Size-Selective Vapochromic Platinum(II) Complex with a Sterically Demanding Pincer-Type N-Heterocyclic Carbene Ligand

Abstract

A pyridine-based pincer-type N-heterocyclic carbene complex of Pt(II), [Pt(II)(mesC∧N∧C)CO](PF6)2 (mesC∧N∧C = 2,6-bis(1-mestylimidazol-2-ylidenyl)pyridine), displays size-selective vapochromic behavior upon exposure to small molecules with donor atoms. An acetone adduct showing a weak interaction between acetone and a CO ligand is also structurally determined.

Vapochromism in Organometallic and Coordination Complexes: Chemical Sensors for Volatile Organic Compounds

“…Vapochromism and vapoluminescence in coordination complexes is possible through a variety of different mechanisms. Changes in metal-metal interactions play an important role in many platinum(II) and gold(I) based substances, 13,14,17,35,37,36,50,41,66,67,68,69,70,72,73,88,91,92,93,95,97,98,99,100,102,105,106,116,117,118,121,129,128,135,144,146,148,149,156,155,158,157,160,164,212 and modifications in π-π stacking are relatively widespread as well. 59,88,91,93,…”

“…Transition-metal complexes with N-heterocyclic carbenes (NHCs) are playing an increasingly important role in organometallic chemistry, [113][114][115] and until now two vapochromic Pt(II) complexes with such ligands have been reported (Scheme 25). 116,117 However, the hydrate exhibits orange luminescence (λ max = 614 nm) whereas the anhydrate form emits green (λ max = 555 nm) which is difficult to explain by the observed structural changes. At any rate, when the green-emitting dehydrated form (53Cl) is exposed to moisture, the emission changes to orange and powder X-ray analysis is in line with the formation of 53Cl•2.5H 2 O. and an anti-isomer (55b) (Scheme 26).…”

Photofunctional Platinum Complexes Featuring N‐heterocyclic Carbene‐Based Pincer Ligands

“…In spite of the rich photophysics of platinum(II) NHC complexes, [11c, 13a, 14, 17, 22] reports on their vapochromic or mechanochromic properties are scarce. [1f, 23] Previously, we have recognized the luminescence response to a hydration-dehydration phenomenon in the crystal lattices [1f] and vapor-size-selective color changes [23] in platinum(II) complexes featuring CNC-pincer-bis(NHC) ligands. In this contribution, we report a series of platinum complexes of type [Pt( R CCC R )L] (R = Me, nBu; L =ÀCN, ÀC CPh, ÀN CCH 3 (AN), ÀPy and ÀCO) with vapochromic and mechanochromic properties, of which few complexes exhibit high luminescence efficiency in the solid state.…”

Palladium(II) Acetylide Complexes with Pincer‐Type Ligands: Photophysical Properties, Intermolecular Interactions, and Photo‐cytotoxicity

“…[19a] For the [Pd(C^N^C)]-acetylide complex (7), the PdÀC carbene lengths of 2.042(3) and 2.037(3) are similar to the values reported for [Pd(C^N^C)X](X) (X = Br, [14b] I [14d] )a nd the PtÀC carbene lengths found in related[ Pt(C^N^C)] complexes. [15] The dihedral angle between the [Pd(C^N^C)] plane and the phenyl ring of phenylacetylide ligand is 5.68.T he complex cations are arranged in ah ead-to-tail manner with Pd II ···Pd II distance of 3.292 ,w hich is shorter than that observed in the crystal structures of 1 and [Pd(C^N^C)X](X) (X = Br,I ;3 .51 and 3.48 ). [14b,d] The crystal data of the Pt II congener of 7 is not availablef or comparison.…”

“…[12] In view of their applicationsi nd iversea reas, various kinds of NHC-based ligandsh ave been designed and used for coordination to metal ions. One pincer-type ligand with C^N^C (C^N^C = 2,6-bis (1-butylimidazol-2-ylidenyl)pyridine and derivatives) as at ypicale xample has been adopted for the preparation of transition metal-NHC complexes (M = Fe II , [13] Pd II , [14] Pt II , [15] Ru II , [16, 17b] Os II , [17] etc. ), which generally show favorable luminescence properties compared with its terpy analogs.…”