The First Example of a Dinuclear Platinum(III) Complex with Three Bridging Ligands

Abstract

The first triply bridged dinuclear platinum(III) compound\ud with acetamidate ligands, X[Pt2Cl4{N(H)C(CH3)O}3] (X = K+\ud or AsPh4\ud +), has been isolated in the solid state and characterized\ud by one- and two-dimensional NMR spectroscopy and\ud X-ray crystallography. Owing to the asymmetry of the bridging\ud acetamidate ligands, three isomers can be formed (HHH,\ud HHT, and HTH), although only two are found in the crude\ud reaction product: HHT and HTH. The HTH species is thermodynamically\ud less stable and slowly (half life of around two\ud days at room temperature) isomerizes into the HHT form.\ud The more stable and less symmetric HHT isomer crystallizes from chloroform/pentane (AsPh4\ud + counter ion). The two\ud [Pt2Cl4{N(H)C(CH3)O}3]– anions of the unit cell are linked by\ud two strong N–H···O H-bonds while contiguous anions of adjacent\ud cells are linked together by two, slightly weaker N–\ud H···Cl H-bonds. The result is a chain of anions running along\ud the a direction. The crystal packing allows for the formation\ud of one-dimensional pore channels, also running along the a\ud direction, which are filled with disordered pentane molecules

Diplatinum(III) [Cl2(μ2-amidinate)4] compound derived from air oxidation of mononuclear cis-[PtII(NH3)2(amidine-κ1)2]2+ complex

“…Among described Pt III species , di-and polynuclear complexes [2,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] bearing the homo Pt-Pt and the heteronuclear Pt-M (e.g., M = Au [6], Ru [7], Pd [8]) metal-metal bonds, are the most common. In the vast majority of cases, the metal-metal bond in these species is stabilized by O,O-(phosphates [19], sulphates [2], carboxylates [11,12,18]) O,N-(amidates [2,9,10,[14][15][16][17]23]), P,P-(pyrophosphites [2]), S,N-(pyrimidinthiolates, pyridinethiolates [2,19]), and S,S-(dithiocarboxylates [2]) bridging ligands. Up to date only few examples of dimeric Pt III species having N,N-bridges (i.e., nucleobases [21] or formamidinates [22]) were reported.…”

“Lantern-Shaped” Platinum(III) Complexes with Axially Bound 9-Ethylguanine or 1-Methylcytosine (L) of General Formula[Pt2{HN=C(But

“…As for 1 , the platinum coordination squares are perfectly eclipsed (maximum twist angle of 0.8°), and the platinum atoms are displaced from the equatorial coordination planes by 0.090 Å towards the axial cytosine. Also the equatorial Pt–N [1.967(5) and 1.982(5) Å] and Pt–O distances [2.011(4) and 2.025(4) Å] are in the range of those observed in 1 and reported for four-coordinate platinum(II) and six-coordinate platinum(IV) complexes [ 4 ].…”

“…The equatorial Pt–N [1.993(7)–1.996(6) Å] and Pt–O distances [2.019(5)–2.035(5) Å] are in the range of those reported for doubly and quadruply bridged dinuclear platinum(III) [17, 22, 23, 46], four-coordinate platinum(II), and six-coordinate platinum(IV) complexes [4]. …”

“…They contain a metal-metal single bond which is generally supported by two or four bridging ligands (the latter generally indicated as “lantern shaped” complexes) ([1–3] and references therein). Only few exceptions with three bridging ligands [4], or unsupported by covalent bridges [5, 6], have been so far reported. Usually the bridging ligands form five-member rings comprising the two platinum centers and a set of three atoms providing a suitable bite, for example, NCO [6–23] (including pyrimidine nucleobases), NCS, NCN, SCS, OXO (X = C, S, P), or PXP (X = O, C) [24–29].…”

Platinum(II) Complexes with the Diethyl Aminomethylphosphonate Ligand (amp): Characterization, Properties, and Unusual Solution Behavior

“…Starting Compounds: (PPh 4 ) 2 [PtCl 4 ] was prepared from K 2 [PtCl 4 ] by using the procedure reported in the literature for the preparation of (AsPh 4 ) 2 [PtCl 4 ], [21] and ampH hydrogen oxalate was purchased from Acros Organics, Belgium.…”