PMID- 29131954
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20180305
LR  - 20180305
IS  - 1520-5215 (Electronic)
IS  - 1089-5639 (Linking)
VI  - 121
IP  - 48
DP  - 2017 Dec 7
TI  - Ultrafast Wiggling and Jiggling: Ir(2)(1,8-diisocyanomenthane)(4)(2).
PG  - 9275-9283
LID - 10.1021/acs.jpca.7b10215 [doi]
AB  - Binuclear complexes of d(8) metals (Pt(II), Ir(I), Rh(I),) exhibit diverse 
      photonic behavior, including dual emission from relatively long-lived singlet and 
      triplet excited states, as well as photochemical energy, electron, and atom 
      transfer. Time-resolved optical spectroscopic and X-ray studies have revealed the 
      behavior of the dimetallic core, confirming that M-M bonding is strengthened upon 
      dsigma* --> psigma excitation. We report the bridging ligand dynamics of 
      Ir(2)(1,8-diisocyanomenthane)(4)(2+) (Ir(dimen)), investigated by fs-ns 
      time-resolved IR spectroscopy (TRIR) in the region of C identical withN stretching vibrations, 
      nu(C identical withN), 2000-2300 cm(-1). The nu(C identical withN) IR band of the singlet and triplet dsigma*psigma 
      excited states is shifted by -22 and -16 cm(-1) relative to the ground state due 
      to delocalization of the psigma LUMO over the bridging ligands. Ultrafast relaxation 
      dynamics of the (1)dsigma*psigma state depend on the initially excited Franck-Condon 
      molecular geometry, whereby the same relaxed singlet excited state is populated 
      by two different pathways depending on the starting point at the excited-state 
      potential energy surface. Exciting the long/eclipsed isomer triggers two-stage 
      structural relaxation: 0.5 ps large-scale Ir-Ir contraction and 5 ps Ir-Ir 
      contraction/intramolecular rotation. Exciting the short/twisted isomer induces a 
       approximately 5 ps bond shortening combined with vibrational cooling. Intersystem crossing (70 
      ps) follows, populating a (3)dsigma*psigma state that lives for hundreds of nanoseconds. 
      During the first 2 ps, the nu(C identical withN) IR bandwidth oscillates with the frequency of 
      the nu(Ir-Ir) wave packet, ca. 80 cm(-1), indicating that the dephasing time of 
      the high-frequency (16 fs)(-1) C identical withN stretch responds to much slower ( approximately 400 fs)(-1) 
      Ir-Ir coherent oscillations. We conclude that the bonding and dynamics of 
      bridging di-isocyanide ligands are coupled to the dynamics of the metal-metal 
      unit and that the coherent Ir-Ir motion induced by ultrafast excitation drives 
      vibrational dephasing processes over the entire binuclear cation.
FAU - Pizl, Martin
AU  - Pizl M
AD  - J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech 
      Republic , Dolejskova 3, CZ-182 23 Prague, Czech Republic.
AD  - Department of Inorganic Chemistry, University of Chemistry and Technology, Prague 
      , Technicka 5, CZ-166 28 Prague, Czech Republic.
FAU - Hunter, Bryan M
AU  - Hunter BM
AD  - Beckman Institute, California Institute of Technology , Pasadena, California 
      91125, United States.
FAU - Greetham, Gregory M
AU  - Greetham GM
AD  - Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton 
      Laboratory , Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom.
FAU - Towrie, Michael
AU  - Towrie M
AD  - Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton 
      Laboratory , Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom.
FAU - Zalis, Stanislav
AU  - Zalis S
AD  - J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech 
      Republic , Dolejskova 3, CZ-182 23 Prague, Czech Republic.
FAU - Gray, Harry B
AU  - Gray HB
AD  - Beckman Institute, California Institute of Technology , Pasadena, California 
      91125, United States.
FAU - Vlcek, Antonin
AU  - Vlcek A
AUID- ORCID: 0000-0002-6413-8311
AD  - J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech 
      Republic , Dolejskova 3, CZ-182 23 Prague, Czech Republic.
AD  - School of Biological and Chemical Sciences, Queen Mary University of London , 
      Mile End Road, London E1 4NS, United Kingdom.
LA  - eng
PT  - Journal Article
DEP - 20171129
PL  - United States
TA  - J Phys Chem A
JT  - The journal of physical chemistry. A
JID - 9890903
EDAT- 2017/11/14 06:00
MHDA- 2017/11/14 06:01
CRDT- 2017/11/14 06:00
PHST- 2017/11/14 06:00 [pubmed]
PHST- 2017/11/14 06:01 [medline]
PHST- 2017/11/14 06:00 [entrez]
AID - 10.1021/acs.jpca.7b10215 [doi]
PST - ppublish
SO  - J Phys Chem A. 2017 Dec 7;121(48):9275-9283. doi: 10.1021/acs.jpca.7b10215. Epub 
      2017 Nov 29.