A panel of peralkylated sulfur–guanidine type bases: Novel pro-ligands for use in biomimetic coordination chemistry

Neuba, Adam; Rohrmüller, Martin; Hölscher, R.; Schmidt, Wolf Gero; Henkel, Gerald

doi:10.1016/j.ica.2015.03.015

Cited by 5 publications

(3 citation statements)

References 102 publications

(19 reference statements)

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“…The C−N single bond lengths range from 1.392(3) to 1.415(3) Å and 1.384(3) to 1.410(4) Å, while the C=N double bonds have similar values with a mean of 1.267 and 1.269 Å. Thus, the guanidyl double bonds are clearly localized with a structural parameter ρ of 0.905 and 0.906 which is in agreement with literature known guanidines ,,,…”

Section: Resultsmentioning

confidence: 99%

A Powerful Synthesis Strategy of Novel Non‐Symmetrical Camphor‐Based Guanidines

et al. 2018

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A convenient synthesis strategy for chiral camphor-based nonsymmetrical bis-guanidines with different peralkylated units is presented. The modular synthetic pathway to the first C 1symmetric guanidines enables the implementation of chirality together with steric and electronic asymmetry via a step by step guanidinisation of camphor bis-amine. The described guanidines were characterized using 1 H and 13 C NMR spectroscopy, ESI mass spectrometry, elemental analysis and X-ray crystallographic analysis.

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Section: Resultsmentioning

confidence: 99%

A Powerful Synthesis Strategy of Novel Non‐Symmetrical Camphor‐Based Guanidines

et al. 2018

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“…TMG has strong donor properties and strong basicity and is a part of various ligand systems. 57,58 The ground-state structure of the molecule has D 2 symmetry. The compound was synthesised with two counter-anions -OTf À and PF 6…”

Section: Dft Calculationsmentioning

confidence: 99%

Structural dynamics upon photoexcitation-induced charge transfer in a dicopper(i)–disulfide complex

Naumova

Khakhulin

Rębarz

et al. 2018

Phys. Chem. Chem. Phys.

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The structural dynamics of charge-transfer states of nitrogen-ligated copper complexes has been extensively investigated in recent years following the development of pump-probe X-ray techniques. In this study we extend this approach towards copper complexes with sulfur coordination and investigate the influence of charge transfer states on the structure of a dicopper(i) complex with coordination by bridging disulfide ligands and additionally tetramethylguanidine units [Cu(NSSN)]. In order to directly observe and refine the photoinduced structural changes in the solvated complex we applied picosecond pump-probe X-ray absorption spectroscopy (XAS) and wide-angle X-ray scattering (WAXS). Additionally, the ultrafast evolution of the electronic excited states was monitored by femtosecond transient absorption spectroscopy in the UV-Vis probe range. DFT calculations were used to predict molecular geometries and electronic structures of the ground and metal-to-ligand charge transfer states with singlet and triplet spin multiplicities, i.e. S, MLCT andMLCT, respectively. Combining these techniques we elucidate the electronic and structural dynamics of the solvated complex upon photoexcitation to the MLCT states. In particular, femtosecond optical transient spectroscopy reveals three distinct timescales of 650 fs, 10 ps and >100 ps, which were assigned as internal conversion to the ground state (S → S), intersystem crossing MLCT →MLCT, and subsequent relaxation of the triplet to the ground state, respectively. Experimental data collected using both X-ray techniques are in agreement with the DFT-predicted structure for the triplet state, where coordination bond lengths change and one of the S-S bridges is cleaved, causing the movement of two halves of the molecule relative to each other. Extended X-ray absorption fine structure spectroscopy resolves changes in Cu-ligand bond lengths with precision on the order of 0.01 Å, whereas WAXS is sensitive to changes in the global shape related to relative movement of parts of the molecule. The results presented herein widen the knowledge on the electronic and structural dynamics of photoexcited copper-sulfur complexes and demonstrate the potential of combining the pump-probe X-ray absorption and scattering for studies on photoinduced structural dynamics in copper-based coordination complexes.

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“…Furthermore, hybrid ligands with additional nitrogen donor functionalities, like amine‐N and pyridine‐N, were described. Continuous work induced the creation of abundant libraries containing different guanidine ligands . In 2017, Himmel et al reported on the realization of a benzene with six guanidino moieties .…”

Section: Introductionmentioning

confidence: 99%

Combining a Phenanthroline Moiety with Peralkylated Guanidine Residues: Homometallic Cu^II, Ni^II and Zn^II Halide Complexes with Site‐Differentiating Janus Head Ligands

et al. 2018

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The unique core portion of Janus head pro-ligands based on a tailored phenanthroline-bis(guanidine) architecture has been utilized to generate a multiplicity of homometallic copper(II), nickel(II) and zinc(II) complexes terminated by halide constituents. The bis-bidentate nitrogen donor ligands provide coordination sites with metal-differentiating properties which can be loaded successively starting with the phenanthroline interface as can be demonstrated by mononuclear species which form under metal deficient conditions. Furthermore, depending on both the alkylation and metalation stage of the guanidine residues comprising variants with tetramethyl-, tetraethyl-, dimethylethylene-, and dipentylene-guanidino function- [a] 5177 molecular structures, which are presented in Scheme 2, were identified by crystal structure analysis or mass spectrometry (see crystal structures and experimental section). Scheme 2. Synthesized mononuclear copper(II) (1-4) and nickel(II) (5 and 6) complexes.

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A panel of peralkylated sulfur–guanidine type bases: Novel pro-ligands for use in biomimetic coordination chemistry

Cited by 5 publications

References 102 publications

A Powerful Synthesis Strategy of Novel Non‐Symmetrical Camphor‐Based Guanidines

A Powerful Synthesis Strategy of Novel Non‐Symmetrical Camphor‐Based Guanidines

Structural dynamics upon photoexcitation-induced charge transfer in a dicopper(i)–disulfide complex

Combining a Phenanthroline Moiety with Peralkylated Guanidine Residues: Homometallic Cu^II, Ni^II and Zn^II Halide Complexes with Site‐Differentiating Janus Head Ligands

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A panel of peralkylated sulfur–guanidine type bases: Novel pro-ligands for use in biomimetic coordination chemistry

Cited by 5 publications

References 102 publications

A Powerful Synthesis Strategy of Novel Non‐Symmetrical Camphor‐Based Guanidines

A Powerful Synthesis Strategy of Novel Non‐Symmetrical Camphor‐Based Guanidines

Structural dynamics upon photoexcitation-induced charge transfer in a dicopper(i)–disulfide complex

Combining a Phenanthroline Moiety with Peralkylated Guanidine Residues: Homometallic CuII, NiII and ZnII Halide Complexes with Site‐Differentiating Janus Head Ligands

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Combining a Phenanthroline Moiety with Peralkylated Guanidine Residues: Homometallic Cu^II, Ni^II and Zn^II Halide Complexes with Site‐Differentiating Janus Head Ligands