Three-dimensional macrocyclic encapsulation reactions. III. Geometrical and electronic features of tris(diimine) complexes of trigonal-prismatic, antiprismatic, and intermediate stereochemistry

Larsen, Erik; LaMar, Gerd N.; Wagner, Burkhard E.; Parks, John E.; Holm, R. H.

doi:10.1021/ic50117a019

Cited by 104 publications

(53 citation statements)

References 2 publications

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“…Recently there has been considerable interest in the geometry of trigonal metal complexes from the viewpoint of their reaction mechanism (Larsen, LaMar, Wagner, Parks & Holm, 1972) and their circular dichroism spectra (Butler & Snow, 1972). In 32 (Da) symmetry the geometry of the metal and ligand atom core (here CON6) can be represented by the metalligand distance and two of three interrelated angles.…”

Section: The Tris(biguanide)cobait(iii) Cationmentioning

confidence: 99%

The structure and absolute configuration of (+)₅₈₉-tris(biguanide)cobalt(III) trichloride monohydrate Co(C₂H₇N₅)₃Cl₃.H₂O

Snow¹

1974

Acta Crystallogr Sect B

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The crystal structure of (+)ssg[Co(biguanide)3]CI3.H20 has been determined from 2161 reftexions collected by counter methods. The red crystals are orthorhombic, space group C2221, with a = 18-675 (9), b= 14.086 (7), and c= 15.004 (7) /~. The measured density is 1.65 (2) g cm -3 which agrees with the calculated density of 1-637 for Z= 8. The absorption corrected data gave a conventional R value of 0-021 on full-matrix least-squares refinement which included the hydrogen atoms. Bonding to cobalt in the six-coordinate tris(bidentate chelate) complex is through the terminal NH functions of the ligand, the average Co-N distance is 1.912 (3) A. The carbon-nitrogen bond distances and valence bond numbers are N(ligand)-C, 1.282 (2), 1.5; C-N(ring), 1.365 (5), 1.2; and C-N(terminal), 1.353 (4), 1-3. The chelate ring is only approximately planar with displacements near 0.1 ,~ of the cobalt, a ligand nitrogen and the ring nitrogen from the least-squares planes. The absolute configuration of the complex is A. This result shows that the exciton method of determining absolute configuration from the ultraviolet components of the circular dichroism spectrum is not generally applicable.

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Section: The Tris(biguanide)cobait(iii) Cationmentioning

confidence: 99%

The structure and absolute configuration of (+)₅₈₉-tris(biguanide)cobalt(III) trichloride monohydrate Co(C₂H₇N₅)₃Cl₃.H₂O

Snow¹

1974

Acta Crystallogr Sect B

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“…[14][15][16] This successful strategy has resulted in many examples of trigonal-prismatic complexes.…”

Section: Introductionmentioning

confidence: 99%

Trigonal‐Prismatic vs. Octahedral Geometry for Mn^II Complexes with Innocent Didentate Ligands: A Subtle Difference as Shown by XRD and DFT on [Mn(acac)₂(bpy)]

et al. 2005

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In this paper the first example of a mixed-ligand Mn II complex, having a trigonal-prismatic coordination geometry with simple, innocent, didentate ligands is presented. The solution and solid-state structures of [Mn(acac) 2 (bpy)] as studied by EPR spectroscopy, magnetic susceptibility measurements and XRD are presented: single crystals are hexagonal, space group P6 1 with unit cell dimensions a = 8.0482(9) Å, c = 51.602(10) Å, V = 2894.6(7) Å 3 and Z = 6. The complex has the trigonal-prismatic geometry only in the solid state. Density functional theory (DFT) calculations were performed to

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“…Actually, L and derived ligands are known to facilitate the synthesis of trigonal prismatic complexes [29][30][31]. This correlation acknowledges previous structure-spin state correlations [32], that are based on structural-chemical considerations going back to the early 1970s [33][34][35][36][37][38][39][40][41][42]. In particular, the idea of a taming of the SCO dynamics via ligand-imposed trigonal torsion is a recurrent motif of research.…”

Section: Introductionmentioning

confidence: 64%

Structural Dynamics of Spin Crossover in Iron(II) Complexes with Extended-Tripod Ligands

et al. 2017

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Selective manipulation of spin states in iron(II) complexes by thermal or photonic energy is a desirable goal in the context of developing molecular functional materials. As dynamic spin-state equilibration in isolated iron(II) complexes typically limits the lifetime of a given spin state to nanoseconds, synthetic strategies need to be developed that aim at inhibited relaxation. Herein we show that modulation of the reaction coordinate through careful selection of the ligand can indeed massively slow down dynamic exchange. Detailed structural analysis of [FeL] 2+ and [ZnL] 2+ (L: tris(1-methyl-2-{[pyridin-2-yl]-methylene}hydrazinyl)phosphane sulfide) with crystallographic and computational methods clearly reveals a unique trigonal-directing effect of the extended-tripod ligand L during spin crossover, which superimposes the ubiquitous [FeN 6 ] breathing with trigonal torsion, akin to the archetypal Bailar twist. As a consequence of the diverging reaction coordinates in [FeL] 2+ and in the tren-derived complex [Fe(tren)py 3 ] 2+ , their thermal barriers differ massively, although the spin crossover energies are close to identical. As is shown by time-resolved transient spectroscopy and dynamic 1 H-NMR line broadening, reference systems deriving from tren (tris-(2-aminoethyl)amine), which greatly lack such trigonal torsion, harbor very rapid spin-state exchange.

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Three-dimensional macrocyclic encapsulation reactions. III. Geometrical and electronic features of tris(diimine) complexes of trigonal-prismatic, antiprismatic, and intermediate stereochemistry

Cited by 104 publications

References 2 publications

The structure and absolute configuration of (+)₅₈₉-tris(biguanide)cobalt(III) trichloride monohydrate Co(C₂H₇N₅)₃Cl₃.H₂O

The structure and absolute configuration of (+)₅₈₉-tris(biguanide)cobalt(III) trichloride monohydrate Co(C₂H₇N₅)₃Cl₃.H₂O

Trigonal‐Prismatic vs. Octahedral Geometry for Mn^II Complexes with Innocent Didentate Ligands: A Subtle Difference as Shown by XRD and DFT on [Mn(acac)₂(bpy)]

Structural Dynamics of Spin Crossover in Iron(II) Complexes with Extended-Tripod Ligands

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Three-dimensional macrocyclic encapsulation reactions. III. Geometrical and electronic features of tris(diimine) complexes of trigonal-prismatic, antiprismatic, and intermediate stereochemistry

Cited by 104 publications

References 2 publications

The structure and absolute configuration of (+)589-tris(biguanide)cobalt(III) trichloride monohydrate Co(C2H7N5)3Cl3.H2O

The structure and absolute configuration of (+)589-tris(biguanide)cobalt(III) trichloride monohydrate Co(C2H7N5)3Cl3.H2O

Trigonal‐Prismatic vs. Octahedral Geometry for MnII Complexes with Innocent Didentate Ligands: A Subtle Difference as Shown by XRD and DFT on [Mn(acac)2(bpy)]

Structural Dynamics of Spin Crossover in Iron(II) Complexes with Extended-Tripod Ligands

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The structure and absolute configuration of (+)₅₈₉-tris(biguanide)cobalt(III) trichloride monohydrate Co(C₂H₇N₅)₃Cl₃.H₂O

The structure and absolute configuration of (+)₅₈₉-tris(biguanide)cobalt(III) trichloride monohydrate Co(C₂H₇N₅)₃Cl₃.H₂O

Trigonal‐Prismatic vs. Octahedral Geometry for Mn^II Complexes with Innocent Didentate Ligands: A Subtle Difference as Shown by XRD and DFT on [Mn(acac)₂(bpy)]