Synthesis and Structure of New Neutral Bimetallic Platinum Hydride Complexes

Abstract

The reactions of mononuclear hydride complexes trans -[PtHXL2] with the solvated species cis-[Pt(C6F5)2(thf)2] constitute a simple methodology to high-yield synthesis of dinuclear compounds with a mixed bridging system H/X. Thus, trans -[Pt(C⋮CPh)H(PPh3)2] reacts readily with cis-[Pt(C6F5)2(thf)2] to give trans -[(C6F5)(PPh3)Pt(μ-H)(μ-C⋮CPh)Pt(C6F5)(PPh3)] (1b), containing (X-ray) a μ-η1:η2-C⋮CPh alkynyl ligand. trans -[Pt(C6F5)H(PPh3)2] reacts with cis-[Pt(C6F5)2(thf)2] under mild conditions to afford initially the 1:1 adduct trans,cis -[(C6F5)(PPh3)Pt(μ-H)(μ(P)-η2-PPh3)Pt(C6F5)2] (2a), which finally rearranges quantitatively to form cis-[(C6F5)(PPh3)Pt(μ-H)(μ-C6F5)Pt(C6F5)(PPh3)] (2c). The crystal structures of 2a, a compound displaying an unusual PPh3 bridging ligand via the P donor atom and an η2-phenyl interaction, and 2c with a mixed pentafluorophenyl/hydride bridged system are reported. Similar hydride/chloride bridged diplatinum complexes [(C6F5)LPt(μ-H)(μ-Cl)Pt(C6F5)L] (3, L = PPh3; 4, L = PEt3), are also quantitatively formed by treatment of trans -[PtClHL2] with cis-[Pt(C6F5)2(thf)2] in CHCl3. Both complexes are obtained as trans isomers (3b and 4b), but their NMR data in CD3COCD3 indicate that they are present as a mixture of trans (3b, 4b) and cis (3c, 4c) isomers. Slow crystallization of 3b (CH2Cl2/hexane) in the presence of light gave crystals of the cis isomer 3c (X-ray), which is also quantitatively formed by photolysis of 3b. The presence of hydride bridging ligands in all complexes 1−4 is unambiguously confirmed by 1H NMR spectroscopy.

An organometallic tetranuclear cluster with phosphine and phosphido ligands in nonclassical bonding modes: X-ray structural characterization

“…Thus, the P(1)Ph 2 (C 6 F 5 ) phosphine group is acting as a bridging ligand between Pt(2) and Pd(2) although using different donor atoms to each metal centre. Precedents of this coordination mode for an aryl phosphine ligand are already known [1,[11][12][13][14][15][16][17]. The interaction between the phosphido containing P(2) and the Pd(2) centre is very noteworthy and different to the previously proposed interaction.…”

“…Some very rare examples of polynuclear complexes in which the sp 3 -hybridised P atom can adopt a bridging bonding mode are known [10,28,[31][32][33][34][35][36][37][38][39]. The bridging mode shown by the P(1)Ph 2 (C 6 F 5 ) ligand in 1, in which the phosphorous atom clearly interacts with only one metal centre and the other metal is bonded through a g 2 -C@C interaction of a P-phenyl fragment, are more frequent but not usual [1,[11][12][13][14][15]40]. The classical coordination mode for phosphido groups (PR 2 ) is as bridging ligand between two metal centres through the phosphorous atom [41].…”

Synthesis, Structure, and Electronic Properties of Monomeric and Dimeric Trispyrazolylborate Platinum(II) Hydride Complexes

“…[21][22][23] Spencer's dimeric complexes containing the [Pt 2 H 2 (P∩P) 2 ] 2+ core (C in Figure 1), 14,15 which are yellow or red, are particularly relevant since they are direct analogues of the dicationic, N-supported dihydride-bridged dimer reported in this paper. The second large group of complexes contains mixed bridging ligands consisting of a hydride and a carbon, 11,24 sulfur, 25 phosphido, [26][27][28][29] or phosphine bridging ligand. [30][31][32][33][34][35] "Aframe" complexes are the principal subgroup in this set (E in Figure 1).…”

C–H and N–H activation by Pt(0) in N- and O-heteroaromatic compounds

“…However, an indication of the nature of the bridging hydride could be gleaned from the NMR data. [43]. The hydride proton is coupled to three nonequivalent phosphines: 2 J PðtransÞ;H 74.5, 2 J PðcisÞ;H 19.1 and 12.9 Hz (J trans > J cis [44]).…”