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Takahiko Kojima

Takahiko Kojima

D-Index & Metrics

Discipline name D-Index World Ranking Current World Ranking National Ranking Current National Ranking Publications Citations
Chemistry 48 15381 13870 1207 1096 224 7055

Takahiko Kojima publications per year

The chart shows the history of publications by Takahiko Kojima between 1984 and 2025, highlighting the no. of papers published in each year and offering an overview of the publication velocity of this scholar. Takahiko Kojima published across 42 years, from 1984 to 2025, averaging 5.7 papers a year. Output peaked at 18 publications in 2020. 14 of the 240 publications appeared in the last two years.

No. of publications
5 10 15
Bar chart. Horizontal axis: year, 1984 to 2025. Vertical axis: number of publications, 0 to 18. Peak 18 publications in 2020. 1984: 1 publication 1985: 0 publications 1986: 0 publications 1987: 1 publication 1988: 1 publication 1989: 2 publications 1990: 7 publications 1991: 3 publications 1992: 1 publication 1993: 3 publications 1994: 1 publication 1995: 1 publication 1996: 1 publication 1997: 3 publications 1998: 3 publications 1999: 1 publication 2000: 3 publications 2001: 1 publication 2002: 0 publications 2003: 3 publications 2004: 8 publications 2005: 9 publications 2006: 3 publications 2007: 5 publications 2008: 15 publications 2009: 9 publications 2010: 10 publications 2011: 16 publications 2012: 9 publications 2013: 13 publications 2014: 5 publications 2015: 11 publications 2016: 8 publications 2017: 7 publications 2018: 11 publications 2019: 15 publications 2020: 18 publications 2021: 4 publications 2022: 6 publications 2023: 8 publications 2024: 7 publications 2025: 7 publications
1984 2025

240 publications in total across all disciplines

View publications per year as a table
Takahiko Kojima: publications per year, 1984 to 2025
Year Publications
1984 1
1985 0
1986 0
1987 1
1988 1
1989 2
1990 7
1991 3
1992 1
1993 3
1994 1
1995 1
1996 1
1997 3
1998 3
1999 1
2000 3
2001 1
2002 0
2003 3
2004 8
2005 9
2006 3
2007 5
2008 15
2009 9
2010 10
2011 16
2012 9
2013 13
2014 5
2015 11
2016 8
2017 7
2018 11
2019 15
2020 18
2021 4
2022 6
2023 8
2024 7
2025 7
Total 240
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Takahiko Kojima publication distribution in Chemistry in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Chemistry in 2026. The highlighted bar marks where Takahiko Kojima sits on this spectrum.

No. of scientists
250 500 750 1,000 1,250
Bar chart with 63 bars. Horizontal axis: publications, 61–80 to 1,295+. Vertical axis: number of scientists, 0 to 1,350. Most scientists, 1,350, have 161–180 publications. The last bar groups every scientist with 1,295 publications or more. The highlighted bar, 221–240 publications, is where this scientist sits. 61–80 publications: 66 scientists 81–100 publications: 302 scientists 101–120 publications: 623 scientists 121–140 publications: 918 scientists 141–160 publications: 1,218 scientists 161–180 publications: 1,350 scientists 181–200 publications: 1,344 scientists 201–220 publications: 1,281 scientists 221–240 publications: 1,216 scientists 241–260 publications: 1,100 scientists 261–280 publications: 979 scientists 281–300 publications: 939 scientists 301–320 publications: 764 scientists 321–340 publications: 643 scientists 341–360 publications: 628 scientists 361–380 publications: 522 scientists 381–400 publications: 459 scientists 401–420 publications: 397 scientists 421–440 publications: 327 scientists 441–460 publications: 270 scientists 461–480 publications: 265 scientists 481–500 publications: 252 scientists 501–520 publications: 201 scientists 521–540 publications: 185 scientists 541–560 publications: 148 scientists 561–580 publications: 148 scientists 581–600 publications: 132 scientists 601–620 publications: 114 scientists 621–640 publications: 104 scientists 641–660 publications: 91 scientists 661–680 publications: 92 scientists 681–700 publications: 73 scientists 701–720 publications: 57 scientists 721–740 publications: 54 scientists 741–760 publications: 67 scientists 761–780 publications: 45 scientists 781–800 publications: 46 scientists 801–820 publications: 39 scientists 821–840 publications: 32 scientists 841–860 publications: 36 scientists 861–880 publications: 29 scientists 881–900 publications: 26 scientists 901–920 publications: 24 scientists 921–940 publications: 14 scientists 941–960 publications: 23 scientists 961–980 publications: 28 scientists 981–1,000 publications: 15 scientists 1,001–1,020 publications: 29 scientists 1,021–1,040 publications: 12 scientists 1,041–1,060 publications: 19 scientists 1,061–1,080 publications: 12 scientists 1,081–1,100 publications: 6 scientists 1,101–1,120 publications: 8 scientists 1,121–1,140 publications: 12 scientists 1,141–1,160 publications: 5 scientists 1,161–1,180 publications: 6 scientists 1,181–1,200 publications: 14 scientists 1,201–1,220 publications: 7 scientists 1,221–1,240 publications: 2 scientists 1,241–1,260 publications: 6 scientists 1,261–1,280 publications: 4 scientists 1,281–1,294 publications: 6 scientists 1,295+ publications: 100 scientists
61–80 publications 1,295+

This scientist: 224 publications — 41st percentile

41% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 1,295 publications or more.

View publications distribution as a table
Number of Chemistry scientists by publication count, Research.com 2026 ranking edition. Based on 17,934 ranked scientists.
Publications Scientists This scientist
61–80 66
81–100 302
101–120 623
121–140 918
141–160 1,218
161–180 1,350
181–200 1,344
201–220 1,281
221–240 1,216 224
241–260 1,100
261–280 979
281–300 939
301–320 764
321–340 643
341–360 628
361–380 522
381–400 459
401–420 397
421–440 327
441–460 270
461–480 265
481–500 252
501–520 201
521–540 185
541–560 148
561–580 148
581–600 132
601–620 114
621–640 104
641–660 91
661–680 92
681–700 73
701–720 57
721–740 54
741–760 67
761–780 45
781–800 46
801–820 39
821–840 32
841–860 36
861–880 29
881–900 26
901–920 24
921–940 14
941–960 23
961–980 28
981–1,000 15
1,001–1,020 29
1,021–1,040 12
1,041–1,060 19
1,061–1,080 12
1,081–1,100 6
1,101–1,120 8
1,121–1,140 12
1,141–1,160 5
1,161–1,180 6
1,181–1,200 14
1,201–1,220 7
1,221–1,240 2
1,241–1,260 6
1,261–1,280 4
1,281–1,294 6
1,295+ 100
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Takahiko Kojima D-index placement in Chemistry in 2026

The chart shows the D-index (discipline H-index) distribution of Chemistry scientists ranked by Research.com in 2026. The highlighted bar marks where Takahiko Kojima sits on this spectrum.

No. of scientists
250 500 750 1,000
Bar chart with 61 bars. Horizontal axis: D-Index, 40–41 to 159+. Vertical axis: number of scientists, 0 to 1,051. Most scientists, 1,051, have 56–57 D-Index. The last bar groups every scientist with 159 D-Index or more. The highlighted bar, 48–49 D-Index, is where this scientist sits. 40–41 D-Index: 289 scientists 42–43 D-Index: 612 scientists 44–45 D-Index: 808 scientists 46–47 D-Index: 776 scientists 48–49 D-Index: 835 scientists 50–51 D-Index: 861 scientists 52–53 D-Index: 872 scientists 54–55 D-Index: 933 scientists 56–57 D-Index: 1,051 scientists 58–59 D-Index: 930 scientists 60–61 D-Index: 882 scientists 62–63 D-Index: 834 scientists 64–65 D-Index: 731 scientists 66–67 D-Index: 775 scientists 68–69 D-Index: 683 scientists 70–71 D-Index: 646 scientists 72–73 D-Index: 561 scientists 74–75 D-Index: 501 scientists 76–77 D-Index: 437 scientists 78–79 D-Index: 388 scientists 80–81 D-Index: 354 scientists 82–83 D-Index: 292 scientists 84–85 D-Index: 275 scientists 86–87 D-Index: 254 scientists 88–89 D-Index: 235 scientists 90–91 D-Index: 185 scientists 92–93 D-Index: 192 scientists 94–95 D-Index: 155 scientists 96–97 D-Index: 163 scientists 98–99 D-Index: 125 scientists 100–101 D-Index: 105 scientists 102–103 D-Index: 105 scientists 104–105 D-Index: 112 scientists 106–107 D-Index: 88 scientists 108–109 D-Index: 68 scientists 110–111 D-Index: 69 scientists 112–113 D-Index: 65 scientists 114–115 D-Index: 79 scientists 116–117 D-Index: 61 scientists 118–119 D-Index: 44 scientists 120–121 D-Index: 37 scientists 122–123 D-Index: 40 scientists 124–125 D-Index: 33 scientists 126–127 D-Index: 26 scientists 128–129 D-Index: 34 scientists 130–131 D-Index: 35 scientists 132–133 D-Index: 25 scientists 134–135 D-Index: 27 scientists 136–137 D-Index: 17 scientists 138–139 D-Index: 16 scientists 140–141 D-Index: 20 scientists 142–143 D-Index: 20 scientists 144–145 D-Index: 15 scientists 146–147 D-Index: 9 scientists 148–149 D-Index: 9 scientists 150–151 D-Index: 16 scientists 152–153 D-Index: 11 scientists 154–155 D-Index: 9 scientists 156–157 D-Index: 3 scientists 158 D-Index: 3 scientists 159+ D-Index: 98 scientists
40–41 D-Index 159+

This scientist: 48 D-Index — 16th percentile

16% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 159 D-Index or more.

View D-Index distribution as a table
Number of Chemistry scientists by D-index, Research.com 2026 ranking edition. Based on 17,934 ranked scientists.
D-Index Scientists This scientist
40–41 289
42–43 612
44–45 808
46–47 776
48–49 835 48
50–51 861
52–53 872
54–55 933
56–57 1,051
58–59 930
60–61 882
62–63 834
64–65 731
66–67 775
68–69 683
70–71 646
72–73 561
74–75 501
76–77 437
78–79 388
80–81 354
82–83 292
84–85 275
86–87 254
88–89 235
90–91 185
92–93 192
94–95 155
96–97 163
98–99 125
100–101 105
102–103 105
104–105 112
106–107 88
108–109 68
110–111 69
112–113 65
114–115 79
116–117 61
118–119 44
120–121 37
122–123 40
124–125 33
126–127 26
128–129 34
130–131 35
132–133 25
134–135 27
136–137 17
138–139 16
140–141 20
142–143 20
144–145 15
146–147 9
148–149 9
150–151 16
152–153 11
154–155 9
156–157 3
158 3
159+ 98
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Overview

Takahiko Kojima is affiliated with the University of Tsukuba in Japan. Their research primarily focuses on materials science, with a specialization in materials chemistry. Their body of work includes significant contributions across several subfields, such as renewable energy, sustainability and the environment, inorganic chemistry, organic chemistry, and oncology.

Their scientific interests encompass a range of main topics including crystallization and solubility studies, X-ray diffraction in crystallography, and porphyrin and phthalocyanine chemistry. Additional areas of research cover metal-catalyzed oxygenation mechanisms, CO2 reduction techniques and catalysts, metal complexes synthesis and properties, as well as electrocatalysts for energy conversion.

Kojima has co-authored many publications in collaboration with researchers such as Tomoya Ishizuka, Hiroaki Kotani, Yoshihito Shiota, Kazunari Yoshizawa, and Hiroto Fujisaki.

The scientist's work has been published extensively in several venues. Notable frequent publication venues include The Cambridge Structural Database, the Journal of the American Chemical Society, Dalton Transactions, the Journal of Porphyrins and Phthalocyanines, and Chemistry - A European Journal.

Recent papers by Takahiko Kojima include:

  • Nonplanar porphyrins: synthesis, properties, and unique functionalities (2022) Chemical Society Reviews
  • Selective methane oxidation by molecular iron catalysts in aqueous medium (2023) Nature
  • Mechanistic Insight into Concerted Proton-Electron Transfer of a Ru(IV)-Oxo Complex: A Possible Oxidative Asynchronicity (2020) Journal of the American Chemical Society
  • Self-Photosensitizing Dinuclear Ruthenium Catalyst for CO2 Reduction to CO (2023) Journal of the American Chemical Society
  • Long-Range Order in Supramolecular π Assemblies in Discrete Multidecker Naphthalenediimides (2021) Journal of the American Chemical Society

Best Publications

  • Photofunctional nanomaterials composed of multiporphyrins and carbon-based π-electron acceptors

    Shunichi Fukuzumi;Takahiko Kojima

  • Alkane functionalization at nonheme iron centers. Stoichiometric transfer of metal-bound ligands to alkane

    Takahiko Kojima;Randolph A. Leising;Shiping Yan;Lawrence Que

  • Visible-Light-Driven Photocatalytic CO2 Reduction by a Ni(II) Complex Bearing a Bioinspired Tetradentate Ligand for Selective CO Production.

    Dachao Hong;Yuto Tsukakoshi;Hiroaki Kotani;Tomoya Ishizuka

  • Ruthenium-catalyzed selective and efficient oxygenation of hydrocarbons with water as an oxygen source.

    Yuichirou Hirai;Takahiko Kojima;Yasuhisa Mizutani;Yoshihito Shiota

  • Charge separation in metallomacrocycle complexes linked with electron acceptors by axial coordination

    Shunichi Fukuzumi;Tatsuhiko Honda;Kei Ohkubo;Takahiko Kojima

  • Efficient Photocatalytic CO2 Reduction by a Ni(II) Complex Having Pyridine Pendants through Capturing a Mg2+ Ion as a Lewis-Acid Cocatalyst.

    Dachao Hong;Takuya Kawanishi;Takuya Kawanishi;Yuto Tsukakoshi;Hiroaki Kotani

  • A discrete supramolecular conglomerate composed of two saddle-distorted zinc(II)-phthalocyanine complexes and a doubly protonated porphyrin with saddle distortion undergoing efficient photoinduced electron transfer.

    Takahiko Kojima;Tatsuhiko Honda;Kei Ohkubo;Motoo Shiro

  • Formation of a ruthenium(IV)-oxo complex by electron-transfer oxidation of a coordinatively saturated ruthenium(II) complex and detection of oxygen-rebound intermediates in C-H bond oxygenation.

    Takahiko Kojima;Kazuya Nakayama;Kenichiro Ikemura;Takashi Ogura

  • Structures and photoinduced electron transfer of protonated complexes of porphyrins and metallophthalocyanines

    Shunichi Fukuzumi;Shunichi Fukuzumi;Tatsuhiko Honda;Takahiko Kojima

  • A discrete conglomerate of a distorted Mo(v)-porphyrin with a directly coordinated Keggin-type polyoxometalate.

    Atsutoshi Yokoyama;Takahiko Kojima;Kei Ohkubo;Shunichi Fukuzumi

  • Synthesis and Characterization of Mononuclear and Dinuclear Ruthenium Complexes with Tris(2-pyridylmethyl)amine and Tris(5-methyl-2-pyridylmethyl)amine.

    Takahiko Kojima;Takayuki Amano;Youichi Ishii;Masaaki Ohba

  • A Directly Linked Ferrocene–Naphthalenediimide Conjugate: Precise Control of Stacking Structures of π‐Systems by Redox Stimuli

    Atsuro Takai;Takeshi Yasuda;Tomoya Ishizuka;Takahiko Kojima

  • Structure and photoinduced electron transfer dynamics of a series of hydrogen-bonded supramolecular complexes composed of electron donors and a saddle-distorted diprotonated porphyrin

    Tatsuhiko Honda;Tatsuaki Nakanishi;Kei Ohkubo;Takahiko Kojima

  • Metal-Oxyl Species and Their Possible Roles in Chemical Oxidations.

    Yoshihiro Shimoyama;Yoshihiro Shimoyama;Takahiko Kojima

  • High-valent metal-oxo complexes generated in catalytic oxidation reactions using water as an oxygen source

    Shunichi Fukuzumi;Shunichi Fukuzumi;Takahiko Kojima;Yong Min Lee;Wonwoo Nam

  • Homogeneous and Heterogeneous Photocatalytic Water Oxidation by Persulfate

    Shunichi Fukuzumi;Shunichi Fukuzumi;Shunichi Fukuzumi;Jieun Jung;Yusuke Yamada;Takahiko Kojima

  • Selective methane oxidation by molecular iron catalysts in aqueous medium

    Unknown

  • Nonplanar porphyrins: synthesis, properties, and unique functionalities.

    Unknown

  • A Porphyrin Nanotube: Size‐Selective Inclusion of Tetranuclear Molybdenum–Oxo Clusters

    Ryosuke Harada;Yoshihisa Matsuda;Hisashi Ōkawa;Takahiko Kojima

  • Supramolecular structures and photoelectronic properties of the inclusion complex of a cyclic free-base porphyrin dimer and C60.

    Hirofumi Nobukuni;Yuichi Shimazaki;Hidemitsu Uno;Yoshinori Naruta

  • Porphyrin nanotubes based on self-assembly of Mo(V)-dodecaphenylporphyrin complexes and inclusion of Mo-Oxo clusters : Synthesis and characterization by X-ray crystallography and transmission electron microscopy

    Takahiko Kojima;Ryosuke Harada;Tatsuaki Nakanishi;Kenji Kaneko

  • Characteristics and reactivity of ruthenium–oxo complexes

    Tomoya Ishizuka;Hiroaki Kotani;Takahiko Kojima

  • Mechanistic insight into catalytic oxidations of organic compounds by ruthenium(IV)-oxo complexes with pyridylamine ligands

    Shingo Ohzu;Tomoya Ishizuka;Yuichirou Hirai;Hua Jiang

Frequent Co-Authors

Shunichi Fukuzumi
Shunichi Fukuzumi Osaka University
Kazunari Yoshizawa
Kazunari Yoshizawa Kyushu University
Yoshihito Shiota
Yoshihito Shiota Kyushu University
Kei Ohkubo
Kei Ohkubo Osaka University
Motoo Shiro
Motoo Shiro Nagoya Institute of Technology
Masanobu Hidai
Masanobu Hidai University of Tokyo
Masaki Kawano
Masaki Kawano Tokyo Institute of Technology
Yoshinori Naruta
Yoshinori Naruta Chubu University
Reiko Kuroda
Reiko Kuroda Chubu University
Masayuki Takeuchi
Masayuki Takeuchi National Institute for Materials Science

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