Control of the Microarchitecture of a Double Helix − Electrochemical Synthesis and Characterisation of a Novel Dinickel(II) Helicate with Different Groove Sizes

Abstract

Self‐assembly of nickel ions and the N4 Schiff base H2PTs [H2PTs: N,N′‐bis(2‐tosylaminobenzylidene)‐1,3‐diaminopropane] in an electrochemical cell leads to the novel neutral double‐stranded dinuclear helicate [NiPTs]2·CH3CN (1). Complex 1 was fully characterised by elemental analysis, IR and EPR spectroscopy, FAB mass spectrometry, and magnetic measurements. The single X‐ray crystal structure of 1 shows that both ligands are asymmetrically positioned around the Ni−Ni axis, leading to a double‐helical complex that presents a major and a minor groove.

New Helical Complexes with a Bis(bidentate) Schiff Base Ligand Containing a Flexible Spacer

“…[17,18] The electrochemical efficiency of the cell E f was approximately 0.5 mol·F Ϫ1 in all cases, which is compatible with the reaction mechanism shown in Scheme 2.…”

“…All the complexes were prepared by an electrochemical method previously described 17,18. The electrochemical efficiency of the cell E f was approximately 0.5 mol·F −1 in all cases, which is compatible with the reaction mechanism shown in Scheme .…”

“…6.031 Å . This distance compares fairly well with that observed in its analogue nickel complex, [17] but is clearly shorter than that found for dizinc complexes with bis(bidentate) ligands containing a propylene spacer (11.29 Å ). [21] The wrapping angle of both strands is ca.…”

New Helical Complexes with a Bis(bidentate) Schiff Base Ligand Containing a Flexible Spacer

“…[17,18] The electrochemical efficiency of the cell E f was approximately 0.5 mol·F Ϫ1 in all cases, which is compatible with the reaction mechanism shown in Scheme 2.…”

“…All the complexes were prepared by an electrochemical method previously described 17,18. The electrochemical efficiency of the cell E f was approximately 0.5 mol·F −1 in all cases, which is compatible with the reaction mechanism shown in Scheme .…”

“…6.031 Å . This distance compares fairly well with that observed in its analogue nickel complex, [17] but is clearly shorter than that found for dizinc complexes with bis(bidentate) ligands containing a propylene spacer (11.29 Å ). [21] The wrapping angle of both strands is ca.…”

Mono‐ and Dinuclear Complexes of a Flexible Schiff Base Ligand − Crystal Structures of a Bishelicate and Two Acentric Monohelicates

“…This could be caused by a considerable distortion from the ideal geometry, resulting in a fall in the orbital contribution to this value 24. In fact, we have found a similar value (3.3 BM per mol of Ni 2+ ) for Ni 2 (SB 1 ) 2 ·MeCN,16 in which the ligand, helical arrangement and the Ni ··· Ni distance (ca. 6.2 Å) are not very different from those observed for Ni 2 (SB) 2 ·2H 2 O.…”

Using Noncovalent Intra‐strand and Inter‐strand Interactions To Prescribe Helix Formation within a Metallo‐supramolecular System

“…We have previously reported a double helix in which face‐edge π interactions (CH⋅⋅⋅π) pull two strands together thereby creating a helix with two distinct grooves (major and minor) 11a. Similar effects induced by (face‐face) π–π interactions19 have subsequently been reported by Bermejo and co‐workers20 and more recently by Love and co‐workers 21. In these previous systems the inter‐strand interactions influence the precise microarchitecture of the helix but not the global architecture adopted.…”

New Helical Complexes with a Bis(bidentate) Schiff Base Ligand Containing a Flexible Spacer

“…[17,18] The electrochemical efficiency of the cell E f was approximately 0.5 mol·F Ϫ1 in all cases, which is compatible with the reaction mechanism shown in Scheme 2.…”

“…All the complexes were prepared by an electrochemical method previously described 17,18. The electrochemical efficiency of the cell E f was approximately 0.5 mol·F −1 in all cases, which is compatible with the reaction mechanism shown in Scheme .…”

“…6.031 Å . This distance compares fairly well with that observed in its analogue nickel complex, [17] but is clearly shorter than that found for dizinc complexes with bis(bidentate) ligands containing a propylene spacer (11.29 Å ). [21] The wrapping angle of both strands is ca.…”

Mono‐ and Dinuclear Complexes of a Flexible Schiff Base Ligand − Crystal Structures of a Bishelicate and Two Acentric Monohelicates

“…This could be caused by a considerable distortion from the ideal geometry, resulting in a fall in the orbital contribution to this value 24. In fact, we have found a similar value (3.3 BM per mol of Ni 2+ ) for Ni 2 (SB 1 ) 2 ·MeCN,16 in which the ligand, helical arrangement and the Ni ··· Ni distance (ca. 6.2 Å) are not very different from those observed for Ni 2 (SB) 2 ·2H 2 O.…”

Using Noncovalent Intra‐strand and Inter‐strand Interactions To Prescribe Helix Formation within a Metallo‐supramolecular System

“…We have previously reported a double helix in which face‐edge π interactions (CH⋅⋅⋅π) pull two strands together thereby creating a helix with two distinct grooves (major and minor) 11a. Similar effects induced by (face‐face) π–π interactions19 have subsequently been reported by Bermejo and co‐workers20 and more recently by Love and co‐workers 21. In these previous systems the inter‐strand interactions influence the precise microarchitecture of the helix but not the global architecture adopted.…”

New Helical Complexes with a Bis(bidentate) Schiff Base Ligand Containing a Flexible Spacer

“…[17,18] The electrochemical efficiency of the cell E f was approximately 0.5 mol·F Ϫ1 in all cases, which is compatible with the reaction mechanism shown in Scheme 2.…”

“…All the complexes were prepared by an electrochemical method previously described 17,18. The electrochemical efficiency of the cell E f was approximately 0.5 mol·F −1 in all cases, which is compatible with the reaction mechanism shown in Scheme .…”

“…6.031 Å . This distance compares fairly well with that observed in its analogue nickel complex, [17] but is clearly shorter than that found for dizinc complexes with bis(bidentate) ligands containing a propylene spacer (11.29 Å ). [21] The wrapping angle of both strands is ca.…”

Mono‐ and Dinuclear Complexes of a Flexible Schiff Base Ligand − Crystal Structures of a Bishelicate and Two Acentric Monohelicates

“…This could be caused by a considerable distortion from the ideal geometry, resulting in a fall in the orbital contribution to this value 24. In fact, we have found a similar value (3.3 BM per mol of Ni 2+ ) for Ni 2 (SB 1 ) 2 ·MeCN,16 in which the ligand, helical arrangement and the Ni ··· Ni distance (ca. 6.2 Å) are not very different from those observed for Ni 2 (SB) 2 ·2H 2 O.…”

Using Noncovalent Intra‐strand and Inter‐strand Interactions To Prescribe Helix Formation within a Metallo‐supramolecular System

“…We have previously reported a double helix in which face‐edge π interactions (CH⋅⋅⋅π) pull two strands together thereby creating a helix with two distinct grooves (major and minor) 11a. Similar effects induced by (face‐face) π–π interactions19 have subsequently been reported by Bermejo and co‐workers20 and more recently by Love and co‐workers 21. In these previous systems the inter‐strand interactions influence the precise microarchitecture of the helix but not the global architecture adopted.…”