The synthesis and characterization of the donor-acceptor substituted cyclometalated ruthenium(II) polypyridine complex isomers [Ru(dpb-NHCOMe)(tpy-COOEt)](PF6) 1(PF6) and [Ru(dpb-COOEt)(tpy-NHCOMe)](PF6) 2(PF6) (dpbH = 1,3-dipyridin-2-ylbenzene, tpy = 2,2';6,2"-terpyridine) with inverted functional group pattern are described. A combination of resonance Raman spectroscopic and computational techniques shows that all intense visible range absorption bands arise from mixed Ru → tpy/Ru → dpb metal-to-ligand charge transfer (MLCT) excitations. 2(PF6) is weakly phosphorescent at room temperature in fluid solution and strongly emissive at 77 K in solid butyronitrile matrix, which is typical for ruthenium(II) polypyridine complexes. Density functional theory calculations revealed that the weak emission of 2(PF6) arises from a (3)MLCT state that is efficiently thermally depopulated via metal-centered ((3)MC) excited states. The activation barrier for the deactivation process was estimated experimentally from variable-temperature emission spectroscopic measurements as 11 kJ mol(-1). In contrast, 1(PF6) is nonemissive at room temperature in fluid solution and at 77 K in solid butyronitrile matrix. Examination of the electronic excited states of 1(PF6) revealed a ligand-to-ligand charge-transfer ((3)LL'CT) as lowest-energy triplet state due to the very strong push-pull effect across the metal center. Because of the orthogonality of the participating ligands, emission from the (3)LL'CT is symmetry-forbidden. Hence, in this type of complex a stronger push-pull effect does not increase the phosphorescence quantum yields but completely quenches the emission.

A single-crystal neutron diffraction analysis along with density functional calculations and incoherent inelastic neutron scattering studies has conclusively shown that the dihydrogen adduct of [P 2 N 2 ]Zr(µ-η 2 -N 2 )-Zr[P 2 N 2 ] (1) (where P 2 N 2 ) PhP(CH 2 SiMe 2 NSiMe 2 CH 2 ) 2 PPh) is [P 2 N 2 ]Zr(µ-η 2 -N 2 H)(µ-H)Zr[P 2 N 2 ] (2), the complex with a bridging hydride and a N-N-H moiety, and not the dihydrogen complex [P 2 N 2 ]Zr(µ-η 2 -N 2 )(µ-η 2 -H 2 )Zr[P 2 N 2 ] (3), as was proposed on the basis of X-ray crystallographic data. In addition, DFT calculations show that the reaction of 1 with both H 2 and SiH 4 is exothermic while an endothermic reaction is found for the reaction of 1 with CH 4 .

Der tripodale Hexathiol‐Ligand H61 ist durch Kupplung von 2,3‐Dimercaptobenzoesäure 2 mit 1,3,5‐Tris(aminomethyl)benzol zugänglich. Der sechszähnige Ligand H6‐1 bildet mit [(C5H5)2TiCl2] einen dreikernigen Komplex und mit [Mo(O)2(acac)2] die Verbindung [Mo(1)] .

Dipnictadiazanediyls, [E(μ-NR)]2 (E = P, As), the pnictogen analogues of cyclobutandiyl, were found to react readily with alkynes forming [2.1.1]bicyclic structures. These, in turn, rearrange in an unprecedented reaction to [3.1.o]bicycles leading to the isolation of the first azadiarsiridine and the determination of its solid-state structure. All new species were comprehensively characterized, and the reaction pathways and bonding situations were computationally studied.

Reactions of the group 4 metallocene alkyne complexes [Cp 2 M(L)(btmsa)] (Cp = η 5 -cyclopentadienyl = η 5 -C 5 H 5 , btmsa = η 2 -Me 3 SiC 2 SiMe 3 ; 1: M = Ti, L = none; 2: M = Zr, L = pyridine) and of the [(triphos)Co I ] moiety [triphos = 1,1,1tris(diphenylphosphanylmethyl)ethane] with the benzylsulfanyl-substituted acetylenes PhCH 2 S-C 2 -SCH 2 Ph (3) and PhCH 2 S-C 2 -SFmoc (4) (Fmoc = fluorenylmethoxycarbonyl) have been investigated. Complex 1 reacted with 3 to give a mixture of a violet solid and [Cp 2 Ti(SCH 2 Ph) 2 ] (5). Subsequently, the violet solid transformed in toluene at 70°C into the dinuclear complex [(Cp 2 Ti) 2 (μ-κ 2 -κ 2 -BnSC 4 SBn)] (6) displaying two [Cp 2 Ti] moieties bridged by a 1,4-bis(benzylsulfanyl)-1,3-butadiyne in the trans configuration. Complex 6 was further degraded in toluene at 100°C to the tetranuclear cluster [CpTiS] 4 (7). Similar reactivity was deduced indirectly for the reaction partners 1/4 and 2/3. For Co I , the side-on[a] Leibniz-