In the past decade new syntheses and numerous structural determinations have enlivened studies in the still relatively young field of nitrido-transition-metal complexes. Aside from the terminal function of the nitrido ligand MEN:, this group also occurs as linear p,-bridging ligand in symmetric and asymmetric coordination; examples are known with almost rightangled bridge function; and, finally, it also functions as p3-bridging ligand. Accordingly, the fresh impulses given to synthetic chemistry by nitrido complexes are also many-sided: such complexes are used, inter aha, for the preparation of phosphaniminato and thionitrosyl complexes as well as for the synthesis of metallaheterocycles of the type MN,S, and MN,P2 with delocalized x-systems. In technetium chemistry complexes with terminal nitrido group are employed as radiopharmaceuticals, and, owing to the strong trans influence of the M=N: group, nitrido complexes of molybdenum are suitable as catalysts in olefin metathesis. Finally, nitrido complexes are also of wide interest in theoretical studies.
Oxo-phthalocyaninato-titan(IV) (PcTiO) shows weak electrical conductivity of 5 · 10~1 0 Ω" 1 cm" 1 at room temperature. Doping of PcTiO with I 2 is accompanied by an increase of conductivity up to 5· 10" 3 Ω" 1 cm" 1 . PcTiO was found to exist in two modifications built up by monomeric complexes: Phase I crystallizes monoclinic in the space group Ρ 2 l /c with the lattice constants a = 1341.1(6) pm, b = 1323.0(3) pm, c = 1381.0(4) pm, β = 103.72(3)°, Ζ = 4. Phase II forms a triclinic structure in space group PT and an unit cell of dimensions a = 1216.6(4)pm, b = 1258.4(5)pm, c = 864.1 (3)pm, α = 96.28(3)°, β = 95.03(4)°, y = 67.86(4)°, Ζ = 2. In both modifications the Ti-atom exhibits a square pyramidal coordination with a short Ti -Ο distance of 165 pm and 163 pm, respectively. Close contacts exist between the phthalocyaninato planes of neighbouring molecules. Einleitung Phthalocyaninato-Metallkomplexe (PcM), die mit axialen Brückenliganden zu linearen Ketten verknüpft sind, können Eigenschaften eindimensionaler, elektrischer Leiter aufweisen [2, 3], Beispiele dieser eindimensionalen Leiter sind (PcMC 2 ) x und (PcM pyz)^, in denen das Acetylidion (C|") oder Pyrazin (pyz) als Brückenliganden fungieren und das Zentralatom Μ ein * 14. Mitteilung über "Synthese und Eigenschaften neuartiger eindimensionaler Leiter". 13. Mitteilung siehe [1] * * Anschrift des Korrespondenzautors: Prof. Dr. J. Strähle,
Numerous nitrido complexes of transition metals show very short metal-nitrogen bond lengths, suggesting M=N-triple bonds. At present, compounds of this type are being intensively investigated. In particular the molybdenum complexes are considered as model substances for the study of at least an intermediate step of N,-assimilation. This article contains a review of the structure and bonding, as well as syntheses and reactions of these complexes. The terminal nitrido ligand occurs, for example, in the tetragonal pyramidal complex anions [MNCI,] -(M = Mo, W, Re, Ru, OS)['-~] (see Fig. 1). The M=N bond is ex-Fig. 1. Structure of anions [MNX41-(M=Mo, Re, Ru, 0 s ; X = F, CI, Br, I) with terminal nitrido ligands.Angew. Chem. Int. Ed. Engl. 20, 413-426 (1981) 0 Verlag Chemie GmbH, 6940 Weinheim. 1981 057~0833/81/0505-0413 $ 02.50/0 teresting to compare these nitrido complexes with the tetrameric 0x0 (6) and fluoro complexes (7), in which the differences between the alternating bond lengths decrease in the succession [MoNCI, . POC13]4[81, [NbOCl, . POCl&"] and [NbFs]4[121: Mo-N-Mo Nb-N-Nb Nb-F-Nb 166 216 174 209 207 207 [pm]The solvating POCl, molecules are always arranged trans to the n bonded ligand and are coordinated to the metal center via the oxygen atom (see Fig. 3). Accordingly, the bonding in the trinuclear nitridomolybdenum complex [((Et,NCS2)3Mo~N]2Mo(SzCNEt2)3]3+r which contains the Mo-N-Mo-N=Mo group as a structural element can be understood[131. The structures of these types of compounds are discussed in Section 6.3. 414 Angew. Chem. Inr. Ed. Engl. 20. 413-426 (1981) Received: December 1, 1980 [A 365 IE] German version: Angew. Chem. 93, 451 (1981)
Ba3N2 reacts at 950°C under pure N2 with Zr to yield dark red, air‐sensitive Ba[ZrN2]. This new compound crystallizes in the tetragonal space group P4/nmm with a = 416.10(2), c = 839.2(1) pm and Z = 2. The crystal structure was solved and refined using X‐ray and neutron powder diffraction data. In the nitrido zirconate [ZrN2]2− the Zr atoms exhibit a square‐pyramidal coordination by five N atoms at distances of 201(3) and 220.2(2) pm. The pyramids share all the edges in the basal plane to form layers parallel to (001) with their apices alternately pointing up and down. The Ba2+ cations are integrated into these layers at the levels of the pyramidal apices. The structure can be interpreted as a stuffed PbFCl type. Ba2[NbN3] is formed by the reaction of Ba3N2 and NbN or of Ba and Nb at 1 000°C under N2. Isostructural to Ba2[TaN3] it crystallizes in the monoclinic space group C2/c with a = 613.2(3), b = 1 176.8(3), c = 1 322.9(4) pm, β = 91.65(2)°, Z = 8. The nitrido niobate anions form chains of corner sharing NbN4 tetrahedra with distances NbN between 188(1) and 199.9(9) pm.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.