Unusual Coordination Behavior of P_n‐Ligand Complexes with Tl⁺

Abstract

Pentaphosphaferrocene coordinates as a π ligand to the large monocation Tl+. In addition, one of the phosphorus atoms of each cyclo‐P5 moiety coordinates to a neighboring Tl+ ion to give a one‐dimensional polymer. Even at low temperatures, fast rotation of the P5 rings is observed in solution and in the solid state.

Remarkable Differences in the Coordination Chemistry of Structurally Related 1,2,4‐Triphosphaferrocenes with Copper(I) Halides and Silver(I) Salts

“…This P-P bond length is almost the same as that in the complex [ [14] synthesized by Zenneck and co-workers and both P-P bond lengths are shorter than that in the complex [15] reported by Binger et al This presumably arises because the lone pairs of the two phosphorus atoms of the P 2 C 2 ring participate in η 1 -bonding to the metal atoms. The average P-C bond lengths within the P 2 C 2 ring in complex 9 [P1-C2 1.866(17) Å and P2-C1 1.805(18) Å] are similar to that in the two 1,2-diphosphete complexes [1,2-μ-{(η 4 -P 2 C 2 tBu 2 )Fe(CO) 3 }{Cr(CO) 5 } 2 ] and…”

“…However now, when the two reactants had diffused completely, the reaction mixture was concentrated and kept at -28°C for two weeks to afford dark-brown plates of complex 9 [Equation (5)]. (5) The molecular structure of 9 (determined by a singlecrystal X-ray diffraction study vide infra) is remarkable since the P 3 C 2 tBu 2 ring in the starting material 3 has unexpectedly been fragmented with formal elimination of one phosphorus atom resulting in a 1,2-diphospha-3,4-di-tertbutyl cyclobutadiene ring. The two [FeCpЈЈЈ(η 4 -P 2 C 2 tBu 2 )] fragments are now linked by two CuBr units to form a novel dimeric complex [{FeCpЈЈЈ(η 4 :η 1 :η 1 -P 2 C 2 tBu 2 )}(μ-CuBr)] 2 (9).…”

“…[6a] The ability to form polymeric or oligomeric structures is not limited to [FeCp*(η 5 -P 5 )]. The P n ligand complexes [{MCp(CO) 2 } 2 ][(μ,η 2 -P 2 )] (M = Cr, Mo), [5,7] and [(MoCp*) 2 (μ,η 3 -P 3 )(μ,η 2 -PS)] [8] form oligomeric or polymeric aggregates whereas [TaCpЈЈ(CO) 2 (η 4 -P 4 )] [9] forms spherical clusters.…”

“…[2] The most commonly used P n ligand complex as a building block is [FeCp*(η 5 -P 5 )] (Cp* = C 5 Me 5 ) which is able to form onedimensional and two-dimensional polymeric structures with Cu I , [3] Ag I , [4] and Tl I [5] salts. A highlight of the coordination chemistry of [FeCp*(η 5 -P 5 )] was achieved in the reaction the initially five-membered 1,2,4-triphospholyl ring into a four-membered 1,2-diphosphete ligand is observed, which is linked by CuBr moieties forming the dimeric paramagnetic complex [{FeCpЈЈЈ(η 4 :η 1 :η 1 -P 2 C 2 tBu 2 )}(μ-CuBr)] 2 (9).…”

Das Redox‐ und Koordinationsverhalten des Hexaphosphabenzol‐Liganden in [(Cp*Mo)2(μ,η6:η6‐P6)] gegenüber den “nackten” Kationen Cu+, Ag+ und Tl+

“…[30,31] Diese Koordination ergibt eine geringfügige Verlängerung dieser P-P-Bindungen auf 2.22 , während das dritte Molekül von 1 (P5'-P6')e ine unsymmetrische Koordination mit langen Tl-P-Abständen von 3.42 und 3.69 u nd keine P-P-Bindungsverlängerung zeigt. Obwohl die Umgebung von Tl + in 6 wesentlich verschieden von den Umgebungen von Cu + und Ag + in 4a und 4b ist, sind ihre Strukturen verwandt.…”