Sorption-based heat transformation and storage appliances are very promising for utilizing solar heat and waste heat in cooling or heating applications. The economic and ecological efficiency of sorption-based heat transformation depends on the availability of suitable hydrophilic and hydrothermally stable sorption materials. We investigated the feasibility of using the metal-organic frameworks UiO-66(Zr), UiO-67(Zr), H2N-UiO-66(Zr) and H2N-MIL-125(Ti) as sorption materials in heat transformations by means of volumetric water adsorption measurements, determination of the heat of adsorption and a 40-cycle ad/desorption stress test. The amino-modified compounds H2N-UiO-66 and H2N-MIL-125 feature high heat of adsorption (89.5 and 56.0 kJ mol(-1), respectively) and a very promising H2O adsorption isotherm due to their enhanced hydrophilicity. For H2N-MIL-125 the very steep rise of the H2O adsorption isotherm in the 0.1 < p/p0 < 0.2 region is especially beneficial for the intended heat pump application.

A series of dinickel(II) complexes with the 24-membered macrocyclic hexaazadithiophenol ligand H(2)L(Me) was prepared and examined. The doubly deprotonated form (L(Me))(2-) forms complexes of the type [(L(Me))Ni2II(mu-L')](n+) with a bioctahedral N(3)Ni(II)(mu-SR)(2)(mu-L')Ni(II)N(3) core and an overall calixarene-like structure. The bridging coordination site L' is accessible for a wide range of exogenous coligands. In this study L'=NO(3)(-), NO(2)(-), N(3)(-), N(2)H(4), pyrazolate (pz), pyridazine (pydz), phthalazine (phtz), and benzoate (OBz). Crystallographic studies reveal that each substrate binds in a distinct fashion to the [(L(Me))Ni(2)](2+) portion: NO(2)(-), N(2)H(4), pz, pydz, and phtz form mu(1,2)-bridges, whereas NO(3)(-), N(3)(-), and OBz(-) are mu(1,3)-bridging. These distinctive binding motifs and the fact that some of the coligands adopt unusual conformations is discussed in terms of complementary host-guest interactions and the size and form of the binding pocket of the [(L(Me))Ni(2)](2+) fragment. UV/Vis and electrochemical studies reveal that the solid-state structures are retained in the solution state. The relative stabilities of the complexes indicate that the [(L(Me))Ni(2)](2+) fragment binds anionic coligands preferentially over neutral ones and strong-field ligands over weak-field ligands. Secondary van der Waals interactions also contribute to the stability of the complexes. Intramolecular ferromagnetic exchange interactions are present in the nitrito-, pyridazine-, and the benzoato-bridged complexes where J=+6.7, +3.5, and +5.8 cm(-1) (H=-2 JS(1)S(2), S(1)=S(2)=1) as indicated by magnetic susceptibility data taken from 300 to 2 K. In contrast, the azido bridge in [(L(Me))Ni(2)(mu(1,3)-N(3))](+) results in an antiferromagnetic exchange interaction J=-46.7 cm(-1). An explanation for this difference is qualitatively discussed in terms of bonding differences.

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Dihalogenometal() complexes with bidentate phosphane ligands of the general type [M{Ph 2 P(CH 2 ) n PPh 2 }X 2 ] with n = 2 to 5, X = Cl or Br and M = Co, Ni or Pd have been utilized as catalysts for the vinyl/addition polymerization of norbornene. These complexes can be activated with the Lewis-acids methylalumoxane (MAO) or tris(pentafluorophenyl)borane, B(C 6 F 5 ) 3 in combination with triethylaluminium (AlEt 3 ). The nickel() and palladium() complexes show very high polymerization activities up to 10 7 g polymer mol metal Ϫ1 h Ϫ1 . Yet, the complexes Pd(dppe)Cl 2 (5, 1.9 × 10 7 g polymer mol Pd Ϫ1 h Ϫ1 ) and Pd(dppp)Cl 2 (6, 3.0 × 10 3 g polymer mol Pd Ϫ1 h Ϫ1 ) demonstrated that small changes in the ligand structure could have great effects on the polymerization activity [dppe = 1,2-bis(diphenylphosphino)ethane, Ph 2 P(CH 2 ) 2 PPh 2 ; dppp = 1,3-bis(diphenylphosphino)propane, Ph 2 P(CH 2 ) 3 PPh 2 ]. The activation process of the pre-catalysts 5 and 6 in combination with B(C 6 F 5 ) 3 /AlEt 3 was followed by multinuclear ( 1 H, 19 F, and 31 P) NMR investigations and by reaction with B(C 6 F 5 ) 3 and Ag[closo-1-CB 11 H 12 ]. The reaction of B(C 6 F 5 ) 3 and AlEt 3 leads to an aryl/alkyl group exchange resulting in the formation of AlEt 3 Ϫ n (C 6 F 5 ) n and B(C 6 F 5 ) 3 Ϫ n Et n with Al(C 6 F 5 ) 3 and BEt 3 as main products for an about equimolar ratio. AlEt 3 Ϫ n (C 6 F 5 ) n will then react with the pre-catalysts and abstract the chloride atoms to form [M{Ph 2 P(CH 2 ) n PPh 2 }] 2ϩ as the active species for the polymerization. The higher polymerization activity of 5/B(C 6 F 5 ) 3 /AlEt 3 compared to 6/B(C 6 F 5 ) 3 /AlEt 3 can be explained by a ligand redistribution reaction of unstable [Pd II (dppe)] 2ϩ to give inactive and isolable [Pd II (dppe) 2 ] 2ϩ and highly active, "naked" Pd 2ϩ cations together with the lower coordinating ability of the anionic adduct [Cl-Al(C 6 F 5 ) 3 ] Ϫ in comparison to [Cl-B(C 6 F 5 ) 3 ] Ϫ . The Lewis-acid Al(C 6 F 5 ) 3 is much more activating than B(C 6 F 5 ) 3 . The [Pd(dppe) 2 ] 2ϩ cation from the ligand redistribution was isolated in the (X-ray) structurally elucidated compounds [Pd II (dppe) 2 ]-[ClB(C 6 F 5 ) 3 ] 2 ؒ4CH 2 Cl 2 and [Pd II (dppe) 2 ][CB 11 H 11 Cl] 2 ؒ3CH 2 Cl 2 . The stable [Pd(dppp)] 2ϩ cation from 6 could be crystallized as [Pd II (dppp)(CB 11 H 12 )][CB 11 H 12 ] (CB 11 H 12 = mono-anionic carborane [closo-1-CB 11 H 12 ] Ϫ ).

Classes of mainly nickel(II) and palladium(II) complexes are comparatively presented in their norbornene polymerization activity to vinyl polynorbornene when activated with methylalumoxane, MAO, tris(pentafluorophenyl)borane/triethylaluminum, B(C6F5)3/AlEt3 or even B(C6F5)3 alone. Classes include Ni and Pd complexes with α‐dioxime ligands, salts with [PdCl4]2− and [Pd2Cl6]2− units, dinuclear Ni and Pd complexes with multidentate Schiff‐base ligands, polynuclear Ni‐ and Cr/Ni‐carboxylate cage complexes, and dihalo(bisphosphane) Ni and Pd complexes. The study of activation mechanism by 31P‐ and 19F‐NMR together with X‐ray structural data points to the formation of PdCl2 units and “naked” Pd2+ cations as highly active species.