Unusual platinum hydrides with nitrogen ligands

Dinuclear platinum(II) complexes with bridging twofold deprotonated 2,2′:6′,2″-terpyridine. New molecules with a 3,5-diplatinated-pyridyl inner core: [Pt2(terpy-2H)(Me)2(L)2], [Pt2(terpy-2H)(X)2(L)2] and [Pt2(terpy-2H)(H)2(L)2] (L=neutral ligand; X=halide) – Crystal and molecular structure of [Pt2(terpy-2H)(Cl)2(PPh3)2]

“…Complex 15 is unstable in the solid state and its characterization mainly rests on the 1 H NMR spectra: a signal in the hydridic region, d À15.54, with satellites (1:4:1), gives evidence for a terminal Pt-H bond. The high value of the platinum-hydrogen coupling constant, 1 J Pt-H = 1567 Hz, is in line with that previously reported for a N,N,C-cyclometallated species, 1606 Hz [21], where the hydride is trans to an sp 2 nitrogen atom: this implies that substitution of H À for Cl À occurs with isomerization, as expected taking account of the high trans-influence of both a carbon and a hydride donor (trans-phobia) [22]. At variance, complex 16, [Pt 2 (terpy-2H)(H) 2 (PPh 3 ) 2 ], is stable in the solid state: the analytical data fit the indicated formulation.…”

“…Complexes 15 and 16 are rare examples of cyclometalated N,C platinum(II) hydrides: as far as we know the only species isolated is [Pt(L-H)H] (L = 6-(1-methylbenzyl)-2,2 0 -bipyridine) where L-H is the tridentate N,N,C ligand coordinated via the two bipyridine nitrogens and an ortho carbon of the phenyl of the chiral methylbenzyl group [21]. Quite recently evidence for a similar [Pt(N,N,C)H] species has been detected in solution [23].…”

Novel T‐Shaped 14‐Electron Platinum(II) Complexes Stabilized by One Agostic Interaction

“…When a solution of 3 (CD 2 Cl 2 , 20 °C) is treated with dihydrogen (1 atm), the 31 P{ 1 H} NMR spectrum exhibits one sharp resonance at δ =29.0 ppm with 1 J (P,Pt)=2717 Hz for 5 , in addition to signals for 3 ( 5 : 3 molar ratio=1:4). The 1 H NMR spectrum reveals one signal at δ =2.22 ppm with J (H,Pt)=11.3 Hz for the four o ‐methyl groups and one broad signal at δ =−20.83 for the hydrido ligand with a remarkably high 1 J (H,Pt) coupling constant of 2052 Hz 18. Similarly to 3 , the reaction of 4 with H 2 leads to the formation of complex 6 ( δ ( 31 P)=54.5; 1 J (P,Pt)=2631 Hz), where 6 and 4 are recovered in a molar ratio of 2:1, which indicates that for the Cy derivative the equilibrium is more shifted to the right.…”

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

“…Few dimeric hydrido platinum complexes contain nitrogen-donor ligands in the platinum coordination sphere. [40][41][42][43][44] The chemistry of TpPt(R)(R′)H [Tp ) hydridotris(pyrazolyl)-borate; Tp′ ) hydridotris(3,5-dimethylpyrazolyl)borate; R, R′ ) combinations of alkyl, hydride, and aryl groups] has been extensively studied. [45][46][47][48][49] The stability of these complexes stems from tridentate coordination of the tris(pyrazolyl)borate ligand, 50 which anchors the octahedral coordination sphere of the platinum(IV) center and inhibits formation of a five-coordinate platinum(IV) intermediate which is on the pathway for reductive elimination.…”