{
  "meta": {
    "api_type": "NWO Projects API",
    "version": "1.0.2",
    "licence": {
      "name": "CC0 1.0 Universal",
      "url": "https://creativecommons.org/publicdomain/zero/1.0",
      "description": "To the extent possible under law, all copyright and related or neighbouring rights have been waived worldwide to the data made available through this API."
    },
    "documentation": "https://doi.org/10.5281/zenodo.14918287",
    "release_date": "2025-08-20T00:00:00",
    "funder": "https://doi.org/10.13039/501100003246",
    "ror_id": "https://ror.org/04jsz6e67",
    "date": "2026-11-05T00:00:00",
    "count": 1,
    "per_page": 100,
    "pages": 1,
    "page": 1
  },
  "projects": [
    {
      "project_id": "MP-07-138",
      "title": "Investigating anion-pi interactions with quantum Monte Carlo",
      "funding_scheme_id": 2266,
      "funding_scheme": "Rekentijd nationale computersystemen Rekentijd nationale computersystemen 2007 EW",
      "department": "Exacte en Natuurwetenschappen",
      "sub_department": "Exacte Wetenschappen",
      "start_date": "2007-05-15T00:00:00",
      "end_date": "2010-06-21T00:00:00",
      "reporting_year": 2007,
      "summary_nl": "\n\nIn recent years, a number of experimental and theoretical studies have investigated the possibility of building anion-sensing receptors for their potential application in diverse areas as biology, medicine, and catalysis. Contrary to the expectation that the interactions are repulsive, theoretical investigations on simple model systems suggest that the binding of an anion to one and more electron-deficient aromatic rings is possible.\n\nRecent crystallographic experiments in the group of Prof. Reedijk in Leiden confirm the existence of anion-aromatic binding for a complex organic ligand based on triazine moieties.\n\n\n\nThe proposed project is inspired by these experiments and follows preliminary DFT studies on this anion-triazine complex by Dr. Buda, with whom we closely collaborate on this project. The DFT calculations were performed on a simplified model and were not conclusive in explaining the experimental findings due to the well-known limitations of standard DFT approaches in describing van der Waals interactions. An unusual position of the anion with respect to the aromatic ring was observed and the calculations were unable to predict whether the presence of two triazine rings could further stabilize the binding of the anion.\n\n\n\nHere, we propose to use a combination of approaches to answer the questions raised by the experiments. First, we intend to test the use of novel ab-initio electron-ion DFT pseudopotentials recently proposed in the literature to overcome the shortcomings of DFT in describing weak non-covalent interactions.\n\nA series of model systems consisting of one anion interacting with one triazine ring will be selected and the DFT equilibrium structures and binding energies compared to the accurate results obtained using highly-correlated quantum Monte Carlo (QMC) approaches. Then, we will proceed to study the interaction of the stacked triazine rings with an NO3 anion which closely resembles the system investigated experimentally.\n\nThese first calculations in vacuum will be followed by a study of the anion-aromatic unit in the full compound through the use of quantum mechanics/molecular mechanics approaches both at the DFT and at the many-body QMC level.\n\n\n\nb) Motivations of the requested computational facilities.\n\n\n\nWe currently have a large number of hours on the Teras/Aster system. However, since Teras was decommissioned, the large number of users who moved to Aster renders the use of Aster impossible.\n\n\n\nWe know that we will be able to use Lisa in the most effective way for the proposed project: The Car-Parrinello molecular dynamics (CPMD) code is routinely used on Lisa by our collaborator Dr.\n\nBuda and our quantum Monte Carlo code (CHAMP) can be also used on such a PC cluster since the demands for this project are high in CPU but not in memory.\n\n\n\nTherefore, as suggested by Dr. Michielse at NCF/NWO, we are submitting a pilot project with a relatively small request in CPU of the order of 10000 hours. The pilot project will allow us to familiarize ourselves with Lisa and to access whether it is actually possible to have a sufficiently high turnaround time on this system. If the experience is positive, we will ask to move part of the CPU time currently available on Aster/Teras to Lisa.\n\n\n\nThe requested CPU time will be 10000 CPU-UUR.\n\n\n\n\n\n",
      "summary_en": "\n\nIn recent years, a number of experimental and theoretical studies have investigated the possibility of building anion-sensing receptors for their potential application in diverse areas as biology, medicine, and catalysis. Contrary to the expectation that the interactions are repulsive, theoretical investigations on simple model systems suggest that the binding of an anion to one and more electron-deficient aromatic rings is possible.\n\nRecent crystallographic experiments in the group of Prof. Reedijk in Leiden confirm the existence of anion-aromatic binding for a complex organic ligand based on triazine moieties.\n\n\n\nThe proposed project is inspired by these experiments and follows preliminary DFT studies on this anion-triazine complex by Dr. Buda, with whom we closely collaborate on this project. The DFT calculations were performed on a simplified model and were not conclusive in explaining the experimental findings due to the well-known limitations of standard DFT approaches in describing van der Waals interactions. An unusual position of the anion with respect to the aromatic ring was observed and the calculations were unable to predict whether the presence of two triazine rings could further stabilize the binding of the anion.\n\n\n\nHere, we propose to use a combination of approaches to answer the questions raised by the experiments. First, we intend to test the use of novel ab-initio electron-ion DFT pseudopotentials recently proposed in the literature to overcome the shortcomings of DFT in describing weak non-covalent interactions.\n\nA series of model systems consisting of one anion interacting with one triazine ring will be selected and the DFT equilibrium structures and binding energies compared to the accurate results obtained using highly-correlated quantum Monte Carlo (QMC) approaches. Then, we will proceed to study the interaction of the stacked triazine rings with an NO3 anion which closely resembles the system investigated experimentally.\n\nThese first calculations in vacuum will be followed by a study of the anion-aromatic unit in the full compound through the use of quantum mechanics/molecular mechanics approaches both at the DFT and at the many-body QMC level.\n\n\n\nb) Motivations of the requested computational facilities.\n\n\n\nWe currently have a large number of hours on the Teras/Aster system. However, since Teras was decommissioned, the large number of users who moved to Aster renders the use of Aster impossible.\n\n\n\nWe know that we will be able to use Lisa in the most effective way for the proposed project: The Car-Parrinello molecular dynamics (CPMD) code is routinely used on Lisa by our collaborator Dr.\n\nBuda and our quantum Monte Carlo code (CHAMP) can be also used on such a PC cluster since the demands for this project are high in CPU but not in memory.\n\n\n\nTherefore, as suggested by Dr. Michielse at NCF/NWO, we are submitting a pilot project with a relatively small request in CPU of the order of 10000 hours. The pilot project will allow us to familiarize ourselves with Lisa and to access whether it is actually possible to have a sufficiently high turnaround time on this system. If the experience is positive, we will ask to move part of the CPU time currently available on Aster/Teras to Lisa.\n\n\n\nThe requested CPU time will be 10000 CPU-UUR.\n\n\n\n\n\n",
      "project_members": [
        {
          "role": "Project leader",
          "member_id": 176883,
          "last_name": "Saarloos",
          "degree_pre_nominal": "prof. dr. ir.",
          "initials": "W.",
          "first_name": "Wim",
          "prefix": "van",
          "organisation": "Universiteit Leiden||Faculteit der Wiskunde en Natuurwetenschappen||Leids Instituut voor Onderzoek in de Natuurkunde (LION)",
          "organisation_id": 79644,
          "ror": "https://ror.org/027bh9e22",
          "active": false
        },
        {
          "role": "Main Applicant",
          "member_id": 176883,
          "last_name": "Saarloos",
          "degree_pre_nominal": "prof. dr. ir.",
          "initials": "W.",
          "first_name": "Wim",
          "prefix": "van",
          "organisation": "Nederlandse Organisatie voor Wetenschappelijk Onderzoek||Directie Transitie-Organisatie",
          "organisation_id": 47513,
          "ror": "-",
          "active": true
        }
      ],
      "products": [
        {
          "title": "Anion and Cooperative Interactions Regulating the Self-Assembly of\nNitrate-Triazine-Triazine Complexes",
          "year": 2007,
          "type": "Wetenschappelijk artikel",
          "authors": [
            {
              "last_name": "Filippi",
              "initials": "C.",
              "first_name": "Claudia",
              "role": "Auteur",
              "index_number": 2
            },
            {
              "last_name": "Zaccheddu",
              "initials": "M.",
              "first_name": "Maurizio",
              "role": "Auteur",
              "index_number": 1
            }
          ]
        }
      ]
    }
  ]
}