octahedral Iron Complexes

Spin transition and symmetry-breaking in new mononuclear FeII tren-complexes with up to 38 K hysteresis around room temperature

Effective Repression of the Fragmentation of a Hexadentate Ligand Bearing an Auto‐Immolable Pendant Arm by Iron Coordination

Contact Info

Product

Resources

About

Spin transition and symmetry-breaking in new mononuclear Fe^II tren-complexes with up to 38 K hysteresis around room temperature