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p-Donor/Acceptor charge-transfer (CT) interactions between redox-complementary p-systems often give rise to non-native optical and electronic properties that are beneficial for modern electronics and energy technologies. However, the formation of extended supramolecular p-donor/acceptor stacks capable of long-range charge transport requires ingenious design strategies that can help reinforce otherwise weak p-donor/acceptor noncovalent interactions. Herein, we demonstrate that a large tetragonal prismatic metal–organic cage (MOC28+) having two parallel p-donor tetrakis(4- carboxyphenyl)-Zn-porphyrin (ZnTCPP) faces located B14 Å apart can accommodate up to three redox-complementary planar aromatic guests (either three p-acceptor guests or two p-acceptors surrounding one p-donor guest) between the ZnTCPP faces, forming extended p-donor/acceptor stacks. While empty MOC28+ behaves as an insulator due to the lack of charge delocalization across its large cavity, its inclusion complexes saturated with p-acidic hexaazatriphenylene hexacarbonitrile (HATHCN) and hexacyanotriphenylene (HCTP) displayed noticeably higher electrical conductivity (8.7   10 6 and 1.3   10 6 S m 1, respectively) owing to more facile charge transport through the p-donor/ acceptor stacks composed of the p-acidic guests intercalated between the ZnTCPP faces. Thus, this work demonstrates that tetragonal prismatic metallacages with two parallel electroactive faces can facilitate the creation of extended p-donor/acceptor stacks by encapsulating redox-complementary planar guests, which in turn facilitates through-space charge delocalization, generating non-native electrical conductivity. 

Novel columnar lanthanide metal–organic frameworks (Ln-MOFs) based on a butterfly-shaped electron-rich π-extended tetrathia-fulvalene ligand (ExTTFTB) were synthesized and their electronic properties were investigated. Upon iodine-induced ligand oxidation, the Tb-MOF displayed ca. 100-fold higher electrical conductivity (5 × 10 −7 S m −1 ) than the neutral pristine MOF. 

Thermodynamically favored simultaneous coordination of Pt(II) corners with aza- and carboxylate ligands yields tricomponent coordination complexes with sophisticated structures and functions, which require careful structural characterization to paint accurate depiction of their structure–function relationships. Previous reports had claimed that heteroleptic coordination of cis-(Et3P)2PtII with tetrapyridyl porphyrins (M'TPP, M' = Zn or H2) and dicarboxylate ligands (XDC) yielded 3D tetragonal prisms containing two horizontal M'TPP faces and four vertical XDC pillars connected by eight Pt(II) corners, even though such structures were not supported by their 1H NMR data. Through extensive X-ray crystallographic and NMR studies, herein, we demonstrate that self-assembly of cis-(Et3P)2PtII, M'TPP, and four different XDC linkers having varied lengths and rigidity actually yields bow-tie (⋈)-shaped 2D [{cis-(Et3P)2Pt}4(M'TPP)(XDC)2]4+ complexes featuring a M'TPP core and two parallel XDC linkers connected by four heteroleptic PtII corners instead of 3D prisms. This happened because (i) irrespective of their length (~7–11 Å) and rigidity, the XDC linkers intramolecularly bridged two adjacent pyridyl-N atoms of a M'TPP core via PtII corners instead of connecting two cofacial M'TPP ligands and (ii) the bow-tie complexes are entropically more favored over prisms. The electron-rich ZnTPP core of a bow-tie complex selectively formed a charge-transfer complex with highly π-acidic 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-heaxacarbonitrile but not with a π-donor like pyrene. Thus, this work not only produced novel M'TPP-based bow-tie complexes and demonstrated their selective π-acid recognition capability, but also underscored the importance of proper structural characterization of supramolecular assemblies to ensure accurate depiction of their structure–property relationships. 

A new electrically conducting 3D metal-organic framework (MOF) with a unique architecture was synthesized using 1,2,4,5-tetrakis-(4-carboxyphenyl)benzene (TCPB) a redox-active cis -dipyridyl-tetrathiafulvalene ( Z -DPTTF) ligand. While TCPB formed Zn 2 (COO) 4 secondary building units (SBUs), instead of connecting the Zn 2 -paddlewheel SBUs located in different planes and forming a traditional pillared paddlewheel MOF, the U-shaped Z -DPTTF ligands bridged the neighboring SBUs formed by the same TCPB ligand like a sine-curve along the b axis that created a new sine -MOF architecture. The pristine sine -MOF displayed an intrinsic electrical conductivity of 1 × 10 −8  S/m, which surged to 5 × 10 −7  S/m after I 2 doping due to partial oxidation of electron rich Z -DPTTF ligands that raised the charge-carrier concentration inside the framework. However, the conductivities of the pristine and I 2 -treated sine -MOFs were modest possibly because of large spatial distances between the ligands that prevented π-donor/acceptor charge-transfer interactions needed for effective through-space charge movement in 3D MOFs that lack through coordination-bond charge transport pathways. 

Abstract Two‐dimensional graphitic metal–organic frameworks (GMOF) often display impressive electrical conductivity chiefly due to efficient through‐bond in‐plane charge transport, however, less efficient out‐of‐plane conduction across the stacked layers creates large disparity between two orthogonal conduction pathways and dampens their bulk conductivity. To address this issue and engineer higher bulk conductivity in 2D GMOFs, we have constructed via an elegant bottom‐up method the first π‐intercalated GMOF (iGMOF1) featuring built‐in alternate π‐donor/acceptor (π‐D/A) stacks of Cu^II‐coordinated electron‐rich hexaaminotriphenylene (HATP) ligands and non‐coordinatively intercalated π‐acidic hexacyano‐triphenylene (HCTP) molecules, which facilitated out‐of‐plane charge transport while the hexagonal Cu₃(HATP)₂scaffold maintained in‐plane conduction. As a result, iGMOF1 attained an order of magnitude higher bulk electrical conductivity and much smaller activation energy than Cu₃(HATP)₂(σ=25 vs. 2 S m⁻¹,E_a=36 vs. 65 meV), demostrating that simultaneous in‐plane (through‐bond) and out‐of‐plane (through πD/A stacks) charge transport can generate higher electrical conductivity in novel iGMOFs.