The application of our newly developed B–C coupling method by catalytic Si/B exchange is demonstrated for the synthesis of a series of triarylboranes (1), monodisperse thienyl‐ and furylborane dimers ...(2) and trimers (9), extended oligomers (3) and polymers (3′), as well as mixed (oligo)thienyl‐/furylboranes. The structures of 1 aaTip, 1 bbTip, and 2 bbbMes*, determined by X‐ray crystallography, reveal largely coplanar hetarene rings and BR3 environments, which are most pronounced in the furylborane species. Photophysical investigations, supported by TD‐DFT calculations, revealed pronounced π‐electron delocalization over the hetarene backbones including the boron centers. With an extended series of derivatives of varying chain lengths available, we were able to determine the effective conjugation lengths (ECL) of poly(thienylborane)s and poly(furylborane)s, which have been reached with the highest‐molecular‐weight derivatives of our study. Through variation of the furan‐to‐thiophene ratio, the photophysical properties of these materials are effectively modulated. Significantly, higher furan contents lead to considerably increased fluorescence intensities. Compounds 1 aaTip, 1 bbTip, and 3 aTip showed the ability to bind fluoride anions. The binding process is signaled by a distinct change in their optical absorption characteristics, thus rendering these materials attractive targets for sensory applications.
Ob‐La‐B Ob‐La‐Si: Catalytic Si/B exchange polycondensation provided access to a series of thienyl‐ and furylboranes, monodisperse oligomers, and polymers. The photophysical properties of such species are effectively modulated through variation of the ratio of the heterocycles in the backbone (see scheme).
Substitution of selected CC units in π‐conjugated organic frameworks by their isoelectronic and isosteric BN units (BN/CC isosterism) has proven to be a successful concept for the development of ...BN‐doped polycyclic aromatic hydrocarbons (PAHs) with intriguing properties and functions. The first examples have just demonstrated the applicability of this approach to polymer chemistry. Herein, we present the synthesis and comprehensive characterization of the first poly(p‐phenylene iminoborane). This novel inorganic–organic hybrid polymer can be regarded as a BN analogue of the well‐known poly(p‐phenylene vinylene) (PPV). Photophysical investigations on the polymer and a series of model oligomers provide clear evidence of some π‐conjugation across the B=N bonds and extension of the conjugation path with increasing chain length. TD‐DFT calculations provide deeper insight into the electronic structure of the new materials.
Très BN: A BN analogue of the well‐known semiconducting organic polymer poly(p‐phenylene vinylene) (PPV) was synthesized through a facile Si/B exchange polycondensation. The novel inorganic–organic hybrid polymer and monodisperse oligomers of this type show some π‐conjugation across the B=N units along the backbone and extension of the conjugation path with increasing chain length.
Conjugated organoboranes have emerged as attractive hybrid materials for optoelectronic applications. Herein, a highly efficient, environmentally benign catalytic B–C bond formation method is ...presented that uses organosilicon compounds, dibromoboranes, and the metal-free organocatalyst Me3SiNTf2. This Si/B exchange approach has been successfully applied to the synthesis of arylborane molecules 4a–c, oligomers 8a,b, and polymers 8a′,b′. Photophysical investigations, supported by TD-DFT calculations, reveal highly effective π-conjugation in thienyl- and furylborane species; the latter are also highly emissive.
Despite the great potential of both π‐conjugated organoboron polymers and BN‐doped polycyclic aromatic hydrocarbons in organic optoelectronics, our knowledge of conjugated polymers with B−N bonds in ...their main chain is currently scarce. Herein, the first examples of a new class of organic–inorganic hybrid polymers are presented, which consist of alternating NBN and para‐phenylene units. Polycondensation with B−N bond formation provides facile access to soluble materials under mild conditions. The photophysical data for the polymer and molecular model systems of different chain lengths reveal a low extent of π‐conjugation across the NBN units, which is supported by DFT calculations. The applicability of the new polymers as macromolecular polyligands is demonstrated by a cross‐linking reaction with ZrIV.
Polymerization through B−N bond formation provides facile access to the first derivatives of a new class of organic–inorganic hybrid polymers, which show some π‐conjugation across the NBN units. Cross‐linking with ZrIV demonstrates the applicability of these materials as macromolecular polyligand systems. Mes=2,4,6‐trimethylphenyl.
A series of phosphonate ester supported lanthanide complexes bearing functionalities for subsequent immobilisation on semiconductor surfaces are prepared. Six phosphonate ester ligands (
L1-L6
) with ...varying aromatic residues are synthesised. Subsequent complexation with lanthanide chloride or -nitrate precursors (Ln = La, Nd, Dy, Er) affords the corresponding mono- or dimeric lanthanide model complexes LnX
3
(
L1-L3
or
L5-L6
)
3
n
(X = NO
3
, Cl;
n
= 1 (Nd, Dy, Er), 2 (La, Nd)) or LnCl
2
Br(
L4-Br
)
2
(
L4-Cl
)
n
(
n
= 1 (Nd, Dy, Er), 2 (La, Nd)) (
1-32
). All compounds are thoroughly characterised, and their luminescence properties are investigated in the visible and NIR spectral regions, where applicable.
A series of electronically diverse phosphonate ester ligands is synthesized and coordinated to La, Nd, Dy and Er ions for which their luminescence properties in the visible and NIR spectral regions are investigated.
Stereospecific access to the unprecedented P-B-P bridged 3ferrocenophane Fe(C
H
PtBu)
BMes is presented. In contrast to acyclic ferrocenylphosphanes, we find evidence for a shift of spin-density from ...Fe to P upon pyramidal inversion of the P centers in the mono-cation; the latter has a lifetime of τ = 0.31(4) s.
A series of methylene‐bridged bis(triarylboranes) has been synthesized via two complementary routes using metal‐free catalytic Si/B exchange condensation under mild conditions. The title compounds ...comprise two borane moieties that show effective internal π‐conjugation involving the respective boron centers and the adjacent hetaryl groups. Conjugation between both borane units, however, is disrupted by the aliphatic linker. Cyclic voltammetry revealed minimal electronic communication between the boron centers, as evidenced by two closely spaced reduction processes. The UV‐vis spectra showed bathochromic shifted absorption bands compared to related monoboranes, which is attributed to the methylene bridge. A further red‐shift results upon introduction of methyl or SiMe3 groups at the terminal thiophene rings.
Stereospecific access to the unprecedented P-B-P bridged 3ferrocenophane Fe(C
5
H
4
P
t
Bu)
2
BMes is presented. In contrast to acyclic ferrocenylphosphanes, we find evidence for a shift of ...spin-density from Fe to P upon pyramidal inversion of the P centers in the mono-cation; the latter has a lifetime of
τ
= 0.31(4) s.
An unprecedented PBP-bridged 3ferrocenophane shows a unique intramolecular electron transfer process in the mono-oxidized state triggered by pyramidal inversion at phosphorus.
Der isoelektronische und isostere Austausch ausgewählter CC‐ durch BN‐Einheiten in π‐konjugierten organischen Systemen (BN/CC‐Isosterie) hat sich als erfolgreiche Strategie zur Entwicklung ...BN‐dotierter polycyclischer aromatischer Kohlenwasserstoffe (PAKs) mit faszinierenden Eigenschaften und Funktionen erwiesen. Unlängst haben erste Beispiele die Nützlichkeit dieses Konzepts in der Polymerchemie gezeigt. Hier stellen wir die Synthese und Charakterisierung des ersten Poly(p‐phenyleniminoborans) vor. Dieses neue anorganisch‐organische Hybridpolymer kann als BN‐Analogon des bekannten Poly(p‐phenylenvinylens) (PPV) angesehen werden. Photophysikalische Untersuchungen am Polymer und einer Reihe von Modelloligomeren geben eindeutige Hinweise auf π‐Konjugation über die B=N‐Bindungen und eine Erweiterung der Konjugationslänge mit wachsender Kettenlänge. TD‐DFT‐Rechnungen verschaffen einen tieferen Einblick in die elektronische Struktur der neuen Materialien.
Ein BN‐Analogon des halbleitenden organischen Polymers Poly(p‐phenylenvinylen) (PPV) wurde mittels einer hocheffizienten Si/B‐Austausch‐Polykondensation hergestellt. Das neue anorganisch‐organische Hybridpolymer und verwandte monodisperse Oligomere zeigen ein gewisses Maß an π‐Konjugation über die B=N‐Einheiten entlang des Rückgrats und eine Erweiterung der Konjugationslänge mit wachsender Kettenlänge.
Der isoelektronische und isostere Austausch ausgewählter CC- durch BN-Einheiten in π-konjugierten organischen Systemen (BN/CC-Isosterie) hat sich als erfolgreiche Strategie zur Entwicklung ...BN-dotierter polycyclischer aromatischer Kohlenwasserstoffe (PAKs) mit faszinierenden Eigenschaften und Funktionen erwiesen. Unlängst haben erste Beispiele die Nutzlichkeit dieses Konzepts in der Polymerchemie gezeigt. Hier stellen wir die Synthese und Charakterisierung des ersten Poly(p-phenyleniminoborans) vor. Dieses neue anorganisch-organische Hybridpolymer kann als BN-Analogon des bekannten Poly(p-phenylenvinylens) (PPV) angesehen werden. Photophysikalische Untersuchungen am Polymer und einer Reihe von Modelloligomeren geben eindeutige Hinweise auf π-Konjugation uber die B=N-Bindungen und eine Erweiterung der Konjugationslänge mit wachsender Kettenlänge. TD-DFT-Rechnungen verschaffen einen tieferen Einblick in die elektronische Struktur der neuen Materialien.
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![PBP bridged [3]ferrocenopha...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1359-7345/small "PBP bridged [3]ferrocenophane: a bisphosphanylborane with a redox trigger")
