Covalent Organic Frameworks (COFs) exhibiting kagome (kgm) structures are promising crystalline porous materials with two distinct pores. However, the challenge arises from the potential formation of the polymorphic square-lattice (sql) structure, which is undesired in some cases. To this, we introduce a novel linker design strategy featuring bulky functional groups, enforcing the preferred kgm structure, while hindering sql network formation. Implementing this design, we synthesized a terphenyl core-based tetraaldehyde linker (4A2E) incorporating a bulky methoxycarbonyl-terminated phenyl group. By varying the diamine linker lengths, using phenylenediamine (PDA) and benzidine (Bz), the steric interaction was tuned leading to the formation of different topologies. Structural analysis revealed the formation of a kgm network formation with an unusual ABC stacking for the 4A2E-PDA-COF with the short PDA linker, in contrast to the sql network in 4A2E-Bz-COF with the longer benzidine. This steric interaction-driven design enhances control over COF structures, expanding the design toolbox, but also provides valuable insights into network formation and polymorphism.

Reaction of a trinuclear triangular macrocyclic complex Pb3L(CF3SO3)6 with bidentate linkers in a ratio of 3 equiv. of linker per 2 equiv. of complex, produces a prismatic structure with 4,4'-dipyridyl, and two unprecedented, extended 3D frustum-like structures with 1,2-di(4-pyridyl)ethylene and 1,4-di(4-pyridyl)benzene. The cavities of these structures encapsulate triflate anions.

A Ca12Al14O33 mayenite single crystal was grown by the floating zone technique with 0.26(1) at. % of the metals Ca and Al substituted by Ni. Single crystal XRD confirms the presence of the ‘cage oxygen’ anion on a fourfold split position and that about 10 at. % of Al and Ca partially occupy split crystallographic sites with lowered point symmetry. Ni K-edge X-ray absorption spectroscopy (XAS) reveals that Ni is present as Ni2+ and substitutes Al on tetrahedral oxygen coordinated sites. UV-VIS analysis further points to the partial occupation of the Al(1) and Al(1B) site by Ni2+ that are characterized by a trigonal distortion (resp. quasi trigonal for Al1(B) site) of the coordination tetrahedra. The magnetometry data can well be explained by a magnetic model that makes use of the T–P isomorphism (T for triplet state and P for p orbital) to handle the orbital momentum contribution within the framework of a phenomenological Hamiltonian approach. In accordance with the results from the analytical methods, the magnetic model consists of Ni2+ with spin S = 1 on a trigonally distorted tetrahedral coordination site. The 3T1 ground state of the d8 electronic configuration in ideal tetrahedral crystal field allows for first order orbital momentum contribution to the spin angular momentum. The J-mulitplet splitting due to spin-orbit coupling with a non-magnetic J = 0 ground state determines the characteristic thermomagnetic properties which show a maximum of the effective paramagnetic moment of 3.61(1) µB at about 191 K (compared to 2.83 µB of a pure spin S = 1 system). Furthermore, an uniaxial anisotropy, as expected for the trigonal distorted Ni2+ coordination tetrahedron, has been parametrized by a crystal field parameter = 69.5(2) cm−1 (easy-plane).

A Ca12Al14O33 mayenite single crystal with 0.26(1) at.% of the metals substituted by Ni was synthesized. Single crystal XRD confirms that about 10 at.% of Al and Ca partially occupy split crystallographic sites with lowered point symmetry. Ni K-edge XAS reveals that Ni is present as Ni2+ and substitutes Al on tetrahedral oxygen coordinated sites. UV-VIS analysis further points to the partial occupation of the trigonally distorted Al(1) and Al (1B) sites by Ni2+. In accordance with the results from the analytical methods, the magnetic model consists of Ni2+ with spin S = 1 on a trigonally distorted tetrahedral coordination site. The J-mulitplet splitting due to spin orbit coupling with a non-magnetic J = 0 ground state determines the characteristic thermomagnetic properties which show a maximum of the effective paramagnetic moment of 3.61(1) & mu;B at about 191 K and an uniaxial anisotropy (crystal field parameter B20 = 69.5(2) cm  1).

Three [Cr6E8(PEt3)6] cluster molecules with E = S, Se, and Te have been synthesized by reaction of stoichiometric mixtures of Cr(II) and Cr(III) metal salts with silylated chalcogen reagents E(SiMe3)2 (E = S, Se, Te) in the presence of L = PEt3 = triethylphosphine. For the sulfide- and selenide-bridged clusters two crystallographic forms (trigonal R3̄ and triclinic P1̄), which differ in the presence of lattice solvent molecules, have been isolated. Structural data, optical spectra and quantum chemical calculations reveal the presence of low-lying excited states in [Cr6E8(PEt3)6] (E = S, Se), which would help in rationalizing the non-vanishing magnetic moments at 2 K revealed by DC magnetic measurements and EPR spectroscopy. These findings are partially in contrast to a previous report by Saito and co-workers (S. Kamiguchi, H. Imoto, T. Saito, Inorg. Chem., 1998, 37, 6852-6857.), who postulated an incorporated hydrogen atom as the source of paramagnetism at low temperatures for the trigonal forms of [Cr6E8(PEt3)6] (E = S, Se).

7Li NMR shifts and magnetic properties have been determined for three so-called ate complexes [LiM{N(SiMe3)2}3] (M2+ = Mn, Fe, Co; e.g., named lithium-tris(bis(trimethylsilylamide))-manganate(II) in accordance with a formally negative charge assigned to the complex fragment [M{N(SiMe3)2}3]-, which comprises the transition metal). They are formed by addition reactions of LiN(SiMe3)2 and [M{N(SiMe3)2}2] and stabilized by Lewis base/Lewis acid interactions. The results are compared to those of the related "ion-separated" complexes [Li(15-crown-5)][M{N(SiMe3)2}3]. The ate complexes with the lithium atoms connected to the 3d metal atoms manganese, iron, or cobalt via μ2 nitrogen bridges reveal strong 7Li NMR paramagnetic shifts of about -75, 125, and 171 ppm, respectively, whereas the shifts for the lithium ions coordinated by the 15-crown-5 ether are close to zero. The observed trends of the 7Li NMR shifts are confirmed by density-functional theory calculations. The magnetic dc and ac properties display distinct differences for the six compounds under investigation. Both manganese compounds, [LiMn{N(SiMe3)2}3] and [Li(15-crown-5)][Mn{N(SiMe3)2}3], display almost pure and ideal spin-only paramagnetic behavior of a 3d5 high-spin complex. In this respect slightly unexpected, both complexes show slow relaxation behavior at low temperatures under applied dc fields, which is especially pronounced for the ate complex [LiMn{N(SiMe3)2}3]. Dc magnetic properties of the iron complexes reveal moderate g-factor anisotropies with small values of the axial magnetic anisotropy parameter D and a larger E (transversal anisotropy). Both complexes display at low temperatures and, under external dc fields of up to 5000 Oe, only weak ac signals with no maxima in the frequency range from 1 to 1500 s-1. In contrast, the two cobalt complexes display strong g-factor anisotropies with large values of D and E. In addition, in both cases, the ac measurements at low temperatures and applied dc fields reveal two, in terms of their frequency range, well separated relaxation processes with maxima lying for the most part outside of the measurement range between 1 and 1500 s-1.

For the synthesis of the ferric bistrimethylsilylamido complex [Fe{N(SiMe3)(3)}(3)] literature gives differing synthetic protocols based on crystallization from solution. In this report we present a 'solvent-free' structural phase of [Fe{N(SiMe3)(3)}(3)] which was obtained by sublimation of the product obtained from the reaction of 2 eq FeCl3 with 3 eq LiN(SiMe3)(2) in benzene. It could be characterized by single crystal as well as powder XRD and elemental analysis. However, Fe-57 Mossbauer spectroscopy suggests a contamination of the main product with an Fe(II) species. Also, a part of the solid reaction byproducts from the reactions in solution were identified by powder XRD and Li-7 MAS NMR which indicate distinct redox side reactions between oxidizing FeCl3 and reducing LiN(SiMe3)(2), a fact which rationalizes the lower than expected yields and the observation of an Fe(II) impurity compound. AC magnetic measurements of [Fe{N(SiMe3)(3)}(3)] have been performed in an extended frequency range up to 10(4) s(-1), allowing for a more precise evaluation of the magnetic relaxation parameters when compared to previously published measurements.

The optical properties of four new trinuclear chalcogenolato bridged metal complexes [Ag2Ti(SPh)6(PPh3)2], [Na(thf)3]2[Ti(SPh)6], [Cu2Ti(SePh)6(PPh3)2], and [Ag2Ti(SePh)6(PPh3)2] have been investigated by absorption and photoluminescence spectroscopy as well as time-dependent density functional theory (TDDFT) calculations and compared to the results published recently for [Cu2Ti(SPh)6(PPh3)2]. All of these compounds are distinguished by efficient near-infrared luminescence at ∼880-1200 nm in the solid state at low temperatures, which remains quite intense for the copper-titanium complexes at ambient temperature with PL quantum yields of 9.5 and 4.8% at λPL = 1090 and 1240 nm for [Cu2Ti(EPh)6(PPh3)2], E = S, Se, respectively. According to the calculations, a peculiar feature of the lowest-energy electronic transitions in these complexes is their high localization on the metal and chalcogen atoms, with negligible contributions of the "external" ligand groups. Correspondingly, the type of atoms in the M2TiE6 (M = Cu, Ag, Na) core structure determines optical properties such as the absorption and emission wavelengths and PL lifetime.

We present the syntheses of trigonal planar coordinated Fe(ii) carbodiphosphorane (CDPR) complexes, starting from iron(ii)-bis(trimethylsilylamide) [Fe{N(SiMe3)2}2] and hexaphenyl-(CDPPh) and sym-dimethyltetraphenyl-carbodiphosphoranes (CDPMe), respectively. Both complexes [CDPPh-Fe{N(SiMe3)2}2] (1) and [CDPMe-Fe{N(SiMe3)2}2] (2) were examined in solution and in the solid state. 1 shows a dissociation equilibrium in solution which we monitored by variable temperature 1H-NMR spectroscopy. Magnetic measurements of 1 and 2 yielded a high spin configuration (S = 2) for both complexes. Quantum chemical calculations were performed to analyze the bonding situation in compound 1.

The first examples of polymeric homoleptic iron(II) thiolato complexes ∞1[Fe(SPh)2] and ∞1[Fe(SMes)2] (Ph = phenyl = C6H5, Mes = mesityl = C6H2–2,4,6‐(CH3)3) have been both prepared by reaction of [{Fe(N(SiMe3)2)2}2] with four equivalents of HSR ( R = Ph, Mes). In the crystal the two compounds form one‐dimensional chains with bridging thiolato ligands comprising distinctly different Fe–S–Fe bridging angles namely 75.20–75.25° in ∞1[Fe(SPh)2] and 91.38° in ∞1[Fe(SMes)2]. Reaction of ∞1[Fe(SPh)2] with stoichiometric amounts of NH3, generated by reaction of HN(SiMe3)2 with CH3OH, resulted in the formation of the polymeric ammonia thiolato complexes ∞1[Fe(NH3)(SPh))(µ‐SPh)] and ∞1[(µ‐SPh)Fe(NH3)2(µ‐SPh)2Fe(µ‐SPh)], which crystallize in the form of two structural isomers comprising either one or two µ2‐bridging phenyl‐thiolato groups with a bridging angle of 102.96° and 81.79–83.52°, respectively. Magnetic measurements reveal that this bridging angle has a distinct influence on the antiferromagnetic exchange interactions of the unpaired electrons along the chains in the different compounds. UV‐vis‐NIR spectra indicate low lying d‐d transitions (< 10000 cm–1) for all complexes.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The bidentate phosphine bis(diphenylphosphino)-N-phenyl-maleimide (L1) is used to synthesize a series of complexes from coinage metals and palladium. Some of them are mononuclear species where one metal atom is coordinated by two phosphine ligands. Three of these complexes have been investigated in detail because they contain the initial ligand in an anionic, radical form (L1') i.e. [Cu(L1L1')] (1), [Ag(L1L1')] (7), [Pd(L1')2] (11). L1' in 1, 7 and 11 shows significant differences in its bonding parameters compared to free or coordinating L1. By magnetic measurements the radical nature of these three compounds could be verified. Quantum chemical calculations prove the existence of either one (1 and 7) or two (11) unpaired electrons localized on the ligand. Furthermore these calculations can explain that 1 and 7 show an asymmetric structure in solid state where one can clearly differ L1 from L1'.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Systematic ac (alternating current) magnetic investigations on four new trigonal planar high-spin Fe2+ complexes [Fe{N(SiMe3)(2)}(2)L] reveal that complexes which comprise a phosphine or arsine type ligand (L = PPh3, PMe3 and AsPh3) display slow magnetic relaxation at temperatures below 8 K under applied dc (direct current) fields, whereas a complex with a phosphine oxide ligand (L = OPPh3) does not. Accordingly, the parameters characteristic for magnetic anisotropy, derived both from dc magnetic measurements and quantum chemical calculations, reveal distinct differences for these two types of complexes. Extensive ab initio calculations of multi-reference wave function type were performed on the four new complexes listed above and the related reported ones with L = py, thf and PCy3 in order to get a reasonable description of the local electronic states involved in the magnetic relaxation. These calculations confirm that strong spin-orbit effects generate the magnetic anisotropy of complexes with L = PPh3, PMe3, AsPh3 and PCy3. On the other hand, the complexes with L = OPPh3, py and THF exhibit only small spin-orbit splittings, consistent with the fast relaxation found experimentally.

The first examples of polymeric homoleptic iron(II) thiolato complexes (1)(infinity)[Fe(SPh)(2)] and (1)(infinity)[Fe(SMes)(2)] (Ph = phenyl = C6H5, Mes = mesityl = C(6)H(2-)2,4,6-(CH3)(3)) have been both prepared by reaction of [{Fe(N(SiMe3)(2))(2)}(2)] with four equivalents of HSR ( R = Ph, Mes). In the crystal the two compounds form one-dimensional chains with bridging thiolato ligands comprising distinctly different Fe-S-Fe bridging angles namely 75.20-75.25 degrees in (1)(infinity)[Fe(SPh)(2)] and 91.38 degrees in (1)(infinity)[Fe(SMes)(2)]. Reaction of (1)(infinity)[Fe(SPh)(2)] with stoichiometric amounts of NH3, generated by reaction of HN(SiMe3)(2) with CH3OH, resulted in the formation of the polymeric ammonia thiolato complexes (1)(infinity)[Fe(NH3)(SPh))(mu-SPh)] and (1)(infinity)[(mu-SPh)Fe(NH3)(2)(mu-SPh)(2)Fe(mu-SPh)], which crystallize in the form of two structural isomers comprising either one or two mu(2)-bridging phenyl-thiolato groups with a bridging angle of 102.96 degrees and 81.79-83.52 degrees, respectively. Magnetic measurements reveal that this bridging angle has a distinct influence on the antiferromagnetic exchange interactions of the unpaired electrons along the chains in the different compounds. UV-vis-NIR spectra indicate low lying d-d transitions (< 10000 cm(-1)) for all complexes.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.